Spectroscopic observations of the extended corona during the SOHO whole sun month

NASA Technical Reports Server (NTRS)

Strachan, L.; Raymond, J. C.; Panasyuk, A. V.; Fineschi, S.; Gardner, L. D.; Antonucci, E.; Giordano, S.; Romoli, M.; Noci, G.; Kohl, J. L.

1997-01-01

The spatial distribution of plasma parameters in the extended corona, derived from the ultraviolet coronagraph spectrometer (UVCS) onboard the Solar and Heliospheric Observatory (SOHO), was investigated. The observations were carried out during the SOHO whole month campaign. Daily coronal scans in the H I Lyman alpha and O VI lambda-lambda 1032 A and 1037 A were used. Maps of outflow velocities of O(5+), based on Doppler dimming of the O VI lines, are discussed. The velocity distribution widths of O(5+) are shown to be a clear signature of coronal holes while the velocity distributions for H(0) show a much smaller effect. The possible physical explanations for some of the observed features are discussed.

Microchannel Plates for the UVCS and SUMER Instruments on the SOHO Satellite

NASA Technical Reports Server (NTRS)

Siegmund, O. H. W.; Gummin, M. A.; Sasseen, T.; Jelinsky, P.; Gaines, G. A.; Hull, J.; Stock, J. M.; Edgar, M.; Welsh, B.; Jelinsky, S.;

Low-Latitude Solar Wind During the Fall 1998 SOHO-Ulysses Quadrature

NASA Technical Reports Server (NTRS)

Poletto, G.; Suess, Steven T.; Biesecker, D.; Esser, R.; Gloeckler, G.; Zurbuchen, T.; Whitaker, Ann F. (Technical Monitor)

2001-01-01

The Fall 1998 SOlar-Heliospheric Observatory (SOHO) - Ulysses quadrature occurred when Ulysses was at 5.2 AU, 17.4 deg South of the equator, and off the West line of the Sun. SOHO coronal observations, at heliocentric distances of a few solar radii, showed that the line through the solar center and Ulysses crossed, over the first days of observations, a dark, weakly emitting area and through the northern edge of a streamer complex during the second half of the quadrature campaign. Ulysses in situ observations showed this transition to correspond to a decrease from higher speed wind typical of coronal hole flow to low speed wind. Physical parameters (density, temperature, flow speed) of the low latitude coronal plasma sampled over the campaign are determined using constraints from what is the same plasma measured later in situ and simulating the intensities of the Hydrogen Lyman-alpha and OVI 1032 and 1037 Angstrom lines, measured by the Ultra Violet Coronagraph Spectrometer (UVCS) on SOHO. The densities, temperatures and outflow speed are compared with the same characteristic flow parameters for high-latitude fast wind streams and typical slow solar wind.

Identifying clouds over the Pierre Auger Observatory using infrared satellite data

NASA Astrophysics Data System (ADS)

Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Barbosa, A. F.; Bardenet, R.; Baughman, B.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buroker, L.; Burton, R. E.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chirinos, J.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; De La Vega, G.; de Mello, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fliescher, S.; Fox, B. D.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gemmeke, H.; Ghia, P. L.; Giller, M.; Gitto, J.; Glaser, C.; Glass, H.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Jansen, S.; Jarne, C.; Jiraskova, S.; Josebachuili, M.; Kadija, K.; Kampert, K. H.; Karhan, P.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J. L.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kulbartz, J. K.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, J.; Marin, V.; Mariş, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Nierstenhoefer, N.; Niggemann, T.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Peķala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrolini, A.; Petrov, Y.; Pfendner, C.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Ponce, V. H.; Pontz, M.; Porcelli, A.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivera, H.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovancova, J.; Schovánek, P.; Schröder, F. G.; Schulz, J.; Schuster, D.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Straub, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Tapia, A.; Tartare, M.; Taşcău, O.; Tcaciuc, R.; Thao, N. T.; Thomas, D.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Tridapalli, D. B.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Westerhoff, S.; Whelan, B. J.; Widom, A.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wundheiler, B.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano Garcia, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.

2013-12-01

We describe a new method of identifying night-time clouds over the Pierre Auger Observatory using infrared data from the Imager instruments on the GOES-12 and GOES-13 satellites. We compare cloud identifications resulting from our method to those obtained by the Central Laser Facility of the Auger Observatory. Using our new method we can now develop cloud probability maps for the 3000 km2 of the Pierre Auger Observatory twice per hour with a spatial resolution of ˜2.4 km by ˜5.5 km. Our method could also be applied to monitor cloud cover for other ground-based observatories and for space-based observatories.

Identifying clouds over the Pierre Auger Observatory using infrared satellite data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abreu, Pedro; et al.,

2013-12-01

We describe a new method of identifying night-time clouds over the Pierre Auger Observatory using infrared data from the Imager instruments on the GOES-12 and GOES-13 satellites. We compare cloud identifications resulting from our method to those obtained by the Central Laser Facility of the Auger Observatory. Using our new method we can now develop cloud probability maps for the 3000 km^2 of the Pierre Auger Observatory twice per hour with a spatial resolution of ~2.4 km by ~5.5 km. Our method could also be applied to monitor cloud cover for other ground-based observatories and for space-based observatories.

Studies of Solar EUV Irradiance from SOHO

NASA Technical Reports Server (NTRS)

Floyd, Linton

2002-01-01

The Extreme Ultraviolet (EUV) irradiance central and first order channel time series (COC and FOC) from the Solar EUV Monitor aboard the Solar and Heliospheric observatory (SOHO) issued in early 2002 covering the time period 1/1/96-31/1201 were analyzed in terms of other solar measurements and indices. A significant solar proton effect in the first order irradiance was found and characterized. When this effect is removed, the two irradiance time series are almost perfectly correlated. Earlier studies have shown good correlation between the FOC and the Hall core-to-wing ratio and likewise, it was the strongest component of the COC. Analysis of the FOC showed dependence on the F10.7 radio flux. Analysis of the CDC signals showed additional dependences on F10.7 and the GOES x-ray fluxes. The SEM FOC was also well correlated with thein 30.4 nm channel of the SOHO EUV Imaging Telescope (EIT). The irradiance derived from all four EIT channels (30.4 nm, 17.1 nm, 28.4 nm, and 19.5 nm) showed better correlation with MgII than F10.7.

Limb shape observations at the Pic du Midi Observatory. Determination of the solar gravitational moments

NASA Astrophysics Data System (ADS)

Rozelot, J. P.; Lefebvre, S.

The accurate shape of the Sun has been actively debated since 1974. So far, balloon and satellite experiments achieved the required sensibility to measure the expected small asphericities of the solar limb shape. However, exceptional good meteorological conditions encountered during several missions at the Pic du Midi Observatory have permitted to measure the coefficients shape of the solar limb on the two first Legendre polynomials expansion. In theory, this photospheric outer shape is sensitive to the interior rate, and asphericities can be explained both in terms of gravitational moments and thermal wind. We present observations made at the Pic du Midi Observatory and we compare results with these obtained by SDS (Sofia et al., 1994, 1996) and SOHO/MDI (Kuhn, 1999). The accepted and dedicated PICARD space mission on this subject is briefly presented.

The Water Production Rate of Recent Comets (2013-2014) by SOHO/SWAN: 2P/Encke (2013), C/2013 R1 (Lovejoy), and C/2013 A1 (Siding Spring)

NASA Astrophysics Data System (ADS)

Combi, Michael R.; Mäkinen, J. T.; Bertaux, J. L.; Quémerais, Eric; Ferron, Stéphane

2014-11-01

The all-sky hydrogen Lyman-alpha camera, SWAN (Solar Wind Anisotropies), on the SOlar and Heliospheric Observatory (SOHO) satellite makes observations of the hydrogen comae of comets. Most water vapor produced by the comet is ultimately photodissociated into two H atoms and one O atom producing a huge atomic hydrogen coma that is routinely observed in the daily full-sky SWAN images in comets of sufficient brightness. Water production rates are calculated using our time-resolved model (Mäkinen & Combi, 2005, Icarus 177, 217), typically yielding about 1 observation every 2 days on the average. Here we describe the progress in analysis of observations of comets observed during 2013-2014 and those selected from the archive for analysis. These include comets 2P/Encke (2013), 45P/Honda Mrkos-Pajdusakova (2011), C/2013 R1 (Lovejoy), as well as C/2013 A1 (Siding Spring), for which results are expected. A status report on the entire SOHO/SWAN archive of water production rates in comets will be given. SOHO is an international cooperative mission between ESA and NASA. Support from grants NNX11AH50G from the NASA Planetary Astronomy Program and NNX13AQ66G from the NASA Planetary Mission Data Analysis Program are gratefully acknowledged.

SOHO EIT Carrington maps from synoptic full-disk data

NASA Technical Reports Server (NTRS)

Thompson, B. J.; Newmark, J. S.; Gurman, J. B.; Delaboudiniere, J. P.; Clette, F.; Gibson, S. E.

1997-01-01

The solar synoptic maps, obtained from observations carried out since May 1996 by the extreme-ultraviolet imaging telescope (EIT) onboard the Solar and Heliospheric Observatory (SOHO), are presented. The maps were constructed for each Carrington rotation with the calibrated data. The off-limb maps at 1.05 and 1.10 solar radii were generated for three coronal lines using the standard applied to coronagraph synoptic maps. The maps reveal several aspects of the solar structure over the entire rotation and are used in the whole sun month modeling campaign. @txt extreme-ultraviolet imaging telescope

SOHO hunts elusive solar prey

NASA Astrophysics Data System (ADS)

1995-10-01

SOHO will carry twelve sophisticated telescopes and other instruments, developed in record time by twelve international consortia involving scientific institutes in 15 countries. Roger M. Bonnet, the Director of ESA’s Scientific Programme said: "Each one of these instruments by itself would be enough to make major breakthroughs in our understanding of the Sun. But what makes SOHO such an exciting mission is that we will operate all the instruments together and find possible links between various phenomena at different levels in the volume of the Sun and in the interplanetary medium". Four years of intense efforts by space engineering teams in ESA and across Europe, under the leadership of the prime contractor Matra Marconi Space of Toulouse, France, have fulflled the dream of scientists who wished to build a superb space observatory for examining the Sun. SOHO, together with the four-spacecraft Cluster mission - which will explore near-Earth space, forms the Solar-Terrestrial Science Programme, the first cornerstone in ESA’s long-term programme 'Horizon 2000'. No night time for SOHO Instead of being placed in orbit around the Earth, SOHO will be lofted to a position where the gravitational pulls of the Earth and the Sun cancel each other out exactly, at 1.5 million kilometres sunward from the Earth. This is known in astronomy as the inner Lagrangian point after the French mathematician, Joseph Louis Lagrange, who first calculated its position near the end of the eighteenth century. SOHO will fly in an elliptical, or "halo" orbit around the Lagrangian point, with an orbit radius of about 600,000 kilometres, allowing the spacecraft to experience perpetual day. It will have a continuous, uninterrupted view of the Sun for twenty four hours of the day, all three hundred and sixty five days of the year, producing an extraordinary amount of data. All previous solar observatories have either been on the Earth or in orbit around our planet. On the Earth, telescopes are

Gone in a Blaze of Glory: The Demise of Comet C/2015 D1 (SOHO)

NASA Astrophysics Data System (ADS)

Hui, Man-To; Ye, Quan-Zhi; Knight, Matthew; Battams, Karl; Clark, David

2015-11-01

We present studies of C/2015 D1 (SOHO), the first sunskirting comet ever seen from ground stations over the past half century. The Solar and Heliospheric Observatory (SOHO) witnessed its peculiar light curve with a huge dip followed by a flare-up around perihelion: the dip was likely caused by sublimation of olivines, directly evidenced by a coincident temporary disappearance of the tail. The flare-up likely reflects a disintegration event, which we suggest was triggered by intense thermal stress established within the nucleus interior. Photometric data reveal an increasingly dusty coma, indicative of volatile depletion. A catastrophic mass-loss rate of ˜105 kg s-1 around perihelion was seen. Ground-based Xingming Observatory spotted the post-perihelion debris cloud. Our morphological simulations of post-perihelion images find newly released dust grains of size a ≳ 10 μm in radius however, a temporal increase in amin was also witnessed, possibly owing to swift dispersions of smaller grains swept away by radiation forces without replenishment. Together with the fading profile of the light curve, a power-law dust size distribution with index γ = 3.2 ± 0.1 is derived. We detected no active remaining cometary nuclei over ˜0.1 km in radius in post-perihelion images acquired at Lowell Observatory. Applying a radial nongravitational parameter, {{A}}1=≤ft(1.209+/- 0.118\\right)× {10}-6 AU day-2, from an isothermal water-ice sublimation model to the SOHO astrometry significantly reduces residuals and sinusoidal trends in the orbit determination. The nucleus mass ˜108-109 kg and the radius ˜50-150 m (bulk density ρd = 0.4 g cm-3 assumed) before the disintegration are deduced from the photometric data; consistent results were determined from the nongravitational effects.

Gone in a Blaze of Glory: the Demise of Comet C/2015 D1 (SOHO)

NASA Astrophysics Data System (ADS)

Hui, Man-To; Ye, Quan-Zhi; Manning Knight, Matthew; Battams, Karl; Clark, David

2015-11-01

We present studies of C/2015 D1 (SOHO), the first sunskirting comet ever seen from ground stations over the past half century. The Solar and Heliospheric Observatory (SOHO) witnessed its peculiar light curve with a huge dip followed by a flareup around perihelion: the dip was likely caused by sublimation of olivines, directly evidenced by a coincident temporary disappearance of the tail. The flareup likely reflects a disintegration event, which we suggest was triggered by intense thermal stress established within the nucleus interior. Photometric data reveal an increasingly dusty coma, indicative of volatile depletion. A catastrophic mass loss rate of ~105 kg s-1 around perihelion was seen. Ground-based Xingming Observatory spotted the post-perihelion debris cloud. Our morphological simulations of post-perihelion images find newly released dust grains of size a >~ 15 μm in radius, however, a temporal increase in amin was also witnessed, possibly due to swift dispersions of smaller grains swept away by radiation forces without replenishment. Together with the fading profile of the light curve, a power law dust size distribution with index γ = 3.2 ± 0.1 is derived. We detected no active remaining cometary nuclei over ~0.1 km in radius in post-perihelion images acquired at Lowell Observatory. Applying radial non-gravitational parameter, A1 = (1.209 ± 0.118) × 10-6 AU day-2, from an isothermal water-ice sublimation model to the SOHO astrometry significantly reduces residuals and sinusoidal trends in the orbit determination. The nucleus mass ~108--109 kg, and the radius ~50--150 m (bulk density ρd = 0.4 g cm-3 assumed) before the disintegration are deduced from the photometric data; consistent results were determined from the non-gravitational effects.

Prestigious award for SOHO

NASA Astrophysics Data System (ADS)

2003-09-01

SOHO spacecraft artist's impression hi-res Size hi-res: 451 Kb Credits: ESA SOHO spacecraft SOHO is a project of international cooperation between ESA and NASA. SOHO's science ranges from the Sun's hot interior, through its visible surface and stormy atmosphere, and out to distant regions where the wind from the Sun battles with a breeze of atoms coming from among the stars. The award recognises both the outstanding achievements in designing, building and operating the mission, as well as the science it has performed. It is a tribute to a team that has contributed to one of the most successful space missions in history. The International Academy of Astronautics presents this award in recognition of extraordinary performance and achievement by teams of scientists, engineers and managers in the field of astronautics. This honour has been awarded only twice before - to the Russian Mir Space Station Team and the US Space Shuttle Team. Now the SOHO team joins this select group. The citation of the award for the SOHO team reads: "To the team of scientists, engineers and managers for the development and operation of a world-class mission leading to substantial advancements in understanding the Sun and the solar-terrestrial relationship." SOHO has an impressive and unique list of achievements. For instance, it produced the first ever images of the turbulent outer shell of the Sun and of the structure below sunspots. It gave the most precise measurements of the solar temperature structure, the interior rotation and the gas flows inside the Sun. It measured the acceleration of the fast and slow solar winds and discovered new solar phenomena, such as solar tornadoes. It revolutionised our ability to forecast space weather, and helped our understanding of the impact of solar variability on Earth's climate. During eight years of operation, the team has had to face several heart-stopping moments, but with extraordinary team spirit, skill and competence, they turned these

White Light Stray Light Test of the SOHO UVCS

NASA Technical Reports Server (NTRS)

Gardner, L. N.; Gardner, L. N.; Fineschi, S.

1998-01-01

During the late stages of the integration phase of the Ultraviolet Coronagraph Spectrometer (UVCS) instrument for the Solar and Heliospheric Observatory (SOHO) at MATRA-Marconi in Toulouse, France, SOHO Project management at Goddard Space Flight Center (GSFC) became concerned that the elaborate stray light rejection system for the instrument had not been tested and might possibly be misaligned such that the instrument could not deliver promised scientific returns. A white light stray light test, which would place an upper bound on the value of UVCS's stray light rejection capability, was commissioned, conceived, and carried out. This upper bound value would be indicative of the weakest coronal features the spectrometer would be capable of discerning. The test was rapidly developed at GSFC in coordination with science team members from Harvard-Smithsonian Center for Astrophysics (CFA) and was carried out at MATRA in late February 1995. The outcome of this test helped to justify similar, much desired tests with visible and far ultraviolet light at CFA in a facility specifically designed to perform such testing.

SOHO reveals violent action on the quiet Sun

NASA Astrophysics Data System (ADS)

1996-05-01

SOHO's scientists are impressed by the vigorous action that they see going on every day, because the Sun is in the very quietest phase of its eleven-year cycle of activity. To ground-based observatories it appears extremely calm just now. The early indications of SOHO's performance amply justify the creation of a sungazing spacecraft capable of observing ultraviolet emissions that are blotted out by the Earth's atmosphere. Apart from the imager, two ultraviolet spectrometers and an ultraviolet coronagraph (an imager for the outer atmosphere) are busy analysing the violent processes at a wide range of wavelengths. Between them, these instruments should cure long-lasting ignorance concerning the Sun, especially about why the atmosphere is so hot and what drives the solar wind that blows non-stop into the Solar System. Scientists from other experimental teams use SOHO to explore the Sun from its deep interior to the far reaches of the solar wind. They have watched the supposedly quiet Sun belching huge masses of gas into space. They have mapped a hole burnt by the solar wind in a breeze of gas coming from the stars. And they have detected currents of gas flowing just below the visible surface. SOHO is a project of international cooperation between the European Space Agency and NASA. The spacecraft was built in Europe and instrumented by scientists on both sides of the Atlantic. NASA launched SOHO on 2 December 1995, and also provides the ground stations and an operations centre near Washington. The first results are the more remarkable because SOHO arrived at its vantage point 1,500,000 kilometres out in space only in February, and formally completed its commissioning on 16 April. It has a long life ahead of it. All scientific instruments are working well. The luminosity oscillation imager belonging to the VIRGO experiment had trouble with its lens cover. When opened, the cover rebounded on its hinges and closed again. Commands were devised that gave a shorter impulse

Comet 322P/SOHO 1: An Asteroid with the Smallest Perihelion Distance?

NASA Astrophysics Data System (ADS)

Knight, Matthew M.; Fitzsimmons, Alan; Kelley, Michael S. P.; Snodgrass, Colin

2016-05-01

We observed comet 322P/SOHO 1 (P/1999 R1) from the ground and with the Spitzer Space Telescope when it was between 2.2 and 1.2 au from the Sun. These are the first observations of any Solar and Heliospheric Observatory (SOHO)-discovered periodic comet by a non-solar observatory and allow us to investigate its behavior under typical cometary circumstances. 322P appeared inactive in all images. Its light curve suggests a rotation period of 2.8 ± 0.3 hr and has an amplitude ≳0.3 mag, implying a density of at least 1000 kg m-3, considerably higher than that of any known comet. It has average colors of {g}\\prime -{r}\\prime =0.52+/- 0.04 and {r}\\prime -{I}\\prime =0.03+/- 0.06. We converted these to Johnson colors and found that the V - R color is consistent with average cometary colors, but R - I is somewhat bluer; these colors are most similar to V- and Q-type asteroids. Modeling of the optical and IR photometry suggests it has a diameter of 150-320 m and a geometric albedo of 0.09-0.42, with diameter and albedo inversely related. Our upper limits to any undetected coma are still consistent with a sublimation lifetime shorter than the typical dynamical lifetimes for Jupiter-family comets. These results suggest that 322P may be of asteroidal origin and only active in the SOHO fields of view via processes different from the volatile-driven activity of traditional comets. If so, it has the smallest perihelion distance of any known asteroid. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 095.C-0853, with Lowell Observatory’s Discovery Channel Telescope, and with Spitzer Space Telescope under program 11104.

SOHO celebrates its first year in space with new results on the solar wind

NASA Astrophysics Data System (ADS)

1996-12-01

In the equatorial regions of the Sun, SOHO's extreme ultraviolet imager EIT reveals frenzied activity in a hot atmosphere. It contrasts with more orderly conditions near the poles, in cooler regions called coronal holes. Another instrument in SOHO, the ultraviolet coronagraph UVCS, makes images of emissions from charged oxygen atoms high above the Sun's visible surface, where the generators of the solar wind are at work. In the equatorial zone, the Sun's magnetic field tries to bottle up the superheated gas. The gas wins the fight and some of it bursts out in funnel-shaped features called helmets. This break-out creates the "slow" solar wind, at 350-400 kilometres per second, which drags the magnetic lines of force with it, far out into the solar system. It seems to be a heat-driven wind, as indicated by UVCS measurements that indicate lower speeds for heavy atoms such as oxygen, compared with the nimbler hydrogen atoms. The wind generator over the coronal holes is completely different. Here the Sun's magnetic field offers no resistance to the outflow of material. Another mechanism accelerates the "fast" solar wind that blows from the coronal holes at 700-800 kilometres per second. It may involve high frequency magnetic waves. John Kohl of the Smithsonian Astrophysical Observatory (USA) and Giancarlo Noci of the University of Florence (Italy) believe that their instrument in SOHO will identify the fast wind generator. "UVCS reveals an amazing state of affairs at a height of about 1,700,000 kilometres above the coronal holes," Kohl explains. "There our oxygen atoms are far more agitated than the hydrogen, with 60 times more energy of motion. They rush about as if they were scalded at 200 million degrees C. So we are homing in on the mechanism that accelerates the fast solar wind, with this very strong clue that it favours the heavier elements". At greater distances from the Sun, SOHO's visible-light coronagraph LASCO traces the flow of the slow solar wind far into

ESA to launch six scientific satellites

NASA Astrophysics Data System (ADS)

1995-09-01

The Infrared Space Observatory, ISO, will lead the trio into space. It will be launched on an Ariane 4 rocket in early November from the European launch site at Kourou, French Guiana. It will be followed in mid-December by SOHO, the Solar and Heliospheric Observatory, which will be launched by an Atlas IIAS rocket from Cape Canaveral, USA. Finally, in mid-January the four Cluster probes will be carried into space on the inaugural flight of Ariane 5. ISO is the world's only orbiting infrared observatory and is the most sophisticated ever. Its sensitive detectors will be cooled to below -270 degrees C, allowing it to observe cool objects in space, invisible through ordinary telescopes. ISO's many scientific goals include studying newly formed stars and planets, investigating the aging process of galaxies and search for the universe's elusive 'dark matter' that is believed to outweigh visible stars and galaxies. The SOHO observatory will provide scientists with a comprehensive study of the sun, the nuclear powerhouse in the centre of our solar system. Its twelve experiments, developed by scientists from Europe and the United States, will investigate the sun from its core outwards -from the very inner workings of the star, to the solar wind which blows through the solar system. The four identical Cluster spacecraft will focus on studying the interaction of the sun with plasmas of the Earth and the magnetic field in a region known as the magnetosphere. The four probes, flying in formation, will allow scientists to build up a three-dimensional picture of the battle between the sun's streams of wind and the Earth's protective magnetic field. These missions represent years of work by scientists across Europe and around the world. The data they gather will provide us with a greater understanding of our own solar neighbourhood and deep space. SPACECRAFT STATUS AS AT 1 SEPTEMBER 95 ISO The ISO satellite, together with all the associated equipment, was transported in June by

European X-ray observatory satellite (Exosat)

NASA Technical Reports Server (NTRS)

1983-01-01

Initially planned to be launched on the Ariane L6, the 510 kilogram European X-Ray Observatory Satellite (EXOSAT) is to be placed into orbit from Space Launch Complex 2 West by NASA's Delta 3914 launch vehicle. Objectives of the mission are to study the precise position, structure, and temporal and spectral characteristics of known X-ray sources as well as search for new sources. The spacecraft is described as well as its payload, principal subsystems, and the stages of the Delta 3914. The flight sequence of events, land launch operations are discussed. The ESA management structure for EXOSAT, the NASA/industry team, and contractors are listed.

EIT: Solar corona synoptic observations from SOHO with an Extreme-ultraviolet Imaging Telescope

NASA Technical Reports Server (NTRS)

Delaboudiniere, J. P.; Gabriel, A. H.; Artzner, G. E.; Michels, D. J.; Dere, K. P.; Howard, R. A.; Catura, R.; Stern, R.; Lemen, J.; Neupert, W.

1988-01-01

The Extreme-ultraviolet Imaging Telescope (EIT) of SOHO (solar and heliospheric observatory) will provide full disk images in emission lines formed at temperatures that map solar structures ranging from the chromospheric network to the hot magnetically confined plasma in the corona. Images in four narrow bandpasses will be obtained using normal incidence multilayered optics deposited on quadrants of a Ritchey-Chretien telescope. The EIT is capable of providing a uniform one arc second resolution over its entire 50 by 50 arc min field of view. Data from the EIT will be extremely valuable for identifying and interpreting the spatial and temperature fine structures of the solar atmosphere. Temporal analysis will provide information on the stability of these structures and identify dynamical processes. EIT images, issued daily, will provide the global corona context for aid in unifying the investigations and in forming the observing plans for SOHO coronal instruments.

Water production rates of recent comets (2016-2017) by SOHO/SWAN: 2P/Encke, 41P/Tuttle-Giacobini-Kresak, 45P/ Honda-Mrkos-Pajdusakova, and C/2015 ER61 (PanSTARRS)

NASA Astrophysics Data System (ADS)

Combi, Michael R.; Mäkinen, Terhi; Bertaux, Jean-Loup; Quémerais, Eric; Ferron, Stephane

2017-10-01

The all-sky hydrogen Lyman-alpha camera, SWAN (Solar Wind Anisotropies), on the SOlar and Heliospheric Observatory (SOHO) satellite makes observations of the hydrogen coma of comets. Most water molecules produced by comets are ultimately photodissociated into two H atoms and one O atom producing a huge atomic hydrogen coma that is routinely observed in the daily full-sky SWAN images in comets of sufficient brightness. Water production rates are calculated using our time-resolved model (Mäkinen & Combi, 2005, Icarus 177, 217), typically yielding about 1 observation every 2 days on the average for each comet over the brightest part of its apparition. Here we describe the progress in analysis of observations of comets observed in 2016 and 2017. These include comets 2P/Encke, 41P/Tuttle-Giacobini-Sresak, 45P/ Honda-Mrkos-Pajdusakova, and C/2015 ER61 (PanSTARRS). A status update on the entire SOHO/SWAN archive of water production rates in comets will also be given.SOHO is an international cooperative mission between ESA and NASA. Support from grants NNX15AJ81G from the NASA Solar System Observations Planetary Astronomy Program and a previous grant NNX13AQ66G from the NASA Planetary Mission Data Analysis Program are gratefully acknowledged, as is support from CNRS, CNES, and the Finnish Meteorological Institute (FMI).

Water production in comets C/2011 L4 (PanSTARRS) and C/2012 F6 (Lemmon) from observations with Soho/Swan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Combi, M. R.; Aptekar, G.; Bertaux, J.-L.

2014-06-01

Comets C/2011 L4 (PanSTARRS) and C/2012 F6 (Lemmon) were observed throughout their 2012-2013 apparitions with the Solar Wind Anisotropies (SWAN) all-sky hydrogen Lyα camera on board the Solar and Heliosphere Observatory (SOHO) satellite. SOHO has been in a halo orbit around the L1 Earth-Sun Lagrange point since early 1996 and has been observing the interplanetary medium and comets beginning with C/1996 B2 (Hyakutake). The global water production from these comets was determined from an analysis of the SWAN Lyα camera observations. Comet C/2011 L4 (PanSTARRS), which reached its perihelion distance of 0.302 AU on 2013 March 10.17, was observed onmore » 50 days between 2013 January 29 and April 30. Comet C/2012 F6 (Lemmon), which reached its perihelion distance of 0.731 AU on 2013 March 24.51, was observed on 109 days between 2012 November 29 and 2013 June 31. The maximum water production rates were ∼1 × 10{sup 30} molecules s{sup –1} for both comets. The activities of both comets were asymmetric about perihelion. C/2011 L4 (PanSTARRS) was more active before perihelion than after, but C/2012 F6 (Lemmon) was more active after perihelion than before.« less

Variation of the water production rate of comet C/2013 X1 (PanSTARRS) from SOHO/SWAN observations throughout its apparition

NASA Astrophysics Data System (ADS)

Combi, Michael R.; Makinen, Terhi; Bertaux, Jean-Loup; Quémerais, Eric; Ferron, Stephane

2016-10-01

The all-sky hydrogen Lyman-alpha camera, SWAN (Solar Wind ANisotropies), on the SOlar and Heliospheric Observatory (SOHO) satellite makes observations of the hydrogen coma of comets. Most water vapor produced by comets is ultimately photodissociated into two H atoms (in addition to one O atom) producing a huge atomic hydrogen coma that is routinely observed in the daily full-sky SWAN images in comets of sufficient brightness. Water production rates are calculated using our time-resolved model (Mäkinen & Combi, 2005, Icarus 177, 217), typically yielding about 1 observation every 2 days on the average over an apparition. Here we describe the analysis of observations of bright comet C/2013 X1 (PanSTARRS) observed during 2016. C/2013 X1 reached a perihelion distance of 1.314278 AU on 20.72 April 2016. Its brightening toward the end of June 2016 is influenced by a somewhat close geocentric distance of 0.64 AU. A status update on the entire SOHO/SWAN archive of water production rates in comets will also be given. Support from grants NNX15AJ81G from the NASA Solar System Observations Planetary Astronomy Program and NNX13AQ66G from the NASA Planetary Mission Data Analysis Program are gratefully acknowledged, as is support from CNRS, CNES, and the Finnish Meteorological Institute (FMI).

Atronomical CCD observations of the main Saturn's satellites at Pulkovo Observatory in 2004-2007

NASA Astrophysics Data System (ADS)

Khrutskaya, E. V.; Kiseleva, T. P.; Izmailov, I. S.; Khovrichev, M. Yu.; Berezhnoy, A. A.

2009-08-01

The results of astrometric observations of Saturn’s satellites (S1-S8) obtained using a 26-inch refractor and a normal astrograph at Pulkovo Observatory in 2004-2007 are given. High-accuracy equatorial coordinates of Saturn’s satellites in the system of the UCAC2 reference catalog and the relative “satellite-satellite” positions suitable for specifying their motion theories are obtained. The observations are compared with the DE405 + TASS1.7 and INPOP06 + TASS1.7 theories of motion. The root-mean-square errors of the obtained satellite positions lie within the range of 10-50 mas, as far as the intrinsic convergence is concerned, and 20-70 mas, as far as the extrinsic one is concerned. The observation results are included into the astrometrical database of the Pulkovo Observatory ( www.puldb.ru ).

Can SOHO SWAN detect CMEs?

NASA Technical Reports Server (NTRS)

St.Cyr, O. C.; Malayeri, M. L.; Yashiro, S.; Quernerais, E.; Bertaux, Jean-Loup; Howard, Russ

2003-01-01

We have investigated the possibility that the Solar Wind Anisotropies (SWAN) remote sensing instrument on SOHO may be able to detect coronal mass ejections (CMEs) in neutral Hydrogen Lyman-? emission. We have identified CMEs near the Sun in observations by the SOHO LASCO white-light coronagraphs and in extreme ultraviolet emissions using SOHO E n . There are very few methods of tracking CMEs after they leave the coronagraph's field-of-view, so this is an important topic to study. The primary science goal of the SWAN investigation is the measurement of large-scale structures in the solar wind, and these are obtained by detecting intensity fluctuations in Lyman-?. SWAN consists of a pair of Sensors on opposite panels of SOHO. The instantaneous field-of-view of each sensor unit is a So x So square, divided into lo pixels. A gimbaled periscope system allows each sensor to map the intensity distribution of Lyman-?, and the entire sky can be scanned in less than one day. This is the typical mode of operation for this instrument.

Sensor lighting considerations for earth observatory satellite missions

NASA Technical Reports Server (NTRS)

Cooley, J. L.

1972-01-01

Facets of sensor lighting conditions for Earth observatory satellite missions are considered. Assuming onboard sensors of a given width viewing perpendicular to the subsatellite ground track along sun-synchronous orbits with various nodes, the ground trace of the ends of the sensor coverage were found, as well as the variation in solar illumination on the ground across the line covered by the sensor during the day for any point along the orbit. The changes with season and variation during the year were also found.

Searching the SOHO online catalogs

NASA Technical Reports Server (NTRS)

Thompson, William; Yurow, Ron

1994-01-01

The SOHO on-line catalogs will contain information about the observations from several made or planned campaigns, that must be available to scientists who wish to use SOHO data. The World Wide Web (WWW) was chosen as the interface to the SOHO on-line catalogs, because it is easy to use, well suited to a geographically distributed user community, and freely available. Through the use of a forms-capable WWW client such as Mosaic or Lynx, a scientist will be able to browse through the catalogs of observations in a very simple, self explanatory way. Data files can then be selected from the returned lists for either immediate transferring or sending on tape by mail, with appropriate checks for whether data is in the public domain or not.

Management approach recommendations. Earth Observatory Satellite system definition study (EOS)

NASA Technical Reports Server (NTRS)

1974-01-01

Management analyses and tradeoffs were performed to determine the most cost effective management approach for the Earth Observatory Satellite (EOS) Phase C/D. The basic objectives of the management approach are identified. Some of the subjects considered are as follows: (1) contract startup phase, (2) project management control system, (3) configuration management, (4) quality control and reliability engineering requirements, and (5) the parts procurement program.

PRELIMINARY ANALYSIS OF SOHO/STEREO OBSERVATIONS OF SUNGRAZING COMET ISON (C/2012 S1) AROUND PERIHELION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knight, Matthew M.; Battams, Karl, E-mail: knight@lowell.edu

2014-02-20

We present photometric and morphological analysis of the behavior of sungrazing comet C/2012 S1 ISON in Solar and Heliospheric Observatory (SOHO) and Solar TErrestrial RElations Observatory (STEREO) images around its perihelion on 2013 November 28.779 UT. ISON brightened gradually November 20-26 with a superimposed outburst on November 21.3-23.5. The slope of brightening changed about November 26.7 and was significantly steeper in SOHO's orange and clear filter images until November 27.9 when it began to flatten out, reaching a peak about November 28.1 (r {sub H} ≈ 17 R {sub ☉}), then fading before brightening again from November 28.6 (r {submore » H} ≈ 5 R {sub ☉}) until disappearing behind the occulting disk. ISON brightened continuously as it approached perihelion while visible in all other telescopes/filters. The central condensation disappeared about November 28.5 and the leading edge became progressively more elongated until perihelion. These photometric and morphological behaviors are reminiscent of the tens of meter-sized Kreutz comets regularly observed by SOHO and STEREO and strongly suggest that the nucleus of ISON was destroyed prior to perihelion. This is much too small to support published gas production rates and implies significant mass loss and/or disruption in the days and weeks leading up to perihelion. No central condensation was seen post-perihelion. The post-perihelion lightcurve was nearly identical in all telescopes/filters and fell slightly steeper than r{sub H}{sup −2}. This implies that the brightness was dominated by reflected solar continuum off of remnant dust in the coma/tail and that any remaining active nucleus was <10 m in radius.« less

Lyman-α Models for LRO LAMP from MESSENGER MASCS and SOHO SWAN Data

NASA Astrophysics Data System (ADS)

Pryor, Wayne R.; Holsclaw, Gregory M.; McClintock, William E.; Snow, Martin; Vervack, Ronald J.; Gladstone, G. Randall; Stern, S. Alan; Retherford, Kurt D.; Miles, Paul F.

From models of the interplanetary Lyman-α glow derived from observations by the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) interplanetary Lyman-α data obtained in 2009-2011 on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft mission, daily all-sky Lyman-α maps were generated for use by the Lunar Reconnaissance Orbiter (LRO) LAMP Lyman-Alpha Mapping Project (LAMP) experiment. These models were then compared with Solar and Heliospheric Observatory (SOHO) Solar Wind ANistropy (SWAN) Lyman-α maps when available. Although the empirical agreement across the sky between the scaled model and the SWAN maps is adequate for LAMP mapping purposes, the model brightness values best agree with the SWAN values in 2008 and 2009. SWAN's observations show a systematic decline in 2010 and 2011 relative to the model. It is not clear if the decline represents a failure of the model or a decline in sensitivity in SWAN in 2010 and 2011. MESSENGER MASCS and SOHO SWAN Lyman-α calibrations systematically differ in comparison with the model, with MASCS reporting Lyman-α values some 30 % lower than SWAN.

Space-shuttle interfaces/utilization. Earth Observatory Satellite system definition study (EOS)

NASA Technical Reports Server (NTRS)

1974-01-01

The economic aspects of space shuttle application to a representative Earth Observatory Satellite (EOS) operational mission in the various candidate Shuttle modes of launch, retrieval, and resupply are discussed. System maintenance of the same mission capability using a conventional launch vehicle is also considered. The studies are based on application of sophisticated Monte Carlo mission simulation program developed originally for studies of in-space servicing of a military satellite system. The program has been modified to permit evaluation of space shuttle application to low altitude EOS missions in all three modes. The conclusions generated by the EOS system study are developed.

Earth Observatory Satellite system definition study. Report no. 3: Design/cost tradeoff studies

NASA Technical Reports Server (NTRS)

1974-01-01

The key issues in the Earth Observatory Satellite (EOS) program which are subject to configuration study and tradeoff are identified. The issue of a combined operational and research and development program is considered. It is stated that cost and spacecraft weight are the key design variables and design options are proposed in terms of these parameters. A cost analysis of the EOS program is provided. Diagrams of the satellite configuration and subsystem components are included.

System design and specifications. Earth Observatory Satellite system definition study (EOS)

NASA Technical Reports Server (NTRS)

1974-01-01

A design summary of the Earth Observatory Satellite (EOS) is presented. The systems considered in the summary are: (1) the spacecraft structure, (2) electrical power modules, (3) communications and data handling module, (4) attitude determination module, (5) actuation module, and (6) solar array and drive module. The documents which provide the specifications for the systems and the equipment are identified.

Design/cost tradeoff studies. Earth Observatory Satellite system definition study (EOS)

NASA Technical Reports Server (NTRS)

1974-01-01

The results of design/cost tradeoff studies conducted during the Earth Observatory Satellite system definition studies are presented. The studies are concerned with the definition of a basic modular spacecraft capable of supporting a variety of operational and/or research and development missions, with the deployment either by conventional launch vehicles or by means of the space shuttle. The three levels investigated during the study are: (1) subsystem tradeoffs, (2) spacecraft tradeoffs, and (3) system tradeoffs. The range of requirements which the modular concept must span is discussed. The mechanical, thermal, power, data and electromagnetic compatibility aspects of modularity are analyzed. Other data are provided for the observatory design concept, the payloads, integration and test, the ground support equipment, and ground data management systems.

Press briefing on results from the solar spacecraft SOHO

NASA Astrophysics Data System (ADS)

1998-04-01

After its launch on 2 December 1995, SOHO travelled to take up a special orbit 1.5 million kilometres away on the sunward side of the Earth, where the Sun never sets. The full scientific programme began in April 1996. The occasion for the briefing is the celebration of that second anniversary and of the mission's extension to 2003. Organized by the European Space Agency, the briefing will be hosted by the Rutherford Appleton Laboratory, which is near Oxford. Leading scientists associated with SOHO will announce to the press some remarkable new discoveries about the Sun's interior, atmosphere and solar wind. They will also briefly review the main achievements of the past two years. The role of SOHO as the chief watchdog for storms on the Sun that may affect the Earth will be demonstrated. Europe's creation of the finest spacecraft ever built to observe the Sun will be recalled by a top engineer from ESA. A speaker from NASA will explain transatlantic contributions to SOHO, which is a project of international cooperation between ESA and NASA. ESA's director of science will also be present, to relate SOHO to ESA's general science programme. A lunch-time talk by the BNSC's director of science completes the line-up of speakers. This is also an exceptional opportunity for the press to meet and interview scientists from all over Europe and the USA, who are attending a meeting at the Rutherford Appleton Laboratory of SOHO's Science Working Team (SWT). Journalists are usually excluded from such meetings. The Rutherford Appleton Laboratory plays a prominent part in SOHO, particularly through its provision of the CDS ultraviolet spectrometer. A visit to the CDS group will provide a chance to see what space research is really like. Please indicate your intention to attend, on the accreditation form that follows the schedule. Guidance on how to get to the Rutherford Appleton Laboratory is appended. PROGRAMME Rutherford Appleton Laboratory (RAL), 28 April 1998 10:30 Assembly of

Destruction of Sun-Grazing Comet C-2011 N3 (SOHO) Within the Low Solar Corona

NASA Technical Reports Server (NTRS)

Schrijver, C. J.; Brown, J. C.; Battams, K.; Saint-Hilaire, P.; Liu, W.; Hudson, H.; Pesnell, W. D.

2012-01-01

Observations of comets in Sun-grazing orbits that survive solar insolation long enough to penetrate into the Suns inner corona provide information on the solar atmosphere and magnetic field as well as on the makeup of the comet. On 6 July 2011, the Solar Dynamics Observatory (SDO) observed the demise of comet C2011 N3 (SOHO) within the low solar corona in five wavelength bands in the extreme ultraviolet (EUV). The comet penetrated to within 0.146 solarradius (100,000 kilometers) of the solar surface before its EUV signal disappeared.

100 and counting : SOHO's score as the world's top comet finder

NASA Astrophysics Data System (ADS)

2000-02-01

comet hunters," said Shanklin, who is director of the British Astronomical Association's comet section. "It allows amateurs to discover some of the smallest comets ever seen. Yet they link us to sightings of great comets going back more than 2000 years." Nine of the comets found with LASCO, including SOHO-100, 101 and 102, passed the Sun at a safe distance. SOHO-49, which showed up in LASCO images in May 1998 and was designated as Comet 1998 J1, became visible to the naked eye in the southern hemisphere. But the great majority of SOHO's comets failed to survive very close encounters with the Sun. Snowballs in hell Of the first 100 SOHO comets, 92 vaporized in the solar atmosphere. Isaac Newton suggested 300 years ago that infalling comets might supply the Sun with fuel, but no one has ever tracked a comet that definitely hit the bright surface. Near misses are well known, and 100 years ago Heinrich Kreutz in Kiel, Germany, realized that several comets seen buzzing the Sun seemed to have a common origin, because they came from the same direction among the stars. These comets are now called the Kreutz sungrazers, and the 92 vanishing SOHO comets belong to that class. They were not unexpected. Between 1979 and 1989 the P78-1 and SMM solar satellites spotted 16 comets closing with the Sun. Life is perilous for a sungrazer. The mixture of ice and dust that makes up a comet's nucleus is heated like the proverbial snowball in hell, and can survive its visit to the Sun only if it is quite large. What's more, the very strong tidal effect of the Sun's gravity can tear the loosely glued nucleus apart. The disruption that created the many SOHO sungrazers was similar to the fate of Comet Shoemaker-Levy 9, which went too close to Jupiter and broke up into many pieces that eventually fell into the massive planet in 1994. "SOHO is seeing fragments from the gradual break-up of a great comet, perhaps the one that the Greek astronomer Ephorus saw in 372 BC," commented Brian Marsden of the

Earth Observatory Satellite system definition study. Report no. 7: EOS system definition report

NASA Technical Reports Server (NTRS)

1974-01-01

The design concept and operational aspects of the Earth Observatory Satellite (EOS) are presented. A table of the planned EOS missions is included to show the purpose of the mission, the instruments involved, and the launch date. The subjects considered in the analysis of the EOS development are: (1) system requirements, (2) design/cost trade methodology, (3) observatory design alternatives, (4) the data management system, (5) the design evaluation and preferred approach, (6) program cost compilation, (7) follow-on mission accommodation, and (8) space shuttle interfaces and utilization. Illustrations and block diagrams of the spacecraft configurations are provided.

SOHO starts a revolution in the science of the Sun

NASA Astrophysics Data System (ADS)

1996-07-01

In addition, SOHO has found clues to the forces that accelerate the solar wind of atomic particles blowing unceasingly through the Solar System. By relating the huge outbursts called coronal mass ejections to preceding magnetic changes in the Sun, SOHO scientists hope to predict such events which, in the Earth's vicinity, endanger power supplies and satellites. SOHO sees differences in the strength of the solar wind in various directions, by mapping a cavity in the cloud of interstellar hydrogen surrounding the Sun. As a bonus, SOHO secured remarkable images of Comet Hyakutake, by ultraviolet and visible light. The revolution in solar science will seem more complete when all the pieces and actions of the Sun, detected by twelve different instruments, are brought together in observations and concepts. Fundamental questions will then be open to re-examination, about the origin of the Sun's magnetism, the cause of its variations in the 11-year cycle of sunspot activity, and the consequences for the Solar System at large. SOHO is greater than the sum of its parts. "SOHO takes solar science by storm," says Roger Bonnet, the European Space Agency's Director of Science, "thanks to its combination of instruments. Unprecedented results from individual telescopes and spectrometers are impressive, of course, but what is breathtaking is SOHO's ability to explore the Sun all the way from its nuclear core to the Earth's vicinity and beyond. We can expect a completely new picture of how agitation inside the Sun, transmitted through the solar atmosphere, directly affects us on the Earth." SOHO is a project of international cooperation between the European Space Agency and NASA. The spacecraft was built in Europe and instrumented by scientists on both sides of the Atlantic. NASA launched SOHO and provides the ground stations and an operations centre at the Goddard Space Flight Center near Washington. SOHO has an uninterrupted view of the Sun from a halo orbit around Lagrangian

Satellites, scientists track storm from Sun to surface

NASA Astrophysics Data System (ADS)

Carlowicz, Michael

1997-02-01

On January 6, the Sun spat a coronal mass ejection (CME) into the solar wind and toward Earth; by January 10, a cloud of charged particles buffeted the face of the planet. It was, by several accounts, a run-of-the-mill space weather event. But the scientific work surrounding the storm was anything but run-of-the-mill. For the first time, space physicists observed and recorded a space weather event from start to finish, from solar surface to earthly impact. Researchers are calling it the first true success story of the four-year-old International Solar Terrestrial Physics program (ISTP), which includes NASA's WIND and POLAR spacecraft; the joint Solar and Heliospheric Observatory (SOHO) mission of NASA and the European Space Agency; the joint Geotail mission of NASA and Japan's Institute of Space and Aeronautical Science; and Russia's Interball satellites.

Earth Observatory Satellite system definition study. Report no. 7: EOS system definition report. Appendixes A through D

NASA Technical Reports Server (NTRS)

1974-01-01

An analysis of the systems involved in the operation and support of the Earth Observatory Satellite (EOS) is presented. Among the systems considered are the following: (1) the data management system, (2) observatory to primary ground station communications links, (3) local user system, (4) techniques for recognizing ground control points, (5) the central data processing-implementation concept, and (6) program effectiveness analysis.

The Fall 2000 and Fall 2001 SOHO-Ulysses Quadratures

NASA Technical Reports Server (NTRS)

Suess, S. T.; Poletto, G.; Rose, M. Franklin (Technical Monitor)

2001-01-01

SOHO-Ulysses quadrature occurs when the SOHO-Sun-Ulysses included angle is 90 degrees. It is only at such times that the same plasma leaving the Sun in the direction of Ulysses can first be remotely analyzed with SOHO instruments and then later be sampled in situ by Ulysses instruments. The quadratures in December 2000 and 2001 are of special significance because Ulysses will be near the south and north heliographic poles, respectively, and the solar cycle will be near sunspot maximum. Quadrature geometry is sometimes confusing and observations are influenced by solar rotation. The Fall 2000 and 2001 quadratures are more complex than usual because Ulysses is not in a true polar orbit and the orbital speed of Ulysses about the Sun is becoming comparable to the speed of SOHO about the Sun. In 2000 Ulysses will always be slightly behind the pole but will appear to hang over the pole for over two months because it is moving around the Sun in the same direction as SOHO. In 2001 Ulysses will be slightly in front of the pole so that its footpoint will be directly observable. Detailed plots will be shown of the relative positions of SOHO and Ulysses will their relative positions. In neither case is true quadrature actually achieved, but this works to the observers advantage in 2001.

The Fall 2000 and Fall 2001 SOHO-Ulysses Quadratures

NASA Technical Reports Server (NTRS)

Suess, S. T.; Poletto, G.

2000-01-01

SOHO-Ulysses quadrature occurs when the SOHO-Sun-Ulysses included angle is 90 degrees. It is only at such times that the same plasma leaving the Sun in the direction of Ulysses can first be remotely analyzed with SOHO instruments and then later be sampled in situ by Ulysses instruments. The quadratures in December 2000 and 2001 are of special significance because Ulysses will be near the south and north heliographic poles, respectively, and the solar cycle will be near sunspot maximum. Quadrature geometry is sometimes confusing and observations are influenced by solar rotation. The Fall 2000 and 2001 quadratures are more complex than usual because Ulysses is not in a true polar orbit and the orbital speed of Ulysses about the Sun is becoming comparable to the speed of SOHO about the Sun. In 2000 Ulysses will always be slightly behind the pole but will appear to hang over the pole for over two months because it is moving around the Sun in the same direction as SOHO. In 20001, Ulysses will be slightly in front of the pole so that its footpoint will be directly observable. Detailed plots will be shown of the relative positions of SOHO and Ulysses will their relative positions. In neither case is true quadrature actually achieved, but this works to the observers advantage in 2001.

Earth Observatory Satellite system definition study. Report no. 4: Management approach recommendations

NASA Technical Reports Server (NTRS)

1974-01-01

A management approach for the Earth Observatory Satellite (EOS) which will meet the challenge of a constrained cost environment is presented. Areas of consideration are contracting techniques, test philosophy, reliability and quality assurance requirements, commonality options, and documentation and control requirements. The various functional areas which were examined for cost reduction possibilities are identified. The recommended management approach is developed to show the primary and alternative methods.

Catalogue of {>} 55 MeV Wide-longitude Solar Proton Events Observed by SOHO, ACE, and the STEREOs at {≈} 1 AU During 2009 - 2016

NASA Astrophysics Data System (ADS)

Paassilta, Miikka; Papaioannou, Athanasios; Dresing, Nina; Vainio, Rami; Valtonen, Eino; Heber, Bernd

2018-04-01

Based on energetic particle observations made at {≈} 1 AU, we present a catalogue of 46 wide-longitude ({>} 45°) solar energetic particle (SEP) events detected at multiple locations during 2009 - 2016. The particle kinetic energies of interest were chosen as {>} 55 MeV for protons and 0.18 - 0.31 MeV for electrons. We make use of proton data from the Solar and Heliospheric Observatory/Energetic and Relativistic Nuclei and Electron Experiment (SOHO/ERNE) and the Solar Terrestrial Relations Observatory/High Energy Telescopes (STEREO/HET), together with electron data from the Advanced Composition Explorer/Electron, Proton, and Alpha Monitor (ACE/EPAM) and the STEREO/ Solar Electron and Proton Telescopes (SEPT). We consider soft X-ray data from the Geostationary Operational Environmental Satellites (GOES) and coronal mass ejection (CME) observations made with the SOHO/ Large Angle and Spectrometric Coronagraph (LASCO) and STEREO/ Coronagraphs 1 and 2 (COR1, COR2) to establish the probable associations between SEP events and the related solar phenomena. Event onset times and peak intensities are determined; velocity dispersion analysis (VDA) and time-shifting analysis (TSA) are performed for protons; TSA is performed for electrons. In our event sample, there is a tendency for the highest peak intensities to occur when the observer is magnetically connected to solar regions west of the flare. Our estimates for the mean event width, derived as the standard deviation of a Gaussian curve modelling the SEP intensities (protons {≈} 44°, electrons {≈} 50°), largely agree with previous results for lower-energy SEPs. SEP release times with respect to event flares, as well as the event rise times, show no simple dependence on the observer's connection angle, suggesting that the source region extent and dominant particle acceleration and transport mechanisms are important in defining these characteristics of an event. There is no marked difference between the speed

MLRS - A lunar/artificial satellite laser ranging facility at the McDonald Observatory

NASA Technical Reports Server (NTRS)

Shelus, P. J.

1985-01-01

Experience from lunar and satellite laser ranging experiments carried out at McDonald Observatory has been used to design the McDonald Laser Ranging Station (MLRS). The MLRS is a dual-purpose installation designed to obtain observations from the LAGEOS satellite and lunar targets. The instruments used at the station include a telescope assembly 0.76 meters in diameter; a Q-switched doubled neodymium YAG laser with a pulse rate of three nanoseconds; and a GaAs photodetector with Fabry-Perot interferometric filter. A functional diagram of the system is provided. The operating parameters of the instruments are summarized in a table.

Instrument constraints and interface specifications. Earth Observatory Satellite system definition study (EOS)

NASA Technical Reports Server (NTRS)

1974-01-01

The equipment specifications for the thematic mapper and high resolution pointable imager for use on the Earth Observatory Satellite (EOS) are presented. The interface requirements of the systems are defined. The interface requirements are extracted from the equipment specifications and are intended as a summary to be used by the system and spacecraft designer. The appropriate documentation from which the specifications of the equipment are established are identified.

Soho and Cluster - The scientific instruments

NASA Technical Reports Server (NTRS)

Domingo, V.; Schmidt, R.; Poland, A. I.; Goldstein, M. L.

1988-01-01

The mission goals and instrumentation of the Soho and cluster spacecraft to be launched in 1995 as part of the international Solar-Terrestrial Science Program are discussed. Instruments such as normal-incidence, grazing-incidence, and EUV coronal spectrometers aboard the Soho spacecraft will study the origin of the solar wind and the physical properties of the solar atmosphere. The four Cluster spacecraft will measure electric and magnetic fields, plasmas, and energetic particles using instruments including a wide-band receiver system, a relaxation sounder, and a search coil magnetometer.

A study to define meteorological uses and performance requirements for the Synchronous Earth Observatory Satellite

NASA Technical Reports Server (NTRS)

Suomi, V. E.; Krauss, R. J.; Barber, D.; Levanon, N.; Martin, D. W.; Mclellan, D. W.; Sikdar, D. N.; Sromovsky, L. A.; Branch, D.; Heinricy, D.

1973-01-01

The potential meteorological uses of the Synchronous Earth Observatory Satellite (SEOS) were studied for detecting and predicting hazards to life, property, or the quality of the environment. Mesoscale meteorological phenonmena, and the observations requirements for SEOS are discussed along with the sensor parameters.

Hinode ``a new solar observatory in space''

NASA Astrophysics Data System (ADS)

Tsuneta, S.; Harra, L. K.; Masuda, S.

2009-05-01

Since its launch in September 2006, the Japan-US-UK solar physics satellite, Hinode, has continued its observation of the sun, sending back solar images of unprecedented clarity every day. Hinode is equipped with three telescopes, a visible light telescope, an X-ray telescope, and an extreme ultraviolet imaging spectrometer. The Hinode optical telescope has a large primary mirror measuring 50 centimeters in diameter and is the world's largest space telescope for observing the sun and its vector magnetic fields. The impact of Hinode as an optical telescope on solar physics is comparable to that of the Hubble Space Telescope on optical astronomy. While the optical telescope observes the sun's surface, the Hinode X-ray telescope captures images of the corona and the high-temperature flares that range between several million and several tens of millions of degrees. The telescope has captured coronal structures that are clearer than ever. The Hinode EUV imaging spectrometer possesses approximately ten times the sensitivity and four times the resolution of a similar instrument on the SOHO satellite. The source of energy for the sun is in the nuclear fusion reaction that takes place at its core. Here temperature drops closer to the surface, where the temperature measures about 6,000 degrees. Mysteriously, the temperature starts rising again above the surface, and the temperature of the corona is exceptionally high, several millions of degrees. It is as if water were boiling fiercely in a kettle placed on a stove with no fire, inconceivable as it may sound. The phenomenon is referred to as the coronal heating problem, and it is one of the major astronomical mysteries. The Hinode observatory was designed to solve this mystery. It is expected that Hinode would also provide clues to unraveling why strong magnetic fields are formed and how solar flares are triggered. An overview on the initial results from Hinode is presented. Dynamic video pictures captured by Hinode can be

Brightness Variations in the Solar Atmosphere as Seen by SOHO

NASA Astrophysics Data System (ADS)

Brkovic, A.; Rüedi, I.; Solanki, S. K.; Huber, M. C. E.; Stenflo, J. O.; Stucki, K.; Harrison, R.; Fludra, A.

We present preliminary results of a statistical analysis of the brightness variations of solar features at different levels in the solar atmosphere. We observed quiet Sun regions at disc centre using the Coronal Diagnostic Spectrometer (CDS) onboard the Solar and Heliospheric Observatory (SOHO). We find significant variability at all time scales in all parts of the quiet Sun, from darkest intranetwork to brightest network. Such variations are observed simultaneously in the chromospheric He I 584.33 Angstroms (2 \\cdot 10^4 K) line, the transition region O V 629.74 Angstroms (2.5 \\cdot 10^5 K) and coronal Mg IX 368.06 Angstroms (10^6 K) line. The relative variability is independent of brightness and most of the variability appears to take place on time scales longer than 5 minutes for all 3 spectral lines. No significant differences are observed between the different data sets.

Five years of discoveries with SOHO have made the Sun transparent

NASA Astrophysics Data System (ADS)

2001-04-01

teams have streamlined their data gathering and analyses to the point where they can offer routine long-range forecasts of intense solar activity based on far-side foresight. The techniques are complementary, with MDI seeing the sunspot regions and SWAN reporting how active they are. "When we started work with SOHO five years ago, most experts thought it would be impossible to see right through the Sun," comments Philip Scherrer of Stanford University, principal investigator for the MDI instrument. "Now we do it regularly in real time. For practical purposes we’ve made the Sun transparent". Although conceived for scientific research, SOHO has proved invaluable as a watchdog for spotting sunstorms. Forecasters already rely heavily on SOHO’s round-the-clock observations of flares and mass ejections that can have harmful effects on satellites, power lines and other technological systems. The new long-range, far-side forecasts may be especially useful for scheduling manned space operations, during which astronauts might be exposed to dangerous particles from solar explosions. Watching the solar striptease SOHO examines the Sun from a vantage point 1.5 million kilometres out, on the sunward side of the Earth. Its instruments probe the Sun from its nuclear core, through its turbulent interior and stormy atmosphere, and all the way out to the Earth’s orbit and beyond, where a non-stop stream of atomic nuclei and electrons travels outwards as the solar wind. To the naked eye the Sun looks calm and unchanging, but for SOHO it has performed a dramatic striptease. Here are just ten of the revelations. The Sun’s surprising heart beat. Currents of gas far beneath the visible surface speed up and slacken again every 16 months -- a wholly unexpected pulse-rate. It was detected by combining data from SOHO and a US-led network of ground stations called GONG. Brighter sunbeams. Watching minute by minute and year by year, SOHO has seen the Sun brighten, as expected, by 0.1 per

Solar Wind Characteristics from SOHO-Sun-Ulysses Quadrature Observations

NASA Technical Reports Server (NTRS)

Poletto, Giannina; Suess, Steve T.; Six, N. Frank (Technical Monitor)

2002-01-01

Over the past few years, we have been running SOHO (Solar and Heliospheric Observatory)-Sun-Ulysses quadrature campaigns, aimed at comparing the plasma properties at coronal altitudes with plasma properties at interplanetary distances. Coronal plasma has been observed by SOHO experiments: mainly, we used LASCO (Large Angle and Spectrometric Coronagraph Experiment) data to understand the overall coronal configuration at the time of quadratures and analyzed SUMER (Solar Ultraviolet Measurements of Emitted Radiation), CDS (Coronal Diagnostic Spectrometer) and UVCS (Ultraviolet Coronagraph Spectrometer) data to derive its physical characteristics. At interplanetary distances, SWICS (Solar Wind Ion Composition Spectrometer) and SWOOPS (Solar Wind Observation over the Poles of the Sun) aboard Ulysses provided us with interplanetary plasma data. Here we report on results from some of the campaigns. We notice that, depending on the geometry of the quadrature, i.e. on whether the radial to Ulysses traverses the corona at high or low latitudes, we are able to study different kinds of solar wind. In particular, a comparison between low-latitude and high-latitude wind, allowed us to provide evidence for differences in the acceleration of polar, fast plasma and equatorial, slow plasma: the latter occurring at higher levels and through a more extended region than fast wind. These properties are shared by both the proton and heavy ions outflows. Quadrature observations may provide useful information also on coronal vs. in situ elemental composition. To this end, we analyzed spectra taken in the corona, at altitudes ranging between approx. 1.02 and 2.2 solar radii, and derived the abundances of a number of ions, including oxygen and iron. Values of the O/Fe ratio, at coronal levels, have been compared with measurements of this ratio made by SWICS at interplanetary distances. Our results are compared with previous findings and predictions from modeling efforts.

UNDERFLIGHT CALIBRATION OF SOHO/CDS AND HINODE/EIS WITH EUNIS-07

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Tongjiang; Brosius, Jeffrey W.; Thomas, Roger J.

2011-12-01

Flights of Goddard Space Flight Center's Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS) sounding rocket in 2006 and 2007 provided updated radiometric calibrations for Solar and Heliospheric Observatory/Coronal Diagnostic Spectrometer (SOHO/CDS) and Hinode/Extreme Ultraviolet Imaging Spectrometer (Hinode/EIS). EUNIS carried two independent imaging spectrographs covering wavebands of 300-370 A in first order and 170-205 A in second order. After each flight, end-to-end radiometric calibrations of the rocket payload were carried out in the same facility used for pre-launch calibrations of CDS and EIS. During the 2007 flight, EUNIS, SOHO/CDS, and Hinode/EIS observed the same solar locations, allowing the EUNIS calibrations to bemore » directly applied to both CDS and EIS. The measured CDS NIS 1 line intensities calibrated with the standard (version 4) responsivities with the standard long-term corrections are found to be too low by a factor of 1.5 due to the decrease in responsivity. The EIS calibration update is performed in two ways. One uses the direct calibration transfer of the calibrated EUNIS-07 short wavelength (SW) channel. The other uses the insensitive line pairs, in which one member was observed by the EUNIS-07 long wavelength (LW) channel and the other by EIS in either the LW or SW waveband. Measurements from both methods are in good agreement, and confirm (within the measurement uncertainties) the EIS responsivity measured directly before the instrument's launch. The measurements also suggest that the EIS responsivity decreased by a factor of about 1.2 after the first year of operation (although the size of the measurement uncertainties is comparable to this decrease). The shape of the EIS SW response curve obtained by EUNIS-07 is consistent with the one measured in laboratory prior to launch. The absolute value of the quiet-Sun He II 304 A intensity measured by EUNIS-07 is consistent with the radiance measured by CDS NIS in quiet regions near

Long Term Missions at the Sun-Earth Libration Point L1: ACE, SOHO, and WIND

NASA Technical Reports Server (NTRS)

Roberts, Craig E.

2011-01-01

Three heliophysics missions -- the Advanced Composition Explorer (ACE), Solar Heliospheric Observatory (SOHO), and the Global Geoscience WIND -- have been orbiting the Sun-Earth interior libration point L1 continuously since 1997, 1996, and 2004, respectively. ACE and WIND (both NASA missions) and SOHO (an ESA-NASA joint mission) are all operated from the NASA Goddard Space Flight Center (GSFC). While ACE and SOHO have been dedicated libration point orbiters since their launches, WIND has had also a remarkable 10-year career flying a deep-space, multiple lunar-flyby trajectory prior to 2004. That era featured 36 targeted lunar flybys with excursions to both L1 and L2 before its final insertion in L1 orbit. A figure depicts the orbits of the three spacecraft, showing projections of the orbits onto the orthographic planes of a solar rotating ecliptic frame of reference. The SOHO orbit is a quasi-periodic halo orbit, where the frequencies of the in-plane and out-of-plane motions are practically equal. Such an orbit is seen to repeat itself with a period of approximately 178 days. For ACE and WIND, the frequencies of the in-plane and out-of-plane motions are unequal, giving rise to the characteristic Lissajous motion. ACE's orbit is of moderately small amplitude, whereas WIND's orbit is a large-amplitude Lissajous of dimensions close to those of the SOHO halo orbit. As motion about the collinear points is inherently unstable, stationkeeping maneuvers are necessary to prevent orbital decay and eventual escape from the L1 region. Though the three spacecraft are dissimilar (SOHO is a 3-axis stabilized Sun pointer, WIND is a spin-stabilized ecliptic pole pointer, and ACE is also spin-stabilized with its spin axis maintained between 4 and 20 degrees of the Sun), the stationkeeping technique for the three is fundamentally the same. The technique consists of correcting the energy of the orbit via a delta-V directed parallel or anti-parallel to the Spacecraft-to-Sun line. SOHO

Why a geoeffective CME was missed by SOHO LASCO?

NASA Astrophysics Data System (ADS)

Chi, Y.; Zhang, J.; Shen, C.; Hess, P.; Feng, L.; Wang, Y.; Mishra, W.

2017-12-01

During 2011 May 25, two Earth directed coronal mass ejections (CMEs) were recorded by STEREO COR2 as limb CMEs, when the separation between twin STEREO spacecraft and Earth was approximately 90°. At the same time, SOHO LASCO did not record corresponding halo or partial halo CME. These CMEs provided an opportunity to study why SOHO LASCO may miss Earth direction CME. According to GCS model, we find the two CMEs both have small half angle and aspect ratio. Most part of CMEs are behind the occulter of SOHO LASCO C2. We also estimated the two CMEs' mass and find the both CMEs' mass is small. The expected CME brightness according to the CME's mass is in the same order of the noise of SOHO LASCO. In the HI1 Fov, We have found evidence of interaction between the two CMEs. Combining with the WIND in situ observations, we find the CMEs are adjacent to each other. The duration of the two flux rope structure are 7 and 6.6 hours, respectively. This may provide an evidence that small flux structure without corresponding CME is also the solar erupted structure.

Can SOHO SWAN Detect CMEs?

NASA Astrophysics Data System (ADS)

St. Cyr, O. C.; Malayeri, M. L.; Yashiro, S.; Quemerais, E.; Bertaux, J.; Howard, R.

2003-12-01

We have investigated the possibility that the Solar Wind Anisotropies (SWAN) remote sensing instrument on SOHO may be able to detect coronal mass ejections (CMEs) in neutral Hydrogen Lyman-α emission. We have identified CMEs near the Sun in observations by the SOHO LASCO white-light coronagraphs and in extreme ultraviolet emissions using SOHO EIT. There are very few methods of tracking CMEs after they leave the coronagraph's field-of-view, so this is an important topic to study. The primary science goal of the SWAN investigation is the measurement of large-scale structures in the solar wind, and these are obtained by detecting intensity fluctuations in Lyman-α . SWAN consists of a pair of sensors on opposite panels of SOHO. The instantaneous field-of-view of each sensor unit is a 5° x 5° square, divided into 1° pixels. A gimbaled periscope system allows each sensor to map the intensity distribution of Lyman-α , and the entire sky can be scanned in less than one day. This is the typical mode of operation for this instrument (Bertaux et al., Solar Physics, 162, 403-439, 1995). Beginning in May 2002 the sky-scan mode of the SWAN detectors was interrupted, and they were held stationary for one-or-more 15-hour campaigns each week. During those campaigns the SWAN sensors were positioned above the East or West equator of the Sun at locations chosen to be as close to the Sun as possible (typically 50 solar radii from Sun-center). Based on the LASCO and EIT data, we have identified CMEs whose extrapolated height-time measurements indicated that the events would cross the SWAN field during the campaign period. During 12 months' observation, there were ˜10 CMEs that met two criteria: (1) an event low in the corona near the solar limb could be unambiguously identified in EIT; and (2) the CME could be tracked beyond 20 R⊙ in LASCO C3. We consider these CMEs to be particularly well-observed since the speed measured in LASCO could be reliably extrapolated to the SWAN

Lockheed Solar Observatory and the Discovery of Moreton-Ramsey Waves

NASA Astrophysics Data System (ADS)

Tarbell, Theodore D.

2014-06-01

Moreton Waves are high-speed disturbances seen traveling away from large solar flares in H-alpha movies of the solar chromosphere. They were discovered by the observer Harry Ramsey in the late 1950s, and then published and publicized by the director Gail Moreton, both of the Lockheed Solar Observatory in the Hollywood Hills of Southern California. These efforts established the scientific reputation and secured continuing funding of the observatory, whose present-day successor is the Lockheed Martin Solar and Astrophysics Lab in Palo Alto. Moreton waves are rare, and there was limited interest in them until the EIT instrument on SOHO began seeing large numbers of similar waves in the corona in the late 1990s. The exact relation between the two observations is still a research topic today. This talk will describe some of the history of the observatory and the discovery and early interpretation of the waves.

Earth Observatory Satellite system definition study. Report 2: Instrument constraints and interfaces

NASA Technical Reports Server (NTRS)

1974-01-01

The instrument constraints and interface specifications for the Earth Observatory Satellite (EOS) are discussed. The Land Use Classification Mission using a 7 band Thematic Mapper and a 4 band High Resolution Pointable Imager is stressed. The mission and performance of the instruments were reviewed and expanded to reflect the instrument as a part of the total remote sensing system. A preliminary EOS interface handbook is provided to describe the mission and system, to specify the spacecraft interfaces to potential instrument contractors, and to describe the instrument interface data required by the system integration contractor.

Earth Observatory Satellite system definition study. Report no. 2: Instrument constraints and interface specifications

NASA Technical Reports Server (NTRS)

1974-01-01

The instruments to be flown on the Earth Observatory Satellite (EOS) system are defined. The instruments will be used to support the Land Resources Management (LRM) mission of the EOS. Program planning information and suggested acquisition activities for obtaining the instruments are presented. The subjects considered are as follows: (1) the performance and interface of the Thematic Mapper (TM) and the High Resolution Pointing Imager (HRPI), (2) procedure for interfacing the TM and HRPI with the EOS satellite, (3) a space vehicle integration plan suggesting the steps and sequence of events required to carry out the interface activities, and (4) suggested agreements between the contractors for providing timely and equitable solution of problems at minimum cost.

Coronal Magnetography of Solar Active Regions Using Coordinated SOHO/CDS and VLA Observations

NASA Technical Reports Server (NTRS)

Brosius, Jeffrey W.

1999-01-01

The purpose of this project is to apply the coronal magnetographic technique to SOHO (Solar Heliospheric Observatory) /CDS (Coronal Diagnostic Spectrometer) EUV (Extreme Ultraviolet Radiation) and coordinated VLA microwave observations of solar active regions to derive the strength and structure of the coronal magnetic field. A CDS observing plan was developed for obtaining spectra needed to derive active region differential emission measures (DEMs) required for coronal magnetography. VLA observations were proposed and obtained. SOHO JOP 100 was developed, tested, approved, and implemented to obtain coordinated CDS (Coronal Diagnostic Spectrometer)/EIT (Ultraviolet Imaging Telescope)/ VLA (Very Large Array)/ TRACE (Transition Region and Coronal Explorer)/ SXT (Solar X Ray Telescope) observations of active regions on April 12, May 9, May 13, and May 23. Analysis of all four data sets began, with heaviest concentration on COS data. It is found that 200-pixel (14 A in NIS1) wavelength windows are appropriate for extracting broadened Gaussian line profile fit parameters for lines including Fe XIV at 334.2, Fe XVI at 335.4, Fe XVI at 360.8, and Mg IX at 368.1 over the 4 arcmin by 4 arcmin CDS field of view. Extensive efforts were focused on learning and applying were focused on learning and applying CDS software, and including it in new IDL procedures to carry out calculations relating to coronal magnetography. An important step is to extract Gaussian profile fits to all the lines needed to derive the DEM in each spatial pixel of any given active region. The standard CDS absolute intensity calibration software was applied to derived intensity images, revealing that ratios between density-insensitive lines like Fe XVI 360.8/335.4 yield good agreement with theory. However, the resulting absolute intensities of those lines are very high, indicating that revisions to the CDS absolute intensity calibrations remain to be included in the CDS software, an essential step to

Data processing system for the intensity monitoring spectrometer flown on the Orbiting Geophysical Observatory-F (OGO-F) satellite

NASA Technical Reports Server (NTRS)

Cronin, A. G.; Delaney, J. R.

1973-01-01

The system is discussed which was developed to process digitized telemetry data from the intensity monitoring spectrometer flown on the Orbiting Geophysical Observatory (OGO-F) Satellite. Functional descriptions and operating instructions are included for each program in the system.

Application of star identification using pattern matching to space ground systems at GSFC

NASA Technical Reports Server (NTRS)

Fink, D.; Shoup, D.

1994-01-01

This paper reports the application of pattern recognition techniques for star identification based on those proposed by Van Bezooijen to space ground systems for near-real-time attitude determination. A prototype was developed using these algorithms, which was used to assess the suitability of these techniques for support of the X-Ray Timing Explorer (XTE), Submillimeter Wave Astronomy Satellite (SWAS), and the Solar and Heliospheric Observatory (SOHO) missions. Experience with the prototype was used to refine specifications for the operational system. Different geometry tests appropriate to the mission requirements of XTE, SWAS, and SOHO were adopted. The applications of these techniques to upcoming mission support of XTE, SWAS, and SOHO are discussed.

Search for Best Astronomical Observatory Sites in the MENA Region using Satellite Measurements

NASA Astrophysics Data System (ADS)

Abdelaziz, G.; Guebsi, R.; Guessoum, N.; Flamant, C.

2017-06-01

We perform a systematic search for astronomical observatory sites in the MENA (Middle-East and North Africa) region using space-based data for all the relevant factors, i.e. altitude (DEM), cloud fraction (CF), light pollution (NTL), precipitable water vapor (PWV), aerosol optical depth (AOD), relative humidity (RH), wind speed (WS), Richardson Number (RN), and diurnal temperature range (DTR). We look for the best locations overall even where altitudes are low (the threshold that we normally consider being 1,500 m) or where the combination of the afore-mentioned determining factors had previously excluded all locations in a given country. In this aim, we use the rich data that Earth-observing satellites provide, e.g. the Terra and Aqua multi-national NASA research satellites, with their MODIS (Moderate Resolution Imaging Spectroradiometer) and AIRS (Atmospheric Infrared Sounder) instruments, the Defense Meteorological Satellite Program’s Operational Linescan System (DMSP-OLS), and other products from climate diagnostics archives (e.g. MERRA). We present preliminary results on the best locations for the region.

Observatory data and the Swarm mission

NASA Astrophysics Data System (ADS)

Macmillan, S.; Olsen, N.

2013-11-01

The ESA Swarm mission to identify and measure very accurately the different magnetic signals that arise in the Earth's core, mantle, crust, oceans, ionosphere and magnetosphere, which together form the magnetic field around the Earth, has increased interest in magnetic data collected on the surface of the Earth at observatories. The scientific use of Swarm data and Swarm-derived products is greatly enhanced by combination with observatory data and indices. As part of the Swarm Level-2 data activities plans are in place to distribute such ground-based data along with the Swarm data as auxiliary data products. We describe here the preparation of the data set of ground observatory hourly mean values, including procedures to check and select observatory data spanning the modern magnetic survey satellite era. We discuss other possible combined uses of satellite and observatory data, in particular those that may use higher cadence 1-second and 1-minute data from observatories.

Earth Observatory Satellite system definition study. Report 4: Low cost management approach and recommendations

NASA Technical Reports Server (NTRS)

1974-01-01

An analysis of low cost management approaches for the development of the Earth Observatory Satellite (EOS) is presented. The factors of the program which tend to increase costs are identified. The NASA/Industry interface is stressed to show how the interface can be improved to produce reduced program costs. Techniques and examples of cost reduction which can be applied to the EOS program are tabulated. Specific recommendations for actions to be taken to reduce costs in prescribed areas are submitted.

SOHO spacecraft observations interrupted

NASA Astrophysics Data System (ADS)

1998-06-01

Efforts to re-establish nominal operations did not succeed and telemetry was lost. Subsequent attempts using the full NASA Deep Space Network capabilities have so far not been successful. ESA and NASA engineers are continuing with the task of re-establishing contact with the spacecraft. The SOHO mission is a joint undertaking of ESA and NASA. The spacecraft was launched aboard an Atlas II rocket from Florida on 2 December 1995 from the Cape Canaveral Air Station. Mission operations are directed from the control center at NASA Goddard Space Flight Center in Maryland, USA. In April 1998 SOHO successfully completed its nominal two-year mission to study the Sun's atmosphere, surface and interior. Major science highlights include the detection of rivers of plasma beneath the surface of the sun; the discovery of a magnetic "carpet" on the solar surface that seems to account for a substantial part of the energy that is needed to cause the very high temperatures of the corona, the Sun's outermost layer; the first detection of flare-induced solar quakes; the discovery of more than 50 sungrazing comets; the most detailed view to date of the solar atmosphere; and spectacular images and movies of Coronal Mass Ejections, which are being used to improve the ability to forecast space weather.

Earth Observatory Satellite system definition study. Report 6: Space shuttle interfaces/utilization

NASA Technical Reports Server (NTRS)

1974-01-01

An analysis was conducted to determine the compatibility of the Earth Observatory Satellite (EOS) with the space shuttle. The mechanical interfaces and provisions required for a launch or retrieval of the EOS by the space shuttle are summarized. The space shuttle flight support equipment required for the operation is defined. Diagrams of the space shuttle in various configurations are provised to show the mission capability with the EOS. The subjects considered are as follows: (1) structural and mechanical interfaces, (2) spacecraft retention and deployment, (3) spacecraft retrieval, (4) electrical interfaces, (5) payload shuttle operations, (6) shuttle mode cost analysis, (7) shuttle orbit trades, and (8) safety considerations.

Orbit/launch vehicle tradeoff studies. Earth Observatory Satellite system definition study (EOS)

NASA Technical Reports Server (NTRS)

1974-01-01

An evaluation of the Earth Observatory Satellite (EOS) design, performance, and cost factors which affect the choices of an orbit and a launch vehicle is presented. Primary emphasis is given to low altitude (300 to 900 nautical miles) land resources management applications for which payload design factors are defined. The subjects considered are: (1) a mission model, (2) orbit analysis and characterization, (3) characteristics and capabilities of candidate conventional launch vehicles, and space shuttle support. Recommendations are submitted for the EOS-A mission, the Single Multispectral Scanner payload, the Single Multispectral Scanner plus Thematic Mapper payload, the Dual Multispectral Scanner payload, and the Dual Multispectral Scanner plus Thematic Mapper payload.

Earth Observatory Satellite system definition study. Report 3: Design cost trade-off studies and recommendations

NASA Technical Reports Server (NTRS)

1974-01-01

An analysis of the design and cost tradeoff aspects of the Earth Observatory Satellite (EOS) development is presented. The design/cost factors that affect a series of mission/system level concepts are discussed. The subjects considered are as follows: (1) spacecraft subsystem cost tradeoffs, (2) ground system cost tradeoffs, and (3) program cost summary. Tables of data are provided to summarize the results of the analyses. Illustrations of the various spacecraft configurations are included.

End of Life Disposal for Three Libration Point Missions through Manipulation of the Jacobi Constant and Zero Velocity Curves

NASA Technical Reports Server (NTRS)

Petersen, Jeremy; Brown, Jonathan

2015-01-01

Flight Dynamics Facility (FDF) located at NASA Goddard Space Flight Center (GSFC) provides the flight dynamics expertise for three Sun-Earth Moon L1 missions. Advanced Composition Explorer (ACE) launched August 1997 Solar and Heliospheric Observatory (SOHO) launched December 1995 Global Geospace Science WIND satellite launched November 1994 entered Lagrange point orbit in 2004.

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 2: EOS-A system specification

NASA Technical Reports Server (NTRS)

1974-01-01

The objectives of the Earth Observatory Satellite (EOS) program are defined. The system specifications for the satellite payload are examined. The broad objectives of the EOS-A program are as follows: (1) to develop space-borne sensors for the measurement of land resources, (2) to evolve spacecraft systems and subsystems which will permit earth observation with greater accuracy, coverage, spatial resolution, and continuity than existing systems, (3) to develop improved information processing, extraction, display, and distribution systems, and (4) to use space transportation systems for resupply and retrieval of the EOS.

Design/cost tradeoff studies. Appendix A. Supporting analyses and tradeoffs, book 1. Earth Observatory Satellite system definition study (EOS)

NASA Technical Reports Server (NTRS)

1974-01-01

A listing of the Earth Observatory Satellite (EOS) candidate missions is presented for use as a baseline in describing the EOS payloads. The missions are identified in terms of first, second, and third generation payloads. The specific applications of the EOS satellites are defined. The subjects considered are: (1) orbit analysis, (2) space shuttle interfaces, (3) thematic mapping subsystem, (4) high resolution pointable imager subsystem, (5) the data collection system, (6) the synthetic aperture radar, (7) the passive multichannel microwave radiometer, and (8) the wideband communications and handling equipment. Illustrations of the satellite and launch vehicle configurations are provided. Block diagrams of the electronic circuits are included.

Observation of galactic cosmic ray spallation events from the SoHO mission 20-yr operation of LASCO

NASA Astrophysics Data System (ADS)

Koutchmy, S.; Tavabi, E.; Urtado, O.

2018-07-01

A shower of secondary cosmic ray (CR) particles is produced at high altitudes in the Earth's atmosphere, so the primordial galactic cosmic rays (GCRs) are never directly measured outside the Earth magnetosphere and atmosphere. They approach the Earth and other planets in the complex pattern of rigidity's dependence, generally excluded by the magnetosphere. GCRs revealed by images of single nuclear reactions also called spallation events are described here. Such an event was seen on 2015 November 29 using a unique Large Angle and Spectrometric Coronagraphs C3 space coronagraph routine image taken during the Solar and Heliospheric Observatory (SoHO) mission observing uninterruptedly at the Lagrangian L1 point. The spallation signature of a GCR identified well outside the Earth's magnetosphere is obtained for the first time. The resulting image includes different diverging linear `tracks' of varying intensity, leading to a single pixel; this frame identifies the site on the silicon CCD chip of the coronagraph camera. There was no solar flare reported at that time, nor coronal mass ejection and no evidence of optical debris around the spacecraft. More examples of smaller CR events have been discovered through the 20 yr of continuous observations from SoHO. This is the first spallation event from a CR, recorded outside the Earth's magnetosphere. We evaluate the probable energy of these events suggesting a plausible galactic source.

Observation of galactic cosmic ray spallation events from the SoHO mission 20-Year operation of LASCO

NASA Astrophysics Data System (ADS)

Koutchmy, S.; Tavabi, E.; Urtado, O.

2018-05-01

A shower of secondary Cosmic Ray (CR) particles is produced at high altitudes in the Earth's atmosphere, so the primordial Galactic Cosmic Rays (GCRs) are never directly measured outside the Earth magnetosphere and atmosphere. They approach the Earth and other planets in the complex pattern of rigidity's dependence, generally excluded by the magnetosphere. GCRs revealed by images of single nuclear reactions also called spallation events are described here. Such an event was seen on Nov. 29, 2015 using a unique LASCO C3 space coronagraph routine image taken during the Solar and Heliospheric Observatory (SoHO) mission observing uninterruptedly at the Lagrangian L1 point. The spallation signature of a GCR identified well outside the Earth's magnetosphere is obtained for the 1st time. The resulting image includes different diverging linear "tracks" of varying intensity, leading to a single pixel; this frame identifies the site on the silicon CCD chip of the coronagraph camera. There was no solar flare reported at that time, nor Coronal Mass Ejection (CME) and no evidence of optical debris around the spacecraft. More examples of smaller CR events have been discovered through the 20 years of continuous observations from SoHO. This is the first spallation event from a CR, recorded outside the Earth's magnetosphere. We evaluate the probable energy of these events suggesting a plausible galactic source.

Earth Observatory Satellite system definition study. Report 7: EOS system definition report

NASA Technical Reports Server (NTRS)

1974-01-01

The Earth Observatory Satellite (EOS) study is summarized to show the modular design of a general purpose spacecraft, a mission peculiar segment which performs the EOS-A mission, an Operations Control Center, a Data Processing Facility, and a design for Low Cost Readout Stations. The study verified the practicality and feasibility of the modularized spacecraft with the capability of supporting many missions in the Earth Observation spectrum. The various subjects considered in the summary are: (1) orbit/launch vehicle tradeoff studies and recommendations, (2) instrument constraints and interfaces, (3) design/cost tradeoff and recommendations, (4) low cost management approach and recommendations, (5) baseline system description and specifications, and (6) space shuttle utilization and interfaces.

Notes on Soho and a Reminiscence.

ERIC Educational Resources Information Center

Melton, Hollis

1992-01-01

Discusses George Maciunas' pivotal contributions to the renaissance of SoHo, the New York City community south of Houston Street. Recounts the establishment of Fluxus cooperatives, the history of the FilmMakers' Cinematheque, Maciunas' long struggle with the Attorney General's office, and closes with a description of the February 1978 erotic Flux…

Opportunities for Coordinated Observations of CO2 with the Orbiting Carbon Observatory (OCO) and Greenhouse Gases Observing Satellite (GOSAT)

NASA Technical Reports Server (NTRS)

Crisp, David

2008-01-01

The Orbiting Carbon Observatory (OCO) and the Greenhouse Gases Observing Satellite (GOSAT) are the first two satellites designed to make global measurements of atmospheric carbon dioxide (CO2) with the precision and sampling needed identify and monitor surface sources and sinks of this important greenhouse gas. Because the operational phases of the OCO and GOSAT missions overlap in time, there are numerous opportunities for comparing and combining the data from these two satellites to improve our understanding of the natural processes and human activities that control the atmospheric CO2 and it variability over time. Opportunities for cross-calibration, cross-validation, and coordinated observations that are currently under consideration are summarized here.

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 3: General purpose spacecraft segment and module specifications

NASA Technical Reports Server (NTRS)

1974-01-01

The specifications for the Earth Observatory Satellite (EOS) general purpose aircraft segment are presented. The satellite is designed to provide attitude stabilization, electrical power, and a communications data handling subsystem which can support various mission peculiar subsystems. The various specifications considered include the following: (1) structures subsystem, (2) thermal control subsystem, (3) communications and data handling subsystem module, (4) attitude control subsystem module, (5) power subsystem module, and (6) electrical integration subsystem.

The SOHO-Stellar Connection

NASA Technical Reports Server (NTRS)

Ayres, Thomas R.

1999-01-01

I discusses practical aspects of the so-called "solar-stellar" connection; namely, the fundamental principles, the tools at the disposal of the stellar astronomer, and a few recent examples of the connection in action. I provide an overall evolutionary context for coronal activity, calling attention to the very different circumstances of low mass main sequence stars like the Sun, which are active mainly early in their lives; compared with more massive stars, whose coronally active phase occurs near the end of their lives, during their brief incursion into the cool half of the Hertzsprung-Russell diagram as yellow and then red giants. On the instrumental slide, I concentrate primarily on spectroscopy, in the ultraviolet and X-ray bands where coronae leave their most obvious signatures. I present an early glimpse of the type of moderate resolution spectra we can expect from the recently launched Chandra observatory, and contemporaneous HST STIS high-resolution UV measurements of the CXO calibration star Capella (alpha Aur; G8 III + G1 III). I compare STIS spectra of solar-type dwarfs-zeta Dor (F7 V), an active coronal source; and alpha Cen A (G2 V), a near twin of the Sun-to a trace obtained with the SOHO SUMER imaging UV spectrometer. I also compare STIS line profiles of the active coronal dwarf to the corresponding features in the mixed-activity "hybrid-chromosphere" bright giant alpha TrA (K2 II) and the archetype "noncoronal" red giant Arcturus (alpha Boo; K2 III). The latter shows dramatic evidence for a "cool absorber" in its outer atmosphere that is extinguishing the "hot lines" (like Si IV lambda1393 and N V lambda1238) below about 1500 A, probably through absorption in the Si I lambda1525 and C I lambda1240 photoionization continua. The disappearance of coronae across the "Linsky-Haisch" dividing line near K1 III thus apparently is promoted by a dramatic overturning in the outer atmospheric structure, namely the coronae of the red giants seem to lie beneath

SOHO Observations of a Coronal Mass Ejection

NASA Astrophysics Data System (ADS)

Akmal, Arya; Raymond, John C.; Vourlidas, Angelos; Thompson, Barbara; Ciaravella, A.; Ko, Y.-K.; Uzzo, M.; Wu, R.

2001-06-01

We describe a coronal mass ejection (CME) observed on 1999 April 23 by the Ultraviolet Coronagraph Spectrometer (UVCS), the Extreme-Ultraviolet Imaging Telescope (EIT), and the Large-Angle and Spectrometric Coronagraphs (LASCO) aboard the Solar and Heliospheric Observatory (SOHO). In addition to the O VI and C III lines typical of UVCS spectra of CMEs, this 480 km s-1 CME exhibits the forbidden and intercombination lines of O V at λλ1213.8 and 1218.4. The relative intensities of the O V lines represent an accurate electron density diagnostic not generally available at 3.5 Rsolar. By combining the density with the column density derived from LASCO, we obtain the emission measure of the ejected gas. With the help of models of the temperature and time-dependent ionization state of the expanding gas, we determine a range of heating rates required to account for the UV emission lines. The total thermal energy deposited as the gas travels to 3.5 Rsolar is comparable to the kinetic and gravitational potential energies. We note a core of colder material radiating in C III, surrounded by hotter material radiating in the O V and O VI lines. This concentration of the coolest material into small regions may be a common feature of CMEs. This event thus represents a unique opportunity to describe the morphology of a CME, and to characterize its plasma parameters.

Determining coronal electron temperatures from observations with UVCS/SOHO

NASA Technical Reports Server (NTRS)

Fineschi, S.; Esser, R.; Habbal, S. R.; Karovska, M.; Romoli, M.; Strachan, L.; Kohl, J. L.; Huber, M. C. E.

1995-01-01

The electron temperature is a fundamental physical parameter of the coronal plasma. Currently, there are no direct measurements of this quantity in the extended corona. Observations with the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the upcoming Solar and Heliospheric Observatory (SOHO) mission can provide the most direct determination of the electron kinetic temperature (or, more precisely, the electron velocity distribution along the line of sight). This measurement is based on the observation of the Thomson-scattered Lyman alpha (Ly-alpha) profile. This observation is made particularly challenging by the fact that the integrated intensity of the electron-scattered Ly-alpha line is about 10(exp 3) times fainter than that of the resonantly-scattered Ly-alpha component. In addition, the former is distributed across 50 A (FWHM), unlike the latter that is concentrated in 1 A. These facts impose stringent requirements on the stray-light rejection properties of the coronagraph/spectrometer, and in particular on the requirements for the grating. We make use of laboratory measurements of the UVCS Ly-alpha grating stray-light, and of simulated electron-scattered Ly-alpha profiles to estimate the expected confidence levels of electron temperature determination. Models of different structures typical of the corona (e.g., streamers, coronal holes) are used for this parameter study.

Solar and Galactic Cosmic Rays Observed by SOHO

NASA Astrophysics Data System (ADS)

Fleck, Bernhard; Curdt, Werner; Olive, Jean-Philippe; van Overbeek, Ton

2015-04-01

Both the Cosmic Ray Flux (CRF) and Solar Energetic Particles (SEPs) have left an imprint on SOHO technical systems. While the solar array efficiency degraded irreversibly down to 75% of its original level over 1 ½ solar cycles, Single Event Upsets (SEUs) in the solid state recorder (SSR) have been reversed by the memory protection mechanism. We compare the daily CRF observed by the Oulu station with the daily SOHO SEU rate and with the degradation curve of the solar arrays. The Oulu CRF and the SOHO SSR SEU rate are both modulated by the solar cycle and are highly correlated, except for sharp spikes in the SEU rate, caused by isolated SEP events, which also show up as discontinuities in the otherwise slowly decreasing solar ray efficiency. This allows to discriminate between effects with solar and non-solar origin and to compare the relative strength of both. We find that the total number of SSR SEUs with solar origin over the 17 ½ years from January 1996 through June 2013 is of the same order as those generated by cosmic ray hits. 49% of the total solar array degradation during that time can be attributed to proton events, i.e. the effect of a series of short-lived, violent events (SEPs) is comparable to the cycle-integrated damage by cosmic rays.

Solar mystery nears solution with data from SOHO spacecraft

NASA Astrophysics Data System (ADS)

1997-11-01

observations with SOHO's Michelson Doppler Imager (MDI) provided long-duration, highly detailed, and well calibrated time-lapse movies of the magnetic fields on the visible surface or "photosphere" of the Sun. These revealed the rapidly changing properties of what Title calls "the Sun's Magnetic Carpet" a sprinkling of tens-of-thousands of magnetic concentrations; These concentrations have both north and south magnetic poles, which are the "foot points" of magnetic loops extending into the solar corona. Like field biologists who study the populations and life cycles of animal herds, the SOHO researchers analysed the appearances and disappearances of large numbers of the small magnetic concentrations on the solar surface. "We find that after a typical small magnetic loop emerges, it fragments and drifts around and then disappears in only 40 hours" Title said. "It's very hard to understand how such a short-lived effect could be driven by the magnetic dynamo layer that is over 150,000 km beneath the surface of the Sun. This may be evidence that unknown processes are at work in or near the solar surface that continuously form these loops all over the Sun". Professor Phillip Scherrer of Stanford University is the MDI Principal Investigator. MDI was built at the LM Technology Center and is a project of the Stanford-Lockheed Institute for Space Research. The EIT and CDS instruments were built by international consortia under the leadership of, respectively, Dr. Richard A. Harrison of Rutherford-Appleton Laboratory near Oxford (UK) and Dr. Jean-Pierre Delaboudini[re of the Institut d'Astrophysique spatiale in Orsay (F). The new observations were made with these three instruments on SOHO, a spacecraft stationed 1,5 million Kilometres sunward of the Earth in interplanetary space, where it has an uninterrupted view of the Sun and of the solar wind particles blown from the Sun. The SOHO satellite developed by ESA and built by European industry is operated from a control center at NASA

Design/cost tradeoff studies. Appendix A. Supporting analyses and tradeoffs, book 2. Earth Observatory Satellite system definition study (EOS)

NASA Technical Reports Server (NTRS)

1974-01-01

Attitude reference systems for use with the Earth Observatory Satellite (EOS) are described. The systems considered are fixed and gimbaled star trackers, star mappers, and digital sun sensors. Covariance analyses were performed to determine performance for the most promising candidate in low altitude and synchronous orbits. The performance of attitude estimators that employ gyroscopes which are periodically updated by a star sensor is established by a single axis covariance analysis. The other systems considered are: (1) the propulsion system design, (2) electric power and electrical integration, (3) thermal control, (4) ground data processing, and (5) the test plan and cost reduction aspects of observatory integration and test.

Inter-Comparison between July 24, 2014 EUV Data from NASA Sounding Rocket 36.289 and Concurrent Measurements from Orbital Solar Observatories

NASA Astrophysics Data System (ADS)

Didkovsky, L. V.; Wieman, S. R.; Judge, D. L.

2014-12-01

Sounding rocket mission NASA 36.289 Didkovsky provided solar EUV irradiance measurements from four instruments built at the USC Space Sciences Center: the Rare Gas Ionization Cell (RGIC), the Solar Extreme ultraviolet Monitor (SEM), the Dual Grating Spectrometer (DGS), and the Optics-Free Spectrometer (OFS), thus meeting the mission comprehensive success criteria. These sounding rocket data allow us to inter-compare the observed absolute EUV irradiance with the data taken at the same time from the SOHO and SDO solar observatories. The sounding rocket data from the two degradation-free instruments (DGS and OFS) can be used to verify the degradation rates of SOHO and SDO EUV channels and serve as a flight-proven prototypes for future improvements of degradation-free instrumentation for solar physics.

Real-Time Visualization Tool Integrating STEREO, ACE, SOHO and the SDO

NASA Astrophysics Data System (ADS)

Schroeder, P. C.; Luhmann, J. G.; Marchant, W.

2011-12-01

The STEREO/IMPACT team has developed a new web-based visualization tool for near real-time data from the STEREO instruments, ACE and SOHO as well as relevant models of solar activity. This site integrates images, solar energetic particle, solar wind plasma and magnetic field measurements in an intuitive way using near real-time products from NOAA and other sources to give an overview of recent space weather events. This site enhances the browse tools already available at UC Berkeley, UCLA and Caltech which allow users to visualize similar data from the start of the STEREO mission. Our new near real-time tool utilizes publicly available real-time data products from a number of missions and instruments, including SOHO LASCO C2 images from the SOHO team's NASA site, SDO AIA images from the SDO team's NASA site, STEREO IMPACT SEP data plots and ACE EPAM data plots from the NOAA Space Weather Prediction Center and STEREO spacecraft positions from the STEREO Science Center.

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 5: Specification for EROS operations control center

NASA Technical Reports Server (NTRS)

1974-01-01

The functional, performance, and design requirements for the Operations Control Center (OCC) of the Earth Observatory Satellite (EOS) system are presented. The OCC controls the operations of the EOS satellite to acquire mission data consisting of: (1) thematic mapper data, (2) multispectral scanner data on EOS-A, or High Resolution Pointable Imager data on EOS-B, and (3) data collection system (DCS) data. The various inputs to the OCC are identified. The functional requirements of the OCC are defined. The specific systems and subsystems of the OCC are described and block diagrams are provided.

Cosmic Rays Variation Before Changes in Sun-Earth Environment

NASA Astrophysics Data System (ADS)

Mukherjee, S.

2011-12-01

Influence of cosmic rays variations on the Sun-Earth Environment has been observed before the changes in the atmospheric temperature, outbreak of influenza, cyclone, earthquake and tsunami. It has been recorded by Sun Observatory Heleospheric Observatory (SOHO) satellite data. Before the earthquake and tsunami the planetary indices (Kp) and Electron flux (E-flux) shows sudden changes followed by the atmospheric perturbations including very high temperature rise to sudden fall resulting snowfall in high altitude and rainfall in tropical areas. The active fault zones shows sudden faulting after the sudden drop in cosmic ray intensity and rise in Kp and E-flux. Besides the geo-environment the extraterrestrial influence on outbreak of H1N1 influenza has also been recorded based on the Mexico Cosmic ray data and its correlation with SOHO records. Distant stars have the potential to influence the heliophysical parameters by showering cosmic rays.

Using a Java Web-based Graphical User Interface to access the SOHO Data Arch ive

NASA Astrophysics Data System (ADS)

Scholl, I.; Girard, Y.; Bykowski, A.

This paper presents the architecture of a Java web-based graphical interface dedicated to the access of the SOHO Data archive. This application allows local and remote users to search in the SOHO data catalog and retrieve the SOHO data files from the archive. It has been developed at MEDOC (Multi-Experiment Data and Operations Centre), located at the Institut d'Astrophysique Spatiale (Orsay, France), which is one of the European Archives for the SOHO data. This development is part of a joint effort between ESA, NASA and IAS in order to implement long term archive systems for the SOHO data. The software architecture is built as a client-server application using Java language and SQL above a set of components such as an HTTP server, a JDBC gateway, a RDBMS server, a data server and a Web browser. Since HTML pages and CGI scripts are not powerful enough to allow user interaction during a multi-instrument catalog search, this type of requirement enforces the choice of Java as the main language. We also discuss performance issues, security problems and portability on different Web browsers and operating syste ms.

Earth Observatory Satellite system definition study. Report no. 5: System design and specifications. Part 2: Ground system element specifications

NASA Technical Reports Server (NTRS)

1974-01-01

The Ground System requirements for the Land Resources Management (LRM) type-A and type-B missions of the Earth Observatory Satellite (EOS) program are presented. Specifications for the Thematic Mapper data processing are provided (LRM A mission). The specifications also cover the R and D instruments (Thematic Mapper and High Resolution Pointable Imager) data processing for the LRM type-B mission.

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 4: Mission peculiar spacecraft segment and module specifications

NASA Technical Reports Server (NTRS)

1974-01-01

The specifications for the Earth Observatory Satellite (EOS) peculiar spacecraft segment and associated subsystems and modules are presented. The specifications considered include the following: (1) wideband communications subsystem module, (2) mission peculiar software, (3) hydrazine propulsion subsystem module, (4) solar array assembly, and (5) the scanning spectral radiometer.

Interacting Coronae of Two T Tauri Stars: First Observational Evidence for Solar-Like Helmet Streamers

DTIC Science & Technology

2008-01-01

for the first time in stars other than the Sun. The complete extent of each helmet streamer above the stellar surface is about 24 R∗ which implies...is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and...Heliospheric Observatory (SOHO) satellite (Schwenn 2006; Suess & Nerney 2004; Vourlidas 2006). Following the analogy with the Sun, Massi & collaborators

Remote observatory access via the Advanced Communications Technology Satellite

NASA Technical Reports Server (NTRS)

Horan, Stephen; Anderson, Kurt; Georghiou, Georghios

1992-01-01

An investigation of the potential for using the ACTS to provide the data distribution network for a distributed set of users of an astronomical observatory has been conducted. The investigation consisted of gathering the data and interface standards for the ACTS network and the observatory instrumentation and telecommunications devices. A simulation based on COMNET was then developed to test data transport configurations for real-time suitability. The investigation showed that the ACTS network should support the real-time requirements and allow for growth in the observatory needs for data transport.

The sunspot databases of the Debrecen Observatory

NASA Astrophysics Data System (ADS)

Baranyi, Tünde; Gyori, Lajos; Ludmány, András

2015-08-01

We present the sunspot data bases and online tools available in the Debrecen Heliophysical Observatory: the DPD (Debrecen Photoheliographic Data, 1974 -), the SDD (SOHO/MDI-Debrecen Data, 1996-2010), the HMIDD (SDO/HMI-Debrecen Data, HMIDD, 2010-), the revised version of Greenwich Photoheliographic Data (GPR, 1874-1976) presented together with the Hungarian Historical Solar Drawings (HHSD, 1872-1919). These are the most detailed and reliable documentations of the sunspot activity in the relevant time intervals. They are very useful for studying sunspot group evolution on various time scales from hours to weeks. Time-dependent differences between the available long-term sunspot databases are investigated and cross-calibration factors are determined between them. This work has received funding from the European Community's Seventh Framework Programme (FP7/2012-2015) under grant agreement No. 284461 (eHEROES).

Time-Series Analyses of Supergranule Characteristics Compared Between SDO/HMI, SOHO/MDI and Simulated Datasets

NASA Technical Reports Server (NTRS)

Williams, Peter E.; Pesnell, William Dean

2012-01-01

Supergranulation is a well-observed solar phenomenon despite its underlying mechanisms remaining a mystery. Originally considered to arise due to convective motions, alternative mechanisms have been suggested such as the cumulative downdrafts of granules as well as displaying wave-like properties. Supergranule characteristics are well documented, however. Supergranule cells are approximately 35 Mm across, have lifetimes on the order of a day and have divergent horizontal velocities of around 300 mis, a factor of 10 higher than their central radial components. While they have been observed using Doppler methods for more than half a century, their existence is also observed in other datasets such as magneto grams and Ca II K images. These datasets clearly show the influence of supergranulation on solar magnetism and how the local field is organized by the flows of supergranule cells. The Heliospheric and Magnetic Imager (HMI) aboard the Solar Dynamics Observatory (SDO) continues to produce Doppler images enabling the continuation of supergranulation studies made with SOHO/MDI, but with superior temporal and spatial resolution. The size-distribution of divergent cellular flows observed on the photosphere now reaches down to granular scales, allowing contemporaneous comparisons between the two flow components. SOHO/MDI Doppler observations made during the minima of cycles 22/23 and 23/24 exhibit fluctuations of supergranule characteristics (global averages of the supergranule size, size-range and horizontal velocity) with periods of 3-5 days. Similar fluctuations have been observed in SDO/HMI Dopplergrams and the high correlation between co-temporal HMI & MOl suggest a solar origin. Their nature has been probed by invoking data simulations that produce realistic Dopplergrams based on MOl data.

Fluxes of MeV particles at Earth's orbit and their relationship with the global structure of the solar corona: Observations from SOHO

NASA Technical Reports Server (NTRS)

Posner, A.; Bothmer, V.; Kunow, H.; Heber, B.; Mueller-Mellin, R.; Delaboudiniere, J.-P.; Thompson, B. J.; Brueckner, G. E.; Howard, R. A.; Michels, D. J.

1997-01-01

The SOHO satellite, launched on 2 December 1995, combines a unique set of instruments which allow comparative studies of the interior of the sun, the outer corona and solar to be carried out. In its halo orbit around the L1 Lagrangian point of the sun-earth system, SOHO's comprehensive suprathermal and energetic particle analyzer (COSTEP) measures in situ energetic particles in the energy range of 44 keV/particle to greater than 53 MeV/n. The MeV proton, electron and helium nuclei measurements from the COSTEP electron proton helium instrument (EPHIN) were used to investigate the relationships of intensity increases of these particle species with the large-scale structures of the solar corona and heliosphere, including temporal variations. Coronal observatons are provided by the large angle spectroscopic coronagraph (LASCO) and the extreme ultraviolet imaging telescope (EIT). It was found that during times of minimum solar activity, intensity increases of the particles have two well defined sources: corotating interaction regions (CIRs) in the heliosphere related to coronal holes at the sun and coronal mass ejections.

MODIS Measures Fraction of Sunlight Absorbed by Plants

NASA Technical Reports Server (NTRS)

2002-01-01

At the height of the solar cycle, the Sun is finally displaying some fireworks. This image from the Solar and Heliospheric Observatory (SOHO) shows a large solar flare from June 6, 2000 at 1424 Universal Time (10:24 AM Eastern Daylight Savings Time). Associated with the flare was a coronal mass ejection that sent a wave of fast moving charged particles straight towards Earth. (The image was acquired by the Extreme ultaviolet Imaging Telescope (EIT), one of 12 instruments aboard SOHO) Solar activity affects the Earth in several ways. The particles generated by flares can disrupt satellite communications and interfere with power transmission on the Earth's surface. Earth's climate is tied to the total energy emitted by the sun, cooling when the sun radiates less energy and warming when solar output increases. Solar radiation also produces ozone in the stratosphere, so total ozone levels tend to increase during the solar maximum. For more information about these solar flares and the SOHO mission, see NASA Science News or the SOHO home page. For more about the links between the sun and climate change, see Sunspots and the Solar Max. Image courtesy SOHO Extreme ultaviolet Imaging Telescope, ESA/NASA

Solar Flare Aimed at Earth

NASA Technical Reports Server (NTRS)

2002-01-01

At the height of the solar cycle, the Sun is finally displaying some fireworks. This image from the Solar and Heliospheric Observatory (SOHO) shows a large solar flare from June 6, 2000 at 1424 Universal Time (10:24 AM Eastern Daylight Savings Time). Associated with the flare was a coronal mass ejection that sent a wave of fast moving charged particles straight towards Earth. (The image was acquired by the Extreme ultaviolet Imaging Telescope (EIT), one of 12 instruments aboard SOHO) Solar activity affects the Earth in several ways. The particles generated by flares can disrupt satellite communications and interfere with power transmission on the Earth's surface. Earth's climate is tied to the total energy emitted by the sun, cooling when the sun radiates less energy and warming when solar output increases. Solar radiation also produces ozone in the stratosphere, so total ozone levels tend to increase during the solar maximum. For more information about these solar flares and the SOHO mission, see NASA Science News or the SOHO home page. For more about the links between the sun and climate change, see Sunspots and the Solar Max. Image courtesy SOHO Extreme ultaviolet Imaging Telescope, ESA/NASA

Effort to recover SOHO spacecraft continue as investigation board focuses on most likely causes

NASA Astrophysics Data System (ADS)

1998-07-01

in its orbit around the Sun, the orientation of the panels with respect to the Sun should gradually change. The orbit of the spacecraft and the seasonal change in the spacecraft-Sun alignment should result in the increased solar illumination of the spacecraft solar arrays over the next few months. The engineers predict that in late September 1998, illumination of the solar arrays and, consequently, power supplied to the spacecraft, should approach a maximum. The probability of successfully establishing contact reaches a maximum at this point. After this time, illumination of the solar arrays gradually diminishes as the spacecraft-Sun alignment continues to change. In an attempt to recover SOHO as soon as possible, the Flight Operations Team is uplinking commands to the spacecraft via NASA's Deep Space Network, managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, approximately 12 hours per day with no success to date. A recovery plan is under development by ESA and NASA to provide for orderly restart of the spacecraft and to mitigate risks involved. The recovery of the Olympus spacecraft by ESA in 1991 under similar conditions leads to optimism that the SOHO spacecraft may be recoverable once contact is re-established. In May 1991, ESA's Olympus telecommunications satellite experienced a similar major anomaly which resulted in the loss of attitude, leading to intermittent power availability. As a consequence, there was inadequate communication, and the batteries and fuel froze. From analysis of the data available prior to the loss, there was confidence that the power situation would improve over the coming months. A recovery plan was prepared, supported by laboratory tests, to assess the characteristics of thawing batteries and propellants. Telecommand access of Olympus was regained four weeks later, and batteries and propellant tanks were thawed out progressively over the next four weeks. The attitude was then fully recovered and the payload switched back on

Design of a Lunar Farside Observatory

NASA Technical Reports Server (NTRS)

1989-01-01

The design of a mantendable lunar farside observatory and science base is presented. A farside observatory will allow high accuracy astronomical observations, as well as the opportunity to perform geological and low gravity studies on the Moon. The requirements of the observatory and its support facilities are determined, and a preliminary timeline for the project development is presented. The primary areas of investigation include observatory equipment, communications, habitation, and surface operations. Each area was investigated to determine the available options, and each option was evaluated to determine the advantages and disadvantages. The options selected for incorporation into the design of the farside base are presented. The observatory equipment deemed most suitable for placement on the lunar farside consist of large optical and radio arrays and seismic equipment. A communications system consisting of a temporary satellite about the L sub 2 libration point and followed by a satellite at the stable L sub 5 libration point was selected. A space station common module was found to be the most practical option for housing the astronauts at the base. Finally, a support system based upon robotic construction vehicles and the use of lunar materials was determined to be a necessary component of the base.

The role of geomagnetic observatory data during the Swarm mission

NASA Astrophysics Data System (ADS)

Ridley, Victoria; Macmillan, Susan; Beggan, Ciaran

2014-05-01

The scientific use of Swarm magnetic data and Swarm-derived products is greatly enhanced through combination with observatory data and indices. The strength of observatory data is their long-term accuracy, with great care being taken to ensure temperature control and correction, platform stability and magnetic cleanliness at each site. Observatory data are being distributed with Swarm data as an auxiliary product. We describe the preparation of the data set of ground observatory hourly mean values, including procedures to check and select observatory data spanning the modern magnetic survey satellite era. Existing collaborations, such as INTERMAGNET and the World Data Centres for Geomagnetism, are proving invaluable for this. We also discuss how observatory measurements are being used to ground-truth Swarm data as part of the Calibration/Validation effort. Recent efforts to improve the coverage and timeliness of observatory data have been encouraged and now over 60 INTERMAGNET observatories and several other high-quality observatories are providing close-to-definitive data within 3 months of measurement. During the Calibration/Validation period these data are gathered and homogenised on a regular basis by BGS. We then identify measurements collected during overhead passes of the Swarm satellites. For each pass, we remove an estimate of the main field from both the data collected at altitude and that collected on the ground. Both sets of data are then normalised relative to the data variance during all passes in the Calibration/Validation period. The absolute differences of the two sets of normalised data can be used as a metric of satellite data quality relative to observatory data quality. This can be examined by universal time, local time, disturbance level and geomagnetic latitude, for example. A preliminary study of CHAMP data, using definitive minute mean observatory data, has shown how this approach can provide a baseline for detecting abnormalities at all

Solar and Galactic Cosmic Rays Observed by SOHO

NASA Astrophysics Data System (ADS)

Curdt, W.; Fleck, B.

Both the Cosmic Ray Flux (CRF) and Solar Energetic Particles (SEPs) have left an imprint on SOHO technical systems. While the solar array efficiency degraded irreversibly down to ≈77% of its original level over roughly 1 1/2 solar cycles, Single Event Upsets (SEUs) in the solid state recorder (SSR) have been reversed by the memory protection mechanism. We compare the daily CRF observed by the Oulu station with the daily SOHO SEU rate and with the degradation curve of the solar arrays. The Oulu CRF and the SOHO SSR SEU rate are both modulated by the solar cycle and are highly correlated, except for sharp spikes in the SEU rate, caused by isolated SEP events, which also show up as discontinuities in the otherwise slowly decreasing solar ray efficiency. This allows to discriminate between effects with solar and non-solar origin and to compare the relative strength of both. We find that during solar cycle 23 (1996 Apr 1 -- 2008 Aug 31) only 6% of the total number of SSR SEUs were caused by SEPs; the remaining 94% were due to galactic cosmic rays. During the maximum period of cycle 23 (2000 Jan 1 -- 2003 Dec 31), the SEP contribution increased to 22%, and during 2001, the year with the highest SEP rate, to 30%. About 40% of the total solar array degradation during the 17 years from Jan 1996 through Feb 2013 can be attributed to proton events, i.e. the effect of a series of short-lived, violent SEP events is comparable to the cycle-integrated damage by cosmic rays.

Water production activity of nine long-period comets from SOHO/SWAN observations of hydrogen Lyman-alpha: 2013-2016

NASA Astrophysics Data System (ADS)

Combi, M. R.; Mäkinen, T. T.; Bertaux, J.-L.; Quémerais, E.; Ferron, S.; Avery, M.; Wright, C.

2018-01-01

Nine recently discovered long-period comets were observed by the Solar Wind Anisotropies (SWAN) Lyman-alpha all-sky camera on board the Solar and Heliosphere Observatory (SOHO) satellite during the period of 2013 to 2016. These were C/2012 K1 (PanSTARRS), C/2013 US10 (Catalina), C/2013 V5 (Oukaimeden), C/2013 R1 (Lovejoy), C/2014 E2 (Jacques), C/2014 Q2 (Lovejoy), C/2015 G2 (MASTER), C/2014 Q1 (PanSTARRS) and C/2013 XI (PanSTARRS). Of these 9 comets 6 were long-period comets and 3 were possibly dynamically new. Water production rates were calculated from each of the 885 images using our standard time-resolved model that accounts for the whole water photodissociation chain, exothermic velocities and collisional escape of H atoms. For most of these comets there were enough observations over a broad enough range of heliocentric distances to calculate power-law fits to the variation of production rate with heliocentric distances for pre- and post-perihelion portions of the orbits. Comet C/2014 Q1 (PanSTARRS), with a perihelion distance of only ∼0.3 AU, showed the most unusual variation of water production rate with heliocentric distance and the resulting active area variation, indicating that when the comet was within 0.7 AU its activity was dominated by the continuous release of icy grains and chunks, greatly increasing the active sublimation area by more than a factor of 10 beyond what it had at larger heliocentric distances. A possible interpretation suggests that a large fraction of the comet's mass was lost during the apparition.

High Energy Astronomy Observatory

NASA Technical Reports Server (NTRS)

1980-01-01

An overview of the High Energy Astronomy Observatory 2 contributions to X-ray astronomy is presented along with a brief description of the satellite and onboard telescope. Observations relating to galaxies and galactic clusters, black holes, supernova remnants, quasars, and cosmology are discussed.

A multi-scale automatic observatory of soil moisture and temperature served for satellite product validation in Tibetan Plateau

NASA Astrophysics Data System (ADS)

Tang, S.; Dong, L.; Lu, P.; Zhou, K.; Wang, F.; Han, S.; Min, M.; Chen, L.; Xu, N.; Chen, J.; Zhao, P.; Li, B.; Wang, Y.

2016-12-01

Due to the lack of observing data which match the satellite pixel size, the inversion accuracy of satellite products in Tibetan Plateau(TP) is difficult to be evaluated. Hence, the in situ observations are necessary to support the calibration and validation activities. Under the support of the Third Tibetan Plateau Atmospheric Scientific Experiment (TIPEX-III) projec a multi-scale automatic observatory of soil moisture and temperature served for satellite product validation (TIPEX-III-SMTN) were established in Tibetan Plateau. The observatory consists of two regional scale networks, including the Naqu network and the Geji network. The Naqu network is located in the north of TP, and characterized by alpine grasslands. The Geji network is located in the west of TP, and characterized by marshes. Naqu network includes 33 stations, which are deployed in a 75KM*75KM region according to a pre-designed pattern. At Each station, soil moisture and temperature are measured by five sensors at five soil depths. One sensor is vertically inserted into 0 2 cm depth to measure the averaged near-surface soil moisture and temperature. The other four sensors are horizontally inserted at 5, 10, 20, and 30 cm depths, respectively. The data are recorded every 10 minutes. A wireless transmission system is applied to transmit the data in real time, and a dual power supply system is adopted to keep the continuity of the observation. The construction of Naqu network has been accomplished in August, 2015, and Geji network will be established before Oct., 2016. Observations acquired from TIPEX-III-SMTN can be used to validate satellite products with different spatial resolution, and TIPEX-III-SMTN can also be used as a complementary of the existing similar networks in this area, such as CTP-SMTMN (the multiscale Soil Moistureand Temperature Monitoring Network on the central TP) . Keywords: multi-scale soil moisture soil temperature, Tibetan Plateau Acknowledgments: This work was jointly

The Solar and Heliospheric Observatory (SOHO) Mission: An Overview of Flight Dynamics Support of the Early Mission Phase

NASA Technical Reports Server (NTRS)

Short, R.; Behuncik, J.

1996-01-01

The SOHO spacecraft was successfully launched by an Atlas 2AS from the Eastern Range on December 2, 1995. After a short time in a nearly circular parking orbit, the spacecraft was placed by the Centaur upper stage on a transfer trajectory to the L1 libration point where it was inserted into a class 1 Halo orbit. The nominal mission lifetime is two years which will be spent collecting data from the Sun using a complement of twelve instruments. An overview of the early phases of Flight Dynamics Facility support of the mission is given. Maneuvers required for the mission are discussed, and an evaluation of these maneuvers is given with the attendent effects on the resultant orbit. Thruster performance is presented as well as real time monitoring of thruster activity during maneuvers. Attitude areas presented are the star identification process and role angle determination, momentum management, operating constraints on the star tracker, and guide star switching. A brief description of the two Heads Up displays is given.

Earth Observatory Satellite system definition study. Report no. 6: Space shuttle interfaces/utilization

NASA Technical Reports Server (NTRS)

1974-01-01

The impacts of achieving compatibility of the Earth Observatory Satellite (EOS) with the space shuttle and the potential benefits of space shuttle utilization are discussed. Mission requirements and mission suitability, including the effects of multiple spacecraft missions, are addressed for the full spectrum of the missions. Design impact is assessed primarily against Mission B, but unique requirements reflected by Mission A, B, and C are addressed. The preliminary results indicated that the resupply mission had the most pronounced impact on spacecraft design and cost. Program costs are developed for the design changes necessary to achieve EOS-B compatibility with Space Shuttle operations. Non-recurring and recurring unit costs are determined, including development, test, ground support and logistics, and integration efforts. Mission suitability is addressed in terms of performance, volume, and center of gravity compatibility with both space shuttle and conventional launch vehicle capabilities.

Aquarius Principal Investigator with Observatory

NASA Image and Video Library

2011-04-19

NASA Aquarius Principal Investigator Gary Lagerloef photographed in front of the Aquarius/SAC-D satellite observatory as it is being readied for transportation from Brazil to Vandenberg Air Force Base in California for a June 2011 launch.

Radiometric calibration of the vacuum-ultraviolet spectrograph SUMER on the SOHO spacecraft with the B detector.

PubMed

Schühle, U; Curdt, W; Hollandt, J; Feldman, U; Lemaire, P; Wilhelm, K

2000-01-20

The Solar Ultraviolet Measurement of Emitted Radiation (SUMER) vacuum-ultraviolet spectrograph was calibrated in the laboratory before the integration of the instrument on the Solar and Heliospheric Observatory (SOHO) spacecraft in 1995. During the scientific operation of the SOHO it has been possible to track the radiometric calibration of the SUMER spectrograph since March 1996 by a strategy that employs various methods to update the calibration status and improve the coverage of the spectral calibration curve. The results for the A Detector were published previously [Appl. Opt. 36, 6416 (1997)]. During three years of operation in space, the B detector was used for two and one-half years. We describe the characteristics of the B detector and present results of the tracking and refinement of the spectral calibration curves with it. Observations of the spectra of the stars alpha and rho Leonis permit an extrapolation of the calibration curves in the range from 125 to 149.0 nm. Using a solar coronal spectrum observed above the solar disk, we can extrapolate the calibration curves by measuring emission line pairs with well-known intensity ratios. The sensitivity ratio of the two photocathode areas can be obtained by registration of many emission lines in the entire spectral range on both KBr-coated and bare parts of the detector's active surface. The results are found to be consistent with the published calibration performed in the laboratory in the wavelength range from 53 to 124 nm. We can extrapolate the calibration outside this range to 147 nm with a relative uncertainty of ?30% (1varsigma) for wavelengths longer than 125 nm and to 46.5 nm with 50% uncertainty for the short-wavelength range below 53 nm.

Past and Future SOHO-Ulysses Quadratures

NASA Technical Reports Server (NTRS)

Suess, Steven; Poletto, G.

2006-01-01

With the launch of SOHO, it again became possible to carry out quadrature observations. In comparison with earlier observations, the new capabilities of coronal spectroscopy with UVCS and in situ ionization state and composition with Ulysses/SWICS enabled new types of studies. Results from two studies serve as examples: (i) The acceleration profile of wind from small coronal holes. (ii) A high-coronal reconnecting current sheet as the source of high ionization state Fe in a CME at Ulysses. Generally quadrature observations last only for a few days, when Ulysses is within ca. 5 degrees of the limb. This means luck is required for the phenomenon of interest to lie along the radial direction to Ulysses. However, when Ulysses is at high southern latitude in winter 2007 and high northern latitude in winter 2008, there will be unusually favorable configurations for quadrature observations with SOHO and corresponding bracketing limb observations from STEREO A/B. Specifically, Ulysses will be within 5 degrees of the limb from December 2006 to May 2007 and within 10 degrees of the limb from December 2007 to May 2008. These long-lasting quadratures and bracketing STEREO A/B observations overcome the limitations inherent in the short observation intervals of typical quadratures. Furthermore, ionization and charge state measurements like those on Ulysses will also be made on STEREO and these will be essential for identification of CME ejecta - one of the prime objectives for STEREO.

Affordable Earth Observatories for Developing Countries

NASA Astrophysics Data System (ADS)

Meurer, R. H.

Traditionally high cost has been the principal impediment to developing nations desiring to pursue space programs. More particularly, the benefits derivable from a space system have been less than adequate to justify the investment required. Chief among the causes has been the inability of the system to produce results with sufficient direct economic value to the peoples of their countries. Over the past 15 years, however, "the Microspace Revolution" has resulted in dramatic reductions in the cost of space systems, while at the same time technology has improved to provide greater capabilities in the smallest micro- and nano-class1 satellites. Because of these advances, it behooves developing nations to reevaluate space as an option for their national development. This paper summarizes two new micro-satellite concepts - NanoObservatoryTM and MicroObservatoryTM that offer the prom- ise of a dedicated Earth remote sensing capability at costs comparable to or less than simply buying data from the best known large systems, Landsat and SPOT. Each system is defined both by its observation capabilities and technical parameters of the system's design. Moreover, the systems are characterized in terms of the other potential benefits to developing economies, i.e., education of a technical workforce or applications of Earth imagery in solving national needs. Comparisons are provided with more traditional Earth observing satellites. NanoObservatoryTM is principally intended to serve as a developmental system to build general technical expertise space technology and Earth observation. MicroObservatoryTM takes the next step by focusing on a more sophisticated optical imag- ing camera while keeping the spacecraft systems simple and affordable. For both programs, AeroAstro is working with non- profit institutions to develop a corresponding program of technical participation with the nations that elect to pursue such programs. Dependent upon current capabilities, this might include

Using SOHO to Understand CME-Producing Quiet-Region Filament Eruptions

NASA Technical Reports Server (NTRS)

Sterling, A. C.; Moore, R. L.; Harra, L. K.

2006-01-01

In recent years we have been studying solar eruptions in an attempt to determine their primary initiation mechanism. We have focused on events involving filaments, because motions of the filaments just prior to their violent eruption are indicative of changes in the entire magnetic field system involved in the eruption. When the pre-eruption filament resides in a quiet region, the motions leading up to eruption are slower than in similar eruptions in active regions due to the weaker magnetic field strength and correspondingly lower Alfven velocities. These early motions manifest themselves in a slow rise (a few km/s) of the filament, in some cases lasting several hours. After this the filament and associated magnetic structures erupt rapidly, accelerating to speeds of a few 10 kmh over a few minutes. Because of their slow evolution, quiet-region eruptions such as these can be effectively studied in EUV with SOHO/EIT, with its regular cadence of about 12 min. For several cases we have combined EIT images with SOHO/MDI magnetograms and data from other other instruments, and compared our observations with predictions from various eruption scenarios, in particular the "breakout" (Antiochos 1998), "tether cutting" (e.g., Moore et al. 2001), and MHD instability mechanisms. Here we present a representative example of a quiet-region eruption involving a filament ejection, that occurred on 2001 February 28 in a magnetically quadrupolar region and produced a halo CME in SOHO/LASCO images. In addition to EIT and MDI, we analyzed spectral data from SOHO/CDS and soft X-ray (SXR) images from Yohkoh/SXT. We found that flux emergence occurred near one end of the filament, and that both this emergence and resulting microflaring in SXRs and EUV were temporally and spatially closely related to the start of the filament's slow rise. Intensity changes (dimmings and brightenings) in the EIT and SXT images indicate that fields far removed from the erupting core were involved in the

The Paris Observatory has 350 years

NASA Astrophysics Data System (ADS)

Lequeux, James

2017-01-01

The Paris Observatory is the oldest astronomical observatory that has worked without interruption since its foundation to the present day. The building due to Claude Perrault is still in existence with few modifications, but of course other buildings have been added all along the centuries for housing new instruments and laboratories. In particular, a large dome has been built on the terrace in 1847, with a 38-cm diameter telescope completed in 1857: both are still visible. The main initial purpose of the Observatory was to determine longitudes. This was achieved by Jean-Dominique Cassini using the eclipses of the satellites of Jupiter: a much better map of France was the produced using this method, which unfortunately does not work at sea. Incidentally, the observation of these eclipses led to the discovery in 1676 of the finite velocity of light by Cassini and Rømer. Cassini also discovered the differential rotation of Jupiter and four satellites of Saturn. Then, geodesy was to be the main activity of the Observatory for more than a century, culminating in the famous Cassini map of France completed around 1790. During the first half of the 19th century, under François Arago, the Observatory was at the centre of French physics, which then developed very rapidly. Arago initiated astrophysics in 1810 by showing that the Sun and stars are made of incandescent gas. In 1854, the new director, Urbain Le Verrier, put emphasis on astrometry and celestial mechanics, discovering in particular the anomalous advance of the perihelion of Mercury, which was later to be a proof of General Relativity. In 1858, Leon Foucault built the first modern reflecting telescopes with their silvered glass mirror. Le Verrier created on his side modern meteorology, including some primitive forecasts. The following period was not so bright, due to the enormous project of the Carte du Ciel, which took much of the forces of the Observatory for half a century with little scientific return. In

Earth Observatory Satellite system definition study. Report no. 3: Design/cost tradeoff studies. Appendix C: EOS program requirements document

NASA Technical Reports Server (NTRS)

1974-01-01

An analysis of the requirements for the Earth Observatory Satellite (EOS) system specifications is presented. The analysis consists of requirements obtained from existing documentation and those derived from functional analysis. The requirements follow the hierarchy of program, mission, system, and subsystem. The code for designating specific requirements is explained. Among the subjects considered are the following: (1) the traffic model, (2) space shuttle related performance, (3) booster related performance, (4) the data collection system, (5) spacecraft structural tests, and (6) the ground support requirements.

Earth Observatory Satellite system definition study. Report no. 1: Orbit/launch vehicle tradeoff studies and recommendations

NASA Technical Reports Server (NTRS)

1974-01-01

A study was conducted to determine the recommended orbit for the Earth Observatory Satellite (EOS) Land Resources Mission. It was determined that a promising sun synchronous orbit is 366 nautical miles when using an instrument with a 100 nautical mile swath width. The orbit has a 17 day repeat cycle and a 14 nautical mile swath overlap. Payloads were developed for each mission, EOS A through F. For each mission, the lowest cost booster that was capable of lifting the payload to the EOS orbit was selected. The launch vehicles selected for the missions are identified on the basis of tradeoff studies and recommendations. The reliability aspects of the launch vehicles are analyzed.

Time synchronization via the transit satellite at Mizusawa

NASA Technical Reports Server (NTRS)

Hara, J.; Sato, K. H.

1978-01-01

Time signals emitted from Transit satellites and received by the NAVICODE type receiver at Mizusawa, Japan are presented. The International Latitude Observatory of Mizusawa and the U. S. Naval Observatory were compared using the time signals. Propagation delays, a receiver delay, effects of relative motion of satellites, and effects of the ionosphere are discussed.

Two Distinct Types of CME-flare Relationships Based on SOHO and STEREO Observations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang, Soojeong; Moon, Yong-Jae; Kim, Rok-Soon

In this paper, we present two distinct types of coronal mass ejection (CME)-flare relationships according to their observing time differences using 107 events from 2010 to 2013. The observing time difference, Δ T , is defined as flare peak time minus CME first appearance time at Solar Terrestrial Relations Observatory ( STEREO ) COR1 field of view. There are 41 events for group A (Δ T < 0) and 66 events for group B (Δ T ≥ 0). We compare CME 3D parameters (speed and kinetic energy) based on multi-spacecraft data ( SOlar and Heliospheric Observatory ( SOHO ) andmore » STEREO A and B ) and their associated flare properties (peak flux, fluence, and duration). Our main results are as follows. First, there are better relationships between CME and flare parameters for group B than that of group A. In particular, CME 3D kinetic energy for group B is well correlated with flare fluence with the correlation coefficient of 0.67, which is much stronger than that (cc = 0.31) of group A. Second, the events belonging to group A have short flare durations of less than 1 hr (mean = 21 minutes), while the events for group B have longer durations up to 4 hr (mean = 81 minutes). Third, the mean value of height at peak speed for group B is 4.05 Rs, which is noticeably higher than that of group A (1.89 Rs). This is well correlated with the CME acceleration duration (cc = 0.75). A higher height at peak speed and a longer acceleration duration of CME for group B could be explained by the fact that magnetic reconnections for group B continuously occur for a longer time than those for group A.« less

SOHO-Ulysses Coordinated Studies During the Two Extended Quadratures and the Radial Alignment of 2007-2008

NASA Technical Reports Server (NTRS)

Suess, S. T.; Poletto, G.

2007-01-01

During quadrature, plasma seen on the limb of the Sun, along the radi al direction to Ulysses, by SOHO or STEREO can be sampled in situ as lt later passes Ulysses. A figure shows a coronagraph image, the rad ial towards Ulysses at 58 deg. S. and the SOHO/UVCS slit positions d uring one set of observations. A CME subsequently occurred and passed Ulysses (at 3/4 AU) 15 days later.

Satellite Remote Sensing Tools at the Alaska Volcano Observatory

NASA Astrophysics Data System (ADS)

Dehn, J.; Dean, K.; Webley, P.; Bailey, J.; Valcic, L.

2008-12-01

Volcanoes rarely conform to schedules or convenience. This is even more the case for remote volcanoes that still have impact on local infrastructure and air traffic. With well over 100 eruptions in the North Pacific over 20 years, the Alaska Volcano Observatory has developed a series of web-based tools to rapidly assess satellite imagery of volcanic eruptions from virtually anywhere. These range from automated alarms systems to detect thermal anomalies and ash plumes at volcanoes, as well as efficient image processing that can be done at a moments notice from any computer linked to the internet. The thermal anomaly detection algorithm looks for warm pixels several standard deviations above the background as well as pixels which show stronger mid infrared (3-5 microns) signals relative to available thermal channels (10-12 microns). The ash algorithm primarily uses the brightness temperature difference of two thermal bands, but also looks for shape of clouds and noise elimination. The automated algorithms are far from perfect, with 60-70% success rates, but improve with each eruptions. All of the data is available to the community online in a variety of forms which provide rudimentary processing. The website, avo-animate.images.alaska.edu, is designed for use by AVO's partners and "customers" to provide quick synoptic views of volcanic activity. These tools also have been essential in AVO's efforts in recent years and provide a model for rapid response to eruptions at distant volcanoes anywhere in the world. animate.images.alaska.edu

A new method to detect anisotropic electron events with SOHO/EPHIN

NASA Astrophysics Data System (ADS)

Banjac, Saša; Kühl, Patrick; Heber, Bernd

2016-07-01

The EPHIN instrument (Electron Proton Helium INstrument) forms a part of the COSTEP experiment (COmprehensive SupraThermal and Energetic Particle Analyzer) within the CEPAC collaboration on board of the SOHO spacecraft (SOlar and Heliospheric Observatory). The EPHIN sensor is a stack of six solid-state detectors surrounded by an anti-coincidence. It measures energy spectra of electrons in the range 250 keV to >8.7 MeV, and hydrogen and helium isotopes in the range 4~MeV/n to >53~MeV/n. In order to improve the isotopic resolution, the first two detectors have been segmented: 5 segments form a ring enclosing a central segment. This does not only allow to correct the energy-losses in the detectors for the different path-length in the detectors but allows also an estimation of the arrival direction of the particles with respect to the sensor axis. Utilizing an extensive GEANT 4 Monte-Carlo simulation of the sensor head we computed the scattering-induced modifications to the input angular distribution and developed an inversion method that takes into account the poor counting statistics by optimizing the corresponding algorithm. This improvement makes it possible for the first time to detect long lasting anisotropies in the 1~MeV-3~MeV electron flux with a single telescope on a three-axis stabilized spacecraft. We present the method and its application to several events with strong anisotropies. For validation, we compare our data with the WIND-3DP results.

Satellite-tracking and earth-dynamics research programs. [NASA Programs on satellite orbits and satellite ground tracks of geodetic satellites

NASA Technical Reports Server (NTRS)

1974-01-01

Observations and research progress of the Smithsonian Astrophysical Observatory are reported. Satellite tracking networks (ground stations) are discussed and equipment (Baker-Nunn cameras) used to observe the satellites is described. The improvement of the accuracy of a laser ranging system of the ground stations is discussed. Also, research efforts in satellite geodesy (tides, gravity anomalies, plate tectonics) is discussed. The use of data processing for geophysical data is examined, and a data base for the Earth and Ocean Physics Applications Program is proposed. Analytical models of the earth's motion (computerized simulation) are described and the computation (numerical integration and algorithms) of satellite orbits affected by the earth's albedo, using computer techniques, is also considered. Research efforts in the study of the atmosphere are examined (the effect of drag on satellite motion), and models of the atmosphere based on satellite data are described.

A Modern Operating System for Near-real-time Environmental Observatories

NASA Astrophysics Data System (ADS)

Orcutt, John; Vernon, Frank

2014-05-01

The NSF Ocean Observatory Initiative (OOI) provided an opportunity for expanding the capabilities for managing open, near-real-time (latencies of seconds) data from ocean observatories. The sensors deployed in this system largely return data from seafloor, cabled fiber optic cables as well as satellite telemetry. Bandwidth demands range from high-definition movies to the transmission of data via Iridium satellite. The extended Internet also provides an opportunity to not only return data, but to also control the sensors and platforms that comprise the observatory. The data themselves are openly available to any users. In order to provide heightened network security and overall reliability, the connections to and from the sensors/platforms are managed without Layer 3 of the Internet, but instead rely upon message passing using an open protocol termed Advanced Queuing Messaging Protocol (AMQP). The highest bandwidths in the system are in the Regional Scale Network (RSN) off Oregon and Washington and on the continent with highly reliable network connections between observatory components at 10 Gbps. The maintenance of metadata and life cycle histories of sensors and platforms is critical for providing data provenance over the years. The integrated cyberinfrastructure is best thought of as an operating system for the observatory - like the data, the software is also open and can be readily applied to new observatories, for example, in the rapidly evolving Arctic.

Time and Frequency Activities at the U.S. Naval Observatory

DTIC Science & Technology

2005-01-01

Naval Observatory, Washington, D.C.), pp. 325-332. [15] D. Kirchner, 1999, “Two Way Satellite Time and Frequency Transfer ( TWSTFT ),” Review of...of Carrier- Phase-Based Two-Way Satellite Time and Frequency Transfer ( TWSTFT ),” in Proceedings of the 36th Annual Precise Time and Time Interval

KSC-95PC-1159

NASA Image and Video Library

1994-09-13

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, technicians in the Spacecraft Assembly and Encapsulation Facility-2 SAEF-2) lift the Solar and Heliospheric Observatory SOHO after its removal from the crate it was shipped in from France. The SOHO spacecraft will carry a complement of 11 instruments from NASA and the European Space Agency ESA to study the origin of the energy within the sun which reaches the sun’s surface. SOHO was manufactured in France by Matra Marconi under a contract with ESA. The observatory will receive final testing and preparations for launch in SAEF-2. SOHO is targeted for launch on an Atlas IIAS from Launch Complex 36, Cape Canaveral Air Station, between Oct. 31 and Nov. 7, 1995. Photo Credit: NASA

Visibility Analysis of Domestic Satellites on Proposed Ground Sites for Optical Surveillance

NASA Astrophysics Data System (ADS)

Kim, Jae-Hyuk; Jo, Jung Hyun; Choi, Jin; Moon, Hong-Kyu; Choi, Young-Jun; Yim, Hong-Suh; Park, Jang-Hyun; Park, Eun-Seo; Park, Jong-Uk

2011-12-01

The objectives of this study are to analyze the satellite visibility at the randomly established ground sites, to determine the five optimal ground sites to perform the optical surveillance and tracking of domestic satellites, and to verify the acquisition of the optical observation time sufficient to maintain the precise ephemeris at optimal ground sites that have been already determined. In order to accomplish these objectives, we analyzed the visibility for sun-synchronous orbit satellites, low earth orbit satellites, middle earth orbit satellites and domestic satellites as well as the continuous visibility along with the fictitious satellite ground track, and calculate the effective visibility. For the analysis, we carried out a series of repetitive process using the satellite tool kit simulation software developed by Analytical Graphics Incorporated. The lighting states of the penumbra and direct sun were set as the key constraints of the optical observation. The minimum of the observation satellite elevation angle was set to be 20 degree, whereas the maximum of the sun elevation angle was set to be -10 degree which is within the range of the nautical twilight. To select the candidates for the optimal optical observation, the entire globe was divided into 84 sectors in a constant interval, the visibility characteristics of the individual sectors were analyzed, and 17 ground sites were arbitrarily selected and analyzed further. Finally, five optimal ground sites (Khurel Togoot Observatory, Assy-Turgen Observatory, Tubitak National Observatory, Bisdee Tier Optical Astronomy Observatory, and South Africa Astronomical Observatory) were determined. The total observation period was decided as one year. To examine the seasonal variation, the simulation was performed for the period of three days or less with respect to spring, summer, fall and winter. In conclusion, we decided the optimal ground sites to perform the optical surveillance and tracking of domestic

Solar wind structure suggested by bimodal correlations of solar wind speed and density between the spacecraft SOHO and Wind

NASA Astrophysics Data System (ADS)

Ogilvie, K. W.; Coplan, M. A.; Roberts, D. A.; Ipavich, F.

2007-08-01

We calculate the cross-spacecraft maximum lagged-cross-correlation coefficients for 2-hour intervals of solar wind speed and density measurements made by the plasma instruments on the Solar and Heliospheric Observatory (SOHO) and Wind spacecraft over the period from 1996, the minimum of solar cycle 23, through the end of 2005. During this period, SOHO was located at L1, about 200 R E upstream from the Earth, while Wind spent most of the time in the interplanetary medium at distances of more than 100 R E from the Earth. Yearly histograms of the maximum, time-lagged correlation coefficients for both the speed and density are bimodal in shape, suggesting the existence of two distinct solar wind regimes. The larger correlation coefficients we suggest are due to structured solar wind, including discontinuities and shocks, while the smaller are likely due to Alfvénic turbulence. While further work will be required to firmly establish the physical nature of the two populations, the results of the analysis are consistent with a solar wind that consists of turbulence from quiet regions of the Sun interspersed with highly filamentary structures largely convected from regions in the inner solar corona. The bimodal appearance of the distributions is less evident in the solar wind speed than in the density correlations, consistent with the observation that the filamentary structures are convected with nearly constant speed by the time they reach 1 AU. We also find that at solar minimum the fits for the density correlations have smaller high-correlation components than at solar maximum. We interpret this as due to the presence of more relatively uniform Alfvénic regions at solar minimum than at solar maximum.

Time and Frequency Activities at the U.S. Naval Observatory

DTIC Science & Technology

2012-01-01

Satellite Time Transfer (TWSTT), also referred to as Two-Way Satellite Time and Frequency Transfer ( TWSTFT ) The most accurate means of operational long...satellite broadcasts, and the BIPM uses that reported by the Observatory of Paris (OP), transferred to the BIPM via TWSTFT . This is compared to...Frequency Transfer ( TWSTFT ),” Review of Radio Science (Oxford Science Publications), pp. 27-44. [25] L. A. Breakiron, A. L. Smith, B. C. Fonville

SOHO reveals how sunspots take a stranglehold on the Sun

NASA Astrophysics Data System (ADS)

2001-11-01

Bernhard Fleck, ESA's project scientist for SOHO, comments, "The origin and stability of sunspots has been one of the long-standing mysteries in solar physics. I am delighted to see that with SOHO we are beginning to crack this problem." The gas flows around and beneath a sunspot have been detected by a team of scientists in the USA, using the Michelsen Doppler Imager (MDI) on SOHO. The instrument explores the solar interior by detecting natural sound waves at a million points on the Sun's surface. "After many years of contradictory theories about sunspots, MDI on SOHO is at last telling us what really happens," comments Junwei Zhao of Stanford University, California, lead author of a report published in the Astrophysical Journal. Inflows and downflows similar to those now detected with SOHO were envisaged in 1974 by Friedrich Meyer of Germany's Max-Planck- Institut für Physik und Astrophysik, and his colleagues. A similar expectation figured in a theory of sunspots advanced in 1979 by Eugene Parker of Chicago. "Our observation seems to provide strong evidence for both predictions," Zhao says. Sunspots have fascinated scientists since Galileo's time, 400 years ago, when they shattered a belief that the Sun was divinely free of any blemish. As symptoms of intense magnetic activity, sunspots are often associated with solar flares and mass ejections that affect space weather and the Earth itself. The Sun's activity peaks roughly every 11 years, and the latest maximum in the sunspot count occurred in 2000. Even with huge advances in helioseismology, which deduces layers and flows inside the Sun by analysis of sound waves that travel through it and agitate the surface, seeing behind the scenes in sunspots was never going to be easy. The MDI team refined a method of measuring the travel time of sound waves, invented in 1993 by Thomas Duvall of NASA Goddard, called solar tomography. It is like deducing what obstacles cross-country runners have faced, just by seeing in

Orbiting Carbon Observatory-2 Ready to Blast Off

NASA Image and Video Library

2014-06-30

The launch gantry, surrounding the United Launch Alliance Delta II rocket with the Orbiting Carbon Observatory-2 OCO-2 satellite onboard, is seen at Space Launch Complex 2, Sunday, June 29, 2014, Vandenberg Air Force Base, Calif.

High Energy Astronomy Observatory (HEAO)

NASA Image and Video Library

1975-01-01

The family of High Energy Astronomy Observatory (HEAO) instruments consisted of three unmarned scientific observatories capable of detecting the x-rays emitted by the celestial bodies with high sensitivity and high resolution. The celestial gamma-ray and cosmic-ray fluxes were also collected and studied to learn more about the mysteries of the universe. High-Energy rays cannot be studied by Earth-based observatories because of the obscuring effects of the atmosphere that prevent the rays from reaching the Earth's surface. They had been observed initially by sounding rockets and balloons, and by small satellites that do not possess the needed instrumentation capabilities required for high data resolution and sensitivity. The HEAO carried the instrumentation necessary for this capability. In this photograph, an artist's concept of three HEAO spacecraft is shown: HEAO-1, launched on August 12, 1977; HEAO-2, launched on November 13, 1978; and HEAO-3, launched on September 20. 1979.

Earth Observatory Satellite system definition study. Report 1: Orbit/launch vehicle trade-off studies and recommendations

NASA Technical Reports Server (NTRS)

1974-01-01

A summary of the constraints and requirements on the Earth Observatory Satellite (EOS-A) orbit and launch vehicle analysis is presented. The propulsion system (hydrazine) and the launch vehicle (Delta 2910) selected for EOS-A are examined. The rationale for the selection of the recommended orbital altitude of 418 nautical miles is explained. The original analysis was based on the EOS-A mission with the Thematic Mapper and the High Resolution Pointable Imager. The impact of the revised mission model is analyzed to show how the new mission model affects the previously defined propulsion system, launch vehicle, and orbit. A table is provided to show all aspects of the EOS multiple mission concepts. The subjects considered include the following: (1) mission orbit analysis, (2) spacecraft parametric performance analysis, (3) launch system performance analysis, and (4) orbits/launch vehicle selection.

Astronomical Research at the U.S. Air Force Academy Observatory

NASA Astrophysics Data System (ADS)

Della-Rose, Devin J.; Carlson, Randall E.; Chun, Francis K.; Giblin, Timothy W.; Novotny, Steven J.; Polsgrove, Daniel E.

2018-01-01

The U.S. Air Force Academy (USAFA) Observatory houses 61-cm and 41-cm Ritchey-Chrétien (RC) reflecting telescopes, and serves as the hub for a world-wide network of 50-cm RC reflectors known as the Falcon Telescope Network (FTN). Since the 1970s, the USAFA Observatory has hosted a wide range of student and faculty research projects including variable star photometry, exoplanet light curve and radial velocity studies, near-Earth object astrometry, and “lucky imaging” of manmade spacecraft. Further, the FTN has been used extensively for LEO through GEO satellite photometry and spectroscopy, and for exoplanet photometry. Future capabilities of our observatory complex include fielding several new FTN observatory sites and the acquisition of a 1-meter RC fast-tracking telescope at the USAFA Observatory.

ScienceCast 151: NASA to Launch Carbon Observatory

NASA Image and Video Library

2014-06-24

NASA is about to launch a satellite dedicated to the study of the greenhouse gas carbon dioxide. The Orbiting Carbon Observatory (OCO-2) will quantify global CO2 sources and sinks, and help researchers predict the future of climate change.

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 1: Baseline system description

NASA Technical Reports Server (NTRS)

1974-01-01

A system baseline design oriented to the requirements of the next generation of Earth Observatory Satellite missions is presented. The first mission (EOS-A) is envisioned as a two-fold mission which (1) provides a continuum of data of the type being supplied by ERTS for the emerging operational applications and also (2) expands the research and development activities for future instrumentation and analysis techniques. The baseline system specifically satisfies the requirements of this first mission. However, EOS-A is expected to be the first of a series of earth observation missions. Thus the baseline design has been developed so as to accommodate these latter missions effectively as the transition is made from conventional, expendable launch vehicles and spacecraft to the Shuttle Space Transportation System era. Further, a subset of alternative missions requirements including Seasat, SEOS, SMM and MSS-5 have been analyzed to verify that the spacecraft design to serve a multi-mission role is economically sound. A key feature of the baseline system design is the concept of a modular observatory system whose elements are compatible with varying levels of launch vehicle capability. The design configuration can be used with either the Delta or Titan launch vehicles and will adapt readily to the space shuttle when that system becomes available in the early 1980's.

Developing an astronomical observatory in Paraguay

NASA Astrophysics Data System (ADS)

Troche-Boggino, Alexis E.

Background: Paraguay has some heritage from the astronomy of the Guarani Indians. Buenaventura Suarez S.J. was a pioneer astronomer in the country in the XVIII century. He built various astronomical instruments and imported others from England. He observed eclipses of Jupiter's satellites and of the Sun and Moon. He published his data in a book and through letters. The Japanese O.D.A. has collaborated in obtaining equipment and advised their government to assist Paraguay in building an astronomical observatory, constructing a moving-roof observatory and training astronomers as observatory operators. Future: An astronomical center is on the horizon and some possible fields of research are being considered. Goal: To improve education at all possible levels by not only observing sky wonders, but also showing how instruments work and teaching about data and image processing, saving data and building a data base. Students must learn how a modern scientist works.

Space volcano observatory (SVO): a metric resolution system on-board a micro/mini-satellite

NASA Astrophysics Data System (ADS)

Briole, P.; Cerutti-Maori, G.; Kasser, M.

2017-11-01

1500 volcanoes on the Earth are potentially active, one third of them have been active during this century and about 70 are presently erupting. At the beginning of the third millenium, 10% of the world population will be living in areas directly threatened by volcanoes, without considering the effects of eruptions on climate or air-trafic for example. The understanding of volcanic eruptions, a major challenge in geoscience, demands continuous monitoring of active volcanoes. The only way to provide global, continuous, real time and all-weather information on volcanoes is to set up a Space Volcano Observatory closely connected to the ground observatories. Spaceborne observations are mandatory and implement the ground ones as well as airborne ones that can be implemented on a limited set of volcanoes. SVO goal is to monitor both the deformations and the changes in thermal radiance at optical wavelengths from high temperature surfaces of the active volcanic zones. For that, we propose to map at high resolution (1 to 1,5 m pixel size) the topography (stereoscopic observation) and the thermal anomalies (pixel-integrated temperatures above 450°C) of active volcanic areas in a size of 6 x 6 km to 12 x 12 km, large enough for monitoring most of the target features. A return time of 1 to 3 days will allow to get a monitoring useful for hazard mitigation. The paper will present the concept of the optical payload, compatible with a micro/mini satellite (mass in the range 100 - 400 kg), budget for the use of Proteus platform in the case of minisatellite approach will be given and also in the case of CNES microsat platform family. This kind of design could be used for other applications like high resolution imagery on a limited zone for military purpose, GIS, evolution cadaster…

Statistical Investigation and Modeling of Sungrazing Comets Discovered with the Solar and Heliospheric Observatory

NASA Astrophysics Data System (ADS)

Sekanina, Zdenek

2002-02-01

More than 300 sungrazing comets, most of them discovered with the Solar and Heliospheric Observatory (SOHO) coronagraphs since the beginning of 1996, are known to belong to the Kreutz group or system. Moving about the Sun in similar orbits, they are of indisputably common parentage and represent by far the most extensive data set in the history of investigations of cometary splitting. This study compares the SOHO sungrazers, which always disappear during their approach to the Sun, with the sungrazers detected earlier with the other space-borne coronagraphs (Solwind and Solar Maximum Mission [SMM]) as well as with the bright members of the Kreutz system, discovered from the ground between 1843 and 1970. Collected, summarized, and reviewed information on the sungrazers' light curves indicates that there is a difference of 20 mag (a factor of 108 in brightness) between the brightest sungrazer, C/1882 R1, and the faintest objects detectable with the SOHO instruments. The headless comet C/1887 B1 is suggested to be a transition object between the bright sungrazers and the coronagraphically discovered ones: its physical behavior was similar to that of the latter comets, but it survived the perihelion passage. This study also (1) examines temporal and spatial distributions of the SOHO sungrazers; (2) depicts correlations among their orbital elements; (3) distinguishes among tidally triggered, post-tidal, and terminal fragmentation; (4) reiterates the conclusion made in an earlier paper that post-tidal, secondary fragmentation events are occurring throughout the orbit, including the region of aphelion; (5) determines the relationship between a breakup's location in the orbit and the perturbations of the orbital elements of a fragment caused by the momentum it acquires during the separation from the parent; (6) shows that collisions of the Kreutz system comets with the Sun are clearly possible; (7) finds that minor fragments acquire enough extra momentum during each of the

Space Environment Modelling with the Use of Artificial Intelligence Methods

NASA Astrophysics Data System (ADS)

Lundstedt, H.; Wintoft, P.; Wu, J.-G.; Gleisner, H.; Dovheden, V.

1996-12-01

Space based technological systems are affected by the space weather in many ways. Several severe failures of satellites have been reported at times of space storms. Our society also increasingly depends on satellites for communication, navigation, exploration, and research. Predictions of the conditions in the satellite environment have therefore become very important. We will here present predictions made with the use of artificial intelligence (AI) techniques, such as artificial neural networks (ANN) and hybrids of AT methods. We are developing a space weather model based on intelligence hybrid systems (IHS). The model consists of different forecast modules, each module predicts the space weather on a specific time-scale. The time-scales range from minutes to months with the fundamental time-scale of 1-5 minutes, 1-3 hours, 1-3 days, and 27 days. Solar and solar wind data are used as input data. From solar magnetic field measurements, either made on the ground at Wilcox Solar Observatory (WSO) at Stanford, or made from space by the satellite SOHO, solar wind parameters can be predicted and modelled with ANN and MHD models. Magnetograms from WSO are available on a daily basis. However, from SOHO magnetograms will be available every 90 minutes. SOHO magnetograms as input to ANNs will therefore make it possible to even predict solar transient events. Geomagnetic storm activity can today be predicted with very high accuracy by means of ANN methods using solar wind input data. However, at present real-time solar wind data are only available during part of the day from the satellite WIND. With the launch of ACE in 1997, solar wind data will on the other hand be available during 24 hours per day. The conditions of the satellite environment are not only disturbed at times of geomagnetic storms but also at times of intense solar radiation and highly energetic particles. These events are associated with increased solar activity. Predictions of these events are therefore

NASA launches carbon dioxide research satellite

NASA Astrophysics Data System (ADS)

Wendel, JoAnna

2014-07-01

Last week NASA launched a new satellite to study atmospheric carbon dioxide (CO2). Once in orbit, the Orbiting Carbon Observatory-2 (OCO-2) satellite, launched from Vandenberg Air Force Base in California, will take more than 100,000 individual measurements of atmospheric CO2 per day.

NASA Extends Chandra X-ray Observatory Contract with the Smithsonian Astrophysical Observatory

NASA Astrophysics Data System (ADS)

2002-07-01

NASA NASA has extended its contract with the Smithsonian Astrophysical Observatory in Cambridge, Mass. to August 2003 to provide science and operational support for the Chandra X- ray Observatory, one of the world's most powerful tools to better understand the structure and evolution of the universe. The contract is an 11-month period of performance extension to the Chandra X-ray Center contract, with an estimated value of 50.75 million. Total contract value is now 298.2 million. The contract extension resulted from the delay of the launch of the Chandra X-ray Observatory from August 1998 to July 1999. The revised period of performance will continue the contract through Aug. 31, 2003, which is 48 months beyond operational checkout of the observatory. The contract type is cost reimbursement with no fee. The contract covers mission operations and data analysis, which includes both the observatory operations and the science data processing and general observer (astronomer) support. The observatory operations tasks include monitoring the health and status of the observatory and developing and distributing by satellite the observation sequences during Chandra's communication coverage periods. The science data processing tasks include the competitive selection, planning, and coordination of science observations with the general observers and the processing and delivery of the resulting scientific data. Each year, there are on the order of 200 to 250 observing proposals selected out of about 800 submitted, with a total amount of observing time about 20 million seconds. X-ray astronomy can only be performed from space because Earth's atmosphere blocks X-rays from reaching the surface. The Chandra Observatory travels one-third of the way to the Moon during its orbit around the Earth every 64 hours. At its highest point, Chandra's highly elliptical, or egg-shaped, orbit is 200 times higher than that of its visible-light- gathering sister, the Hubble Space Telescope. NASA

The Results of Observations of Mutual Phenomena of the Galilean Satellites of Jupiter in 2009 and 2015 IN Nikolaev Astronomical Observatory

NASA Astrophysics Data System (ADS)

Pomazan, A.; Maigurova, N.; Kryuchkovskiy, V.

The Earth and Jupiter once in 6 years have simultaneous passage of the ecliptic plane due to their orbital movement around the Sun. This makes it possible to observe the mutual occultations and eclipses in the Galilean satellites of Jupiter. We took part in the observational campaigns of the mutual phenomena in 2009 and 2014-15. The observations were made with a B/W CCD camera WAT-902H at the telescope MCT (D = 0.115 m, F = 2.0 m) of the Nikolaev Astronomical Observatory. The light curves of mutual phenomena in the satellites of Jupiter were obtained as a result of processing photometric observations. The exact moments of maximum phases and the amplitudes of the light variation have been determined from the analysis of the light curves. The data sets for the light curves have been sent in the IMCCE (Institute de Mecanique et de calcul des ephemerides, France) that coordinates the PHEMU campaigns.

SOHO sees right through the Sun, and finds sunspots on the far side

NASA Astrophysics Data System (ADS)

2000-03-01

The story is told today in the journal Science by Charles Lindsey of Tucson, Arizona, and Doug Braun of Boulder, Colorado. They realised that the analytical witchcraft called helioseismic holography might open a window right through the Sun. And the technique worked when they used it to decode waves seen on the visible surface by one of SOHO's instruments, the Michelson Doppler Imager, or MDI. "We've known for ten years that in theory we could make the Sun transparent all the way to the far side," said Charles Lindsey. "But we needed observations of exceptional quality. In the end we got them, from MDI on SOHO." For more than 100 years scientists have been aware that groups of dark sunspots on the Sun's visible face are often the scene of flares and other eruptions. Nowadays they watch the Sun more closely than ever, because modern systems are much more vulnerable to solar disturbances than old-style technology was. The experts can still be taken by surprise, because the Sun turns on its axis. A large group of previously hidden sunspots can suddenly swing into view on the eastern (left-hand) edge of the Sun. It may already be blazing away with menacing eruptions. With a far-side preview of sunspots, nasty shocks for the space weather forecasters may now be avoidable. Last year, French and Finnish scientists used SWAN, another instrument on SOHO, to detect activity on the far side. They saw an ultraviolet glow lighting up gas in the Solar System beyond the Sun, and moving across the sky like a lighthouse beam as the Sun rotated. The method used by Lindsey and Braun with MDI data is completely different, and it pinpoints the source of the activity on the far side. Solar seismology chalks up another success Detection of sound waves reverberating through the Sun opened its gassy interior for investigation, in much the same way as seismologists learned to explore the Earth's rocky interior with earthquake waves. Using special telescopes on the ground and in space

Micro Coronal Bright Points Observed in the Quiet Magnetic Network by SOHO/EIT

NASA Technical Reports Server (NTRS)

Falconer, D. A.; Moore, R. L.; Porter, J. G.

1997-01-01

When one looks at SOHO/EIT Fe XII images of quiet regions, one can see the conventional coronal bright points (> 10 arcsec in diameter), but one will also notice many smaller faint enhancements in brightness (Figure 1). Do these micro coronal bright points belong to the same family as the conventional bright points? To investigate this question we compared SOHO/EIT Fe XII images with Kitt Peak magnetograms to determine whether the micro bright points are in the magnetic network and mark magnetic bipoles within the network. To identify the coronal bright points, we applied a picture frame filter to the Fe XII images; this brings out the Fe XII network and bright points (Figure 2) and allows us to study the bright points down to the resolution limit of the SOHO/EIT instrument. This picture frame filter is a square smoothing function (hlargelyalf a network cell wide) with a central square (quarter of a network cell wide) removed so that a bright point's intensity does not effect its own background. This smoothing function is applied to the full disk image. Then we divide the original image by the smoothed image to obtain our filtered image. A bright point is defined as any contiguous set of pixels (including diagonally) which have enhancements of 30% or more above the background; a micro bright point is any bright point 16 pixels or smaller in size. We then analyzed the bright points that were fully within quiet regions (0.6 x 0.6 solar radius) centered on disk center on six different days.

Astrometric observations of Saturn's satellites from McDonald Observatory, 1972

NASA Technical Reports Server (NTRS)

Abbot, R. I.; Mulholland, J. D.; Shelus, P. J.

1975-01-01

Observations of Saturn's satellites have been reduced by means of secondary reference stars obtained by reduction of Palomar Sky Survey plates. This involved the use of 29 SAO stars and plate overlap technique to determine the coordinates of 59 fainter stars in the satellite field. Fourteen plate constants were determined for each of the two PSS plates. Comparison of two plate measurement and reduction techniques on the satellite measures appears to demonstrate the existence of a serious background gradient effect and the utility of microdensitometry to eliminate this error source in positional determinations of close satellites.

Calibration and Performance of the Michelson Doppler Imager on SOHO.

NASA Astrophysics Data System (ADS)

Zayer, I.; Morrison, M.; Tarbell, T. D.; Title, A.; Wolfson, C. J.; MDI Engineering Team; Bogart, R. S.; Bush, R. I.; Hoeksema, J. T.; Duvall, T.; Sa, L. A. D.; Scherrer, P. H.; Schou, J.

1996-05-01

The Michelson Doppler Imager (MDI) instrument probes the interior of the Sun by measuring the photospheric manifestations of solar oscillations. MDI was launched in December, 1995, on the Solar and Heliospheric Observatory (SOHO) and has been successfully observing the Sun since then. The instrument images the Sun on a 1024 x 1024 pixel CCD camera through a series of increasingly narrow spectral filters. The final elements, a pair of tunable Michelson interferometers, enable MDI to record filtergrams with FWHM bandwidth of 94 m Angstroms with a resolution of 4 arcseconds over the whole disk. Images can also be collected in MDI's higher resolution (1.25 arcsecond) field centered about 160 arcseconds north of the equator. An extensive calibration program has verified the end-to-end performance of the instrument in flight. MDI is working very well; we present the most important calibration results and a sample of early science observations. The Image Stabilization System (ISS) maintains overall pointing to better than ca. 0.01 arcsec, while the ISS' diagnostic mode allows us to measure spectrally narrow pointing jitter down to less than 1 mili-arcsec. We have confirmed the linearity of each CCD pixel to lie within 0.5%\\ (the FWHM of the distribution is 0.2% ), and have to date not detected any contamination on the detector, which is cooled to -72 C. The noise in a single Dopplergram is of the order of 20 m/s, and initial measurements of transverse velocities are reliable to 100 m/s. The sensitivity of magnetograms reach 5G in a 10 minute average (15G in a single magnetogram). MDI's primary observable, the p-modes from full-disk medium-l data, are of very high quality out to l=300 as seen in the initial l-nu diagram. The SOI-MDI program is supported by NASA contract NAG5-3077.

SOHO Ultraviolet Coronagraph Spectrometer (UVCS) Mission Operations and Data Analysis

NASA Technical Reports Server (NTRS)

Kohl, John L.; Gurman, Joseph (Technical Monitor)

2003-01-01

The scientific goal of UVCS is to obtain detailed empirical descriptions of the extended solar corona as it evolves over the solar cycle and to use these descriptions to identify and understand the physical processes responsible for coronal heating, solar wind acceleration, coronal mass ejections (CMEs), and the phenomena that establish the plasma properties of the solar wind as measured by 'in situ' solar wind instruments. This report covers the period from 01 February 2002 to 15 February 2003. During that time, UVCS observations have consisted of three types: 1) standard synoptic observations comprising, primarily, the H I Ly alpha line profile and the O VI 103.2 and 103.7 nm intensity over a range of heights from 1.5 to about 3.0 solar radii and covering 360 degrees about the sun, 2) sit and stare watches for CMEs, and 3) special observations designed by the UVCS Lead Observer of the Week for a specific scientific purpose. The special observations are often coordinated with those of other space-based and ground-based instruments and they often are part of SOHO joint observation programs and campaigns. Lead observers have included UVCS Co-Investigators, scientists from the solar physics community and several graduate and undergraduate level students. UVCS has continued to achieve its purpose of using powerful spectroscopic diagnostic techniques to obtain a much more detailed description of coronal structures and dynamic phenomena than existed before the SOHO mission. The new descriptions of coronal mass ejections (CMEs) and coronal structures from UVCS have inspired a large number of theoretical studies aimed at identifying the physical processes responsible for CMEs and solar wind acceleration in coronal holes and streamers. UVCS has proven to be a very stable instrument. Stellar observations have demonstrated its stability. UVCS has required no flight software modifications and all mechanisms are operational. The UVCS O VI Channel with its redundant optical

THE VOLATILE COMPOSITION OF COMET C/2003 K4 (LINEAR) AT NEAR-IR WAVELENGTHS—COMPARISONS WITH RESULTS FROM THE NANÇAY RADIO TELESCOPE AND FROM THE ODIN, SPITZER, AND SOHO SPACE OBSERVATORIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paganini, L.; Mumma, M. J.; Villanueva, G. L.

2015-07-20

We observed comet C/2003 K4 (LINEAR) using NIRSPEC at the Keck Observatory on UT 2004 November 28, when the comet was at 1.28 AU from the Sun (post-perihelion) and 1.38 AU from Earth. We detected six gaseous species (H{sub 2}O, OH*, C{sub 2}H{sub 6}, CH{sub 3}OH, CH{sub 4}, and HCN) and obtained upper limits for three others (H{sub 2}CO, C{sub 2}H{sub 2}, and NH{sub 3}). Our results indicate a water production rate of (1.72 ± 0.18) × 10{sup 29} molecules s{sup −1}, in reasonable agreement with production rates from SOHO (on the same day), Odin (one day earlier), and Nançaymore » (about two weeks earlier). We also report abundances (relative to water) for seven trace species: CH{sub 3}OH (∼1.8%), CH{sub 4} (∼0.9%), and C{sub 2}H{sub 6} (∼0.4%) that were consistent with mean values among Oort cloud (OC) comets, while NH{sub 3} (<0.55%), HCN (∼0.07%), H{sub 2}CO (<0.07%), and C{sub 2}H{sub 2} (<0.04%) were “lower” than the mean values in other OC comets. We extracted inner-coma rotational temperatures for four species (H{sub 2}O, C{sub 2}H{sub 6}, CH{sub 3}OH, and CH{sub 4}), all of which are consistent with 70 K (within 1σ). The extracted ortho-para ratio for water was 3.0 ± 0.15, corresponding to spin temperatures larger than 39 K (at the 1σ level) and agreeing with those obtained with the Spitzer Space Telescope at the 2σ level.« less

Earth-Affecting Solar Causes Observatory (EASCO): Results of the Mission Concept Study

NASA Technical Reports Server (NTRS)

Gopalswamy, Natchimuthuk

2011-01-01

Coronal mass ejections (CMEs) corotating interaction regions (CIRs) are two large-scale structures that originate from the Sun and affect the heliosphere in general and Earth in particular. While CIRs are generally detected by in-situ plasma signatures, CMEs are remote-sensed when they are still close to the Sun. The current understanding of CMEs primarily come from the SOHO and STEREO missions. In spite of the enormous progress made, there are some serious deficiencies in these missions. For example, these missions did not carry all the necessary instruments (STEREO did not have a magnetograph; SOHO did not have in-situ magnetometer). From the Sun-Earth line, SOHO was not well-suited for observing Earth-directed CMEs because of the occulting disk. STEREO's angle with the Sun-Earth line is changing constantly, so only a limited number of Earth-directed CMEs were observed in profile. In order to overcome these difficulties, we proposed a news L5 mission concept known as the Earth-Affecting Solar Causes Observatory (EASCO). The mission concept was recently studied at the Mission Design Laboratory (MDL), NASA Goddard Space Flight Center. The aim of the MDL study was to see how the scientific payload consisting of ten instruments can be accommodated in the spacecraft bus, what propulsion system can transfer the payload to the Sun-Earth L5, and what launch vehicles are appropriate. The study found that all the ten instruments can be readily accommodated and can be launched using an intermediate size vehicle such as Taurus II with enhanced faring. The study also found that a hybrid propulsion system consisting of an ion thruster (using approximately 55 kg of Xenon) and hydrazine (approximately 10 kg) is adequate to place the payload at L5. The transfer will take about 2 years and the science mission will last for 4 years around the next solar maximum in 2025. The mission can be readily extended for another solar cycle to get a solar-cycle worth of data on Earth

Correlation and comparative analysis of discriminative validity of the Scale of Oral Health Outcomes for Five-Year-Old Children (SOHO-5) and the Early Childhood Oral Health Impact Scale (ECOHIS) for dental caries.

PubMed

Fernandes, Izabella Barbosa; Ramos-Jorge, Joana; Ramos-Jorge, Maria Letícia; Bönecker, Marcelo; Abanto, Jenny; Marques, Leandro Silva; Paiva, Saul Martins

2015-03-10

The perceptions of parents and children regarding oral health are useful to oral public health and clinical practice in pediatric dentistry. The primary aim of the present study was to evaluate the correlation between the total and item scores of the Scale of Oral Health Outcomes for Five-Year-Old Children (SOHO-5) (parental version and child's self-reports) and the Early Childhood Oral Health Impact Scale (ECOHIS). Subsequently, the discriminative validity of these assessment tools regarding dental caries was compared. One hundred twenty-one children randomly selected in the city of Diamantina (Brazil) were submitted to oral examinations. Parents answered the ECOHIS and SOHO-5p (parental version) and children answered the SOHO-5c (child's self-reports). Statistical analysis involved the Mann-Whitney test as well as the calculation of Spearman's correlation coefficients. A significant correlation was found between the SOHO-5p and ECOHIS (r = 0.85), whereas no significant correlations were found between the SOHO-5c and SOHO-5p (r = 0.00) or between the SOHO-5c and ECOHIS (r = -0.41). Significant differences in the impact on quality of life were found between children with severe decay and no severe decay (caries free, with initial or established caries) both the ECOHIS and SOHO-5p (p ≤ 0.05), whereas no difference was found in SOHO-5c (p > 0.05). The ECOHIS and SOHO-5p were correlated with each other. The accounts of the children differed from their parents' reports and were not capable of discriminating dental caries in advanced stages of progression.

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 6: Specification for EOS Central Data Processing Facility (CDPF)

NASA Technical Reports Server (NTRS)

1974-01-01

The specifications and functions of the Central Data Processing (CDPF) Facility which supports the Earth Observatory Satellite (EOS) are discussed. The CDPF will receive the EOS sensor data and spacecraft data through the Spaceflight Tracking and Data Network (STDN) and the Operations Control Center (OCC). The CDPF will process the data and produce high density digital tapes, computer compatible tapes, film and paper print images, and other data products. The specific aspects of data inputs and data processing are identified. A block diagram of the CDPF to show the data flow and interfaces of the subsystems is provided.

ISS images for Observatory protection

NASA Astrophysics Data System (ADS)

Sánchez de Miguel, Alejandro; Zamorano, Jaime

2015-08-01

Light pollution is the main factor of degradation of the astronomical quality of the sky along the history. Astronomical observatories have been monitoring how the brightness of the sky varies using photometric measures of the night sky brightness mainly at zenith. Since the sky brightness depends in other factors such as sky glow, aerosols, solar activity and the presence of celestial objects, the continuous increase of light pollution in these enclaves is difficult to trace except when it is too late.Using models of light dispersion on the atmosphere one can determine which light pollution sources are increasing the sky brightness at the observatories. The input satellite data has been provided by DMSP/OLS and SNPP/VIIRS. Unfortunately their panchromatic bands (color blinded) are not useful to detect in which extension the increase is due to the dramatic change produced by the irruption of LED technology in outdoor lighting. The only instrument in the space that is able to distinguish between the various lighting technologies are the DSLR cameras used by the astronauts onboard the ISS.Current status for some astronomical observatories that have been imaged from the ISS is presented. We are planning to send an official request to NASA with a plan to get images for the most important astronomical observatories. We ask support for this proposal by the astronomical community and especially by the US-based researchers.

FIP effect for minor heavy solar wind ions as seen with SOHO/CELIAS/MTOF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heidrich-Meisner, Verena, E-mail: heidrich@physik.uni-kiel.de; Berger, Lars; Wimmer-Schweingruber, Robert F.

A recent paper [Shearer et al., 2014] reported that during solar maximum Ne showed a surprisingly low abundance. This leads to the question whether other elements show the same behavior. The good mass resolution of Mass-Time-Of-Flight (MTOF) as part of the Charge ELement and Isotope Analysis System (CELIAS) on the Solar Helioshperic Observatory (SOHO) allows to investigate the composition of heavy minor elements in different types of solar wind. We restrict this study to slow solar wind, where the characterisation of slow solar wind is taken from Xu and Borovsky, 2014. This classification scheme requires magnet field information. Since SOHOmore » does not carry a magnetometer, we use the Magnetometer (MAG) of the Advanced Composition Explorer (ACE) instead. The Solar Wind Ion Composition Spectrometer (ACE/SWICS) also provides composition data for cross-calibration and charge-state distributions as input for the transmission function of MTOF whenever the two spacecraft can be expected to observe the same type of wind. We illustrate the MTOF’s capability to determine the solar wind abundance compared to the photospheric abundance (called the FIP ratio in the following) for rare elements like Ti or Cr on long-time scales as a proof of concept for our analysis. And in this brief study, measurements with both ACE/SWICS indicate that the observed elements exhibit a (weak) dependence on the solar cycle, whereas the MTOF measurements are inconclusive.« less

The High Energy Astronomy Observatory X-ray Telescope

NASA Technical Reports Server (NTRS)

Miller, R.; Austin, G.; Koch, D.; Jagoda, N.; Kirchner, T.; Dias, R.

1978-01-01

The High Energy Astronomy Observatory-Mission B (HEAO-B) is a satellite observatory for the purpose of performing a detailed X-ray survey of the celestial sphere. Measurements will be made of stellar radiation in the range 0.2 through 20 keV. The primary viewing requirement is to provide final aspect solution and internal alignment information to correlate an observed X-ray image with the celestial sphere to within one-and-one-half arc seconds. The Observatory consists of the HEAO Spacecraft together with the X-ray Telescope. The Spacecraft provides the required attitude control and determination system, data telemetry system, space solar power system, and interface with the launch vehicle. The X-ray Telescope includes a high resolution mirror assembly, optical bench metering structure, X-ray detectors, detector positioning system, detector electronics and aspect sensing system.

Compton Gamma-Ray Observatory

NASA Technical Reports Server (NTRS)

1991-01-01

This photograph shows the Compton Gamma-Ray Observatory (GRO) being deployed by the Remote Manipulator System (RMS) arm aboard the Space Shuttle Atlantis during the STS-37 mission in April 1991. The GRO reentered Earth atmosphere and ended its successful mission in June 2000. For nearly 9 years, the GRO Burst and Transient Source Experiment (BATSE), designed and built by the Marshall Space Flight Center (MSFC), kept an unblinking watch on the universe to alert scientists to the invisible, mysterious gamma-ray bursts that had puzzled them for decades. By studying gamma-rays from objects like black holes, pulsars, quasars, neutron stars, and other exotic objects, scientists could discover clues to the birth, evolution, and death of stars, galaxies, and the universe. The gamma-ray instrument was one of four major science instruments aboard the Compton. It consisted of eight detectors, or modules, located at each corner of the rectangular satellite to simultaneously scan the entire universe for bursts of gamma-rays ranging in duration from fractions of a second to minutes. In January 1999, the instrument, via the Internet, cued a computer-controlled telescope at Las Alamos National Laboratory in Los Alamos, New Mexico, within 20 seconds of registering a burst. With this capability, the gamma-ray experiment came to serve as a gamma-ray burst alert for the Hubble Space Telescope, the Chandra X-Ray Observatory, and major gound-based observatories around the world. Thirty-seven universities, observatories, and NASA centers in 19 states, and 11 more institutions in Europe and Russia, participated in the BATSE science program.

Compton Gamma-Ray Observatory

NASA Technical Reports Server (NTRS)

1991-01-01

This photograph shows the Compton Gamma-Ray Observatory being released from the Remote Manipulator System (RMS) arm aboard the Space Shuttle Atlantis during the STS-35 mission in April 1991. The GRO reentered the Earth's atmosphere and ended its successful mission in June 2000. For nearly 9 years, GRO's Burst and Transient Source Experiment (BATSE), designed and built by the Marshall Space Flight Center, kept an unblinking watch on the universe to alert scientist to the invisible, mysterious gamma-ray bursts that had puzzled them for decades. By studying gamma-rays from objects like black holes, pulsars, quasars, neutron stars, and other exotic objects, scientists could discover clues to the birth, evolution, and death of star, galaxies, and the universe. The gamma-ray instrument was one of four major science instruments aboard the Compton. It consisted of eight detectors, or modules, located at each corner of the rectangular satellite to simultaneously scan the entire universe for bursts of gamma-rays ranging in duration from fractions of a second to minutes. In January 1999, the instrument, via the Internet, cued a computer-controlled telescope at Las Alamos National Laboratory in Los Alamos, New Mexico, within 20 seconds of registering a burst. With this capability, the gamma-ray experiment came to serve as a gamma-ray burst alert for the Hubble Space Telescope, the Chandra X-Ray Observatory, and major gound-based observatories around the world. Thirty-seven universities, observatories, and NASA centers in 19 states, and 11 more institutions in Europe and Russia, participated in BATSE's science program.

Orbiting Carbon Observatory-2 (OCO-2) Launch

NASA Image and Video Library

2014-07-02

A United Launch Alliance Delta II rocket launches with the Orbiting Carbon Observatory-2 (OCO-2)satellite onboard from Space Launch Complex 2 at Vandenberg Air Force Base, Calif. on Wednesday, July 2, 2014. OCO-2 will measure the global distribution of carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth’s climate. Photo Credit: (NASA/Bill Ingalls)

The Fram Strait integrated ocean observatory

NASA Astrophysics Data System (ADS)

Fahrbach, E.; Beszczynska-Möller, A.; Rettig, S.; Rohardt, G.; Sagen, H.; Sandven, S.; Hansen, E.

2012-04-01

A long-term oceanographic moored array has been operated since 1997 to measure the ocean water column properties and oceanic advective fluxes through Fram Strait. While the mooring line along 78°50'N is devoted to monitoring variability of the physical environment, the AWI Hausgarten observatory, located north of it, focuses on ecosystem properties and benthic biology. Under the EU DAMOCLES and ACOBAR projects, the oceanographic observatory has been extended towards the innovative integrated observing system, combining the deep ocean moorings, multipurpose acoustic system and a network of gliders. The main aim of this system is long-term environmental monitoring in Fram Strait, combining satellite data, acoustic tomography, oceanographic measurements at moorings and glider sections with high-resolution ice-ocean circulation models through data assimilation. In future perspective, a cable connection between the Hausgarten observatory and a land base on Svalbard is planned as the implementation of the ESONET Arctic node. To take advantage of the planned cabled node, different technologies for the underwater data transmission were reviewed and partially tested under the ESONET DM AOEM. The main focus was to design and evaluate available technical solutions for collecting data from different components of the Fram Strait ocean observing system, and an integration of available data streams for the optimal delivery to the future cabled node. The main components of the Fram Strait integrated observing system will be presented and the current status of available technologies for underwater data transfer will be reviewed. On the long term, an initiative of Helmholtz observatories foresees the interdisciplinary Earth-Observing-System FRAM which combines observatories such as the long term deep-sea ecological observatory HAUSGARTEN, the oceanographic Fram Strait integrated observing system and the Svalbard coastal stations maintained by the Norwegian ARCTOS network. A vision

Resolving Differences in Absolute Irradiance Measurements Between the SOHO/CELIAS/SEM and the SDO/EVE.

PubMed

Wieman, S R; Didkovsky, L V; Judge, D L

The Solar EUV Monitor (SEM) onboard SOHO has measured absolute extreme ultraviolet (EUV) and soft X-ray solar irradiance nearly continuously since January 1996. The EUV Variability Experiment (EVE) on SDO, in operation since April of 2010, measures solar irradiance in a wide spectral range that encompasses the band passes (26 - 34 nm and 0.1 - 50 nm) measured by SOHO/SEM. However, throughout the mission overlap, irradiance values from these two instruments have differed by more than the combined stated uncertainties of the measurements. In an effort to identify the sources of these differences and eliminate them, we investigate in this work the effect of reprocessing the SEM data using a more accurate SEM response function (obtained from synchrotron measurements with a SEM sounding-rocket clone instrument taken after SOHO was already in orbit) and time-dependent, measured solar spectral distributions - i.e ., solar reference spectra that were unavailable prior to the launch of the SDO. We find that recalculating the SEM data with these improved parameters reduces mean differences with the EVE measurements from about 20 % to less than 5 % in the 26 - 34 nm band, and from about 35 % to about 15 % for irradiances in the 0.1 - 7 nm band extracted from the SEM 0.1 - 50 nm channel.

A Green Robotic Observatory for Astronomy Education

NASA Astrophysics Data System (ADS)

Reddy, Vishnu; Archer, K.

2008-09-01

With the development of robotic telescopes and stable remote observing software, it is currently possible for a small institution to have an affordable astronomical facility for astronomy education. However, a faculty member has to deal with the light pollution (observatory location on campus), its nightly operations and regular maintenance apart from his day time teaching and research responsibilities. While building an observatory at a remote location is a solution, the cost of constructing and operating such a facility, not to mention the environmental impact, are beyond the reach of most institutions. In an effort to resolve these issues we have developed a robotic remote observatory that can be operated via the internet from anywhere in the world, has a zero operating carbon footprint and minimum impact on the local environment. The prototype observatory is a clam-shell design that houses an 8-inch telescope with a SBIG ST-10 CCD detector. The brain of the observatory is a low draw 12-volt harsh duty computer that runs the dome, telescope, CCD camera, focuser, and weather monitoring. All equipment runs of a 12-volt AGM-style battery that has low lead content and hence more environmental-friendly to dispose. The total power of 12-14 amp/hrs is generated from a set of solar panels that are large enough to maintain a full battery charge for several cloudy days. This completely eliminates the need for a local power grid for operations. Internet access is accomplished via a high-speed cell phone broadband connection or satellite link eliminating the need for a phone network. An independent observatory monitoring system interfaces with the observatory computer during operation. The observatory converts to a trailer for transportation to the site and is converted to a semi-permanent building without wheels and towing equipment. This ensures minimal disturbance to local environment.

First ISON observations for satellite conjunction analysis in the Western Hemisphere

NASA Astrophysics Data System (ADS)

Zalles, R.; Molotov, I.; Kokina, T.; Zolotov, V.; Condori, R.

2018-01-01

In this paper we report on observations of a pair of approaching space objects in the beginning of June 2016, observed jointly by the Tarija Observatory in Bolivia and the Mexican observatory of Sinaloa University in Cosala in the context of the ISON collaboration. These objects were the STAR ONE C1 (2007-056A) active satellite in GEO position 65\\ deg west, and the passive satellite LES 6 (1968-081D). The large number of measurements obtained in a few nights allowed a precise orbit reconstruction. The passive satellite LES 6 (with a brigtness amplitude variation of 3 magnitudes) was too faint for the small aperture of the Cosala telescope.

Report On Fiducial Points At The Space Geodesy Based Cagliari Astronomical Observatory

NASA Astrophysics Data System (ADS)

Banni, A.; Buffa, F.; Falchi, E.; Sanna, G.

At the present time two research groups are engaged to space-geodesy activities in Sardinia: a staff belonging to the Stazione Astronomica of Cagliari (SAC) and the To- pography Section of the Dipartimento di Ingegneria Strutturale (DIST) of the Cagliari University. The two groups have a share in international campaigns and services. The local structure, consists of permanent stations of satellite observation both on radio and laser techniques. Particularly in the Cagliari Observatory a Satellite Laser Ranging system runs with nearly daily, low, medium and high orbit satellite tracking capability (e. g. Topex, Ajisai, Lageos1/2, Glonass); up to this time the Cagliari laser station has contributed towards the following international campaigns/organizations. Besides in the Observatory's site a fixed GPS system, belonging the Italian Space Agency GPS- Network and to the IGS-Network; and a GPS+GLONASS system, acquired by DIST and belonging to the IGLOS are installed and managed. All the above stations are furnished with meteorological sensors with RINEX format data dissemination avail- ability. Moreover a new 64 meters dish radio telescope (Sardinian Radio Telescope), geodetic VLBI equipped, is under construction not long away from the Observatory. The poster fully shows the facilities and furnishes a complete report on the mark- ers eccentricities, allowing co-location of the different space techniques operating in Sardinia.

Solar Flare Impulsive Phase Observations from SDO and Other Observatories

NASA Technical Reports Server (NTRS)

Chamberlin, Phillip C.; Woods, Thomas N.; Schrijver, Karel; Warren, Harry; Milligan, Ryan; Christe, Steven; Brosius, Jeffrey W.

2010-01-01

With the start of normal operations of the Solar Dynamics Observatory in May 2010, the Extreme ultraviolet Variability Experiment (EVE) and the Atmospheric Imaging Assembly (AIA) have been returning the most accurate solar XUV and EUV measurements every 10 and 12 seconds, respectively, at almost 100% duty cycle. The focus of the presentation will be the solar flare impulsive phase observations provided by EVE and AIA and what these observations can tell us about the evolution of the initial phase of solar flares. Also emphasized throughout is how simultaneous observations with other instruments, such as RHESSI, SOHO-CDS, and HINODE-EIS, will help provide a more complete characterization of the solar flares and the evolution and energetics during the impulsive phase. These co-temporal observations from the other solar instruments can provide information such as extending the high temperature range spectra and images beyond that provided by the EUV and XUV wavelengths, provide electron density input into the lower atmosphere at the footpoints, and provide plasma flows of chromospheric evaporation, among other characteristics.

The May 1997 SOHO-Ulysses Quadrature

NASA Technical Reports Server (NTRS)

Suess, Steven T.; Poletto, G.; Romoli, M.; Neugebauer, M.; Goldstein, B. E.; Simnett, G.

2000-01-01

We present results from the May 1997 SOHO-Ulysses quadrature, near sunspot minimum. Ulysses was at 5.1 AU, 100 north of the solar equator, and off the east limb. It was, by chance, also at the very northern edge of the streamer belt. Nevertheless, SWOOPS detected only slow, relatively smooth wind and there was no direct evidence of fast wind from the northern polar coronal hole or of mixing with fast wind. LASCO images show that the streamer belt at 10 N was narrow and sharp at the beginning and end of the two week observation interval, but broadened in the middle. A corresponding change in density, but not flow speed, occurred at Ulysses. Coronal densities derived from UVCS show that physical parameters in the lower corona are closely related to those in the solar wind, both over quiet intervals and in transient events on the limb. One small transient observed by both LASCO and UVCS is analyzed in detail.

Orbiting Carbon Observatory-2 (OCO-2)

NASA Image and Video Library

2014-06-29

The launch gantry, surrounding the United Launch Alliance Delta II rocket with the Orbiting Carbon Observatory-2 (OCO-2) satellite onboard, is seen at the Space Launch Complex 2, Sunday, June 29, 2014, Vandenberg Air Force Base, Calif. OCO-2 will measure the global distribution of carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth’s climate. OCO-2 is set for a July 1, 2014 launch. Photo Credit: (NASA/Bill Ingalls)

Constellation X-Ray Observatory Unlocking the Mysteries of Black Holes, Dark Matter and Life Cycles of Matter in the Universe

NASA Technical Reports Server (NTRS)

Weaver, Kim; Wanjek, Christopher

2004-01-01

This document provides an overview of the Contellation X-Ray Observatory and its mission. The observatory consists of four x-ray telescopes borne on a satellite constellation at the Earth-Sun L2 point.

Space Science

NASA Image and Video Library

2001-04-02

The largest solar flare ever recorded occurred at 4:51 p.m. EDT, on Monday, April 2, 2001. as Observed by the Solar and Heliospheric Observatory (SOHO) satellite. Solar flares, among the solar systems mightiest eruptions, are tremendous explosions in the atmosphere of the Sun capable of releasing as much energy as a billion megatons of TNT. Caused by the sudden release of magnetic energy, in just a few seconds, solar flares can accelerate solar particles to very high velocities, almost to the speed of light, and heat solar material to tens of millions of degrees. The recent explosion from the active region near the sun's northwest limb hurled a coronal mass ejection into space at a whopping speed of roughly 7.2 million kilometers per hour. Luckily, the flare was not aimed directly towards Earth. Second to the most severe R5 classification of radio blackout, this flare produced an R4 blackout as rated by the NOAA SEC. This classification measures the disruption in radio communications. Launched December 2, 1995 atop an ATLAS-IIAS expendable launch vehicle, the SOHO is a cooperative effort involving NASA and the European Space Agency (ESA). (Image courtesy NASA Goddard SOHO Project office)

Largest Solar Flare on Record

NASA Technical Reports Server (NTRS)

2001-01-01

The largest solar flare ever recorded occurred at 4:51 p.m. EDT, on Monday, April 2, 2001. as Observed by the Solar and Heliospheric Observatory (SOHO) satellite. Solar flares, among the solar systems mightiest eruptions, are tremendous explosions in the atmosphere of the Sun capable of releasing as much energy as a billion megatons of TNT. Caused by the sudden release of magnetic energy, in just a few seconds, solar flares can accelerate solar particles to very high velocities, almost to the speed of light, and heat solar material to tens of millions of degrees. The recent explosion from the active region near the sun's northwest limb hurled a coronal mass ejection into space at a whopping speed of roughly 7.2 million kilometers per hour. Luckily, the flare was not aimed directly towards Earth. Second to the most severe R5 classification of radio blackout, this flare produced an R4 blackout as rated by the NOAA SEC. This classification measures the disruption in radio communications. Launched December 2, 1995 atop an ATLAS-IIAS expendable launch vehicle, the SOHO is a cooperative effort involving NASA and the European Space Agency (ESA). (Image courtesy NASA Goddard SOHO Project office)

SOHO Ultraviolet Coronagraph Spectrometer (UVCS) Mission Operations and Data Analysis

NASA Technical Reports Server (NTRS)

Gurman, Joseph (Technical Monitor); Kohl, John L.

2004-01-01

The scientific goal of UVCS is to obtain detailed empirical descriptions of the extended solar corona as it evolves over the solar cycle and to use these descriptions to identify and understand the physical processes responsible for coronal heating, solar wind acceleration, coronal mass ejections (CMEs), and the phenomena that establish the plasma properties of the solar wind as measured by "in situ" solar wind instruments. This report covers the period from 15 February 2003 to 14 April 2004. During that time, UVCS observations have consisted of three types: 1) standard synoptic observations comprising, primarily, the H I Lyalpha line profile and the 0 VI 103.2 and 103.7 nm intensity over a range of heights from 1.5 to about 3.0 solar radii and covering 360 degrees about the Sun, 2) sit and stare observations for major flare watches, and 3) special observations designed by the UVCS Lead Observer of the Week for a specific scientific purpose. The special observations are often coordinated with those of other space-based and ground-based instruments and they often are part of SOHO joint observation programs and campaigns. Lead observers have included UVCS Co-Investigators, scientists from the solar physics community and several graduate and undergraduate level students. UVCS has continued to achieve its purpose of using powerful spectroscopic diagnostic techniques to obtain a much more detailed description of coronal structures and dynamic phenomena than existed before the SOHO mission. The new descriptions of coronal mass ejections (CMEs) and coronal structures from UVCS have inspired a large number of theoretical studies aimed at identifying the physical processes responsible for CMEs and solar wind acceleration in coronal holes and streamers. UVCS has proven to be a very stable instrument. Stellar observations have demonstrated its radiometric stability. UVCS has not required any flight software modifications and all mechanisms are operational. The UVCS 0 VI

Computer Vision for the Solar Dynamics Observatory (SDO)

NASA Astrophysics Data System (ADS)

Martens, P. C. H.; Attrill, G. D. R.; Davey, A. R.; Engell, A.; Farid, S.; Grigis, P. C.; Kasper, J.; Korreck, K.; Saar, S. H.; Savcheva, A.; Su, Y.; Testa, P.; Wills-Davey, M.; Bernasconi, P. N.; Raouafi, N.-E.; Delouille, V. A.; Hochedez, J. F.; Cirtain, J. W.; Deforest, C. E.; Angryk, R. A.; de Moortel, I.; Wiegelmann, T.; Georgoulis, M. K.; McAteer, R. T. J.; Timmons, R. P.

2012-01-01

In Fall 2008 NASA selected a large international consortium to produce a comprehensive automated feature-recognition system for the Solar Dynamics Observatory (SDO). The SDO data that we consider are all of the Atmospheric Imaging Assembly (AIA) images plus surface magnetic-field images from the Helioseismic and Magnetic Imager (HMI). We produce robust, very efficient, professionally coded software modules that can keep up with the SDO data stream and detect, trace, and analyze numerous phenomena, including flares, sigmoids, filaments, coronal dimmings, polarity inversion lines, sunspots, X-ray bright points, active regions, coronal holes, EIT waves, coronal mass ejections (CMEs), coronal oscillations, and jets. We also track the emergence and evolution of magnetic elements down to the smallest detectable features and will provide at least four full-disk, nonlinear, force-free magnetic field extrapolations per day. The detection of CMEs and filaments is accomplished with Solar and Heliospheric Observatory (SOHO)/ Large Angle and Spectrometric Coronagraph (LASCO) and ground-based Hα data, respectively. A completely new software element is a trainable feature-detection module based on a generalized image-classification algorithm. Such a trainable module can be used to find features that have not yet been discovered (as, for example, sigmoids were in the pre- Yohkoh era). Our codes will produce entries in the Heliophysics Events Knowledgebase (HEK) as well as produce complete catalogs for results that are too numerous for inclusion in the HEK, such as the X-ray bright-point metadata. This will permit users to locate data on individual events as well as carry out statistical studies on large numbers of events, using the interface provided by the Virtual Solar Observatory. The operations concept for our computer vision system is that the data will be analyzed in near real time as soon as they arrive at the SDO Joint Science Operations Center and have undergone basic

Portable coastal observatories

USGS Publications Warehouse

Frye, Daniel; Butman, Bradford; Johnson, Mark; von der Heydt, Keith; Lerner, Steven

2000-01-01

Ocean observational science is in the midst of a paradigm shift from an expeditionary science centered on short research cruises and deployments of internally recording instruments to a sustained observational science where the ocean is monitored on a regular basis, much the way the atmosphere is monitored. While satellite remote sensing is one key way of meeting the challenge of real-time monitoring of large ocean regions, new technologies are required for in situ observations to measure conditions below the ocean surface and to measure ocean characteristics not observable from space. One method of making sustained observations in the coastal ocean is to install a fiber optic cable from shore to the area of interest. This approach has the advantage of providing power to offshore instruments and essentially unlimited bandwidth for data. The LEO-15 observatory offshore of New Jersey (yon Alt et al., 1997) and the planned Katama observatory offshore of Martha's Vineyard (Edson et al., 2000) use this approach. These sites, along with other cabled sites, will play an important role in coastal ocean science in the next decade. Cabled observatories, however, have two drawbacks that limit the number of sites that are likely to be installed. First, the cable and the cable installation are expensive and the shore station needed at the cable terminus is often in an environmentally sensitive area where competing interests must be resolved. Second, cabled sites are inherently limited geographically to sites within reach of the cable, so it is difficult to cover large areas of the coastal ocean.

From SOHO to STEREO: Understanding Propagation of Coronal Mass Ejections

NASA Technical Reports Server (NTRS)

Gopalswamy, Natchimuthuk

2011-01-01

Direct comparison between coronal mass ejections (CMEs) from near the Sun and their solar wind counterparts became possible roughly a decade after the discovery of CMEs (Lindsay et aL 1999). This comparison revealed that fast CMEs decelerate and slow CMEs accelerate due to the interaction with the solar wind. Gopalswamy et al (2000) quantified this interaction as an interplanetary acceleration which is useful in predicting the arrival time and speed of CMEs at 1 AU. The interplanetary acceleration is essentially due to the aerodynamic drag between the CME and the solar wind because the propelling force and the solar gravity are effective only near the Sun. Combined remote-sensing and in situ observations from SOHO and Wind/ACE have helped us estimate the influence of the solar wind on the propagation of CMEs. However, these measurements have severe limitations because the remote sensed and in-situ observations correspond to different portions of the CME. Furthermore, the true speeds of Earth-directed CMEs cannot be measured accurately from a spacecraft located along the Sun-Earth line. There have been attempts to model the CME as a cone and get the space speed of the CME, which did improve the travel time predictions. Instruments on board the Solar Terrestrial Relations Observatory (STEREO) mission were able to provide observations of Earth-arriving CMEs without projection effects, while the same CMEs were observed at Sun-Earth L1 by Wind and ACE spacecraft. The quadrature between STEREO and L1 spacecraft presented an ideal situation to study the interplanetary evolution of CMEs and test earlier model results. The quadrature observations did improve the CME travel time predictions, but additional factors such as the unusually slow solar wind, CME cannibalism, and coronal-hole deflection need to be considered to reconcile the difference between observed and predicted travel times. This point is illustrated using the 2011 February 15 CME

Orbiting Carbon Observatory-2 (OCO-2)

NASA Image and Video Library

2014-06-30

The United Launch Alliance Delta II rocket with the Orbiting Carbon Observatory-2 (OCO-2) satellite onboard, is seen as the launch gantry is moved at the Space Launch Complex 2, Monday, June 30, 2014, Vandenberg Air Force Base, Calif. OCO-2 will measure the global distribution of carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth’s climate. OCO-2 is set for a July 1, 2014 launch. Photo Credit: (NASA/Bill Ingalls)

Orbiting Carbon Observatory-2 (OCO-2)

NASA Image and Video Library

2014-06-30

The United Launch Alliance Delta II rocket with the Orbiting Carbon Observatory-2 (OCO-2) satellite onboard, is seen moments after the launch gantry was moved at the Space Launch Complex 2, Monday, June 30, 2014, Vandenberg Air Force Base, Calif. OCO-2 will measure the global distribution of carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth’s climate. OCO-2 is set for a July 1, 2014 launch. Photo Credit: (NASA/Bill Ingalls)

Orbiting Carbon Observatory-2 (OCO-2)

NASA Image and Video Library

2014-06-30

The launch gantry is rolled back to reveal the United Launch Alliance Delta II rocket with the Orbiting Carbon Observatory-2 (OCO-2) satellite onboard, at the Space Launch Complex 2, Monday, June 30, 2014, Vandenberg Air Force Base, Calif. OCO-2 will measure the global distribution of carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth’s climate. OCO-2 is set for a July 1, 2014 launch. Photo Credit: (NASA/Bill Ingalls)

Orbiting Carbon Observatory-2 (OCO-2)

NASA Image and Video Library

2014-06-29

The upper levels of the launch gantry, surrounding the United Launch Alliance Delta II rocket with the Orbiting Carbon Observatory-2 (OCO-2) satellite onboard, are seen at the Space Launch Complex 2, Sunday, June 29, 2014, Vandenberg Air Force Base, Calif. OCO-2 will measure the global distribution of carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth’s climate. OCO-2 is set for a July 1, 2014 launch. Photo Credit: (NASA/Bill Ingalls)

Orbiting Carbon Observatory-2 (OCO-2) Launch

NASA Image and Video Library

2014-07-02

Lights shine on the umbilical tower shortly after a United Launch Alliance Delta II rocket launched with the Orbiting Carbon Observatory-2 (OCO-2)satellite onboard from Space Launch Complex 2 at Vandenberg Air Force Base, Calif. on Wednesday, July 2, 2014. OCO-2 will measure the global distribution of carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth’s climate. Photo Credit: (NASA/Bill Ingalls)

The high energy astronomy observatories

NASA Technical Reports Server (NTRS)

Neighbors, A. K.; Doolittle, R. F.; Halpers, R. E.

1977-01-01

The forthcoming NASA project of orbiting High Energy Astronomy Observatories (HEAO's) designed to probe the universe by tracing celestial radiations and particles is outlined. Solutions to engineering problems concerning HEAO's which are integrated, yet built to function independently are discussed, including the onboard digital processor, mirror assembly and the thermal shield. The principle of maximal efficiency with minimal cost and the potential capability of the project to provide explanations to black holes, pulsars and gamma-ray bursts are also stressed. The first satellite is scheduled for launch in April 1977.

Co-location satellite GPS and SLR geodetic techniques at the Felix Aguilar Astronomical Observatory of San Juan, Argentina

NASA Astrophysics Data System (ADS)

Podestá, R.; Pacheco, A. M.; Alvis Rojas, H.; Quinteros, J.; Podestá, F.; Albornoz, E.; Navarro, A.; Luna, M.

2018-01-01

This work shows the strategy followed for the co-location of the Satellite Laser Ranging (SLR) ILRS 7406 telescope and the antenna of the permanent Global Positioning System (GPS) station, located at the Félix Aguilar Astronomical Observatory (OAFA) in San Juan, Argentina. The accomplishment of the co-location consisted in the design, construction, measurement, adjustment and compensation of a geodesic net between the stations SLR and GPS, securing support points solidly built in the soil. The co-location allows the coordinates of the station to be obtained by combining the data of both SLR and GPS techniques, achieving a greater degree of accuracy than individually. The International Earth Rotation and Reference Systems Service (IERS) considers the co-located stations as the most valuable and important points for the maintenance of terrestrial reference systems and their connection with the celestial ones. The 3 mm precision required by the IERS has been successfully achieved.

3D Studies of the Solar Corona and its Evolution with SOHO/EIT

NASA Astrophysics Data System (ADS)

Portier-Fozzani, F.

This thesis deals with 3D evolution of coronal structures based upon the ultraviolet telescope of SOHO : EIT. Anaglyphs and incertainties on a complete stereovision reconstruction are described. Stereoscopic methods for loop reconstruction were successfully made to find 3D parameters. With dynamical stereoscopy, physical conditions were derived for 30 loops of temperature around 1MK. A method which is able to derive twist variation were also built. Emerging loops were found highly twisted and they detwist as they grow. According to helicity conservation, this correspond to a transfert of twist into expansion. Long time twist evolution of magnetic flux tubes are followed in relation with flares as relaxation. Interaction between magnetic field lines were analysed. An example of reconnection between open and closed field line were observed. Other interactions were found with multi-wavelength observations : coronal holes borders (and thus CH) are better defined when an active region nearby is growing. Other imaging techniques were used to better take profit as possible of SOHO/EIT. A multiscale vision model (MVM) was applied with success to show small coronal structures evolutions hidden by the noise level.

Operation of U.S. Geological Survey unmanned digital magnetic observatories

USGS Publications Warehouse

Wilson, L.R.

1990-01-01

The precision and continuity of data recorded by unmanned digital magnetic observatories depend on the type of data acquisition equipment used and operating procedures employed. Three generations of observatory systems used by the U.S. Geological Survey are described. A table listing the frequency of component failures in the current observatory system has been compiled for a 54-month period of operation. The cause of component failure was generally mechanical or due to lightning. The average percentage data loss per month for 13 observatories operating a combined total of 637 months was 9%. Frequency distributions of data loss intervals show the highest frequency of occurrence to be intervals of less than 1 h. Installation of the third generation system will begin in 1988. The configuration of the third generation observatory system will eliminate most of the mechanical problems, and its components should be less susceptible to lightning. A quasi-absolute coil-proton system will be added to obtain baseline control for component variation data twice daily. Observatory data, diagnostics, and magnetic activity indices will be collected at 12-min intervals via satellite at Golden, Colorado. An improvement in the quality and continuity of data obtained with the new system is expected. ?? 1990.

New Astrometric Reduction of the USNO Photographic Plates of Planetary Satellites

NASA Astrophysics Data System (ADS)

de Cuyper, J.-P.; Winter, L.; de Decker, G.; Zacharias, N.; Pascu, D.; Arlot, J.-E.; Robert, V.; Lainey, V.

2009-09-01

An international collaboration has been set up between the US Naval Observatory (USNO) in Washington DC, the IMCCE of Paris Observatory (OBSPM) and the Royal Observatory of Belgium (ROB) to make a new astrometric reduction of the USNO archival photographic plates of planetary satellites. In order to obtain a better knowledge of their orbital motions these photographic plates are digitized with the new generation DAMIAN digitizer at the ROB, providing a geometric stability of better than 0.1 μm on the plates. We focus here on a subset of a few hundred photographic plates of the Galilean satellites, taken with the McCormick and the USNO 26-inch refractors between 1967 and 1998. Specific procedures and algorithms are used to obtain highly accurate positions using the Tycho2, UCAC2 (20 - 30 mas) and later the UCAC3 (10 - 20 mas) catalogues. A comparison with the MAMA digitizer of the Paris Observatory is made through the results obtained from digital mosaic images of the plates.

Evaluation and modeling of autonomous attitude thrust control for the Geostation Operational Environmental Satellite (GOES)-8 orbit determination

NASA Technical Reports Server (NTRS)

Forcey, W.; Minnie, C. R.; Defazio, R. L.

1995-01-01

The Geostationary Operational Environmental Satellite (GOES)-8 experienced a series of orbital perturbations from autonomous attitude control thrusting before perigee raising maneuvers. These perturbations influenced differential correction orbital state solutions determined by the Goddard Space Flight Center (GSFC) Goddard Trajectory Determination System (GTDS). The maneuvers induced significant variations in the converged state vector for solutions using increasingly longer tracking data spans. These solutions were used for planning perigee maneuvers as well as initial estimates for orbit solutions used to evaluate the effectiveness of the perigee raising maneuvers. This paper discusses models for the incorporation of attitude thrust effects into the orbit determination process. Results from definitive attitude solutions are modeled as impulsive thrusts in orbit determination solutions created for GOES-8 mission support. Due to the attitude orientation of GOES-8, analysis results are presented that attempt to absorb the effects of attitude thrusting by including a solution for the coefficient of reflectivity, C(R). Models to represent the attitude maneuvers are tested against orbit determination solutions generated during real-time support of the GOES-8 mission. The modeling techniques discussed in this investigation offer benefits to the remaining missions in the GOES NEXT series. Similar missions with large autonomous attitude control thrusting, such as the Solar and Heliospheric Observatory (SOHO) spacecraft and the INTELSAT series, may also benefit from these results.

Orbiting Carbon Observatory-2 (OCO-2)

NASA Image and Video Library

2014-06-27

The launch gantry, surrounding the United Launch Alliance Delta II rocket with the Orbiting Carbon Observatory-2 (OCO-2) satellite onboard, is seen in this black and white infrared view at Space Launch Complex 2, Friday, June 27, 2014, Vandenberg Air Force Base, Calif. OCO-2 will measure the global distribution of carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth’s climate. OCO-2 is set for a July 1, 2014 launch. Photo Credit: (NASA/Bill Ingalls)

Orbiting Carbon Observatory-2 (OCO-2)

NASA Image and Video Library

2014-06-30

NASA Administrator Charles Bolden, left, talks with an engineer at the base of the United Launch Alliance Delta II rocket with the Orbiting Carbon Observatory-2 (OCO-2) satellite onboard, Monday, June 30, 2014, Space Launch Complex 2, Vandenberg Air Force Base, Calif. OCO-2 will measure the global distribution of carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth’s climate. OCO-2 is set for a July 1, 2014 launch. Photo Credit: (NASA/Bill Ingalls)

Orbiting Carbon Observatory-2 (OCO-2)

NASA Image and Video Library

2014-06-30

Workers monitor the progress of the rollback of the launch gantry from the United Launch Alliance Delta II rocket with the Orbiting Carbon Observatory-2 (OCO-2) satellite onboard, at Space Launch Complex 2, Monday, June 30, 2014, Vandenberg Air Force Base, Calif. OCO-2 will measure the global distribution of carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth’s climate. OCO-2 is set for a July 1, 2014 launch. Photo Credit: (NASA/Bill Ingalls)

Earth resources applications of the Synchronous Earth Observatory Satellite (SEOS)

NASA Technical Reports Server (NTRS)

Lowe, D. S.; Cook, J. J.

1973-01-01

The results are presented of a four month study to define earth resource applications which are uniquely suited to data collection by a geosynchronous satellite. While such a satellite could also perform many of the functions of ERTS, or its low orbiting successors, those applications were considered in those situations where requirements for timely observation limit the capability of ERTS or EOS. Thus, the application presented could be used to justify a SEOS.

Digitization and Position Measurement of Astronomical Plates of Saturnian Satellites

NASA Astrophysics Data System (ADS)

Yan, D.; Yu, Y.; Zhang, H. Y.; Qiao, R. C.

2014-05-01

Using the advanced commercial scanners to digitize astronomical plates may be a simple and effective way. In this paper, we discuss the method of digitizing and astrometrically reducing six astronomical plates of Saturnian satellites, which were taken from the 1 m RCC (Ritchey Chretien Coude) telescope of Yunnan Observatory in 1988, by using the 10000XL scanner of Epson. The digitized images of the astronomical plates of Saturnian satellites are re-reduced, and the positions of Saturnian satellites based on the UCAC2 (The Second US Naval Observatory CCD Astrograph Catalog) catalogue are given. A comparison of our measured positions with the IMCCE (Institut de Mecanique Celeste et de Calcul des Ephemerides) ephemeris of Saturnian satellites shows the high quality of our measurements, which have an accuracy of 106 mas in right ascension and 89 mas in declination. Moreover, our measurements appear to be consistent with this ephemeris within only about 56 mas in right ascension and 9 mas in declination.

Earth Observatory Satellite system definition study. Report no. 3: Design/cost tradeoff studies. Appendix D: EOS configuration design data. Part 2: Data management system configuration

NASA Technical Reports Server (NTRS)

1974-01-01

The Earth Observatory Satellite (EOS) data management system (DMS) is discussed. The DMS is composed of several subsystems or system elements which have basic purposes and are connected together so that the DMS can support the EOS program by providing the following: (1) payload data acquisition and recording, (2) data processing and product generation, (3) spacecraft and processing management and control, and (4) data user services. The configuration and purposes of the primary or high-data rate system and the secondary or local user system are explained. Diagrams of the systems are provided to support the systems analysis.

Combining virtual observatory and equivalent source dipole approaches to describe the geomagnetic field with Swarm measurements

NASA Astrophysics Data System (ADS)

Saturnino, Diana; Langlais, Benoit; Amit, Hagay; Civet, François; Mandea, Mioara; Beucler, Éric

2018-03-01

A detailed description of the main geomagnetic field and of its temporal variations (i.e., the secular variation or SV) is crucial to understanding the geodynamo. Although the SV is known with high accuracy at ground magnetic observatory locations, the globally uneven distribution of the observatories hampers the determination of a detailed global pattern of the SV. Over the past two decades, satellites have provided global surveys of the geomagnetic field which have been used to derive global spherical harmonic (SH) models through some strict data selection schemes to minimise external field contributions. However, discrepancies remain between ground measurements and field predictions by these models; indeed the global models do not reproduce small spatial scales of the field temporal variations. To overcome this problem we propose to directly extract time series of the field and its temporal variation from satellite measurements as it is done at observatory locations. We follow a Virtual Observatory (VO) approach and define a global mesh of VOs at satellite altitude. For each VO and each given time interval we apply an Equivalent Source Dipole (ESD) technique to reduce all measurements to a unique location. Synthetic data are first used to validate the new VO-ESD approach. Then, we apply our scheme to data from the first two years of the Swarm mission. For the first time, a 2.5° resolution global mesh of VO time series is built. The VO-ESD derived time series are locally compared to ground observations as well as to satellite-based model predictions. Our approach is able to describe detailed temporal variations of the field at local scales. The VO-ESD time series are then used to derive global spherical harmonic models. For a simple SH parametrization the model describes well the secular trend of the magnetic field both at satellite altitude and at the surface. As more data will be made available, longer VO-ESD time series can be derived and consequently used to

High Time-Resolved Kinetic Temperatures of Solar Wind Minor Ions Measured with SOHO/CELIAS/CTOF

NASA Astrophysics Data System (ADS)

Janitzek, N. P.; Berger, L.; Drews, C.; Wimmer-Schweingruber, R. F.

2017-12-01

Solar wind heavy ions with an atomic number Z > 2 are referred to as minor ions since they represent a fraction of less than one percent of all solar wind ions. They can be therefore regarded as test particles, only reacting to but not driving the dynamics of the solar wind plasma, which makes them a unique diagnostic tool for plasma wave phenomena both in the solar atmosphere and the extended heliosphere. In the past, several studies have investigated the kinetic temperatures of minor ions, but due to low counting statistics these studies are based on ion velocity distribution functions (VDFs) recorded over time periods of several hours. The Charge Time-Of-Flight (CTOF) mass spectrometer as part of the Charge, ELement and Isotope Analysis System (CELIAS) onboard the SOlar and Heliospheric Observatory (SOHO) provides solar wind heavy ion 1D radial VDFs with excellent charge state separation, an unprecedented cadence of 5 minutes and very high counting statistics, exceeding similar state-of-the-art instruments by a factor of ten. In our study, based on CTOF measurements at Langrangian point L1 between DOY 150 and DOY 220 in 1996, we investigate systematically the influence of the VDF time resolution on the derived kinetic temperatures for solar wind silicon and iron ions. The selected ion set spans a wide range of mass-per-charge from 3 amu/e < m/q < 8 amu/e. Therefore, it is suitable for the search of signatures of gyrofrequency-dependent heating processes resulting from the resonant interaction of heavy ions with ion-cyclotron waves.

Operational thermal remote sensing and lava flow monitoring at the Hawaiian Volcano Observatory

USGS Publications Warehouse

Patrick, Matthew R.; Kauahikaua, James P.; Orr, Tim R.; Davies, Ashley G.; Ramsey, Michael S.

2016-01-01

Hawaiian volcanoes are highly accessible and well monitored by ground instruments. Nevertheless, observational gaps remain and thermal satellite imagery has proven useful in Hawai‘i for providing synoptic views of activity during intervals between field visits. Here we describe the beginning of a thermal remote sensing programme at the US Geological Survey Hawaiian Volcano Observatory (HVO). Whereas expensive receiving stations have been traditionally required to achieve rapid downloading of satellite data, we exploit free, low-latency data sources on the internet for timely access to GOES, MODIS, ASTER and EO-1 ALI imagery. Automated scripts at the observatory download these data and provide a basic display of the images. Satellite data have been extremely useful for monitoring the ongoing lava flow activity on Kīlauea's East Rift Zone at Pu‘u ‘Ō‘ō over the past few years. A recent lava flow, named Kahauale‘a 2, was upslope from residential subdivisions for over a year. Satellite data helped track the slow advance of the flow and contributed to hazard assessments. Ongoing improvement to thermal remote sensing at HVO incorporates automated hotspot detection, effusion rate estimation and lava flow forecasting, as has been done in Italy. These improvements should be useful for monitoring future activity on Mauna Loa.

Relationship Between the Expansion Speed and Radial Speed of CMEs Confirmed Using Quadrature Observations from SOHO and STEREO

NASA Technical Reports Server (NTRS)

Gopalswamy, Nat; Makela, Pertti; Yashiro, Seiji

2011-01-01

It is difficult to measure the true speed of Earth-directed CMEs from a coronagraph along the Sun-Earth line because of the occulting disk. However, the expansion speed (the speed with which the CME appears to spread in the sky plane) can be measured by such coronagraph. In order to convert the expansion speed to radial speed (which is important for space weather applications) one can use empirical relationship between the two that assumes an average width for all CMEs. If we have the width information from quadrature observations, we can confirm the relationship between expansion and radial speeds derived by Gopalswamy et al. (2009, CEAB, 33, 115,2009). The STEREO spacecraft were in quadrature with SOHO (STEREO-A ahead of Earth by 87 and STEREO-B 94 behind Earth) on 2011 February 15, when a fast Earth-directed CME occurred. The CME was observed as a halo by the Large-Angle and Spectrometric Coronagraph (LASCO) on board SOHO. The sky-plane speed was measured by SOHO/LASCO as the expansion speed, while the radial speed was measured by STEREO-A and STEREO-B. In addition, STEREO-A and STEREO-B images measured the width of the CME, which is unknown from Earth view. From the SOHO and STEREO measurements, we confirm the relationship between the expansion speed (Vexp ) and radial speed (Vrad ) derived previously from geometrical considerations (Gopalswamy et al. 2009): Vrad = 1/2 (1 + cot w) Vexp, where w is the half width of the CME. STEREO-B images of the CME, we found that CME had a full width of 75 degrees, so w = 37.5 degrees. This gives the relation as Vrad = 1.15 Vexp. From LASCO observations, we measured Vexp = 897 km/s, so we get the radial speed as 1033 km/s. Direct measurement of radial speed from STEREO gives 945 km/s (STEREO-A) and 1057 km/s (STEREO-B). These numbers are different only by 2.3% and 8.5% (for STEREO-A and STEREO-B, respectively) from the computed value.

Orbiting Carbon Observatory-2 (OCO-2)

NASA Image and Video Library

2014-06-30

NASA Administrator Charles Bolden answers social media attendees questions from just outside the launch pad where the United Launch Alliance Delta II rocket with the Orbiting Carbon Observatory-2 (OCO-2) satellite onboard sits ready to launch, Monday, June 30, 2014, Space Launch Complex 2 Vandenberg Air Force Base, Calif. OCO-2 will measure the global distribution of carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth’s climate. OCO-2 is set for a July 1, 2014 launch. Photo Credit: (NASA/Bill Ingalls)

ISAGEX (International Satellite Geodesy Experiment) experience. 1: Data acquisition

NASA Technical Reports Server (NTRS)

Gaposchkin, E. M. (Editor)

1972-01-01

The contributions and methods of the Smithsonian Astrophysical Observatory to the International Satellite Geodesy program are described. The report provides data users with necessary supporting information.

SOHO-Ulysses Coordinated Studies During the Two Extended Quadratures and the Alignment of 2007-2008

NASA Technical Reports Server (NTRS)

Suess, S. T.; Poletto, G.

2007-01-01

During SOHO-Sun-Ulysses quadratures the geometry of the configuration makes it possible to sample "in situ" the plasma parcels that are remotely observed in the corona. Although the quadrature position occurs at a well defined instant in time, we typically take data while Ulysses is within +/- 5 degrees of the limb, with the understanding that plasma sampled by Ulysses over this time interval can all be traced to its source in the corona. The relative positions of SOHO and Ulysses in winter 2007 (19 Dec 2006-28 May 2007) are unusual: the SOHO-Sun-Ulysses included angle is always between 85 and 95 degrees - the quadrature lasts for 5 months! This provides an opportunity for extended observations of specific observing objectives. In addition, in summer 2007, Ulysses (at 1.34 AU) is in near-radial alignment with Earth/ACE/Wind and SOHO, allowing us to analyze radial gradients and propagation in the solar wind and inner heliosphere. Our own quadrature campaigns rely heavily on LASCO and UVCS coronal observations: LASCO giving the overall context above 2 solar radii while the UVCS spectrograph acquired data from - 1.5 to, typically, 4-5 solar radii. In the past, coronal parameters have been derived from data acquired by these two experiments and compared with "in situ" data of Ulysses' SWOOPS and SWICS. Data from other experiments like EIT, CDS, SUMER, Sac Peak Fe XIV maps, magnetic field maps from the Wilcox solar magnetograph, MLSO, from MDI, and from the Ulysses magnetograph experiment have been, and will be, used to complement LASCO/UVCS/SWOOPS and SWICS data. We anticipate that observations by ACE/WIND/STEREO/Hinode and other missions will be relevant as well. During the IHY campaigns, Ulysses will be 52-80 degrees south in winter 2007, near sunspot minimum. Hence, our own scientific objective will be to sample high speed wind or regions of transition between slow and fast wind. This might be a very interesting situation - not met in previous quadratures - allowing

Orbiting Carbon Observatory-2 (OCO-2) Launch

NASA Image and Video Library

2014-07-02

Members of the media are unable to see the launch of the United Launch Alliance Delta II rocket with the Orbiting Carbon Observatory-2 (OCO-2) satellite onboard due to heavy fog at Vandenberg Air Force Base, Calif. on Wednesday, July 2, 2014. OCO-2 launched at 2:56 a.m. PDT. OCO-2 will measure the global distribution of carbon dioxide, the leading human-produced greenhouse gas driving changes in Earth’s climate. Photo Credit: (NASA/Bill Ingalls)

LOI/SOHO constraints on oblique rotation of the solar core

NASA Astrophysics Data System (ADS)

Gizon, L.; Appourchaux, T.; Gough, D. O.

The Sun is usually assumed to rotate about a single axis, tilted with respect to the ecliptic normal by an angle of 7.25 degrees. Although we have an excellent knowledge of the direction of the rotation axis of the photospheric layers, we cannot exclude a priori that the direction of the rotation axis could vary as a function of radius. We have tried to check whether the assumption of rotation about a unique axis is consistent with helioseismic data. We report on an attempt to measure the directions of the pulsation axes of several low-degree modes of oscillation in the LOI/SOHO Fourier spectra.

The NASA CYGNSS Small Satellite Constellation

NASA Astrophysics Data System (ADS)

Ruf, C. S.; Gleason, S.; McKague, D. S.; Rose, R.; Scherrer, J.

2017-12-01

The NASA Cyclone Global Navigation Satellite System (CYGNSS) is a constellation of eight microsatellite observatories that was launched into a low (35°) inclination, low Earth orbit on 15 December 2016. Each observatory carries a 4-channel GNSS-R bistatic radar receiver. The radars are tuned to receive the L1 signals transmitted by GPS satellites, from which near-surface ocean wind speed is estimated. The mission architecture is designed to improve the temporal sampling of winds in tropical cyclones (TCs). The 32 receive channels of the complete CYGNSS constellation, combined with the 30 GPS satellite transmitters, results in a revisit time for sampling of the wind of 2.8 hours (median) and 7.2 hours (mean) at all locations between 38 deg North and 38 deg South latitude. Operation at the GPS L1 frequency of 1575 MHz allows for wind measurements in the TC inner core that are often obscured from other spaceborne remote sensing instruments by intense precipitation in the eye wall and inner rain bands. An overview of the CYGNSS mission wil be presented, followed by early on-orbit status and results.

High-time resolution measurements of solar wind heavy ions with SOHO/CELIAS/CTOF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janitzek, N. P., E-mail: janitzek@physik.uni-kiel.de; Taut, A.; Berger, L.

2016-03-25

The Charge Time-Of-Flight (CTOF) mass spectrometer as part of the Charge, ELement and Isotope Analysis System (CELIAS) onboard the SOlar and Heliospheric Observatory (SOHO) is designed to measure the kinetic properties and elemental/ionic composition of solar wind ions heavier than protons, which we refer to as heavy ions. This is achieved by the combined measurements of the energy-per-charge, the time-of-flight and the energy of incident ions. The CTOF instrument combines a remarkable time-of-flight resolution with a large effective area and a high measurement cadence. This allows to determine the Velocity Distribution Functions (VDFs) of a wide range of heavy ionsmore » with 5-minute time resolution which ensures that the complete VDF is measured under nearly identical solar wind and magnetic field conditions. For the measurement period between Day Of Year (DOY) 150 and 220 in 1996, which covers a large part of the instrument’s short life time, we analyzed VDFs of solar wind iron Fe{sup 8+}, Fe{sup 9+} and Fe{sup 10+} for differential streaming relative to the solar wind proton speed measured simultaneously with the CELIAS Proton Monitor (PM). We find an increasing differential streaming with increasing solar wind proton speed for all investigated ions up to ion-proton velocity differences of 30 - 50 km s{sup −1} at proton velocities of 500 km s{sup −1}, which is contradictory to an earlier CTOF study by [7]. We believe this difference is because in this study we used raw Pulse Height Analysis (PHA) data with a significantly increased mass and mass-per-charge resolution compared to the earlier used onboard preprocessed data.« less

VO-ESD: a virtual observatory approach to describe the geomagnetic field temporal variations with application to Swarm data

NASA Astrophysics Data System (ADS)

Saturnino, Diana; Langlais, Benoit; Amit, Hagay; Mandea, Mioara; Civet, François; Beucler, Éric

2017-04-01

A complete description of the main geomagnetic field temporal variation is crucial to understand dynamics in the core. This variation, termed secular variation (SV), is known with high accuracy at ground magnetic observatory locations. However the description of its spatial variability is hampered by the globally uneven distribution of the observatories. For the past two decades a global coverage of the field changes has been allowed by satellites. Their surveys of the geomagnetic field have been used to derive and improve global spherical harmonic (SH) models through some strict data selection schemes to minimise external field contributions. But discrepancies remain between ground measurements and field predictions by these models. Indeed, the global models do not reproduce small spatial scales of the field temporal variations. To overcome this problem we propose a modified Virtual Observatory (VO) approach by defining a globally homogeneous mesh of VOs at satellite altitude. With this approach we directly extract time series of the field and its temporal variation from satellite measurements as it is done at observatory locations. As satellite measurements are acquired at different altitudes a correction for the altitude is needed. Therefore, we apply an Equivalent Source Dipole (ESD) technique for each VO and each given time interval to reduce all measurements to a unique location, leading to time series similar to those available at ground magnetic observatories. Synthetic data is first used to validate the new VO-ESD approach. Then, we apply our scheme to measurements from the Swarm mission. For the first time, a 2.5 degrees resolution global mesh of VO times series is built. The VO-ESD derived time series are locally compared to ground observations as well as to satellite-based model predictions. The approach is able to describe detailed temporal variations of the field at local scales. The VO-ESD time series are also used to derive global SH models. Without

Earth Science

NASA Image and Video Library

1995-12-02

The Solar Heliospheric Observatory (SOHO) is launched atop an ATLAS-IIAS expendable launch vehicle. Liftoff from launch complex 36B at Cape Canaveral Air Station marked the 10th Atlas launch from the Eastern range for 1995. SOHO is a cooperative effort involving NASA and the European Space Agency (ESA) within the framework of the International Solar-Terrestrial Physics Program. During its 2-year mission, the SOHO spacecraft gathered data on the internal structure of the Sun, its extensive outer atmosphere and the origin of the solar wind.

Earth Science

NASA Image and Video Library

1995-12-01

The reflection of the Atlas IIAS expendable launch vehicle with the Solar Heliospheric Observatory (SOHO) inside its payload fairing can be seen on the surface of a retention pond at Launch Pad 36B on Cape Canaveral Air Station just hours before liftoff. SOHO is a cooperative effort involving NASA and the European Space Agency (ESA) within the framework of the International Solar-Terrestrial Physics Program. During its 2-year mission, the SOHO spacecraft will gather data on the internal structure of the Sun, its extensive outer atmosphere and the origin of the solar wind.

An Overview of the Performance and Scientific Results From the Chandra X-Ray Observatory (CXO)

NASA Technical Reports Server (NTRS)

Weisskopf, M. C.; Brinkman, B.; Canizares, C.; Garmine, G.; Murray, S.; VanSpeybroeck, L. P.; Six, N. Frank (Technical Monitor)

2001-01-01

The Chandra X-Ray Observatory (CXO), the x-ray component of NASA's Great Observatories, was launched on 1999, July 23 by the Space Shuttle Columbia. After satellite systems activation, the first x-rays focused by the telescope were observed on 1999, August 12. Beginning with the initial observation it was clear that the telescope had survived the launch environment and was operating as expected. Despite an initial surprise due to the discovery that the telescope was far more efficient for concentrating CCD-damaging low-energy protons than had been anticipated, the observatory is performing well and is returning superb scientific data. Together with other space observatories, most notably XMM-Newton, it is clear that we have entered a new era of discovery in high-energy astrophysics.

Population of SOHO/STEREO Kreutz sungrazers and the arrival of comet C/2011 W3 (Lovejoy)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sekanina, Zdenek; Kracht, Rainer, E-mail: Zdenek.Sekanina@jpl.nasa.gov, E-mail: r.kracht@t-online.de

2013-11-20

We examine properties of the population of SOHO/STEREO (dwarf) Kreutz sungrazing comets from 2004 to 2013, including the arrival rates, peculiar gaps, and a potential relationship to the spectacular comet C/2011 W3 (Lovejoy). Selection effects, influencing the observed distribution, are largely absent among bright dwarf sungrazers, whose temporal sequence implies the presence of a swarm, with objects brighter at maximum than an apparent magnitude of 3 arriving at a peak rate of ∼4.6 yr{sup –1} in late 2010, while those brighter than magnitude 2 arrived at a peak rate of ∼4.3 yr{sup –1} in early 2011, both a few timesmore » the pre-swarm rate. The entire population of SOHO/STEREO Kreutz sungrazers also peaked about one year before the appearance of C/2011 W3. Orbital data show, however, that a great majority of bright dwarf sungrazers moved in paths similar to that of comet C/1843 D1, deviating 10° or more from the orbit of C/2011 W3 in the angular elements. The evidence from the swarm and the overall elevated arrival rates suggests the existence of a fragmented sizable sungrazer that shortly preceded C/2011 W3 but was independent of it. On the other hand, these findings represent another warning signal that the expected 21st century cluster of spectacular Kreutz comets is on its way to perihelion, to arrive during the coming decades. It is only in this sense that we find a parallel link between C/2011 W3 and the spikes in the population of SOHO/STEREO Kreutz sungrazers.« less

Earth Observatory Satellite system definition study. Report no. 3: Design/cost tradeoff studies. Appendix E: EOS program supporting system trade data. Part 2: System trade studies no. 9 - 19

NASA Technical Reports Server (NTRS)

1974-01-01

The relative merits of several international data acquisition (IDA) alternatives for the Earth Observatory Satellite (EOS) are established and rated on a cost effectiveness basis. The primary alternatives under consideration are: (1) direct transmission to foreign ground stations, (2) a wideband video tape recorder system for collection of foreign data and processing and distribution from the United States, and (3) a tracking and data relay satellite (TDRS) system for the relay of foreign data to the United States for processing and distribution. A requirements model is established for the analysis on the basis of the heaviest concentration of agricultural areas around the world. The model, the orbit path and the constraints of EOS and data volume summaries are presented. Alternative system descriptions and costs are given in addition to cost-performance summaries.

The radio astronomy explorer satellite, a low-frequency observatory.

NASA Technical Reports Server (NTRS)

Weber, R. R.; Alexander, J. K.; Stone, R. G.

1971-01-01

The RAE-1 is the first spacecraft designed exclusively for radio astronomical studies. It is a small, but relatively complex, observatory including two 229-meter antennas, several radiometer systems covering a frequency range of 0.2 to 9.2 MHz, and a variety of supporting experiments such as antenna impedance probes and TV cameras to monitor antenna shape. Since its launch in July, 1968, RAE-1 has sent back some 10 billion data bits per year on measurements of long-wavelength radio phenomena in the magnetosphere, the solar corona, and the Galaxy. In this paper we describe the design, calibration, and performance of the RAE-1 experiments in detail.

History of Chandra X-Ray Observatory

NASA Image and Video Library

1999-01-01

In this photograph, the Chandra X-Ray Observatory (CXO) was installed and mated to the Inertial Upper Stage (IUS) inside the Shuttle Columbia's cargo bay at the Kennedy Space Center. The CXO will help astronomers world-wide better understand the structure and evolution of the universe by studying powerful sources of x-rays such as exploding stars, matter falling into black holes, and other exotic celestial objects. X-ray astronomy can only be done from space because Earth's atmosphere blocks x-rays from reaching the surface. The Observatory provides images that are 50 times more detailed than previous x-ray missions. At more than 45 feet in length and weighing more than 5 tons, the CXO was carried into low-Earth orbit by the Space Shuttle Columbia (STS-93 mission) on July 22, 1999. The Observatory was deployed from the Shuttle's cargo bay at 155 miles above the Earth. Two firings of an attached IUS rocket, and several firings of its own onboard rocket motors, after separating from the IUS, placed the Observatory into its working orbit. The IUS is a solid rocket used to place spacecraft into orbit or boost them away from the Earth on interplanetary missions. Since its first use by NASA in 1983, the IUS has supported a variety of important missions, such as the Tracking and Data Relay Satellite, Galileo spacecraft, Magellan spacecraft, and Ulysses spacecraft. The IUS was built by the Boeing Aerospace Co., at Seattle, Washington and managed by the Marshall Space Flight Center.

Measurements of Heavy Ion Differential Streaming with SOHO/CELIAS/CTOF and ACE/SWICS at 1 AU

NASA Astrophysics Data System (ADS)

Janitzek, Nils; Berger, Lars; Taut, Andreas; Drews, Christian; Wimmer-Schweingruber, Robert

2016-04-01

Helios measurements in the early 1980s showed the existence of a systematic velocity difference, called "differential streaming", between solar wind bulk protons and alpha particles with the alphas streaming faster than the protons. The absolute differential speed between these species decreases with radial distance to the Sun and decreasing proton speed. In the fast wind it was measured to be approximately half of the local Alfvén speed. However, the detailed processes of acceleration and regulation of differential streaming are still not well understood. A proposed key process is resonant wave particle interaction between the ions and Alfvén waves near the ion-cyclotron frequency which is able to accelerate the alphas preferentially due to their higher mass-per-charge ratio. Measuring the differential speed of a wide set of solar wind heavy ions and therefore extending the mass-per-charge range significantly can provide additional information on the underlying processes that we cannot infer from the alphas and protons alone. We analysed data measured at L1 by SOHO/CELIAS/CTOF in 1996 and ACE/SWICS from 2001 to 2010. Both instruments are linear time-of-flight mass spectrometers which measure the ions' radial 1D velocity distributions with a cadence of 5 and 12 minutes, respectively. Comparing the mean ion speed, with the mean proton speed measured routinely by the SOHO/CELIAS/MTOF/PM and ACE/SWEPAM, respectively, we obtain the differential streaming for major charge states of solar wind carbon, oxygen, neon, magnesium, silicon and iron. In the case of the SWICS data the magnetometer on-board ACE (ACE/MAG) allows us to directly relate the differential streaming to the ambient Alfvén velocity while the lack of in-situ magnetic field measurements on SOHO is compensated by a B-field extrapolation from the WIND spacecraft (WIND/MAG) to the SOHO site. Both instruments show a similar result: significant differential streaming between heavy ions and protons on the

Study of the Most Harmful Solar Energetic Particle for Shielding next Human Space Flights

NASA Astrophysics Data System (ADS)

Komei Yamashiro, Bryan

2015-04-01

Solar energetic particles (SEPs) accelerated by solar events such as flares and coronal mass ejections are radiation risks for humans in space on board the International Space Station (ISS), and will be significant obstacles for future long-duration manned space flight missions. This research supported efforts to improve predictions of large solar storms and aimed for a better understanding of Heliophysics. The main objective was to generate a dated catalog of the highest energy range SEPs measured by the Alpha Magnetic Spectrometer (AMS-02). Using online graphical user interfaces from the satellites, Solar and Heliospeheric Observatory (SOHO) and Geostationary Operational Environmental Satellite (GOES-13, 15), the generated data files from the mounted particle detectors were plotted along a specified energy range. The resulting histograms illustrated the low energy range data from SOHO (4 MeV to 53 MeV) and the low-mid energy range from GOES (0.8 MeV to 500 MeV), which collectively provided a low- to mid-energy range spectrum of the specific event energy ranges versus the SEP proton flux. The high energy range results of the AMS-02 (125 MeV to a few TeV) will eventually be incorporated with the two alternative space satellites of lower energy ranges for a complete analysis across a full SEP energy range. X-ray flux from GOES-15 were then obtained and plotted with the corresponding time to portray initial phenomena of the solar events. This procedure was reproduced for 5 different events determined energetic enough to be measured by AMS-02. The generated plots showed correlation between the different satellite detectors.

SOHO/CDS Measurements of Coronal EUV Polarization above the Limb

NASA Technical Reports Server (NTRS)

Thomas, Roger J.; Oegerle, William R. (Technical Monitor)

2002-01-01

Attempts to measure polarization in coronal EUV emission above the solar limb have been made using the SOHO/CDS normal-incidence spectrometer which has a polarization sensitivity of about 50%, a property that causes variations in intensity response as a function of the spacecraft's roll angle for polarized light. Such observations were made on the disk and up to 0.22 solar radii above the solar limb in a number of EUV lines during two special roll-maneuvers of the SOHO spacecraft. Measurements of intensity gradients were made above a modestly active equatorial region in 1997 and above a relatively cool polar region in 2001. Observed emission lines include He I 584A, He II 304A, 0 IV 555+610A, 0 V 630A, Mg IX 368A, Mg X 610+625A, and Si XI 303A, formed at temperatures that evenly cover the range in logT from 4.1 to 6.2. Near the disk, measured intensities of all lines fall off exponentially at different rates that can be used to determine the density scale-heights of the emitting plasma, since this emission is dominated by collisional excitation with an Ne-squared dependence. Assuming hydrostatic equilibrium, the intensity gradient for each line can then be converted into a 'scale-height temperature', which is found to be closely related to the ionization temperature of each line over the wide range of lines and solar conditions observed. Beyond a certain distance, intensity gradients of the cooler lines switch over to a flatter exponential slope, suggesting that this radiation is dominated by resonance scattering which varies as Ne to the first power. Such radiation should also be linearly polarized in the plane containing the line-of-sight and the solar center, a signature that would strongly confirm this interpretation.

On Overview of the Performance and Scientific Results from the Chandra X-Ray Observatory

NASA Technical Reports Server (NTRS)

Weisskopf, M. C.; Brinkman, B.; Canizares, C.; Garmire, G.; Murray, S.; VanSpeybroeck, L. P.

2002-01-01

The Chandra X-Ray Observatory (CXO) was launched on 1999 July 23 by the Columbia Space Shuttle. The first X-rays focused by the telescope were seen on 1999 August 12 after the satellite systems were activated. Beginning with the first observation, it was clear that the telescope was not damaged by the launch environment and was operating as planned. After the early surprise due to the discovery that the telescope concentrated CCD-damaging low-energy protons far more efficiently than had been expected, the observatory is performing optimally and is returning excellent scientific data. Together with other space observatories, especially XMM-Newton, it is obvious that we have entered a new era of discovery in high-energy astrophysics.

Astrometric observations of Saturn's satellites from McDonald Observatory, 1972. [using reference stars

NASA Technical Reports Server (NTRS)

Abbot, R. I.; Mulholland, J. D.; Shelus, P. J.

1974-01-01

Observations of Saturn's satellites were reduced by means of secondary reference stars obtained by reduction of Palomar Sky Survey (PSS) plates. This involved the use of 39 SAO stars and plate overlap technique to determine the coordinates of 59 fainter stars in the satellite field. Fourteen plate constants were determined for each of the two PSS plates. Comparison of two plate measurement and reduction techniques on the satellite measurements demonstrate the existence of a serious background gradient effect and the utility of microdensitometry to eliminate this error source in positional determinations of close satellites.

the Large Aperture GRB Observatory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bertou, Xavier

2009-04-30

The Large Aperture GRB Observatory (LAGO) aims at the detection of high energy photons from Gamma Ray Bursts (GRB) using the single particle technique (SPT) in ground based water Cherenkov detectors (WCD). To reach a reasonable sensitivity, high altitude mountain sites have been selected in Mexico (Sierra Negra, 4550 m a.s.l.), Bolivia (Chacaltaya, 5300 m a.s.l.) and Venezuela (Merida, 4765 m a.s.l.). We report on the project progresses and the first operation at high altitude, search for bursts in 6 months of preliminary data, as well as search for signal at ground level when satellites report a burst.

Precision tethered satellite attitude control. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Kline-Schoder, Robert J.

1990-01-01

Tethered spacecraft possess unique dynamic characteristics which make them advantageous for certain classes of experiments. One use for which tethers are particularly well suited is to provide an isolated platform for spaceborne observatories. The advantages of tethering a pointing platform 1 or 2 km from a space shuttle or space station are that, compared to placing the observatory on the parent spacecraft, vibrational disturbances are attenuated and contamination is eliminated. In practice, all satellites have some requirement on the attitude control of the spacecraft, and tethered satellites are no exception. It has previously been shown that conventional means of performing attitude control for tethered satellites are insufficient for any mission with pointing requirements more stringent than about 1 deg. This is due mainly to the relatively large force applied by the tether to the spacecraft. A particularly effective method of implementing attitude control for tethered satellites is to use this tether tension force to generate control torques by moving the tether attach point relative to the subsatellite center of mass. A demonstration of this attitude control technique on an astrophysical pointing platform has been proposed for a space shuttle flight test project and is referred to as the Kinetic Isolation Tether Experiment (KITE).

Satellite services system analysis study. Volume 3A: Service equipment requirements, appendix

NASA Technical Reports Server (NTRS)

1981-01-01

Spacecraft descriptions and mission sequences, mission and servicing operations functional analyses, servicing requirements, and servicing equipment are discussed for five reference satellites: the X-ray Timing Explorer, the Upper Atmospheric Research Satellite, the Advanced X-ray Astrophysics Facility, the Earth Gravity Field Survey Mission, and the Orbiting Astronomical Observatory.

TRW Ships NASA's Chandra X-ray Observatory To Kennedy Space Center

NASA Astrophysics Data System (ADS)

1999-04-01

Two U.S. Air Force C-5 Galaxy transport planes carrying the observatory and its ground support equipment landed at Kennedy's Space Shuttle Landing Facility at 2:40 p.m. EST this afternoon. REDONDO BEACH, CA.--(Business Wire)--Feb. 4, 1999--TRW has shipped NASA's Chandra X-ray Observatory ("Chandra") to the Kennedy Space Center (KSC), in Florida, in preparation for a Space Shuttle launch later this year. The 45-foot-tall, 5-ton science satellite will provide astronomers with new information on supernova remnants, the surroundings of black holes, and other celestial phenomena that produce vast quantities of X-rays. Cradled safely in the cargo hold of a tractor-trailer rig called the Space Cargo Transportation System (SCTS), NASA's newest space telescope was ferried on Feb. 4 from Los Angeles International Airport to KSC aboard an Air Force C-5 Galaxy transporter. The SCTS, an Air Force container, closely resembles the size and shape of the Shuttle cargo bay. Over the next few months, Chandra will undergo final tests at KSC and be mated to a Boeing-provided Inertial Upper Stage for launch aboard Space Shuttle Columbia. A launch date for the Space Shuttle STS-93 mission is expected to be announced later this week. The third in NASA's family of Great Observatories that includes the Hubble Space Telescope and the TRW-built Compton Gamma Ray observatory, Chandra will use the world's most powerful X-ray telescope to allow scientists to "see" and monitor cosmic events that are invisible to conventional optical telescopes. Chandra's X-ray images will yield new insight into celestial phenomena such as the temperature and extent of gas clouds that comprise clusters of galaxies and the superheating of gas and dust particles as they swirl into black holes. A TRW-led team that includes the Eastman Kodak Co., Raytheon Optical Systems Inc., and Ball Aerospace & Technologies Corp. designed and built the Chandra X-ray Observatory for NASA's Marshall Space Flight Center. The

Statistical analysis of time transfer data from Timation 2. [US Naval Observatory and Australia

NASA Technical Reports Server (NTRS)

Luck, J. M.; Morgan, P.

1974-01-01

Between July 1973 and January 1974, three time transfer experiments using the Timation 2 satellite were conducted to measure time differences between the U.S. Naval Observatory and Australia. Statistical tests showed that the results are unaffected by the satellite's position with respect to the sunrise/sunset line or by its closest approach azimuth at the Australian station. Further tests revealed that forward predictions of time scale differences, based on the measurements, can be made with high confidence.

Pulkovo Observatory - One of the Main Centers of Astronomical Education in Russia

NASA Astrophysics Data System (ADS)

Shakht, Natalia A.

2007-08-01

Since the beginning of the activity in 1839, Pulkovo observatory was an important center of the teaching of astronomy and geodesy in Russia. The first director of Pulkovo observatory W. Ja. Struve together with Pulkovo astronomers taught the topographers and specialists in geodesy and to naval officers the methods of geographic coordinates determinations. Pulkovo observatory was the center of the improvement of such specialists till 1928. Pulkovo astronomers lecture for students in the leading educational centers during many decades and at present and also lead the aspirants and researchers. The works of Pulkovo astronomers have been united in the known textbooks of astronomy and stellar astronomy with several re-editions. In 1957-1965 after the first launch of artificial satellite, many seminars and schools, which were dedicated to study of observations of artificial satellites and to the space geodesy have been organized at Pulkovo. Each year, about 10-15 thousands of guests visit Pulkovo. Our astronomers have the contact with the amateurs of astronomy in many countries and collect the information on their observations. More than 1,000,000 observations of asteroids and comets made by amateurs are collected with the scientific aims, particularly for the enlargement of the information about NEOs. Pulkovo astronomers lecture and give the practical lessons in ecological expeditions, which unite young people of various places of Russia.

The X-ray astronomy satellite ASCA

NASA Technical Reports Server (NTRS)

Tanaka, Yasuo; Inoue, Hajime; Holt, Stephen S.

1994-01-01

Advanced Satellite for Cosmology and Astrophysics (ASCA) is a high-throughput X-ray astronomy observatory which is capable of simultaneous imaging and spectroscopic observations over a wide energy range 0.5-10 keV. The scientific capabilities of ASCA and some aspects related to its operation and observations are briefly described.

Earth Observatory Satellite system definition study. Report no. 3: Design/cost tradeoff studies. Appendix D: EOS configuration design data. Part 1: Spacecraft configuration

NASA Technical Reports Server (NTRS)

1974-01-01

The results of structural studies of the Earth Observatory Satellite (EOS) which define the member sizes to meet the vehicle design requirements are presented. The most significant requirements in sizing the members are the stiffness required to meet the launch vehicle design frequencies both in the late al and in the longitudinal directions. The selected configurations, both baseline and preferred, for the Delta and Titan launch vehicles were evaluated for stiffness requirements. The structural idealization used to estimate the stiffness of each structural arrangement, was based on an evaluation of primary loads paths, effectivity of structural members, and estimated sizes for the preferred configurations. The study included an evaluation of the following structural materials: (1) aluminum alloys, (2) titanium alloys, (3) beryllium, (4) beryllium/aluminum alloy, and (5) composite materials.

NASA to launch European cosmic ray experimental satellite

NASA Technical Reports Server (NTRS)

1975-01-01

Europe's first observatory satellite (COS-B) designed for extraterrestrial gamma radiation study and launched on a Delta rocket for the European Space Agency (ESA) by NASA is briefly described. The COS-B's mission objectives are given along with launch operations.

Introduction to the Infrared Space Observatory (ISO)

NASA Technical Reports Server (NTRS)

Kessler, M. F.; Sibille, F.

1989-01-01

The Infrared Space Observatory (ISO) is an astronomical satellite, which will operate at infrared wavelengths (2.5 to 200 microns) for a period of at least 18 months. Imaging, spectroscopic, photometric and polarimetric observations will be obtained by four scientific instruments in the focal plane of its 60-cm diameter, cryogenically-cooled telescope. Two-thirds of ISO's observing time will be available to the astronomical community. ISO is a fully approved and funded project of the European Space Agency (ESA) with a foreseen launch date of May 1993.

Lunar occultation of Saturn. IV - Astrometric results from observations of the satellites

NASA Technical Reports Server (NTRS)

Dunham, D. W.; Elliot, J. L.

1978-01-01

The method of determining local lunar limb slopes, and the consequent time scale needed for diameter studies, from accurate occultation timings at two nearby telescopes is described. Results for photoelectric observations made at Mauna Kea Observatory during the occultation of Saturn's satellites on March 30, 1974, are discussed. Analysis of all observations of occultations of Saturn's satellites during 1974 indicates possible errors in the ephemerides of Saturn and its satellites.

On the possibility of producing definitive magnetic observatory data within less than one year

NASA Astrophysics Data System (ADS)

Mandić, Igor; Korte, Monika

2017-04-01

Geomagnetic observatory data are fundamental in geomagnetic field studies and are widely used in other applications. Often they are combined with satellite and ground survey data. Unfortunately, the observatory definitive data are only available with a time lag ranging from several months up to more than a year. The reason for this lag is the annual production of the final calibration values, i.e. baselines that are used to correct preliminary data from continuously recording magnetometers. In this paper, we will show that the preparation of definitive geomagnetic data is possible within a calendar year and presents an original method for prompt and automatic estimation of the observatory baselines. The new baselines, obtained in a mostly automatic manner, are compared with the baselines reported on INTERMAGNET DVDs for the 2009-2011 period. The high quality of the baselines obtained by the proposed method indicates its suitability for data processing in fully automatic observatories when automated absolute instruments will be deployed at remote sites.

Experimental Satellite Quantum Communications

NASA Astrophysics Data System (ADS)

Vallone, Giuseppe; Bacco, Davide; Dequal, Daniele; Gaiarin, Simone; Luceri, Vincenza; Bianco, Giuseppe; Villoresi, Paolo

2015-07-01

Quantum communication (QC), namely, the faithful transmission of generic quantum states, is a key ingredient of quantum information science. Here we demonstrate QC with polarization encoding from space to ground by exploiting satellite corner cube retroreflectors as quantum transmitters in orbit and the Matera Laser Ranging Observatory of the Italian Space Agency in Matera, Italy, as a quantum receiver. The quantum bit error ratio (QBER) has been kept steadily low to a level suitable for several quantum information protocols, as the violation of Bell inequalities or quantum key distribution (QKD). Indeed, by taking data from different satellites, we demonstrate an average value of QBER =4.6 % for a total link duration of 85 s. The mean photon number per pulse μsat leaving the satellites was estimated to be of the order of one. In addition, we propose a fully operational satellite QKD system by exploiting our communication scheme with orbiting retroreflectors equipped with a modulator, a very compact payload. Our scheme paves the way toward the implementation of a QC worldwide network leveraging existing receivers.

Pluto-Charon: a test of the astrometric approach for finding asteroid satellites

NASA Astrophysics Data System (ADS)

Kikwaya, J.-B.; Thuillot, W.; Berthier, J.

2003-05-01

The astrometric method to find asteroid satellites is based on the search for the reflex effect on the primary object due to the orbital motion of a possible satellite (Monet & Monet 1998, Kikwaya et al. 2002). As reported by Kikwaya et al. (2003), the astrometric signature of a satellite of 146 Lucina may reach several mas. Spectral analysis might then detect the signal under good conditions of signal/noise ratio, with high quality astrometric measurements and large coverage by different sites of observation. However, the astrometric method cannot be applied to any binary system of asteroids. It depends strongly on the mass ratio of the two bodies and the distance between them (Kikwaya et al. 2002). Pluto-Charon provides a good test of this method. Previous works based on direct imaging of Charon show that its period is 6.357 days and the mass ratio is 0.122 (Wasserman et al. 2000), putting this system into the range that can be observed by our method. Using archived photographic observations (1914-1995) and CCD observations from US Naval Observatory, Flagstaff station (1995-1998), Bordeaux observatory (1996-1997) and Mc Donald Observatory (1997), we are analyzing the position of Pluto to see if its wobble effect due to Charon (amplitude around 95 mas) can be detected and if the orbital period of Charon can be recovered through a spectral analysis. If successful, this will reinforce the ability of our astrometric method to find asteroid satellites.

Ionospheric magnetic signals during conjunctions between ground based and Swarm satellite observations

NASA Astrophysics Data System (ADS)

Saturnino, Diana; Olsen, Nils; Finlay, Chris

2017-04-01

High-precision magnetic measurements collected by satellites such as Swarm or CHAMP,flying at altitudes between 300 and 800km, allow for improved geomagnetic field modelling. An accurate description of the internal (core and crust) field must account for contributions from other sources, such as the ionosphere and magnetosphere. However, the description of the rapidly changing external field contributions, particularly during the quiet times from which the data are selected, constitutes a major challenge of the construction of such models. Our study attempts to obtain improved knowledge on ionospheric field contributions during quiet times conditions, in particular during night local times. We use two different datasets: ground magnetic observatories time series (obtained below the ionospheric E-layer currents), and Swarm satellites measurements acquired above these currents. First, we remove from the data estimates of the core, lithospheric and large-scale magnetospheric magnetic contributions as given by the CHAOS-6 model, to obtain corrected time series. Then, we focus on the differences of the corrected time series: for a pair of ground magnetic observatories, we determine the time series of the difference, and similarly we determine time series differences at satellite altitude, given by the difference between the Swarm Alpha and Charlie satellites taken in the vicinity of the ground observatory locations. The obtained differences time series are analysed regarding their temporal and spatial scales variations, with emphasis on measurements during night local times.

Lessons Learned During the Refurbishment and Testing of an Observatory After Long-Term Storage

NASA Technical Reports Server (NTRS)

Hawk, John; Peabody, Sharon; Stavely, Richard

2015-01-01

Thermal Fluids Analysis Workshop (TFAWS) 2015, Silver Spring, MD NCTS 21070-15. This paper addresses the lessons learned during the refurbishment and testing of the thermal control system for a spacecraft which was placed into long-term storage. The DSCOVR (Deep Space Climate Observatory) Observatory (formerly known as Triana) was originally scheduled to launch on the Space Shuttle in 2002. With the Triana spacecraft nearly complete, the mission was canceled and the satellite was abruptly put into storage in 2001. In 2008 the observatory was removed from storage to begin refurbishment and testing. Problems arose associated with hardware that was not currently manufactured, coatings degradation, and a significant lack of documentation. Also addressed is the conversion of the thermal and geometric math models for use with updated thermal analysis software tools.

SOHO/CDS Measurements of Coronal EUV Polarization above the Limb

NASA Technical Reports Server (NTRS)

Thomas, Roger J.

2002-01-01

Attempts to measure polarization in coronal extreme ultraviolet (EUV) emission above the solar limb have been made using the SOHO/CDS normal-incidence spectrometer which has a polarization sensitivity of about 50%, a property that causes variations in intensity response as a function of the spacecraft's roll angle for polarized light. Such observations were made on the disk and up to 0.22 solar radii above the solar limb in a number of EUV lines during two special roll-maneuvers of the SOHO spacecraft. Measurements of intensity gradients were made above a modestly active equatorial region in 1997 and above a relatively cool polar region in 2001. Observed emission lines include He I 584 A, He II 304 A, O IV 555+610 A, O V 630 A, Mg IX 368 A, Mg X 610+625 A, and Si XI 303 A, formed at temperatures that evenly cover the range in log T from 4.1 to 6.2. Near the disk, measured intensities of all lines fall off exponentially at different rates that can be used to determine the density scale-heights of the emitting plasma, since this emission is dominated by collisional excitation with an Ne-squared dependence. Assuming hydrostatic equilibrium, the intensity gradient for each line can then be converted into a 'scale-height temperature', which is found to be closely related to the ionization temperature of each line over the wide range of lines and solar conditions observed. Thus the large-scale corona is remarkably uniform, even though clearly displaying a great deal of structure and non-uniformity on smaller spatial scales. Beyond a certain distance, intensity gradients of the cooler lines switch over to a flatter exponential slope, suggesting that this radiation is dominated by resonance scattering which varies as Ne to the first power. Such radiation should also be linearly polarized in the plane containing the line-of-sight and the solar center, a signature that would strongly confirm this interpretation.

Sun-Earth L1 Region Halo-To-Halo Orbit and Halo-To-LisaJous Orbit Transfers

NASA Technical Reports Server (NTRS)

Roberts, Craig E.; DeFazio, Robert

2004-01-01

Practical techniques for designing transfer trajectories between Libration Point Orbits (LPOs) are presented. Motivation for development of these techniques was provided by a hardware contingency experienced by the Solar Heliospheric Observatory (SOHO), a joint mission of the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) orbiting the L1 point of the Sun-Earth system. A potential solution to the problem involved a transfer from SOHO s periodic halo orbit to a new LPO of substantially different dimensions. Assuming the SOHO halo orbit as the departure orbit, several practical LPO transfer techniques were developed to obtain new Lissajous or periodic halo orbits that satisfy mission requirements and constraints. While not implemented for the SOHO mission, practical LPO transfer techniques were devised that are generally applicable to current and future LPO missions.

Earth Observatory Satellite system definition study. Report no. 3: Design/cost tradeoff studies. Appendix A: EOS program WBS dictionary. Appendix B: EOS mission functional analysis

NASA Technical Reports Server (NTRS)

1974-01-01

The work breakdown structure (WBS) dictionary for the Earth Observatory Satellite (EOS) is defined. The various elements of the EOS program are examined to include the aggregate of hardware, computer software, services, and data required to develop, produce, test, support, and operate the space vehicle and the companion ground data management system. A functional analysis of the EOS mission is developed. The operations for three typical EOS missions, Delta, Titan, and Shuttle launched are considered. The functions were determined for the top program elements, and the mission operations, function 2.0, was expanded to level one functions. Selection of ten level one functions for further analysis to level two and three functions were based on concern for the EOS operations and associated interfaces.

Volcview: A Web-Based Platform for Satellite Monitoring of Volcanic Activity and Eruption Response

NASA Astrophysics Data System (ADS)

Schneider, D. J.; Randall, M.; Parker, T.

2014-12-01

The U.S. Geological Survey (USGS), in cooperation with University and State partners, operates five volcano observatories that employ specialized software packages and computer systems to process and display real-time data coming from in-situ geophysical sensors and from near-real-time satellite sources. However, access to these systems both inside and from outside the observatory offices are limited in some cases by factors such as software cost, network security, and bandwidth. Thus, a variety of Internet-based tools have been developed by the USGS Volcano Science Center to: 1) Improve accessibility to data sources for staff scientists across volcano monitoring disciplines; 2) Allow access for observatory partners and for after-hours, on-call duty scientists; 3) Provide situational awareness for emergency managers and the general public. Herein we describe VolcView (volcview.wr.usgs.gov), a freely available, web-based platform for display and analysis of near-real-time satellite data. Initial geographic coverage is of the volcanoes in Alaska, the Russian Far East, and the Commonwealth of the Northern Mariana Islands. Coverage of other volcanoes in the United States will be added in the future. Near-real-time satellite data from NOAA, NASA and JMA satellite systems are processed to create image products for detection of elevated surface temperatures and volcanic ash and SO2 clouds. VolcView uses HTML5 and the canvas element to provide image overlays (volcano location and alert status, annotation, and location information) and image products that can be queried to provide data values, location and measurement capabilities. Use over the past year during the eruptions of Pavlof, Veniaminof, and Cleveland volcanoes in Alaska by the Alaska Volcano Observatory, the National Weather Service, and the U.S. Air Force has reinforced the utility of shared situational awareness and has guided further development. These include overlay of volcanic cloud trajectory and

Atlas-Centaur Orbiting Astronomical Observatory Shroud Test

NASA Image and Video Library

1968-04-21

Researchers at the National Aeronautics and Space Administration (NASA) Lewis Research Center conducted a series of shroud jettison tests for the second Orbiting Astronomical Observatory (OAO-2) in the Space Power Chambers during April 1968. The Orbiting Astronomical Observatory satellites were designed by Goddard Space Flight Center to study and retrieve ultraviolet data on stars and galaxies which earthbound and atmospheric telescopes could not view due to ozone absorption. The shroud jettison system was tested in the Space Power Chambers. In 1961, NASA Lewis management decided to convert its Altitude Wind Tunnel into two large test chambers and later renamed it the Space Power Chambers. The conversion, which took over two years, included removing the tunnel’s internal components and inserting bulkheads to seal off the new chambers. The larger chamber, seen here, could simulate altitudes of 100,000 feet. These chambers were used for a variety of tests on the Centaur second-stage rocket until the early 1970s. The first OAO mission in 1965 failed due to problems with the satellite. OAO-2 would be launched on an Atlas/Centaur with a modified Agena shroud. The new shroud was 18 feet longer than the normal Centaur payload shrouds. This new piece of hardware was successfully qualified during three tests at 90,000 feet altitude in the Space Power Chambers in April 1968. For the first time, x-rays were used to verify the payload clearance once the shroud was sealed. OAO-2 was launched on December 7, 1968 and proved to be an extremely successful mission.

AO corrected satellite imaging from Mount Stromlo

NASA Astrophysics Data System (ADS)

Bennet, F.; Rigaut, F.; Price, I.; Herrald, N.; Ritchie, I.; Smith, C.

2016-07-01

The Research School of Astronomy and Astrophysics have been developing adaptive optics systems for space situational awareness. As part of this program we have developed satellite imaging using compact adaptive optics systems for small (1-2 m) telescopes such as those operated by Electro Optic Systems (EOS) from the Mount Stromlo Observatory. We have focused on making compact, simple, and high performance AO systems using modern high stroke high speed deformable mirrors and EMCCD cameras. We are able to track satellites down to magnitude 10 with a Strehl in excess of 20% in median seeing.

Mapping 3D plasma structure in the solar wind with the L1 constellation: joint observations from Wind, ACE, DSCOVR, and SoHO

NASA Astrophysics Data System (ADS)

Stevens, M. L.; Kasper, J. C.; Case, A. W.; Korreck, K. E.; Szabo, A.; Biesecker, D. A.; Prchlik, J.

2017-12-01

At this moment in time, four observatories with similar instrumentation- Wind, ACE, DSCOVR, and SoHO- are stationed directly upstream of the Earth and making continuous observations. They are separated by drift-time baselines of seconds to minutes, timescales on which MHD instabilities in the solar wind are known to grow and evolve, and spatial baselines of tens to 200 earth radii, length scales relevant to the Earth's magnetosphere. By comparing measurements of matched solar wind structures from the four vantage points, the form of structures and associated dynamics on these scales is illuminated. Our targets include shocks and MHD discontinuities, stream fronts, locii of reconnection and exhaust flow boundary layers, plasmoids, and solitary structures born of nonlinear instability. We use the tetrahedral quality factors and other conventions adopted for Cluster to identify periods where the WADS constellation is suitably non-degenerate and arranged in such a way as to enable specific types of spatial, temporal, or spatiotemporal inferences. We present here an overview of the geometries accessible to the L1 constellation and timing-based and plasma-based observations of solar wind structures from 2016-17. We discuss the unique potential of the constellation approach for space physics and space weather forecasting at 1 AU.

Color Survey of the Irregular Planetary Satellites

NASA Astrophysics Data System (ADS)

Graykowski, Ariel; Jewitt, David

2017-10-01

Irregular planetary satellites are characterized by their large orbital distance from their planet, their high eccentricity and their high inclination, all indicating that they were captured. However, the mechanism of capture and the source region of the satellites remain subjects of conjecture. This work presents the optical magnitudes and colors from a photometric survey of 42 irregular satellites with data obtained from the LRIS instrument on the 10-meter telescope at the Keck Observatory in Hawaii. Color is used as a proxy for composition. We compare the satellite populations of different planets and compare the satellites as a whole with other solar system small-body populations. For instance, if irregular satellites were captured from the Kuiper Belt, as is commonly proposed, then some might contain the ultrared material that is common in the trans-Neptunian and Centaur populations. Overall our data show that the irregular satellites lack ultrared matter. They are color-wise more similar to the comets, giant planet Trojans and other bodies of the middle solar system. Implications of our observations, and comparisons with previous color work, will be discussed.

Linking space observations to volcano observatories in Latin America: Results from the CEOS DRM Volcano Pilot

NASA Astrophysics Data System (ADS)

Delgado, F.; Pritchard, M. E.; Biggs, J.; Arnold, D. W. D.; Poland, M. P.; Ebmeier, S. K.; Wauthier, C.; Wnuk, K.; Parker, A. L.; Amelug, F.; Sansosti, E.; Mothes, P. A.; Macedo, O.; Lara, L.; Zoffoli, S.; Aguilar, V.

2015-12-01

Within Latin American, about 315 volcanoes that have been active in the Holocene, but according to the United Nations Global Assessment of Risk 2015 report (GAR15) 202 of these volcanoes have no seismic, deformation or gas monitoring. Following the 2012 Santorini Report on satellite Earth Observation and Geohazards, the Committee on Earth Observation Satellites (CEOS) has developed a 3-year pilot project to demonstrate how satellite observations can be used to monitor large numbers of volcanoes cost-effectively, particularly in areas with scarce instrumentation and/or difficult access. The pilot aims to improve disaster risk management (DRM) by working directly with the volcano observatories that are governmentally responsible for volcano monitoring, and the project is possible thanks to data provided at no cost by international space agencies (ESA, CSA, ASI, DLR, JAXA, NASA, CNES). Here we highlight several examples of how satellite observations have been used by volcano observatories during the last 18 months to monitor volcanoes and respond to crises -- for example the 2013-2014 unrest episode at Cerro Negro/Chiles (Ecuador-Colombia border); the 2015 eruptions of Villarrica and Calbuco volcanoes, Chile; the 2013-present unrest and eruptions at Sabancaya and Ubinas volcanoes, Peru; the 2015 unrest at Guallatiri volcano, Chile; and the 2012-present rapid uplift at Cordon Caulle, Chile. Our primary tool is measurements of ground deformation made by Interferometric Synthetic Aperture Radar (InSAR) but thermal and outgassing data have been used in a few cases. InSAR data have helped to determine the alert level at these volcanoes, served as an independent check on ground sensors, guided the deployment of ground instruments, and aided situational awareness. We will describe several lessons learned about the type of data products and information that are most needed by the volcano observatories in different countries.

Three Short Videos by the Yellowstone Volcano Observatory

USGS Publications Warehouse

Wessells, Stephen; Lowenstern, Jake; Venezky, Dina

2009-01-01

This is a collection of videos of unscripted interviews with Jake Lowenstern, who is the Scientist in Charge of the Yellowstone Volcano Observatory (YVO). YVO was created as a partnership among the U.S. Geological Survey (USGS), Yellowstone National Park, and University of Utah to strengthen the long-term monitoring of volcanic and earthquake unrest in the Yellowstone National Park region. Yellowstone is the site of the largest and most diverse collection of natural thermal features in the world and the first National Park. YVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety. These video presentations give insights about many topics of interest about this area. Title: Yes! Yellowstone is a Volcano An unscripted interview, January 2009, 7:00 Minutes Description: USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers the following questions to explain volcanic features at Yellowstone: 'How do we know Yellowstone is a volcano?', 'What is a Supervolcano?', 'What is a Caldera?','Why are there geysers at Yellowstone?', and 'What are the other geologic hazards in Yellowstone?' Title: Yellowstone Volcano Observatory An unscripted interview, January 2009, 7:15 Minutes Description: USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers the following questions about the Yellowstone Volcano Observatory: 'What is YVO?', 'How do you monitor volcanic activity at Yellowstone?', 'How are satellites used to study deformation?', 'Do you monitor geysers or any other aspect of the Park?', 'Are earthquakes and ground deformation common at Yellowstone?', 'Why is YVO a relatively small group?', and 'Where can I get more information?' Title: Yellowstone Eruptions An unscripted interview, January 2009, 6.45 Minutes Description: USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers the following questions to explain volcanic

Earth Observatory Satellite system definition study. Report no. 3: Design/cost tradeoff studies. Appendix E: EOS program supporting system. Part 1: System trade studies no. 1 through 8

NASA Technical Reports Server (NTRS)

1974-01-01

The design requirements and associated cost impacts for using the space shuttle to deliver the Earth Observatory Satellite (EOS) are identified. The additional impact of achieving full compatibility for resupply and retrieval is considered. Based on the results of the analysis, it is concluded that the EOS-Shuttle compatibility can be realized with reasonable spacecraft weight and cost penalties. Inherent space shuttle capabilities are adequate to meet the requirements of all missions except E and F. Mission E (Tiros 0) may be accommodated by either an EOS orbit transfer capability or a tug. The tug appears to be the only viable approach to satisfying the mission F (SEOS) requirements.

Hinode Satellite Captures Total Solar Eclipse Video Aug. 21

NASA Image and Video Library

2017-08-21

The Japan Aerospace Exploration Agency, the National Astronomical Observatory of Japan and NASA released this video of Aug. 21 total solar eclipse taken by the X-ray telescope aboard the Hinode joint solar observation satellite as it orbited high above the Pacific Ocean.

The study on the new approach to the prediction of the solar flares: The statistical relation from the SOHO archive

NASA Astrophysics Data System (ADS)

Lee, S.; Oh, S.; Lee, J.; Hong, S.

2013-12-01

We have investigated the statistical relationship of the solar active region to predict the solar flare event analyzing the sunspot catalogue, which has been newly constructed from the SOHO MDI observation data during the period from 1996 to 2011 (Solar Cycle 23 & 24) by ASSA(Automatic Solar Synoptic Analyzer) algorithms. The prediction relation has been made by machine-learning algorithms to establish a short- term flare prediction model for operational use in near future. In this study, continuum and magnetogram images observed by SOHO has been processed to yield 15-year sunspot group catalogue that contains various physical parameters such as sunspot area, extent, asymmetry measure of largest penumbral sunspot, roughness of magnetic neutral line as well as McIntosh and Mt. Wilson classification results.The latest result of our study will be presented and the new approach to the prediction of the solar flare will be discussed.

Determination of projection effects of CMEs using quadrature observations with the two STEREO spacecraft

NASA Astrophysics Data System (ADS)

Bronarska, K.; Michalek, G.

2018-07-01

Since 1995 coronal mass ejections (CMEs) have been routinely observed thanks to the sensitive Large Angle and Spectrometric Coronagraphs (LASCO) on board the Solar and Heliospheric Observatory (SOHO) mission. Their observed characteristics are stored, among other, in the SOHO/LASCO catalog. These parameters are commonly used in scientific studies. Unfortunately, coronagraphic observations of CMEs are subject to projection effects. This makes it practically impossible to determine the true properties of CMEs and therefore makes it more difficult to forecast their geoeffectiveness. In this study, using quadrature observations with the two Solar Terrestrial Relations Observatory (STEREO) spacecrafts, we estimate the projection effect affecting velocity of CMEs included in the SOHO/LASCO catalog. It was demonstrated that this effect depends significantly on width and source location of CMEs. It can be very significant for narrow events and originating from the disk center. The effect diminishes with increasing width and absolute longitude of source location of CMEs. For very wide (width ⩾ 250°) or limb events (| longitude ⩾ 70°) projection effects completely disappears.

The COronal Solar Magnetism Observatory (COSMO) Large Aperture Coronagraph

NASA Astrophysics Data System (ADS)

Tomczyk, Steve; Gallagher, Dennis; Wu, Zhen; Zhang, Haiying; Nelson, Pete; Burkepile, Joan; Kolinksi, Don; Sutherland, Lee

2013-04-01

The COSMO is a facility dedicated to observing coronal and chromospheric magnetic fields. It will be located on a mountaintop in the Hawaiian Islands and will replace the current Mauna Loa Solar Observatory (MLSO). COSMO will provide unique observations of the global coronal magnetic fields and its environment to enhance the value of data collected by other observatories on the ground (e.g. SOLIS, BBO NST, Gregor, ATST, EST, Chinese Giant Solar Telescope, NLST, FASR) and in space (e.g. SDO, Hinode, SOHO, GOES, STEREO, Solar-C, Solar Probe+, Solar Orbiter). COSMO will employ a fleet of instruments to cover many aspects of measuring magnetic fields in the solar atmosphere. The dynamics and energy flow in the corona are dominated by magnetic fields. To understand the formation of CMEs, their relation to other forms of solar activity, and their progression out into the solar wind requires measurements of coronal magnetic fields. The large aperture coronagraph, the Chromospheric and Prominence Magnetometer and the K-Coronagraph form the COSMO instrument suite to measure magnetic fields and the polarization brightness of the low corona used to infer electron density. The large aperture coronagraph will employ a 1.5 meter fuse silica singlet lens, birefringent filters, and a spectropolarimeter to cover fields of view of up to 1 degree. It will observe the corona over a wide range of emission lines from 530.3 nm through 1083.0 nm allowing for magnetic field measurements over a wide range of coronal temperatures (e.g. FeXIV at 530.3 nm, Fe X at 637.4 nm, Fe XIII at 1074.7 and 1079.8 nm. These lines are faint and require the very large aperture. NCAR and NSF have provided funding to bring the large aperture coronagraph to a preliminary design review state by the end of 2013. As with all data from Mauna Loa, the data products from COSMO will be available to the community via the Mauna Loa website: http://mlso.hao.ucar.edu

Accuracy of Satellite Optical Observations and Precise Orbit Determination

NASA Astrophysics Data System (ADS)

Shakun, L.; Koshkin, N.; Korobeynikova, E.; Strakhova, S.; Dragomiretsky, V.; Ryabov, A.; Melikyants, S.; Golubovskaya, T.; Terpan, S.

The monitoring of low-orbit space objects (LEO-objects) is performed in the Astronomical Observatory of Odessa I.I. Mechnikov National University (Ukraine) for many years. Decades-long archives of these observations are accessible within Ukrainian network of optical observers (UMOS). In this work, we give an example of orbit determination for the satellite with the 1500-km height of orbit based on angular observations in our observatory (Int. No. 086). For estimation of the measurement accuracy and accuracy of determination and propagation of satellite position, we analyze the observations of Ajisai satellite with the well-determined orbit. This allows making justified conclusions not only about random errors of separate measurements, but also to analyze the presence of systematic errors, including external ones to the measurement process. We have shown that the accuracy of one measurement has the standard deviation about 1 arcsec across the track and 1.4 arcsec along the track and systematical shifts in measurements of one track do not exceed 0.45 arcsec. Ajisai position in the interval of the orbit fitting is predicted with accuracy better than 30 m along the orbit and better than 10 m across the orbit for any its point.

Status of Knowledge after Ulysses and SOHO: Session 2: Investigate the Links between the Solar Surface, Corona, and Inner Heliosphere.

NASA Technical Reports Server (NTRS)

Suess, Steven

2006-01-01

As spacecraft observations of the heliosphere have moved from exploration into studies of physical processes, we are learning about the linkages that exist between different parts of the system. The past fifteen years have led to new ideas for how the heliospheric magnetic field connects back to the Sun and to how that connection plays a role in the origin of the solar wind. A growing understanding these connections, in turn, has led to the ability to use composition, ionization state, the microscopic state of the in situ plasma, and energetic particles as tools to further analyze the linkages and the underlying physical processes. Many missions have contributed to these investigations of the heliosphere as an integrated system. Two of the most important are Ulysses and SOHO, because of the types of measurements they make, their specific orbits, and how they have worked to complement each other. I will review and summarize the status of knowledge about these linkages, with emphasis on results from the Ulysses and SOHO missions. Some of the topics will be the global heliosphere at sunspot maximum and minimum, the physics and morphology of coronal holes, the origin(s) of slow wind, SOHO-Ulysses quadrature observations, mysteries in the propagation of energetic particles, and the physics of eruptive events and their associated current sheets. These specific topics are selected because they point towards the investigations that will be carried out with Solar Orbiter (SO) and the opportunity will be used to illustrate how SO will uniquely contribute to our knowledge of the underlying physical processes.

Colors and Shapes of the Irregular Planetary Satellites

NASA Astrophysics Data System (ADS)

Graykowski, Ariel; Jewitt, David

2018-04-01

It is widely recognized that the irregular satellites of the giant planets were captured from initially heliocentric orbits. However, the mechanism of capture and the source region from which they were captured both remain unknown. We present an optical color survey of 43 irregular satellites of the outer planets conducted using the LRIS camera on the 10 m telescope at the Keck Observatory in Hawaii. The measured colors are compared to other planetary bodies in search for similarities and differences that may reflect upon the origin of the satellites. We find that ultrared matter (with color index B–R ≥ 1.6), while abundant in the Kuiper Belt and Centaur populations, is depleted from the irregular satellites. We also use repeated determinations of the absolute magnitudes to make a statistical estimate of the average shape of the irregular satellites. The data provide no evidence that the satellites and the main-belt asteroids are differently shaped, consistent with collisions as the major agent shaping both.

Coronal O VI emission observed with UVCS/SOHO during solar flares: Comparison with soft X-ray observations

NASA Astrophysics Data System (ADS)

Mancuso, S.; Giordano, S.; Raymond, J. C.

2016-06-01

In this work, we derive the O VI 1032 Å luminosity profiles of 58 flares, during their impulsive phase, based on off-limb measurements by the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the SOlar and Heliospheric Observatory (SOHO). The O VI luminosities from the transition region plasma (here defined as the region with temperatures 5.0 ≤ log T (K) ≤ 6.0) were inferred from the analysis of the resonantly scattered radiation of the O VI coronal ions. The temperature of maximum ionization for O VI is log Tmax (K) = 5.47. By comparison with simultaneous soft X-ray measurements, we investigate the likely source (chromospheric evaporation, footpoint emission, or heated prominence ejecta) for the transition region emission observed during the impulsive phase. In our study, we find evidence of the main characteristics predicted by the evaporation scenario. Specifically, most O VI flares precede the X-ray peaks typically by several minutes with a mean of 3.2 ± 0.1 min, and clear correlations are found between the soft X-ray and transition region luminosities following power laws with indices ~ 0.7 ± 0.3. Overall, the results are consistent with transition region emission originating from chromospheric evaporation; the thermal X-ray emission peaks after the emission from the evaporation flow as the loops fill with hot plasma. Finally, we were able to infer flow speeds in the range ~20-100 km s-1 for one-third of the events, 14 of which showed speeds between 60 and 80 km s-1. These values are compatible with those found through direct spectroscopic observations at transition region temperatures by the EUV Imaging Spectrometer (EIS) on board Hinode.

Solar Terrestrial Relations Observatory (STEREO)

NASA Technical Reports Server (NTRS)

Davila, Joseph M.; SaintCyr, O. C.

2003-01-01

The solar magnetic field is constantly generated beneath the surface of the Sun by the solar dynamo. To balance this flux generation, there is constant dissipation of magnetic flux at and above the solar surface. The largest phenomenon associated with this dissipation is the Coronal Mass Ejection (CME). The Solar and Heliospheric Observatory (SOHO) has provided remarkable views of the corona and CMEs, and served to highlight how these large interplanetary disturbances can have terrestrial consequences. STEREO is the next logical step to study the physics of CME origin, propagation, and terrestrial effects. Two spacecraft with identical instrument complements will be launched on a single launch vehicle in November 2007. One spacecraft will drift ahead and the second behind the Earth at a separation rate of 22 degrees per year. Observation from these two vantage points will for the first time allow the observation of the three-dimensional structure of CMEs and the coronal structures where they originate. Each STEREO spacecraft carries a complement of 10 instruments, which include (for the first time) an extensive set of both remote sensing and in-situ instruments. The remote sensing suite is capable of imaging CMEs from the solar surface out to beyond Earth's orbit (1 AU), and in-situ instruments are able to measure distribution functions for electrons, protons, and ions over a broad energy range, from the normal thermal solar wind plasma to the most energetic solar particles. It is anticipated that these studies will ultimately lead to an increased understanding of the CME process and provide unique observations of the flow of energy from the corona to the near-Earth environment. An international research program, the International Heliophysical Year (IHY) will provide a framework for interpreting STEREO data in the context of global processes in the Sun-Earth system.

Nobeyama Radio Observatory

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

Nobeyama Radio Observatory has telescopes at millimeter and submillimeter wavelengths. It was established in 1982 as an observatory of Tokyo Astronomical Observatory (NATIONAL ASTRONOMICAL OBSERVATORY, JAPAN since 1987), and operates the 45 m telescope, Nobeyama Millimeter Array, and Radioheliograph. High-resolution images of star forming regions and molecular clouds have revealed many aspects of...

About Nano-JASMINE Satellite System and Project Status

NASA Astrophysics Data System (ADS)

Sako, Nobutada

Intelligent Space Systems Laboratory, The University of Tokyo (ISSL) and National Astronomical Observatory of Japan (NAO) have been developing a small infrared astrometry satellite named “Nano-JASMINE”. The satellite size is about 50cm cubic and 20kg, which plays a pre-cursor role of JASMINE Project which is programmed by NAO and JAXA. In addition, since there has been only one astrometry satellite HIPPARCOS by ESA in the past, Nano-JASMINE is also expected to achieve certain scientific results in the field of astrometry. In this project, ISSL aims to develop new advanced small satellite bus system whose performance is comparable to that of 100-500kg sized satellites, including attitude stability of 1 arc-second and thermal stability of the mission subsystem of 1 mK. This paper overviews the Nano-JASMINE bus system with emphasis on attitude and thermal control systems.

MDM Observatory

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

MDM Observatory was founded by the University of Michigan, Dartmouth College and the Massachusetts Institute of Technology. Current operating partners include Michigan, Dartmouth, MIT, Ohio State University and Columbia University. The observatory is located on the southwest ridge of the KITT PEAK NATIONAL OBSERVATORY near Tucson, Arizona. It operates the 2.4 m Hiltner Telescope and the 1.3 m McG...

WIYN Observatory

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

Located at Kitt Peak in Arizona. The WIYN Observatory is owned and operated by the WIYN Consortium, which consists of the University of Wisconsin, Indiana University, Yale University and the National Optical Astronomy Observatories (NOAO). Most of the capital costs of the observatory were provided by these universities, while NOAO, which operates the other telescopes of the KITT PEAK NATIONAL OBS...

Automated recognition and characterization of solar active regions based on the SOHO/MDI images

NASA Technical Reports Server (NTRS)

Pap, J. M.; Turmon, M.; Mukhtar, S.; Bogart, R.; Ulrich, R.; Froehlich, C.; Wehrli, C.

1997-01-01

The first results of a new method to identify and characterize the various surface structures on the sun, which may contribute to the changes in solar total and spectral irradiance, are shown. The full disk magnetograms (1024 x 1024 pixels) of the Michelson Doppler Imager (MDI) experiment onboard SOHO are analyzed. Use of a Bayesian inference scheme allows objective, uniform, automated processing of a long sequence of images. The main goal is to identify the solar magnetic features causing irradiance changes. The results presented are based on a pilot time interval of August 1996.

Private Observatories in South Africa

NASA Astrophysics Data System (ADS)

Rijsdijk, C.

2016-12-01

Descriptions of private observatories in South Africa, written by their owners. Positions, equipment descriptions and observing programmes are given. Included are: Klein Karoo Observatory (B. Monard), Cederberg Observatory (various), Centurion Planetary and Lunar Observatory (C. Foster), Le Marischel Observatory (L. Ferreira), Sterkastaaing Observatory (M. Streicher), Henley on Klip (B. Fraser), Archer Observatory (B. Dumas), Overbeek Observatory (A. Overbeek), Overberg Observatory (A. van Staden), St Cyprian's School Observatory, Fisherhaven Small Telescope Observatory (J. Retief), COSPAR 0433 (G. Roberts), COSPAR 0434 (I. Roberts), Weltevreden Karoo Observatory (D. Bullis), Winobs (M. Shafer)

ESO's Two Observatories Merge

NASA Astrophysics Data System (ADS)

2005-02-01

, a unique instrument capable of measuring stellar radial velocities with an unsurpassed accuracy better than 1 m/s, making it a very powerful tool for the discovery of extra-solar planets. In addition, astronomers have also access to the 2.2-m ESO/MPG telescope with its Wide Field Imager camera. A new control room, the RITZ (Remote Integrated Telescope Zentrum), allows operating all three ESO telescopes at La Silla from a single place. The La Silla Observatory is also the first world-class observatory to have been granted certification for the International Organization for Standardization (ISO) 9001 Quality Management System. Moreover, the infrastructure of La Silla is still used by many of the ESO member states for targeted projects such as the Swiss 1.2-m Euler telescope and the robotic telescope specialized in the follow-up of gamma-ray bursts detected by satellites, the Italian REM (Rapid Eye Mount). In addition, La Silla is in charge of the APEX (Atacama Pathfinder Experiment) 12-m sub-millimetre telescope which will soon start routine observations at Chajnantor, the site of the future Atacama Large Millimeter Array (ALMA). The APEX project is a collaboration between the Max Planck Society in Germany, Onsala Observatory in Sweden and ESO. ESO also operates Paranal, home of the Very Large Telescope (VLT) and the VLT Interferometer (VLTI). Antu, the first 8.2-m Unit Telescope of the VLT, saw First Light in May 1998, starting what has become a revolution in European astronomy. Since then, the three other Unit Telescopes - Kueyen, Melipal and Yepun - have been successfully put into operation with an impressive suite of the most advanced astronomical instruments. The interferometric mode of the VLT (VLTI) is also operational and fully integrated in the VLT data flow system. In the VLTI mode, one state-of-the-art instrument is already available and another will follow soon. With its remarkable resolution and unsurpassed surface area, the VLT is at the forefront of

The CEOS Recovery Observatory Pilot

NASA Astrophysics Data System (ADS)

Hosford, S.; Proy, C.; Giros, A.; Eddy, A.; Petiteville, I.; Ishida, C.; Gaetani, F.; Frye, S.; Zoffoli, S.; Danzeglocke, J.

2015-04-01

Over the course of the last decade, large populations living in vulnerable areas have led to record damages and substantial loss of life in mega-disasters ranging from the deadly Indian Ocean tsunami of 2004 and Haiti earthquake of 2010; the catastrophic flood damages of Hurricane Katrina in 2005 and the Tohoku tsunami of 2011, and the astonishing extent of the environmental impact of the Deepwater Horizon explosion in 2009. These major catastrophes have widespread and long-lasting impacts with subsequent recovery and reconstruction costing billions of euros and lasting years. While satellite imagery is used on an ad hoc basis after many disasters to support damage assessment, there is currently no standard practice or system to coordinate acquisition of data and facilitate access for early recovery planning and recovery tracking and monitoring. CEOS led the creation of a Recovery Observatory Oversight Team, which brings together major recovery stakeholders such as the UNDP and the World Bank/Global Facility for Disaster Reduction and Recovery, value-adding providers and leading space agencies. The principal aims of the Observatory are to: 1. Demonstrate the utility of a wide range of earth observation data to facilitate the recovery and reconstruction phase following a major catastrophic event; 2. Provide a concrete case to focus efforts in identifying and resolving technical and organizational obstacles to facilitating the visibility and access to a relevant set of EO data; and 3. Develop dialogue and establish institutional relationships with the Recovery phase user community to best target data and information requirements; The paper presented here will describe the work conducted in preparing for the triggering of a Recovery Observatory including support to rapid assessments and Post Disaster Needs Assessments by the EO community.

Wisconsin's Role in the First Orbiting Astronomical Observatory

NASA Astrophysics Data System (ADS)

Code, A.

2005-12-01

The Orbiting Astronomical Observatory (OAO-II) launched on December 7, 1968, was the first optical observatory to be operated above the earth's atmosphere. It contained two major instruments, the Smithsonian Celescope and the Wisconsin Experiment Package (WEP), composed of ultraviolet photometers and spectrometers. In 1957 the Soviet "Sputnik" Satellite started the race to space. The National Academy of Science circulated a letter drafted by Lloyd Berkner soliciting suggestions for scientific payloads for a 100 lb satellite. The University of Wisconsin was one of the organizations that responded with a proposal for an ultraviolet photometer. Shortly afterwards when NASA came into existence Wisconsin was one of those that received funding for a study of a 100 lb UV photometric telescope. By the time our preliminary design was completed NASA had developed a plan for an astronomical platform to support all varieties of experiments requiring pointing, power and command and data capability and payload weights over 1000 lbs. To adapt to this new dimension we clustered our telescopes and shared the volume with the four telescope of the Smithsonian Celescope. Celescope would look out one end of the spacecraft and the Wisconsin Experiment Package WEP would look out the other end. Since no one had ever done this before both NASA and ourselves had a lot to learn. One feature of our design was redundancy. The clustering contributed to this approach but there was both hardware and software redundancy throughout. This paper will describe elements of the origin of WEP, it's fabrication, operation and scientific yield

The Russian-Ukrainian Observatories Network for the European Astronomical Observatory Route Project

NASA Astrophysics Data System (ADS)

Andrievsky, S. M.; Bondar, N. I.; Karetnikov, V. G.; Kazantseva, L. V.; Nefedyev, Y. A.; Pinigin, G. I.; Pozhalova, Zh. A.; Rostopchina-Shakhovskay, A. N.; Stepanov, A. V.; Tolbin, S. V.

2011-09-01

In 2004,the Center of UNESCO World Heritage has announced a new initiative "Astronomy & World Heritage" directed for search and preserving of objects,referred to astronomy,its history in a global value,historical and cultural properties. There were defined a strategy of thematic programme "Initiative" and general criteria for selecting of ancient astronomical objects and observatories. In particular, properties that are situated or have significance in relation to celestial objects or astronomical events; representations of sky and/or celestial bodies and astronomical events; observatories and instruments; properties closely connected with the history of astronomy. In 2005-2006,in accordance with the program "Initiative", information about outstanding properties connected with astronomy have been collected.In Ukraine such work was organized by astronomical expert group in Nikolaev Astronomical Observatory. In 2007, Nikolaev observatory was included to the Tentative List of UNESCO under # 5116. Later, in 2008, the network of four astronomical observatories of Ukraine in Kiev,Crimea, Nikolaev and Odessa,considering their high authenticities and integrities,was included to the Tentative List of UNESCO under # 5267 "Astronomical Observatories of Ukraine". In 2008-2009, a new project "Thematic Study" was opened as a successor of "Initiative". It includes all fields of astronomical heritage from earlier prehistory to the Space astronomy (14 themes in total). We present the Ukraine-Russian Observatories network for the "European astronomical observatory Route project". From Russia two observatories are presented: Kazan Observatory and Pulkovo Observatory in the theme "Astronomy from the Renaissance to the mid-twentieth century".The description of astronomical observatories of Ukraine is given in accordance with the project "Thematic study"; the theme "Astronomy from the Renaissance to the mid-twentieth century" - astronomical observatories in Kiev,Nikolaev and Odessa; the

NASA's Earth Observatory: Success Story or Work in Progress?

NASA Astrophysics Data System (ADS)

Herring, D. D.

2004-12-01

After a series of failures and setbacks in a variety of public communications strategies explored, and then despite internal pressure not to build it, a prototype for NASA's Earth Observatory (http://earthobservatory.nasa.gov) was built in the spring of 1998. With no budget and roughly one full-time equivalent (FTE) in personnel, the site was launched in April 1999. Aimed primarily at the "science attentive public," the Earth Observatory is an interactive Web-based magazine focusing on the subjects of climatic and environmental change, with an emphasis on the use of satellite remote sensors to study our planet. Within one year after launch, the site was selected by Popular Science as one of the Web's 50 best, while subscriptions jumped to about 12,000 readers worldwide. Fast forward to 2004, the Earth Observatory core team has grown to 5.5 FTE and enjoys contributions from all across the agency as well as a number of NASA-affiliated agencies and institutions. The site's success hinges on the partnerships that have grown up around it over the years. As a testament to the outstanding content published today in the Earth Observatory, the site was also selected by Scientific American as one of the Web's 50 best, and has twice been nominated by the International Academy of the Digital Arts and Sciences for their annual Webby Awards--in both the "Education" and "Science" categories--winning the Webby once and the People's Voice Award twice. Still, the Earth Observatory is a work in progress as there remain some developmental goals it has yet to attain. In this talk, site founder and Chief Editor David Herring will give a brief tour of the site while elaborating on some of its developmental history, lessons learned along the way, and a brief look ahead at some exciting new developments on its horizon.

The next Landsat satellite; the Landsat Data Continuity Mission

USGS Publications Warehouse

Irons, James R.; Dwyer, John L.; Barsi, Julia A.

2012-01-01

The National Aeronautics and Space Administration (NASA) and the Department of Interior United States Geological Survey (USGS) are developing the successor mission to Landsat 7 that is currently known as the Landsat Data Continuity Mission (LDCM). NASA is responsible for building and launching the LDCM satellite observatory. USGS is building the ground system and will assume responsibility for satellite operations and for collecting, archiving, and distributing data following launch. The observatory will consist of a spacecraft in low-Earth orbit with a two-sensor payload. One sensor, the Operational Land Imager (OLI), will collect image data for nine shortwave spectral bands over a 185 km swath with a 30 m spatial resolution for all bands except a 15 m panchromatic band. The other instrument, the Thermal Infrared Sensor (TIRS), will collect image data for two thermal bands with a 100 m resolution over a 185 km swath. Both sensors offer technical advancements over earlier Landsat instruments. OLI and TIRS will coincidently collect data and the observatory will transmit the data to the ground system where it will be archived, processed to Level 1 data products containing well calibrated and co-registered OLI and TIRS data, and made available for free distribution to the general public. The LDCM development is on schedule for a December 2012 launch. The USGS intends to rename the satellite "Landsat 8" following launch. By either name a successful mission will fulfill a mandate for Landsat data continuity. The mission will extend the almost 40-year Landsat data archive with images sufficiently consistent with data from the earlier missions to allow long-term studies of regional and global land cover change.

Dust Storm Monitoring Using Satellite Observatory and Numerical Modeling Analysis

NASA Astrophysics Data System (ADS)

Taghavi, Farahnaz

In recent years, the frequency of dust pollution events in the Iran Southwest are increased which caused huge damage and imposed a negative impacts on air quality, airport traffic and people daily life in local areas. Dust storms in this area usually start with the formation of a low-pressure center over the Arabian Peninsula. The main objectives of this study is to asses and monitor the movement of aerosols and pollutions from origin source to local areas using satellite imagery and numerical modeling analysis. Observational analyses from NCEP such as synoptic data (Uwind,Vwind,Vorticity and Divergence Fields), upper air radiosonde, measured visibility distributions, land cover data are also used in model comparisons to show differences in occurrence of dust events. The evolution and dynamics of this phenomena are studied on the based a method to modify the initial state of NWP output using discrepancies between dynamic fields and WV imagery in a grid. Results show that satellite images offers a means to control the behavior of numeric models and also the model using land cover data improving the wind-blown dust modeling.

Initial In-flight Results: The Total Solar Irradiance Monitor on the FY-3C Satellite, an Instrument with a Pointing System

NASA Astrophysics Data System (ADS)

Wang, Hongrui; Qi, Jin; Li, Huiduan; Fang, Wei

2017-01-01

The total solar irradiance (TSI) has been recorded daily since October 2013 by the Total Solar Irradiance Monitor (TSIM) onboard the FY-3C satellite, which is mainly designed for Earth observation. The TSIM has a pointing system to perform solar tracking using a sun sensor. The TSI is measured by two electrical substitution radiometers with traceability to the World Radiation Reference. The TSI value measured with the TSIM on 2 October 2013 is 1364.88 W m^{-2} with an uncertainty of 1.08 W m^{-2}. Short-term TSI variations recorded with the TSIM show good agreement with SOHO/VIRGO and SORCE/TIM. The data quality and accuracy of FY-3C/TSIM are much better than its predecessors on the FY-3A and FY-3B satellites, which operated in a scanning mode.

Observatories and Telescopes of Modern Times

NASA Astrophysics Data System (ADS)

Leverington, David

2016-11-01

Preface; Part I. Optical Observatories: 1. Palomar Mountain Observatory; 2. The United States Optical Observatory; 3. From the Next Generation Telescope to Gemini and SOAR; 4. Competing primary mirror designs; 5. Active optics, adaptive optics and other technical innovations; 6. European Northern Observatory and Calar Alto; 7. European Southern Observatory; 8. Mauna Kea Observatory; 9. Australian optical observatories; 10. Mount Hopkins' Whipple Observatory and the MMT; 11. Apache Point Observatory; 12. Carnegie Southern Observatory (Las Campanas); 13. Mount Graham International Optical Observatory; 14. Modern optical interferometers; 15. Solar observatories; Part II. Radio Observatories: 16. Australian radio observatories; 17. Cambridge Mullard Radio Observatory; 18. Jodrell Bank; 19. Early radio observatories away from the Australian-British axis; 20. The American National Radio Astronomy Observatory; 21. Owens Valley and Mauna Kea; 22. Further North and Central American observatories; 23. Further European and Asian radio observatories; 24. ALMA and the South Pole; Name index; Optical observatory and telescope index; Radio observatory and telescope index; General index.

Implementation and Comparison of Acoustic Travel-Time Measurement Procedures for the Solar Dynamics Observatory-Helioseismic and Magnetic Imager Time-Distance Helioseismology Pipeline

NASA Technical Reports Server (NTRS)

Couvidat, S.; Zhao, J.; Birch, A. C.; Kosovichev, A. G.; Duvall, Thomas L., Jr.; Parchevsky, K.; Scherrer, P. H.

2010-01-01

The Helioseismic and Magnetic Imager (HMI) instrument onboard the Solar Dynamics Observatory (SDO) satellite is designed to produce high-resolution Doppler-velocity maps of oscillations at the solar surface with high temporal cadence. To take advantage of these high-quality oscillation data, a time - distance helioseismology pipeline (Zhao et al., Solar Phys. submitted, 2010) has been implemented at the Joint Science Operations Center (JSOC) at Stanford University. The aim of this pipeline is to generate maps of acoustic travel times from oscillations on the solar surface, and to infer subsurface 3D flow velocities and sound-speed perturbations. The wave travel times are measured from cross-covariances of the observed solar oscillation signals. For implementation into the pipeline we have investigated three different travel-time definitions developed in time - distance helioseismology: a Gabor-wavelet fitting (Kosovichev and Duvall, SCORE'96: Solar Convection and Oscillations and Their Relationship, ASSL, Dordrecht, 241, 1997), a minimization relative to a reference cross-covariance function (Gizon and Birch, Astrophys. J. 571, 966, 2002), and a linearized version of the minimization method (Gizon and Birch, Astrophys. J. 614, 472, 2004). Using Doppler-velocity data from the Michelson Doppler Imager (MDI) instrument onboard SOHO, we tested and compared these definitions for the mean and difference traveltime perturbations measured from reciprocal signals. Although all three procedures return similar travel times in a quiet-Sun region, the method of Gizon and Birch (Astrophys. J. 614, 472, 2004) gives travel times that are significantly different from the others in a magnetic (active) region. Thus, for the pipeline implementation we chose the procedures of Kosovichev and Duvall (SCORE'96: Solar Convection and Oscillations and Their Relationship, ASSL, Dordrecht, 241, 1997) and Gizon and Birch (Astrophys. J. 571, 966, 2002). We investigated the relationships among

Real-time Data Access From Remote Observatories

NASA Astrophysics Data System (ADS)

Detrick, D. L.; Lutz, L. F.; Etter, J. E.; Rosenberg, T. J.; Weatherwax, A. T.

2006-12-01

Real-time access to solar-terrestrial data is becoming increasingly important, not only because it is now possible to acquire and access data rapidly via the internet, but also because of the need for timely publication of real-time data for analysis and modeling efforts. Currently, engineering-scaled summary data are available routinely on a daily basis from many observatories, but only when the observatories have continuous, or at least daily network access. Increasingly, the upgrading of remote data acquisition hardware makes it possible to provide data in real-time, and it is becoming normal to expect timely access to data products. The NSF- supported PENGUIn/AGO constellation of autonomous Antarctic research observatories has provided real-time data since December, 2002, when Iridium satellite modems were installed at three sites. The Iridium telecommunications links are maintained continuously, transferring data between the remote observatories and a U.S.-based data acquisition site. The time-limiting factor with this scenario is now the delay in completing a data record before transmission, which can be as short as minutes depending on the sampling rate. The single-channel data throughput of the current systems is 20-MB/day (megabytes per day), but planned installations will be capable of operating with multiple modem channels. The data records are currently posted immediately to a web site accessible by anonymous FTP client software, for use by the instruments' principal investigators, and survey plots of selected signals are published daily. The web publication facilities are being upgraded, in order to allow other interested researchers rapid access to engineering-scaled data products, in several common formats, as well as providing interactive plotting capabilities. The web site will provide access to data from other collaborating observatories (including South Pole and McMurdo Stations), as well as ancillary data accessible from public sites (e.g., Kp

Goddard Geophysical and Astronomical Observatory

NASA Technical Reports Server (NTRS)

Figueroa, Ricardo

2013-01-01

This report summarizes the technical parameters and the technical staff of the VLBI system at the fundamental station GGAO. It also gives an overview about the VLBI activities during the report year. The Goddard Geophysical and Astronomical Observatory (GGAO) consists of a 5-meter radio telescope for VLBI, a new 12-meter radio telescope for VLBI2010 development, a 1-meter reference antenna for microwave holography development, an SLR site that includes MOBLAS-7, the NGSLR development system, and a 48" telescope for developmental two-color Satellite Laser Ranging, a GPS timing and development lab, a DORIS system, meteorological sensors, and a hydrogen maser. In addition, we are a fiducial IGS site with several IGS/IGSX receivers. GGAO is located on the east coast of the United States in Maryland. It is approximately 15 miles NNE of Washington, D.C. in Greenbelt, Maryland.

Okayama Astrophysical Observatory

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

The Okayama Astrophysical Observatory (OAO) is a branch Observatory of the NATIONAL ASTRONOMICAL OBSERVATORY, JAPAN. Its main facilities are 188 cm and 91 cm telescopes, equipped with newly built instruments with CCD/IR cameras (e.g. OASIS). OAO accepts nearly 300 astronomers a year, according to the observation program scheduled by the committee....

The Cyclone Global Navigation Satellite System (CYGNSS) - Analysis and Data Assimilation for Tropical Convection

NASA Technical Reports Server (NTRS)

Li, Xuanli; Lang, Timothy J.; Mecikalski, John; Castillo, Tyler; Hoover, Kacie; Chronis, Themis

2017-01-01

Cyclone Global Navigation Satellite System (CYGNSS): a constellation of 8 micro-satellite observatories launched in November 2016, to measure near-surface oceanic wind speed. Main goal: To monitor surface wind fields of the Tropical Cyclones' inner core, including regions beneath the intense eye wall and rain bands that could not previously be measured from space; Cover 38 deg S -38 deg N with unprecedented temporal resolution and spatial coverage, under all precipitating conditions Low flying satellite: Pass over ocean surface more frequently than one large satellite. A median(mean) revisit time of 2.8(7.2) hrs.

Auroral photometry from the atmosphere Explorer satellite

NASA Technical Reports Server (NTRS)

Rees, M. H.; Abreu, V. J.

1984-01-01

Attention is given to the ability of remote sensing from space to yield quantitative auroral and ionospheric parametrers, in view of the auroral measurements made during two passes of the Explorer C satellite over the Poker Flat Optical Observatory and the Chatanika Radar Facility. The emission rate of the N2(+) 4278 A band computed from intensity measurements of energetic auroral electrons has tracked the same spetral feature that was measured remotely from the satellite over two decades of intensity, providing a stringent test for the measurement of atmospheric scattering effects. It also verifies the absolute intensity with respect to ground-based photometric measurements. In situ satellite measurments of ion densities and ground based electron density profile radar measurements provide a consistent picture of the ionospheric response to auroral input, while also predicting the observed optical emission rate.

Rotation State Evolution of Retired Geosynchronous Satellites

NASA Astrophysics Data System (ADS)

Benson, C.; Scheeres, D. J.; Ryan, W. H.; Ryan, E. V.; Moskovitz, N.

Non-periodic light curve rotation state analysis is conducted for the retired geosynchronous satellite GOES 8. This particular satellite has been observed periodically at the Maui Research and Technology Center as well as Magdalena Ridge and Lowell Observatories since 2013. To extract tumbling periods from the light curves, twodimensional Fourier series fits were used. Torque-free dynamics and the satellite’s known mass properties were then leveraged to constrain the candidate periods. Finally, simulated light curves were generated using a representative shape model for further validation. Analysis of the light curves suggests that GOES 8 transitioned from uniform rotation in 2014 to continually evolving tumbling motion by 2016. These findings are consistent with previous dynamical simulations and support the hypothesis that the Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) effect drives rotation state evolution of retired geosynchronous satellites.

The Great Geospace Observatory and Simultaneous Missions of Opportunity

NASA Technical Reports Server (NTRS)

Donovan, Eric; Brandt, Pontus; Siebeck, David; Spann, James; Lester, Mark

2011-01-01

A predictive understanding of the sun to geospace environment is one of the main goals of ILWS. This can only be achieved through a "system-level" approach, meaning long-term, simultaneous, continuous observations across the relevant scales of the magnetosphere and ionosphere/thermosphere (IT). To date such an approach, which must involve simultaneous, multi-scale, global imaging of different geospace regions, has not been carried out for a complete geomagnetic storm. Such imagery, now routine for the Solar community, is of critical scientific importance and captures public imagination. Its absence in geospace studies has limited the growth and impact of geospace science. In this presentation, we discuss a concept called the Great Geospace Observatory, which would involve coordinated geospace imaging through an international effort of multiple, simultaneous Missions of Opportunity. In this way, the cost would be spread among different agencies as well as putting remote sensors in vantage points optimized for each type of imaging. 24/7 auroral imaging from weather satellites on Molniya (or similar) orbits, EUV imaging of the plasmasphere from high-inclination orbits, continuous and global ENA imaging from geosynchronous commercial satellites, and continuous X-ray imaging of the cusp and magnetosheath from a high-altitude dedicated probe would quantitatively track system-level dynamics at through substorms, sawtooth events, steady magnetospheric convection, and storms; studying energy and mass coupling between the solar wind, magnetosphere, and the upper atmosphere. In our minds, The Great Geospace Observatory represents the next strategic step for ILWS and needs to be seriously considered.

Satellite Relaying of Geophysical Data

NASA Technical Reports Server (NTRS)

Allenby, R. J.

1977-01-01

Data Collection Platforms (DCPs) for transmitting surface data to an orbiting satellite for relaying to a central data distribution center are being used in a number of geophysical applications. "Off-the-shelf" DCP's, transmitting through Landsat or GOES satellites, are fully capable of relaying data from low-data-rate instruments, such as tiltmeters or tide gauges. In cooperation with the Lamont-Doherty Geological Observatory, Goddard has successfully installed DCP systems on a tide gauge and tiltmeter array on Anegada, British Virgin Islands. Because of the high-data-rate requirements, a practical relay system capable of handling seismic information is not yet available. Such a system could become the basis of an operational hazard prediction system for reducing losses due to major natural catastrophies such as earthquakes, volcanic eruptions, landslides or tsunamis.

The Alaska Volcano Observatory - Expanded Monitoring of Volcanoes Yields Results

USGS Publications Warehouse

Brantley, Steven R.; McGimsey, Robert G.; Neal, Christina A.

2004-01-01

Recent explosive eruptions at some of Alaska's 52 historically active volcanoes have significantly affected air traffic over the North Pacific, as well as Alaska's oil, power, and fishing industries and local communities. Since its founding in the late 1980s, the Alaska Volcano Observatory (AVO) has installed new monitoring networks and used satellite data to track activity at Alaska's volcanoes, providing timely warnings and monitoring of frequent eruptions to the aviation industry and the general public. To minimize impacts from future eruptions, scientists at AVO continue to assess volcano hazards and to expand monitoring networks.

GAIA virtual observatory - development and practices

NASA Astrophysics Data System (ADS)

Syrjäsuo, Mikko; Marple, Steve

2010-05-01

The Global Auroral Imaging Access, or GAIA, is a virtual observatory providing quick access to summary data from satellite and ground-based instruments that remote sense auroral precipitation (http://gaia-vxo.org). This web-based service facilitates locating data relevant to particular events by simultaneously displaying summary images from various data sets around the world. At the moment, there are GAIA server nodes in Canada, Finland, Norway and the UK. The development is an international effort and the software and metadata are freely available. The GAIA system is based on a relational database which is queried by a dedicated software suite that also creates the graphical end-user interface if such is needed. Most commonly, the virtual observatory is used interactively by using a web browser: the user provides the date and the type of data of interest. As the summary data from multiple instruments are displayed simultaneously, the user can conveniently explore the recorded data. The virtual observatory provides essentially instant access to the images originating from all major auroral instrument networks including THEMIS, NORSTAR, GLORIA and MIRACLE. The scientific, educational and outreach use is limited by creativity rather than access. The first version of the GAIA was developed at the University of Calgary (Alberta, Canada) in 2004-2005. This proof-of-concept included mainly THEMIS and MIRACLE data, which comprised of millions of summary plots and thumbnail images. However, it was soon realised that a complete re-design was necessary to increase flexibility. In the presentation, we will discuss the early history and motivation of GAIA as well as how the development continued towards the current version. The emphasis will be on practical problems and their solutions. Relevant design choices will also be highlighted.

The McDonnell Douglas geophysical observatory program progress report 13 Conjugate point riometer program

NASA Technical Reports Server (NTRS)

Baker, M. B.

1975-01-01

This report, the thirteenth and final progress report on the McDonnell Douglas Geophysical Observatory Program, discusses history of the program from 1962 through 1973, and results of the research carried out in 1974. Topic areas covered include: Station operation; Ionospheric work; Solar studies, Magnetospheric studies; Satellite measurements; International participation; and, 1974 research on solar activity, ATS-6 studies, magnetospheric physics, and station operation.

Deriving a Core Magnetic Field Model from Swarm Satellite Data

NASA Astrophysics Data System (ADS)

Lesur, V.; Rother, M.; Wardinski, I.

2014-12-01

A model of the Earth's core magnetic field has been built using Swarm satellite mission data and observatory quasi-definitive data. The satellite data processing scheme, which was used to derive previous satellite field models (i.e. GRIMM series), has been modified to handle discrepancies between the satellite total intensity data derived from the vector fluxgate magnetometer and the absolute scalar instrument. Further, the Euler angles, i.e. the angles between the vector magnetometer and the satellite reference frame, have been recalculated on a series of 30-day windows to obtain an accurate model of the core field for 2014. Preliminary derivations of core magnetic field and SV models for 2014 present the same characteristics as during the CHAMP era. The acceleration (i.e. the field second time derivative) has shown a rapid evolution over the last few years, and is present in the current model, which confirms previous observations.

The Little Thompson Observatory

NASA Astrophysics Data System (ADS)

Schweitzer, A.; Melsheimer, T.; Sackett, C.

1999-05-01

The Little Thompson Observatory is believed to be the first observatory built as part of a high school and accessible to other schools remotely, via the Internet. This observatory is the second member of the Telescopes in Education (TIE) project. Construction of the building and dome has been completed, and first light is planned for spring 1999. The observatory is located on the grounds of Berthoud High School in northern Colorado. Local schools and youth organizations will have prioritized access to the telescope, and there will also be opportunities for public viewing. After midnight, the telescope will be open to world-wide use by schools via the Internet following the model of the first TIE observatory, the 24" telescope on Mt. Wilson. Students remotely connect to the observatory over the Internet, and then receive the images on their local computers. The observatory grew out of grassroots support from the local community surrounding Berthoud, Colorado, a town of 3,500 residents. TIE has provided the observatory with a Tinsley 18" Cassegrain telescope on a 10-year loan. The facility has been built with tremendous support from volunteers and the local school district. We have received an IDEAS grant to provide teacher training workshops which will allow K-12 schools in northern Colorado to make use of the Little Thompson Observatory, including remote observing from classrooms.

Minimum Number of Observation Points for LEO Satellite Orbit Estimation by OWL Network

NASA Astrophysics Data System (ADS)

Park, Maru; Jo, Jung Hyun; Cho, Sungki; Choi, Jin; Kim, Chun-Hwey; Park, Jang-Hyun; Yim, Hong-Suh; Choi, Young-Jun; Moon, Hong-Kyu; Bae, Young-Ho; Park, Sun-Youp; Kim, Ji-Hye; Roh, Dong-Goo; Jang, Hyun-Jung; Park, Young-Sik; Jeong, Min-Ji

2015-12-01

By using the Optical Wide-field Patrol (OWL) network developed by the Korea Astronomy and Space Science Institute (KASI) we generated the right ascension and declination angle data from optical observation of Low Earth Orbit (LEO) satellites. We performed an analysis to verify the optimum number of observations needed per arc for successful estimation of orbit. The currently functioning OWL observatories are located in Daejeon (South Korea), Songino (Mongolia), and Oukaïmeden (Morocco). The Daejeon Observatory is functioning as a test bed. In this study, the observed targets were Gravity Probe B, COSMOS 1455, COSMOS 1726, COSMOS 2428, SEASAT 1, ATV-5, and CryoSat-2 (all in LEO). These satellites were observed from the test bed and the Songino Observatory of the OWL network during 21 nights in 2014 and 2015. After we estimated the orbit from systematically selected sets of observation points (20, 50, 100, and 150) for each pass, we compared the difference between the orbit estimates for each case, and the Two Line Element set (TLE) from the Joint Space Operation Center (JSpOC). Then, we determined the average of the difference and selected the optimal observation points by comparing the average values.

Eliminating large-scale magnetospheric current perturbations from long-term geomagnetic observatory data

NASA Astrophysics Data System (ADS)

Pick, L.; Korte, M. C.

2016-12-01

Magnetospheric currents generate the largest external contribution to the geomagnetic field observed on Earth. Of particular importance is the solar-driven effect of the ring current whose fluctuations overlap with internal field secular variation (SV). Recent core field models thus co-estimate this effect but their validity is limited to the last 15 years offering satellite data. We aim at eliminating magnetospheric modulation from the whole geomagnetic observatory record from 1840 onwards in order to obtain clean long-term SV that will enhance core flow and geodynamo studies.The ring current effect takes form of a southward directed external dipole field aligned with the geomagnetic main field axis. Commonly the Dst index (Sugiura, 1964) is used to parametrize temporal variations of this dipole term. Because of baseline instabilities, the alternative RC index was derived from hourly means of 21 stations spanning 1997-2013 (Olsen et al., 2014). We follow their methodology based on annual means from a reduced station set spanning 1960-2010. The absolute level of the variation so determined is "hidden" in the static lithospheric offsets taken as quiet-time means. We tackle this issue by subtracting crustal biases independently calculated for each observatory from an inversion of combined Swarm satellite and observatory data.Our index reproduces the original annual RC index variability with a reasonable offset of -10 nT in the reference time window 2000-2010. Prior to that it depicts a long-term trend consistent with the external dipole term from COV-OBS (Gillet et al., 2013), being the only long-term field model available for comparison. Sharper variations that are better correlated with the Ap index than the COV-OBS solution lend support to the usefulness of our initial modeling approach. Following a detailed sensitivity study of station choice future work will focus on increasing the resolution from annual to hourly means.

McDonald Observatory

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

McDonald Observatory, located in West Texas near Fort Davis, is the astronomical observatory of the University of Texas at Austin. Discoveries at McDonald Observatory include water vapor on Mars, the abundance of rare-earth chemical elements in stars, the discovery of planets circling around nearby stars and the use of the measurements of rapid oscillations in the brightness of white dwarf stars ...

In-Flight Performance of the Water Vapor Monitor Onboard the Sofia Observatory

NASA Technical Reports Server (NTRS)

Roellig, Thomas L.; Yuen, Lunming; Sisson, David; Hang, Richard

2012-01-01

NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA) airborne observatory flies in a modified B747-SP aircraft in the lower stratosphere above more than 99.9% of the Earth's water vapor. As low as this residual water vapor is, it will still affect SOFIA's infrared and sub-millimeter astronomical observations. As a result, a heterodyne instrument has been developed to observe the strength and shape of the 1830Hz rotational line of water, allowing measurements of the integrated water vapor overburden in flight. In order to be useful in correcting the astronomical signals, the required measured precipitable water vapor accuracy must be 2 microns or better, 3 sigma, and measured at least once a minute. The Water Vapor Monitor has flown 22 times during the SOFIA Early Science shared-risk period. The instrument water vapor overburden data obtained were then compared with concurrent data from GOES-V satellites to perform a preliminary calibration of the measurements. This presentation will cover the.results of these flights. The final flight calibration necessary to reach the required accuracy will await subsequent flights following the SOFIA observatory upgrade that is taking place during the spring and summer of 2012.

The Observatory as Laboratory: Spectral Analysis at Mount Wilson Observatory

NASA Astrophysics Data System (ADS)

Brashear, Ronald

2018-01-01

This paper will discuss the seminal changes in astronomical research practices made at the Mount Wilson Observatory in the early twentieth century by George Ellery Hale and his staff. Hale’s desire to set the agenda for solar and stellar astronomical research is often described in terms of his new telescopes, primarily the solar tower observatories and the 60- and 100-inch telescopes on Mount Wilson. This paper will focus more on the ancillary but no less critical parts of Hale’s research mission: the establishment of associated “physical” laboratories as part of the observatory complex where observational spectral data could be quickly compared with spectra obtained using specialized laboratory equipment. Hale built a spectroscopic laboratory on the mountain and a more elaborate physical laboratory in Pasadena and staffed it with highly trained physicists, not classically trained astronomers. The success of Hale’s vision for an astronomical observatory quickly made the Carnegie Institution’s Mount Wilson Observatory one of the most important astrophysical research centers in the world.

Combined Images

NASA Image and Video Library

2017-12-08

Four different instruments on SOHO show a large CME on Nov. 6, 1997. The sun is at the center, with three coronagraph images of different sizes around it. The streaks of white light are from protons hitting the SOHO cameras producing a snowy effect typical of a significant flare. ..Credit: NASA/SOHO..---..CME WEEK: What To See in CME Images Two main types of explosions occur on the sun: solar flares and coronal mass ejections. Unlike the energy and x-rays produced in a solar flare – which can reach Earth at the speed of light in eight minutes – coronal mass ejections are giant, expanding clouds of solar material that take one to three days to reach Earth. Once at Earth, these ejections, also called CMEs, can impact satellites in space or interfere with radio communications. During CME WEEK from Sept. 22 to 26, 2014, we explore different aspects of these giant eruptions that surge out from the star we live with. When a coronal mass ejection blasts off the sun, scientists rely on instruments called coronagraphs to track their progress. Coronagraphs block out the bright light of the sun, so that the much fainter material in the solar atmosphere -- including CMEs -- can be seen in the surrounding space. CMEs appear in these images as expanding shells of material from the sun's atmosphere -- sometimes a core of colder, solar material (called a filament) from near the sun's surface moves in the center. But mapping out such three-dimensional components from a two-dimensional image isn't easy. Watch the slideshow to find out how scientists interpret what they see in CME pictures. The images in the slideshow are from the three sets of coronagraphs NASA currently has in space. One is on the joint European Space Agency and NASA Solar and Heliospheric Observatory, or SOHO. SOHO launched in 1995, and sits between Earth and the sun about a million miles away from Earth. The other two coronagraphs are on the two spacecraft of the NASA Solar Terrestrial Relations Observatory

Astronomical observatories

NASA Technical Reports Server (NTRS)

Ponomarev, D. N.

1983-01-01

The layout and equipment of astronomical observatories, the oldest scientific institutions of human society are discussed. The example of leading observatories of the USSR allows the reader to familiarize himself with both their modern counterparts, as well as the goals and problems on which astronomers are presently working.

NASA'S Great Observatories

NASA Technical Reports Server (NTRS)

1998-01-01

Why are space observatories important? The answer concerns twinkling stars in the night sky. To reach telescopes on Earth, light from distant objects has to penetrate Earth's atmosphere. Although the sky may look clear, the gases that make up our atmosphere cause problems for astronomers. These gases absorb the majority of radiation emanating from celestial bodies so that it never reaches the astronomer's telescope. Radiation that does make it to the surface is distorted by pockets of warm and cool air, causing the twinkling effect. In spite of advanced computer enhancement, the images finally seen by astronomers are incomplete. NASA, in conjunction with other countries' space agencies, commercial companies, and the international community, has built observatories such as the Hubble Space Telescope, the Compton Gamma Ray Observatory, and the Chandra X-ray Observatory to find the answers to numerous questions about the universe. With the capabilities the Space Shuttle provides, scientist now have the means for deploying these observatories from the Shuttle's cargo bay directly into orbit.

The Little Thompson Observatory

NASA Astrophysics Data System (ADS)

Schweitzer, A.; Melsheimer, T.; Rideout, C.; Vanlew, K.

1998-12-01

The Little Thompson Observatory is believed to be the first observatory built as part of a high school and accessible to other schools remotely, via the Internet. This observatory is the second member of the Telescopes in Education (TIE) project. Construction is nearly completed and first light is planned for fall 1998. The observatory is located on the grounds of Berthoud High School in northern Colorado. Local schools and youth organizations will have prioritized access to the telescope, and there will also be opportunities for public viewing. After midnight, the telescope will be open to world-wide use by schools via the Internet following the model of the first TIE observatory, the 24" telescope on Mt. Wilson. That telescope has been in use for the past four years by up to 50 schools per month. Students remotely connect to the observatory over the Internet, and then receive the images on their local computers. The observatory grew out of grassroots support from the local community surrounding Berthoud, Colorado, a town of 3,500 residents. TIE has provided the observatory with a Tinsley 18" Cassegrain telescope on a 10-year loan. The facility has been built with tremendous support from volunteers and the local school district. We have applied for an IDEAS grant to provide teacher training workshops which will allow K-12 schools in northern Colorado to make use of the Little Thompson Observatory, including remote observing from classrooms.

Let Our Powers Combine! Harnessing NASA's Earth Observatory Natural Event Tracker (EONET) in Worldview

NASA Technical Reports Server (NTRS)

Wong, Min Minnie; Ward, Kevin; Boller, Ryan; Gunnoe, Taylor; Baynes, Kathleen; King, Benjamin

2016-01-01

Constellations of NASA Earth Observing System (EOS) satellites orbit the earth to collect images and data about the planet in near real-time. Within hours of satellite overpass, you can discover where the latest wildfires, severe storms, volcanic eruptions, and dust and haze events are occurring using NASA's Worldview web application. By harnessing a repository of curated natural event metadata from NASA Earth Observatory's Natural Event Tracker (EONET), Worldview has moved natural event discovery to the forefront and allows users to select events-of-interest from a curated list, zooms to the area, and adds the most relevant imagery layers for that type of natural event. This poster will highlight NASA Worldviews new natural event feed functionality.

Launch and on-orbit checkout of Aquarius/SAC-D Observatory: an international remote sensing satellite mission measuring sea surface salinity

NASA Astrophysics Data System (ADS)

Sen, Amit; Caruso, Daniel; Durham, David; Falcon, Carlos

2011-11-01

The Aquarius/SAC-D observatory was launch in June 2011 from Vandenberg Air Force Base (VAFB), in California, USA. This mission is the fourth joint earth-observation endeavor between NASA and CONAE. The primary objective of the Aquarius/SAC-D mission is to investigate the links between global water cycle, ocean circulation and climate by measuring Sea Surface Salinity (SSS). Over the last year, the observatory successfully completed system level environmental and functional testing at INPE, Brazil and was transported to VAFB for launch operations. This paper will present the challenges of this mission, the system, the preparation of the spacecraft, instruments, testing, launch, inorbit checkout and commissioning of this Observatory in space.

Satellite-to-Ground Entanglement-Based Quantum Key Distribution.

PubMed

Yin, Juan; Cao, Yuan; Li, Yu-Huai; Ren, Ji-Gang; Liao, Sheng-Kai; Zhang, Liang; Cai, Wen-Qi; Liu, Wei-Yue; Li, Bo; Dai, Hui; Li, Ming; Huang, Yong-Mei; Deng, Lei; Li, Li; Zhang, Qiang; Liu, Nai-Le; Chen, Yu-Ao; Lu, Chao-Yang; Shu, Rong; Peng, Cheng-Zhi; Wang, Jian-Yu; Pan, Jian-Wei

2017-11-17

We report on entanglement-based quantum key distribution between a low-Earth-orbit satellite equipped with a space borne entangled-photon source and a ground observatory. One of the entangled photons is measured locally at the satellite, and the other one is sent via a down link to the receiver in the Delingha ground station. The link attenuation is measured to vary from 29 dB at 530 km to 36 dB at 1000 km. We observe that the two-photon entanglement survives after being distributed between the satellite and the ground, with a measured state fidelity of ≥0.86. We then perform the entanglement-based quantum key distribution protocol and obtain an average final key rate of 3.5  bits/s at the distance range of 530-1000 km.

The Carl Sagan solar and stellar observatories as remote observatories

NASA Astrophysics Data System (ADS)

Saucedo-Morales, J.; Loera-Gonzalez, P.

In this work we summarize recent efforts made by the University of Sonora, with the goal of expanding the capability for remote operation of the Carl Sagan Solar and Stellar Observatories, as well as the first steps that have been taken in order to achieve autonomous robotic operation in the near future. The solar observatory was established in 2007 on the university campus by our late colleague A. Sánchez-Ibarra. It consists of four solar telescopes mounted on a single equatorial mount. On the other hand, the stellar observatory, which saw the first light on 16 February 2010, is located 21 km away from Hermosillo, Sonora at the site of the School of Agriculture of the University of Sonora. Both observatories can now be remotely controlled, and to some extent are able to operate autonomously. In this paper we discuss how this has been accomplished in terms of the use of software as well as the instruments under control. We also briefly discuss the main scientific and educational objectives, the future plans to improve the control software and to construct an autonomous observatory on a mountain site, as well as the opportunities for collaborations.

WNCC Observatory

NASA Astrophysics Data System (ADS)

Snyder, L. F.

2003-05-01

Western Nevada Community College (WNCC), located in Carson City, Nevada, is a small two year college with only 6,000 students. Associate degrees and Cer- tificates of Achievement are awarded. The college was built and started classes in 1971 and about 12 years ago the chair of the physics department along with a few in administration had dreams of building a small observatory for education. Around that time a local foundation, Nevada Gaming Foundation for Education Excellence, was looking for a beneficiary in the education field to receive a grant. They decided an observatory at the college met their criteria. Grants to the foundation instigated by Senators, businesses, and Casinos and donations from the local public now total $1.3 million. This paper will explain the different facets of building the observatory, the planning, construction, telescopes and equipment decisions and how we think it will operate for the public, education and research. The organization of local volunteers to operate and maintain the observatory and the planned re- search will be explained.

``Route of astronomical observatories'' project: Classical observatories from the Renaissance to the rise of astrophysics

NASA Astrophysics Data System (ADS)

Wolfschmidt, Gudrun

2016-10-01

Observatories offer a good possibility for serial transnational applications. For example one can choose groups like baroque or neoclassical observatories, solar physics observatories or a group of observatories equipped with the same kind of instruments or made by famous firms. I will discuss what has been achieved and show examples, like the route of astronomical observatories, the transition from classical astronomy to modern astrophysics. I will also discuss why the implementation of the World Heritage & Astronomy initiative is difficult and why there are problems to nominate observatories for election in the national tentative lists.

Bidirectional reflectance correction model for coastal water and its application to minimization of uncertainties in satellite and in-situ water leaving radiances at Long Island Sound Coastal Observatory site

NASA Astrophysics Data System (ADS)

Hlaing, Soe Min

Ocean Color data validation is the absolute requirement to provide the steady and reliable Ocean Color data stream. In the validation of Ocean Color data, water-leaving radiances, retrieved from in situ or satellite measurements, need to be compared in very accurate manner. Both in-situ and satellite data to be used in the comparisons are required to be the representative of the typical water and environmental condition at the site without being affected by the unexpected natural and environmental perturbation. As the result, assessments of the uncertainties in the water leaving radiance data must be carried out in the measurement and the every step of data processing procedure. With the hyper- and multi-spectral water leaving radiance data retrieved for the different viewing geometries of the instruments at the Long Island Sound Coastal Observatory (LISCO), uncertainties in the water leaving radiance data and processing procedures have been assessed and quantified. Recommendations and algorithm improvements have been also made to reduce the uncertainties in the processing and validation of Ocean Color data. Particularly, remote sensing reflectance model to correct the bidirectional angular dependencies in both in-situ and satellite data have been proposed. The proposed model is first validated with a one year time series of in situ above-water measurements acquired by collocated multi- and hyper-spectral radiometers which have different viewing geometries installed at LISCO. Match-ups and inter-comparisons performed on these concurrent measurements show that the proposed algorithm outperforms the algorithm currently in use at all wavelengths, with spectral average improvement of 2.4%. LISCO's time series data has also been used to evaluate improvements in the match-up comparisons of MODIS satellite data when the proposed Bidirectional Reflectance Distribution Function (BRDF) correction is used in lieu of the current algorithm. It has been shown that the

Systematic Variability of the He+ Pickup Ion Velocity Distribution Function Observed with SOHO/CELIAS/CTOF

NASA Astrophysics Data System (ADS)

Taut, Andreas; Drews, Christian; Berger, Lars; Wimmer-Schweingruber, Robert

2016-04-01

The 1D Velocity Distribution Function (VDF) of He+ pickup ions shows two distinct populations that reflect the sources of these ions. The highly suprathermal population is the result of the ionization and pickup of almost resting interstellar neutrals that are injected into the solar wind as a highly anisotropic torus distribution. The nearly thermalized population is centered around the solar wind bulk speed and is mainly attributed to inner-source pickup ions that originate in the inner heliosphere. Current pickup ion models assume a rapid isotropization of the initial VDF by resonant wave-particle interactions, but recent observations by Drews et al. (2015) of a torus-like VDF strongly limit this isotropization. This in turn means that more observational data is needed to further characterize the kinetic behavior of pickup ions. The Charge-Time-Of-Flight sensor on-board SOHO offers unrivaled counting statistics for He+ and a sufficient mass-per-charge resolution. Thus, the He+ VDF can be observed on comparatively short timescales. We combine this data with the magnetic field data from WIND via an extrapolation to the location of SOHO. On the one hand we investigate the 1D VDF of He+ pickup ions with respect to different magnetic field orientations. Our findings complement on previous studies with other instruments that show an anisotropy of the VDF that is linked to the initial torus VDF. On the other hand we find a significant modification of the VDF during stream-interaction region. This may be linked to a different cooling behaviour in these regions and/or the absence of inner-source He+ during these times. Here, we report on our preliminary results.

Exploring Satellite Galaxy Rotation Curves in the SAGA Survey

NASA Astrophysics Data System (ADS)

Rowland, Danielle; Tollerud, Erik; Watkins, Laura L.

2018-01-01

The Milky Way and its neighbors, known as the Local Group, have been extensively studied; however, it isn’t known if they are representative of similar galaxy groups in the larger universe. The SAGA Survey seeks to find and characterize satellite galaxies around 100 host galaxies that are analogous to the Milky Way to achieve a statistically-significant sample size for comparison to the Local Group. Candidate satellites were first identified using photometry, and then confirmed using redshifts determined from fiber spectroscopy; so far this has yielded 29 satellites around 8 host galaxies. This poster will detail the process of reducing further follow-up data on these 29 confirmed satellites that used the long-slit double spectrograph at Palomar Observatory. I will describe in detail the steps of bias/flat calibration, finding a dispersion solution, subtracting sky emissions, and combining red and blue side spectra to extract a complete 1D spectrum. I will also discuss how this follow-up data uniquely allows for determination of galaxy rotation curves that will help characterize the dark matter content for each satellite.

Satellite Sees Holiday Lights Brighten Cities - Istanbul

NASA Image and Video Library

2017-12-08

In several cities in the Middle East, city lights brighten during the Muslim holy month of Ramadan, as seen using a new analysis of daily data from the NASA-NOAA Suomi NPP satellite. Dark green pixels are areas where the lights are 50 percent brighter, or more, during Ramadan. Credit: Jesse Allen, NASA’s Earth Observatory Read more: www.nasa.gov/content/goddard/satellite-sees-holiday-light... NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Satellite Sees Holiday Lights Brighten Cities - Cairo

NASA Image and Video Library

2017-12-08

In several cities in the Middle East, city lights brighten during the Muslim holy month of Ramadan, as seen using a new analysis of daily data from the NASA-NOAA Suomi NPP satellite. Dark green pixels are areas where the lights are 50 percent brighter, or more, during Ramadan. Credit: Jesse Allen, NASA’s Earth Observatory Read more: www.nasa.gov/content/goddard/satellite-sees-holiday-light... NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

The investigation of tethered satellite system dynamics

NASA Technical Reports Server (NTRS)

Lorenzini, E. C.

1986-01-01

The analysis of the rotational dynamics of the satellite was focused on the rotational amplitude increase of the satellite, with respect to the tether, during retrieval. The dependence of the rotational amplitude upon the tether tension variation to the power 1/4 was thoroughly investigated. The damping of rotational oscillations achievable by reel control was also quantified while an alternative solution that makes use of a lever arm attached with a universal joint to the satellite was proposed. Comparison simulations between the Smithsonian Astrophysical Observatory and the Martin Marietta (MMA) computer code of reteival maneuvers were also carried out. The agreement between the two, completely independent, codes was extremely close, demonstrating the reliability of the models. The slack tether dynamics during reel jams was analytically investigated in order to identify the limits of applicability of the SLACK3 computer code to this particular case. Test runs with SLACK3 were also carried out.

Astronomical publications of Melbourne Observatory

NASA Astrophysics Data System (ADS)

Andropoulos, Jenny Ioanna

2014-05-01

During the second half of the 19th century and the first half of the 20th century, four well-equipped government observatories were maintained in Australia - in Melbourne, Sydney, Adelaide and Perth. These institutions conducted astronomical observations, often in the course of providing a local time service, and they also collected and collated meteorological data. As well, some of these observatories were involved at times in geodetic surveying, geomagnetic recording, gravity measurements, seismology, tide recording and physical standards, so the term "observatory" was being used in a rather broad sense! Despite the international renown that once applied to Williamstown and Melbourne Observatories, relatively little has been written by modern-day scholars about astronomical activities at these observatories. This research is intended to rectify this situation to some extent by gathering, cataloguing and analysing the published astronomical output of the two Observatories to see what contributions they made to science and society. It also compares their contributions with those of Sydney, Adelaide and Perth Observatories. Overall, Williamstown and Melbourne Observatories produced a prodigious amount of material on astronomy in scientific and technical journals, in reports and in newspapers. The other observatories more or less did likewise, so no observatory of those studied markedly outperformed the others in the long term, especially when account is taken of their relative resourcing in staff and equipment.

Early Results from NASA's Assessment of Satellite Servicing

NASA Technical Reports Server (NTRS)

Thronson, Harley A.; Reed, Benjamin B.; Townsend, Jacqueline A.; Ahmed, Mansoor; Whipple, Arthur O.; Oegerle, William R.

2010-01-01

Following recommendations by the NRC, NASA's FY 2008 Authorization Act and the FY 2009 and 2010 Appropriations bills directed NASA to assess the use of the human spaceflight architecture to service existing/future observatory-class scientific spacecraft. This interest in satellite servicing, with astronauts and/or with robots, reflects the success that NASA achieved with the Shuttle program and HST on behalf of the astronomical community as well as the successful construction of ISS. This study, led by NASA GSFC, will last about a year, leading to a final report to NASA and Congress in autumn 2010. We will report on its status, results from our March satellite servicing workshop, and recent concepts for serviceable scientific missions.

Keele Observatory

NASA Astrophysics Data System (ADS)

Theodorus van Loon, Jacco; Albinson, James; Bagnall, Alan; Bryant, Lian; Caisley, Dave; Doody, Stephen; Johnson, Ian; Klimczak, Paul; Maddison, Ron; Robinson, StJohn; Stretch, Matthew; Webb, John

2015-08-01

Keele Observatory was founded by Dr. Ron Maddison in 1962, on the hill-top campus of Keele University in central England, hosting the 1876 Grubb 31cm refractor from Oxford Observatory. It since acquired a 61cm research reflector, a 15cm Halpha solar telescope and a range of other telescopes. Run by a group of volunteering engineers and students under directorship of a Keele astrophysicist, it is used for public outreach as well as research. About 4,000 people visit the observatory every year, including a large number of children. We present the facility, its history - including involvement in the 1919 Eddington solar eclipse expedition which proved Albert Einstein's theory of general relativity - and its ambitions to erect a radio telescope on its site.

Comet ISON Seen Coming and Going

NASA Image and Video Library

2013-11-30

"Timelapse" series of images of comet ISON as viewed by ESA/NASA's Solar and Heliospheric Observatory, or SOHO. This image is a composite, with the sun imaged by NASA's Solar Dynamics Observatory in the center, and SOHO's two coronagraphs showing the solar atmosphere, the corona. The most recent image in this is from 5:30 p.m. EST on Nov. 29, 2013. Continuing a history of surprising behavior, material from Comet ISON appeared on the other side of the sun on the evening on Nov. 28, 2013, despite not having been seen in observations during its closest approach to the sun. The question remains whether it is merely debris from the comet, or if some portion of the comet's nucleus survived, but late-night analysis from scientists with NASA's Comet ISON Observing Campaign suggest that there is at least a small nucleus intact. Image Credit:ESA&NASA/SOHO/SDO NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Lightweight telescopes for lunar observatories

NASA Astrophysics Data System (ADS)

Rozelot, J. P.; Bingham, R.; Walker, D.

1994-06-01

Future optical observatories in space will require telescopes of very high resolution. To satisfy this demand, technology must be developed for large mirrors capable of diffraction-limited imaging. Conventional monolithic glass substrates (light-weight or not) have serious limitations for future development. In particular, glass is susceptible to fracture during ground-handling, transport and launch. An alternative solution is aluminium. It has lower cost, increased strength, easier and safer methods of fixing, amongst other advantages. It is readily lightweighted and can be produced with good polishing quality with nickel coating. We foresee applications for satellite telescope for astronomy, remote sensing, surveys of asteroids and debris in space. Furthermore, this technology is ideally suitable for lunar mounted interferometric experiments - as mirrors can be easily replicate, saving cost - and for telescopes deployed on planetary surfaces. Some results from the European Eureka Large Active Mirrors in Aluminium (LAMA) are here presented, which show the feasibility of such systems.

Exploring the Digital Universe with Europe's Astrophysical Virtual Observatory

NASA Astrophysics Data System (ADS)

2001-12-01

need for virtual observatories has also been recognised by other astronomical communities. The National Science Foundation in the USA has awarded $10 million (EUR 11.4 m) for a National Virtual Observatory (NVO). The AVO project team has formed a close alliance with the NVO and both teams have representatives on each other's committees. It is clear to the NVO and AVO communities that there are no intrinsic boundaries to the virtual observatory concept and that all astronomers should be working towards a truly global virtual observatory that will enable new science to be carried out on the wealth of astronomical data held in the growing number of first-class international astronomical archives. AVO involves six partner organisations led by the European Southern Observatory (ESO) in Munich. The other partner organisations are the European Space Agency (ESA), the United Kingdom's ASTROGRID consortium, the CNRS-supported Centre de Données Astronomiques de Strasbourg (CDS) at the University Louis Pasteur in Strasbourg, the CNRS-supported TERAPIX astronomical data centre at the Institut d'Astrophysique in Paris and the Jodrell Bank Observatory at the University of Manchester. Note for editors A 13-minute background video (broadcast PAL) is available from ESO PR and the Hubble European Space Agency Information Centre (addresses below). It will also be transmitted via satellite on Wednesday 12 December 2001 from 12:00 to 12:15 CET on the ESA TV Service: http://television.esa.int

Continuous day-time time series of E-region equatorial electric fields derived from ground magnetic observatory data

NASA Astrophysics Data System (ADS)

Alken, P.; Chulliat, A.; Maus, S.

2012-12-01

The day-time eastward equatorial electric field (EEF) in the ionospheric E-region plays an important role in equatorial ionospheric dynamics. It is responsible for driving the equatorial electrojet (EEJ) current system, equatorial vertical ion drifts, and the equatorial ionization anomaly (EIA). Due to its importance, there is much interest in accurately measuring and modeling the EEF. However, there are limited sources of direct EEF measurements with full temporal and spatial coverage of the equatorial ionosphere. In this work, we propose a method of estimating a continuous day-time time series of the EEF at any longitude, provided there is a pair of ground magnetic observatories in the region which can accurately track changes in the strength of the EEJ. First, we derive a climatological unit latitudinal current profile from direct overflights of the CHAMP satellite and use delta H measurements from the ground observatory pair to determine the magnitude of the current. The time series of current profiles is then inverted for the EEF by solving the governing electrodynamic equations. While this method has previously been applied and validated in the Peruvian sector, in this work we demonstrate the method using a pair of magnetometers in Africa (Samogossoni, SAM, 0.18 degrees magnetic latitude and Tamanrasset, TAM, 11.5 degrees magnetic latitude) and validate the resulting EEF values against the CINDI ion velocity meter (IVM) instrument on the C/NOFS satellite. We find a very good 80% correlation with C/NOFS IVM measurements and a root-mean-square difference of 9 m/s in vertical drift velocity. This technique can be extended to any pair of ground observatories which can capture the day-time strength of the EEJ. We plan to apply this work to more observatory pairs around the globe and distribute real-time equatorial electric field values to the community.

The Little Thompson Observatory

NASA Astrophysics Data System (ADS)

Schweitzer, A. E.; VanLew, K.; Melsheimer, T.; Sackett, C.

1999-12-01

The Little Thompson Observatory is the second member of the Telescopes in Education (TIE) project. Construction of the dome and the remote control system has been completed, and the telescope is now on-line and operational over the Internet. The observatory is located on the grounds of Berthoud High School in northern Colorado. Local schools and youth organizations have prioritized access to the telescope, and there are monthly opportunities for public viewing. In the future, the telescope will be open after midnight to world-wide use by schools following the model of the first TIE observatory, the 24" telescope on Mt. Wilson. Students remotely connect to the observatory over the Internet, and then receive the images on their local computers. The observatory grew out of grassroots support from the local community surrounding Berthoud, Colorado, a town of 3,500 residents. TIE has provided the observatory with a Tinsley 18" Cassegrain telescope on a 10-year loan. The facility has been built with tremendous support from volunteers and the local school district. With funding from an IDEAS grant, we have begun teacher training workshops which will allow K-12 schools in northern Colorado to make use of the Little Thompson Observatory, including remote observing from classrooms.

The Improved Hydrological Gravity Model for Moxa Observatory, Germany

NASA Astrophysics Data System (ADS)

Weise, A.; Jahr, Th.

2017-04-01

The gravity variations observed by the superconducting gravimeter (SG) CD-034 at Moxa Geodynamic Observatory/Germany were compared with the GRACE results some years ago. The combination of a local hydrological model of a catchment area with a 3D-gravimetric model had been applied successfully for correcting the SG record of Moxa which is especially necessary due to the strong topography nearest to the SG location. Now, the models have been corrected and improved considerably by inserting several details in the very near surrounding. Mainly these are: the observatory building is inserted with the roof covered by a soil layer above the gravity sensor where humidity is varying, snow is placed on top of the roof and on topography (steep slope), and ground water is taken into account, additionally. The result is that the comparison of the corrected gravity residuals with gravity variations of the satellite mission GRACE, now using RL5 data, shows higher agreement, not only in amplitude but also the formerly apparent phase shift is obviously not realistic. The agreement between terrestrial gravity variations (SG) and the GRACE data is improved considerably which is discussed widely.

The Improved Hydrological Gravity Model for Moxa Observatory, Germany

NASA Astrophysics Data System (ADS)

Weise, A.; Jahr, Th.

2018-05-01

The gravity variations observed by the superconducting gravimeter (SG) CD-034 at Moxa Geodynamic Observatory/Germany were compared with the GRACE results some years ago. The combination of a local hydrological model of a catchment area with a 3D-gravimetric model had been applied successfully for correcting the SG record of Moxa which is especially necessary due to the strong topography nearest to the SG location. Now, the models have been corrected and improved considerably by inserting several details in the very near surrounding. Mainly these are: the observatory building is inserted with the roof covered by a soil layer above the gravity sensor where humidity is varying, snow is placed on top of the roof and on topography (steep slope), and ground water is taken into account, additionally. The result is that the comparison of the corrected gravity residuals with gravity variations of the satellite mission GRACE, now using RL5 data, shows higher agreement, not only in amplitude but also the formerly apparent phase shift is obviously not realistic. The agreement between terrestrial gravity variations (SG) and the GRACE data is improved considerably which is discussed widely.

Eclipses of the inner satellites of Jupiter observed in 2015

NASA Astrophysics Data System (ADS)

Saquet, E.; Emelyanov, N.; Colas, F.; Arlot, J.-E.; Robert, V.; Christophe, B.; Dechambre, O.

2016-06-01

Aims: During the 2014-2015 campaign of mutual events, we recorded ground-based photometric observations of eclipses of Amalthea (JV) and, for the first time, Thebe (JXIV) by the Galilean moons. We focused on estimating whether the positioning accuracy of the inner satellites determined with photometry is sufficient for dynamical studies. Methods: We observed two eclipses of Amalthea and one of Thebe with the 1 m telescope at Pic du Midi Observatory using an IR filter and a mask placed over the planetary image to avoid blooming features. A third observation of Amalthea was taken at Saint-Sulpice Observatory with a 60 cm telescope using a methane filter (890 nm) and a deep absorption band to decrease the contrast between the planet and the satellites. After background removal, we computed a differential aperture photometry to obtain the light flux, and followed with an astrometric reduction. Results: We provide astrometric results with an external precision of 53 mas for the eclipse of Thebe, and 20 mas for that of Amalthea. These observation accuracies largely override standard astrometric measurements. The (O - C)s for the eclipse of Thebe are 75 mas on the X-axis and 120 mas on the Y-axis. The (O - C)s for the total eclipses of Amalthea are 95 mas and 22 mas, along the orbit, for two of the three events. Taking into account the ratio of (O - C) to precision of the astrometric results, we show a significant discrepancy with the theory established by Avdyushev and Ban'shikova in 2008, and the JPL JUP 310 ephemeris. Three of the four eclipse observations where recorded at the 1 m telescope of Pic du Midi Observatory (S2P), the other at Saint-Sulpice Observatory.

How To Cover NASA's Chandra X-ray Observatory

NASA Astrophysics Data System (ADS)

1999-07-01

during the mission. NASA Television The launch and early activation of the Chandra X-ray Observatory will be carried live on NASA Television, available through the GE2 satellite system, which is located on Transponder 9C, at 85 degrees west longitude, frequency 3880.0 MHz, audio 6.8 MHz. Around-the-clock, up-to-the minute commentary, television and daily briefings on Chandra's status will originate from the Chandra Operations Control Center in Cambridge, Mass., during Shuttle Mission STS-93. Internet Information Up-to-date, comprehensive information on the Chandra X-ray Observatory is available to news media on the Internet at: http://chandra.harvard.edu The latest status reports, news releases, photos, fact sheets and background archives, as well as links to other Chandra-related sites, are available at this address. Live Shots - Television Back-hauls Television station news departments may conduct live, or live-to-tape interviews via the NASA satellite with Chandra program managers, scientists and control team members prior to, during, and following the launch of Chandra. For additional information or to arrange interviews, broadcasters may contact Dave Drachlis at (256) 544-0031. Interviews Members of the Chandra development, operations, and science teams are available to the news media for interviews upon request. NASA TV on the web

Tools for Coordinated Planning Between Observatories

NASA Technical Reports Server (NTRS)

Jones, Jeremy; Fishman, Mark; Grella, Vince; Kerbel, Uri; Maks, Lori; Misra, Dharitri; Pell, Vince; Powers, Edward I. (Technical Monitor)

2001-01-01

With the realization of NASA's era of great observatories, there are now more than three space-based telescopes operating in different wavebands. This situation provides astronomers with a unique opportunity to simultaneously observe with multiple observatories. Yet scheduling multiple observatories simultaneously is highly inefficient when compared to observations using only one single observatory. Thus, programs using multiple observatories are limited not due to scientific restrictions, but due to operational inefficiencies. At present, multi-observatory programs are conducted by submitting observing proposals separately to each concerned observatory. To assure that the proposed observations can be scheduled, each observatory's staff has to check that the observations are valid and meet all the constraints for their own observatory; in addition, they have to verify that the observations satisfy the constraints of the other observatories. Thus, coordinated observations require painstaking manual collaboration among the observatory staff at each observatory. Due to the lack of automated tools for coordinated observations, this process is time consuming, error-prone, and the outcome of the requests is not certain until the very end. To increase observatory operations efficiency, such manpower intensive processes need to undergo re-engineering. To overcome this critical deficiency, Goddard Space Flight Center's Advanced Architectures and Automation Branch is developing a prototype effort called the Visual Observation Layout Tool (VOLT). The main objective of the VOLT project is to provide visual tools to help automate the planning of coordinated observations by multiple astronomical observatories, as well as to increase the scheduling probability of all observations.

Hemispherical Nature of EUV Shocks Revealed by SOHO, STEREO, and SDO Observations

NASA Technical Reports Server (NTRS)

Gopalswamy, Natchimuthuk; Nitta, N.; Akiyama, S.; Makela, P.; Yashiro, S.

2011-01-01

EUV wave transients associated with type II radio bursts are manifestation of CME-driven shocks in the solar corona. We use recent EUV wave observations from SOHO, STEREO, and SDO for a set of CMEs to show that the EUV transients have a spherical shape in the inner corona. We demonstrate this by showing that the radius of the EUV transient on the disk observed by one instrument is approximately equal to the height of the wave above the solar surface in an orthogonal view provided by another instrument. The study also shows that the CME-driven shocks often form very low in the corona at a heliocentric distance of 1.2 Rs, even smaller than the previous estimates from STEREO/CORl data (Gopalswamy et aI., 2009, Solar Phys. 259, 227). These results have important implications for the acceleration of solar energetic particles by CMEs

Running a distributed virtual observatory: U.S. Virtual Astronomical Observatory operations

NASA Astrophysics Data System (ADS)

McGlynn, Thomas A.; Hanisch, Robert J.; Berriman, G. Bruce; Thakar, Aniruddha R.

2012-09-01

Operation of the US Virtual Astronomical Observatory shares some issues with modern physical observatories, e.g., intimidating data volumes and rapid technological change, and must also address unique concerns like the lack of direct control of the underlying and scattered data resources, and the distributed nature of the observatory itself. In this paper we discuss how the VAO has addressed these challenges to provide the astronomical community with a coherent set of science-enabling tools and services. The distributed nature of our virtual observatory-with data and personnel spanning geographic, institutional and regime boundaries-is simultaneously a major operational headache and the primary science motivation for the VAO. Most astronomy today uses data from many resources. Facilitation of matching heterogeneous datasets is a fundamental reason for the virtual observatory. Key aspects of our approach include continuous monitoring and validation of VAO and VO services and the datasets provided by the community, monitoring of user requests to optimize access, caching for large datasets, and providing distributed storage services that allow user to collect results near large data repositories. Some elements are now fully implemented, while others are planned for subsequent years. The distributed nature of the VAO requires careful attention to what can be a straightforward operation at a conventional observatory, e.g., the organization of the web site or the collection and combined analysis of logs. Many of these strategies use and extend protocols developed by the international virtual observatory community. Our long-term challenge is working with the underlying data providers to ensure high quality implementation of VO data access protocols (new and better 'telescopes'), assisting astronomical developers to build robust integrating tools (new 'instruments'), and coordinating with the research community to maximize the science enabled.

An Overview of Geodetic and Astrometric VLBI at the Hartebeesthoek Radio Astronomy Observatory

NASA Astrophysics Data System (ADS)

de Witt, A.; Gaylard, M.; Quick, J.; Combrinck, L.

2013-08-01

For astronomical Very Long Baseline Interferometry (VLBI), the Hartebeesthoek Radio Astronomy Observatory (HartRAO), in South Africa operates as part of a number of networks including the European and Australian VLBI networks, global arrays and also space VLBI. HartRAO is the only African representative in the international geodetic VLBI network and participates in regular astrometric and geodetic VLBI programmes. HartRAO will play a major role in the realization of the next generation full-sky celestial reference frame, especially the improvement of the celestial reference frame in the South. The observatory also provides a base for developing the African VLBI Network (AVN), a project to convert redundant satellite Earth-station antennas across Africa to use for radio astronomy. The AVN would greatly facilitate VLBI observations of southern objects. We present an overview of the current capabilities as well as future opportunities for astrometric and geodetic VLBI at HartRAO.

The Boulder magnetic observatory

USGS Publications Warehouse

Love, Jeffrey J.; Finn, Carol A.; Pedrie, Kolby L.; Blum, Cletus C.

2015-08-14

The Boulder magnetic observatory has, since 1963, been operated by the Geomagnetism Program of the U.S. Geological Survey in accordance with Bureau and national priorities. Data from the observatory are used for a wide variety of scientific purposes, both pure and applied. The observatory also supports developmental projects within the Geomagnetism Program and collaborative projects with allied geophysical agencies.

A Deep-Ocean Observatory with Near Real-time Telemetry

NASA Astrophysics Data System (ADS)

Berger, J.; Orcutt, J. A.; Laske, G.

2014-12-01

We describe an autonomously deployable, deep-ocean observatory designed to provide long term and near-real-time observations from sites far offshore. The key feature of this new system is its ability to telemeter sensor data from the seafloor to shore without a cable or moored surface buoy. In the future the observatory will be deployable without a ship. The first application of this system is seismology. While permanent ocean seismic stations on the seafloor have long been a goal of global seismology, today there are still no ocean bottom stations in the Global Seismographic Network, mostly for reasons of life-cycle costs. Yet real-time data from stations in oceanic areas are critical for both national and international agencies in monitoring and characterizing earthquakes, tsunamis, and nuclear explosions. The system comprises an ocean bottom instrumentation package and a free-floating surface communications gateway, which uses a Liquid Robotics wave glider. The glider consists of a surfboard-sized float propelled by a tethered, submerged glider, which converts wave motion into thrust. For navigation, the wave gliders are equipped with a small computer, a GPS receiver, a rudder, solar panels and batteries, and an Iridium satellite modem. Wave gliders have demonstrated trans-oceanic range combined with long-term station holding. The 'communications gateway,' which provides the means of communicating between the ocean bottom package and land comprises a wave glider and a towed acoustic communications 'tow body'. Acoustic communications connect the subsea instruments and the surface gateway while communications between the gateway and land is provided by the Iridium satellite constellation. Tests of the surface gateway in 4350 m of water demonstrated the ability to send four channels of compressed 24-bit, 1 sample per second data from the ocean bottom to the gateway with an average power draw of approximately 0.2 W.

Astrometric Research of Asteroidal Satellites

NASA Astrophysics Data System (ADS)

Kikwaya, J.-B.; Thuillot, W.; Rocher, P.; Vieira Martins, R.; Arlot, J.-E.; Angeli, Cl.

2002-09-01

Several observational methods have been applied in order to detect asteroidal satellites. Some of them were rather successful, such as the stellar occultations and mutual eclipse methods. Recently other techniques such as the space imaging, the adaptive optics and the radar imaging inferred a great improvement in the search for these objects. However several limitations appear in the type of data that each of them allow us to access. We propose to apply an astrometric method in order as well to detect new asteroidal satellites as to get complementary data of some already detected objects (mainly their orbital period). This method is founded on the search of the reflex effect of the primary object due to the orbital motion of a possible satellite. Such an astrometric signature, already searched by Monet & Monet (1998), may reach several tens of MAS. Only a spectral analysis could then detect this signal under good conditions of signal/noise ratio and thanks to high quality astrometric measurements and coverage by different sites of observation. We have applied such a method for several asteroids. A preliminary result is obtained thanks to 377 CCD observations of 146 Lucina made at the Haute-Provence Observatory in South of France. A periodical signal appears in this analysis, leading to data compatible with a first detection of a probable satellite made previously (Arlot et al. 1985) by the occultation method.

The Plant Phenology Monitoring Design for the National Ecological Observatory Network

NASA Technical Reports Server (NTRS)

Elmendorf, Sarah C.; Jones, Katherine D.; Cook, Benjamin I.; Diez, Jeffrey M.; Enquist, Carolyn A. F.; Hufft, Rebecca A.; Jones, Matthew O.; Mazer, Susan J.; Miller-Rushing, Abraham J.; Moore, David J. P.;

The plant phenology monitoring design for the National Ecological Observatory Network

USGS Publications Warehouse

Elmendorf, Sarah C; Jones, Katherine D.; Cook, Benjamin I.; Diez, Jeffrey M.; Enquist, Carolyn A.F.; Hufft, Rebecca A.; Jones, Matthew O.; Mazer, Susan J.; Miller-Rushing, Abraham J.; Moore, David J. P.; Schwartz, Mark D.; Weltzin, Jake F.

2016-01-01

Phenology is an integrative science that comprises the study of recurring biological activities or events. In an era of rapidly changing climate, the relationship between the timing of those events and environmental cues such as temperature, snowmelt, water availability or day length are of particular interest. This article provides an overview of the plant phenology sampling which will be conducted by the U.S. National Ecological Observatory Network NEON, the resulting data, and the rationale behind the design. Trained technicians will conduct regular in situ observations of plant phenology at all terrestrial NEON sites for the 30-year life of the observatory. Standardized and coordinated data across the network of sites can be used to quantify the direction and magnitude of the relationships between phenology and environmental forcings, as well as the degree to which these relationships vary among sites, among species, among phenophases, and through time. Vegetation at NEON sites will also be monitored with tower-based cameras, satellite remote sensing and annual high-resolution airborne remote sensing. Ground-based measurements can be used to calibrate and improve satellite-derived phenometrics. NEON’s phenology monitoring design is complementary to existing phenology research efforts and citizen science initiatives throughout the world and will produce interoperable data. By collocating plant phenology observations with a suite of additional meteorological, biophysical and ecological measurements (e.g., climate, carbon flux, plant productivity, population dynamics of consumers) at 47 terrestrial sites, the NEON design will enable continentalscale inference about the status, trends, causes and ecological consequences of phenological change.

Orbital Observatory for Planetary Science on Low Cost Autonomous Platform

NASA Astrophysics Data System (ADS)

Tavrov, Alexander; Bisikalo, Dmitry; Vedenkin, Nikolay; Korablev, Oleg; Markov, Alexander; Kiselev, Alexander; Kokorich, Mikhail

The Space Research Institute of Russian Academy of Science (IKI RAS) and Dauria Aerospace are currently developing the middle class space telescope project aiming to observe Solar system planets by a long term spectroscopy and polarimetry monitoring, as well aiming to extra solar planets (exoplanets) engineering and scientific goals. The spacecraft is scheduled to be launched in 2017. It is planned first to be delivered on board of the ISS by the Progress spacecraft, then it will be released to the desired orbit approx. 550 km by the Progress in the way to its final destination. The “Planetary monitoring” telescope has a 0.6 meter primary mirror diameter Telescope currently includes 5 science instruments: NIR: 1000..4000 nm high-resolution spectrometer with the spectral resolution of R>10000; Visible Field camera with filters wheel; UV-VIS field resolved Fourier spectrometer; UV-VIS spectropolarimeter; Stellar coronagraph linked with a low-resolution spectrometer. The scientific goals of the “Planetary monitoring” telescope are devoted to explore not yet well studied questions on Mars (methane, ozone, dust and clouds, isotope ratio of HDO/H2O), on Venus (UV absorber, night glow, atmosphere dynamics), icy and gaseous Solar system planets, Jovian moons, Lunar exosphere, comets, meteorites. This telescope aims also for engineering development of exoplanet study by stellar coronagraphy linked with a low-resolution spectrometry. This Orbital Observatory mission uses the first low cost small satellite platform developed by the Dauria Aerospace® - Russian private company and reuses the Progress to elevate the observatory orbit. The Progress launches four times per year to provide supplies and scientific instruments to the ISS. The Progress is capable of raising the height of the orbit for the piggyback scientific missions; therefore, the implementation of the Orbital Observatory mission is considered not just as a development of a successful science mission so it

A Small Spacecraft Swarm Deployment and Stationkeeping Strategy for Sun-Earth L1 Halo Orbits

NASA Technical Reports Server (NTRS)

Conn, Tracie R.; Bookbinder, Jay

2018-01-01

Spacecraft orbits about the Sun-Earth librarian point L1 have been of interest since the 1950s. An L1 halo orbit was first achieved with the International Sun-Earth Explorer-3 (ISEE-3) mission, and similar orbits around Sun-Earth L1 were achieved in the Solar and Heliospheric Observatory (SOHO), Advanced Composition Explorer (ACE), Genesis, and Deep Space Climate Observatory (DSCOVR) missions. With recent advancements in CubeSat technology, we envision that it will soon be feasible to deploy CubeSats at L1. As opposed to these prior missions where one large satellite orbited alone, a swarm of CubeSats at L1 would enable novel science data return, providing a topology for intersatellite measurements of heliophysics phenomena both spatially and temporally, at varying spatial scales.The purpose of this iPoster is to present a flight dynamics strategy for a swarm of numerous CubeSats orbiting Sun-Earth L1. The presented method is a coupled, two-part solution. First, we present a deployment strategy for the CubeSats that is optimized to produce prescribed, time-varying intersatellite baselines for the purposes of collecting magnetometer data as well as radiometric measurements from cross-links. Second, we employ a loose control strategy that was successfully applied to SOHO and ACE for minimized stationkeeping fuel expenditure. We emphasize that the presented solution is practical within the current state-of-the-art and heritage CubeSat technology, citing capabilities of CubeSat designs that will launch on the upcoming Exploration Mission 1 (EM-1) to lunar orbits and beyond. Within this iPoster, we present animations of the simulated deployment strategy and resulting spacecraft trajectories. Mission design parameters such as total delta-v required for long-term station keeping and minimummaximummean spacecraft separation distances are also presented.

A Small Spacecraft Swarm Deployment and Stationkeeping Strategy for Sun-Earth L1 Halo Orbits

NASA Astrophysics Data System (ADS)

Renea Conn, Tracie; Bookbinder, Jay

2018-01-01

Spacecraft orbits about the Sun-Earth librarian point L1 have been of interest since the 1950s. An L1 halo orbit was first achieved with the International Sun-Earth Explorer-3 (ISEE-3) mission, and similar orbits around Sun-Earth L1 were achieved in the Solar and Heliospheric Observatory (SOHO), Advanced Composition Explorer (ACE), Genesis, and Deep Space Climate Observatory (DSCOVR) missions. With recent advancements in CubeSat technology, we envision that it will soon be feasible to deploy CubeSats at L1. As opposed to these prior missions where one large satellite orbited alone, a swarm of CubeSats at L1 would enable novel science data return, providing a topology for intersatellite measurements of heliophysics phenomena both spatially and temporally, at varying spatial scales.The purpose of this iPoster is to present a flight dynamics strategy for a swarm of numerous CubeSats orbiting Sun-Earth L1. The presented method is a coupled, two-part solution. First, we present a deployment strategy for the CubeSats that is optimized to produce prescribed, time-varying intersatellite baselines for the purposes of collecting magnetometer data as well as radiometric measurements from cross-links. Second, we employ a loose control strategy that was successfully applied to SOHO and ACE for minimized stationkeeping propellant expenditure. We emphasize that the presented solution is practical within the current state-of-the-art and heritage CubeSat technology, citing capabilities of CubeSat designs that will launch on the upcoming Exploration Mission 1 (EM-1) to lunar orbits and beyond. Within this iPoster, we present animations of the simulated deployment strategy and resulting spacecraft trajectories. Mission design parameters such as total Δv required for long-term station keeping and minimum/maximum/mean spacecraft separation distances are also presented.

"Route of astronomical observatories'' project: classical observatories from the Renaissance to the rise of astrophysics

NASA Astrophysics Data System (ADS)

Wolfschmidt, Gudrun

2015-08-01

Observatories offer a good possibility for serial transnational applications. A well-known example for a thematic programme is the Struve arc, already recognized as World Heritage.I will discuss what has been achieved and show examples, like the route of astronomical observatories or the transition from classical astronomy to modern astrophysics (La Plata, Hamburg, Nice, etc.), visible in the architecture, the choice of instruments, and the arrangement of the observatory buildings in an astronomy park. This corresponds to the main categories according to which the ``outstanding universal value'' (UNESCO criteria ii, iv and vi) of the observatories have been evaluated: historic, scientific, and aesthetic. This proposal is based on the criteria of a comparability of the observatories in terms of the urbanistic complex and the architecture, the scientific orientation, equipment of instruments, authenticity and integrity of the preserved state, as well as in terms of historic scientific relations and scientific contributions.Apart from these serial transnational applications one can also choose other groups like baroque or neo-classical observatories, solar physics observatories or a group of observatories equipped with the same kind of instruments and made by the same famous firm. I will also discuss why the implementation of the Astronomy and World Heritage Initiative is difficult and why there are problems to nominate observatories for election in the national Tentative Lists

Dissemination of satellite-based river discharge and flood data

NASA Astrophysics Data System (ADS)

Kettner, A. J.; Brakenridge, G. R.; van Praag, E.; de Groeve, T.; Slayback, D. A.; Cohen, S.

2014-12-01

In collaboration with NASA Goddard Spaceflight Center and the European Commission Joint Research Centre, the Dartmouth Flood Observatory (DFO) daily measures and distributes: 1) river discharges, and 2) near real-time flood extents with a global coverage. Satellite-based passive microwave sensors and hydrological modeling are utilized to establish 'remote-sensing based discharge stations', and observed time series cover 1998 to the present. The advantages over in-situ gauged discharges are: a) easy access to remote or due to political reasons isolated locations, b) relatively low maintenance costs to maintain a continuous observational record, and c) the capability to obtain measurements during floods, hazardous conditions that often impair or destroy in-situ stations. Two MODIS instruments aboard the NASA Terra and Aqua satellites provide global flood extent coverage at a spatial resolution of 250m. Cloud cover hampers flood extent detection; therefore we ingest 6 images (the Terra and Aqua images of each day, for three days), in combination with a cloud shadow filter, to provide daily global flood extent updates. The Flood Observatory has always made it a high priority to visualize and share its data and products through its website. Recent collaborative efforts with e.g. GeoSUR have enhanced accessibility of DFO data. A web map service has been implemented to automatically disseminate geo-referenced flood extent products into client-side GIS software. For example, for Latin America and the Caribbean region, the GeoSUR portal now displays current flood extent maps, which can be integrated and visualized with other relevant geographical data. Furthermore, the flood state of satellite-observed river discharge sites are displayed through the portal as well. Additional efforts include implementing Open Geospatial Consortium (OGC) standards to incorporate Water Markup Language (WaterML) data exchange mechanisms to further facilitate the distribution of the satellite

New infrastructure at Alboran island (Western Mediterranean): a submarine and on-land Geophysical Observatory

NASA Astrophysics Data System (ADS)

Pazos, Antonio; Martín Davila, José; Buforn, Elisa; Jesús García Fernández, Maria; Bullón, Mercedes; Gárate, Jorge

2010-05-01

The Eurasian-African plate boundary crosses the called "Ibero-Maghrebian" region from San Vicente Cape (SW Portugal) to Tunisia including the South of Iberia, Alboran Sea, and northern of Morocco and Algeria. The low convergence rate at this plate boundary produces a continuous moderate seismic activity of low magnitude and shallow depth, where the occurrence of large earthquakes is separated by long time intervals. In this region, there are also intermediate and very deep earthquakes. Since more than hundred years ago San Fernando Naval Observatory (ROA), in collaboration with other Institutes, has deployed different geophysical and geodetic equipment in the Southern Spain - North-western Africa area in order to study this broad deformation. Currently a Broad Band seismic net (Western Mediterranean, WM net), a permanent geodetic GPS net and a Geomagnetic Observatory have been installed by ROA in this area. To complement the available data, since past October a permanent marine-on land geophysical observatory is being installed by ROA in Alboran Island and surrounding marine zones. Till now the following facilities has been installed: • Submarine: 2 km submarine fibre optics cable (power and data transmission); Broad Band Seismometer (CMG-3T, buried); Accelerometer (Guralp 3 channels), buried); Differential Pressure Gauge (DPG); Thermometer. • On land: Permanent geodetic GPS station; Automatic meteorological station; Data acquisition system for submarine equipment; Satellite Data Transmission system. Data are already being transmitted in real time to ROA headquarters via satellite Intranet. The marine part, currently installed in a 50 m depth platform, has been designed to be enlarged by extending the cable to greater depths and/or installing additional submarine equipment, such a way in short an ADCP profiler will be installed. In this work we aim to show the present status, scientific possibilities and the next future plans of this submarine-on land

Estimating the Mass of the Milky Way Using the Ensemble of Classical Satellite Galaxies

NASA Astrophysics Data System (ADS)

Patel, Ekta; Besla, Gurtina; Sohn, Sangmo Tony; Mandel, Kaisey

2018-06-01

High precision proper motions are currently available for approximately 20% of the Milky Way's known satellite galaxies. Often, the 6D phase space information of each satellite is used separately to constrain the mass of the MW. In this talk, I will discuss the Bayesian framework outlined in Patel et al. 2017b to make inferences of the MW's mass using satellite properties such as specific orbital angular momentum, rather than just position and velocity. By extending this framework from one satellite to a population of satellites, we can now form simultaneous MW mass estimates using the Illustris-Dark cosmological simulation that are unbiased by high speed satellites such as Leo I (Patel et al., submitted). Our resulting MW mass estimates reduce the current factor of two uncertainty in the mass range of the MW and show promising signs for improvement as upcoming ground- and space-based observatories obtain proper motions for additional MW satellite galaxies.

The Virtual Observatory: I

NASA Astrophysics Data System (ADS)

Hanisch, R. J.

2014-11-01

The concept of the Virtual Observatory arose more-or-less simultaneously in the United States and Europe circa 2000. Ten pages of Astronomy and Astrophysics in the New Millennium: Panel Reports (National Academy Press, Washington, 2001), that is, the detailed recommendations of the Panel on Theory, Computation, and Data Exploration of the 2000 Decadal Survey in Astronomy, are dedicated to describing the motivation for, scientific value of, and major components required in implementing the National Virtual Observatory. European initiatives included the Astrophysical Virtual Observatory at the European Southern Observatory, the AstroGrid project in the United Kingdom, and the Euro-VO (sponsored by the European Union). Organizational/conceptual meetings were held in the US at the California Institute of Technology (Virtual Observatories of the Future, June 13-16, 2000) and at ESO Headquarters in Garching, Germany (Mining the Sky, July 31-August 4, 2000; Toward an International Virtual Observatory, June 10-14, 2002). The nascent US, UK, and European VO projects formed the International Virtual Observatory Alliance (IVOA) at the June 2002 meeting in Garching, with yours truly as the first chair. The IVOA has grown to a membership of twenty-one national projects and programs on six continents, and has developed a broad suite of data access protocols and standards that have been widely implemented. Astronomers can now discover, access, and compare data from hundreds of telescopes and facilities, hosted at hundreds of organizations worldwide, stored in thousands of databases, all with a single query.

A CCD search for distant satellites of asteroids 3 Juno and 146 Lucina

NASA Technical Reports Server (NTRS)

Stern, S. Alan; Barker, Edwin S.

1992-01-01

The results of CCD searches for satellites of asteroids 146 Lucina and 3 Juno are reported. Juno is one of the largest asteroids (D = 244 km); no previous deep imaging search for satellites around it has been reported. A potential occultation detection of a small satellite orbiting 146 Lucina (D = 137 km) km was reported by Arlot et al. (1985), but has not been confirmed. Using the 2.1 m reflector at McDonald Observatory in 1990 and 1991 with a CCD camera equipped with a 2.7 arc-sec radius occulting disk, limiting magnitudes of m(sub R) = 19.5 and m(sub R) = 21.4 were achieved around these two asteroids. This corresponds to objects of 1.6 km radius at Juno's albedo and distance, and 0.6 km radius at Lucina's albedo and distance. No satellite detections were made. Unless satellites were located behind our occultation mask, these two asteroids do not have satellites larger than the radii given above.

Astrometric Positioning of the Venezuelan Satellite VeneSat-1 "PASAVEN"

NASA Astrophysics Data System (ADS)

Otero, S.; Abad, C.; Hernández, R.

2014-06-01

By means of this document we inform regarding the collaboration between the Venezuelan institutions, Bolivarian Agency for Space Activities (ABAE) and the Astronomy Research Center (CIDA) with the purpose of using astrometry for the tracking of the Venezuelan Geostationary Satellite Venesat1 by means of optical observation. For this purpose two small astronomical observatories shall be installed on the space tracking ground stations owned by the ABAE in Venezuela and we hope that in a short term they shall be producing the expected results, and also that these observations may be extended to future Venezuelan satellites and to the determination of the geostationary space debris trajectories.

Creating Griffith Observatory

NASA Astrophysics Data System (ADS)

Cook, Anthony

2013-01-01

Griffith Observatory has been the iconic symbol of the sky for southern California since it began its public mission on May 15, 1935. While the Observatory is widely known as being the gift of Col. Griffith J. Griffith (1850-1919), the story of how Griffith’s gift became reality involves many of the people better known for other contributions that made Los Angeles area an important center of astrophysics in the 20th century. Griffith began drawing up his plans for an observatory and science museum for the people of Los Angeles after looking at Saturn through the newly completed 60-inch reflector on Mt. Wilson. He realized the social impact that viewing the heavens could have if made freely available, and discussing the idea of a public observatory with Mt. Wilson Observatory’s founder, George Ellery Hale, and Director, Walter Adams. This resulted, in 1916, in a will specifying many of the features of Griffith Observatory, and establishing a committee managed trust fund to build it. Astronomy popularizer Mars Baumgardt convinced the committee at the Zeiss Planetarium projector would be appropriate for Griffith’s project after the planetarium was introduced in Germany in 1923. In 1930, the trust committee judged funds to be sufficient to start work on creating Griffith Observatory, and letters from the Committee requesting help in realizing the project were sent to Hale, Adams, Robert Millikan, and other area experts then engaged in creating the 200-inch telescope eventually destined for Palomar Mountain. A Scientific Advisory Committee, headed by Millikan, recommended that Caltech Physicist Edward Kurth be put in charge of building and exhibit design. Kurth, in turn, sought help from artist Russell Porter. The architecture firm of John C. Austin and Fredrick Ashley was selected to design the project, and they adopted the designs of Porter and Kurth. Philip Fox of the Adler Planetarium was enlisted to manage the completion of the Observatory and become its

Satellite Sees Holiday Lights Brighten Cities - Saudi Arabia

NASA Image and Video Library

2017-12-08

In several cities in the Middle East, city lights brighten during the Muslim holy month of Ramadan, as seen using a new analysis of daily data from the NASA-NOAA Suomi NPP satellite. Dark green pixels are areas where the lights are 50 percent brighter, or more, during Ramadan. Credit: Jesse Allen, NASA’s Earth Observatory Read more: www.nasa.gov/content/goddard/satellite-sees-holiday-light... NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Two-Way Satellite Time Transfer Between USNO and PTB

DTIC Science & Technology

2005-08-01

Observatory 3450 Massachusetts Ave. NW Washington, DC 20392, USA Abstract—Two completely independent two-way time and frequency transfer ( TWSTFT ...for the realization of TAI. The X- band data are provided as a backup. To reach the full potential of TWSTFT , especially for time scale comparisons...ns for both links were achieved. A change of the TWSTFT transmission frequencies or satellite changes in general cause discontinuities in the series

High Energy Astronomy Observatory (HEAO)

NASA Image and Video Library

1978-01-01

Managed by the Marshall Space Flight Center and built by TRW, the second High Energy Astronomy Observatory was launched November 13, 1978. The observatory carried the largest X-ray telescope ever built and was renamed the Einstein Observatory after achieving orbit.

Some economic benefits of a synchronous earth observatory satellite

NASA Technical Reports Server (NTRS)

Battacharyya, R. K.; Greenberg, J. S.; Lowe, D. S.; Sattinger, I. J.

1974-01-01

An analysis was made of the economic benefits which might be derived from reduced forecasting errors made possible by data obtained from a synchronous satellite system which can collect earth observation and meteorological data continuously and on demand. User costs directly associated with achieving benefits are included. In the analysis, benefits were evaluated which might be obtained as a result of improved thunderstorm forecasting, frost warning, and grain harvest forecasting capabilities. The anticipated system capabilities were used to arrive at realistic estimates of system performance on which to base the benefit analysis. Emphasis was placed on the benefits which result from system forecasting accuracies. Benefits from improved thunderstorm forecasts are indicated for the construction, air transportation, and agricultural industries. The effects of improved frost warning capability on the citrus crop are determined. The benefits from improved grain forecasting capability are evaluated in terms of both U.S. benefits resulting from domestic grain distribution and U.S. benefits from international grain distribution.

Advanced definition study for the determination of atmospheric ozone using the satellite eclipse technique

NASA Technical Reports Server (NTRS)

Emmons, R.; Preski, R. J.; Kierstead, F. H., Jr.; Doll, F. C.; Wight, D. T.; Romick, D. C.

1973-01-01

A study was made to evaluate the potential for remote ground-based measurement of upper atmospheric ozone by determining the absorption ratio of selected narrow bands of sunlight as reflected by satellites while passing into eclipse, using the NASA Mobile Satellite Photometric Observatory (MOSPO). Equipment modifications to provide optimum performance were analyzed and recommendations were made for improvements to the system to accomplish this. These included new sensor tubes, pulse counting detection circuitry, filters, beam splitters and associated optical revision, along with an automatic tracking capability plus corresponding operational techniques which should extend the overall measurement capability to include use of satellites down to 5th magnitude.

A southern Africa harmonic spline core field model derived from CHAMP satellite data

NASA Astrophysics Data System (ADS)

Nahayo, E.; Kotzé, P. B.; McCreadie, H.

2015-02-01

The monitoring of the Earth's magnetic field time variation requires a continuous recording of geomagnetic data with a good spatial coverage over the area of study. In southern Africa, ground recording stations are limited and the use of satellite data is needed for the studies where high spatial resolution data is required. We show the fast time variation of the geomagnetic field in the southern Africa region by deriving an harmonic spline model from CHAMP satellite measurements recorded between 2001 and 2010. The derived core field model, the Southern Africa Regional Model (SARM), is compared with the global model GRIMM-2 and the ground based data recorded at Hermanus magnetic observatory (HER) in South Africa and Tsumeb magnetic observatory (TSU) in Namibia where the focus is mainly on the long term variation of the geomagnetic field. The results of this study suggest that the regional model derived from the satellite data alone can be used to study the small scale features of the time variation of the geomagnetic field where ground data is not available. In addition, these results also support the earlier findings of the occurrence of a 2007 magnetic jerk and rapid secular variation fluctuations of 2003 and 2004 in the region.

The Little Thompson Observatory

NASA Astrophysics Data System (ADS)

Schweitzer, A.; VanLew, K.; Melsheimer, T.; Sackett, C.

2000-12-01

The Little Thompson Observatory is the second member of the Telescopes in Education (TIE) project. The observatory is located on the grounds of Berthoud High School in northern Colorado. The telescope is operational over the Internet, and we are now debugging the software to enable schools to control the telescope from classroom computers and take images. Local schools and youth organizations have prioritized access to the telescope, and there are monthly opportunities for public viewing. In the future, the telescope will be open after midnight to world-wide use by schools following the model of the first TIE observatory, the 24" telescope on Mt. Wilson. The observatory grew out of grassroots support from the local community surrounding Berthoud, Colorado, a town of 3,500 residents. TIE has provided the observatory with a Tinsley 18" Cassegrain telescope on a 10-year loan. The facility has been built with tremendous support from volunteers and the local school district. With funding from an IDEAS grant, we have completed the first teacher training workshops to allow K-12 schools in northern Colorado to make use of the Little Thompson Observatory, including remote observing from classrooms. The workshops were accredited by the school district, and received very favorable reviews.

The Penllergare Observatory

NASA Astrophysics Data System (ADS)

Birks, J. L.

2005-12-01

This rather picturesque and historically important Victorian observatory was built by the wealthy John Dillwyn Llewelyn near to his mansion, some four miles north-west of Swansea, Wales. He had many scientific interests, in addition to astronomy, and was a notable pioneer of photography in Wales. Together with his eldest daughter, Thereza, (who married the grandson of the fifth Astronomer Royal, Nevil Maskelyne), he took some early photographs of the Moon from this site. This paper describes the construction of the observatory, and some of those primarily involved with it. Despite its having undergone restoration work in 1982, the state of the observatory is again the cause for much concern.

Ancient "Observatories" - A Relevant Concept?

NASA Astrophysics Data System (ADS)

Belmonte, Juan Antonio

It is quite common, when reading popular books on astronomy, to see a place referred to as "the oldest observatory in the world". In addition, numerous books on archaeoastronomy, of various levels of quality, frequently refer to the existence of "prehistoric" or "ancient" observatories when describing or citing monuments that were certainly not built with the primary purpose of observing the skies. Internet sources are also guilty of this practice. In this chapter, the different meanings of the word observatory will be analyzed, looking at how their significances can be easily confused or even interchanged. The proclaimed "ancient observatories" are a typical result of this situation. Finally, the relevance of the concept of the ancient observatory will be evaluated.

Low-frequency Radio Observatory on the Lunar Surface (LROLS)

NASA Astrophysics Data System (ADS)

MacDowall, Robert; Network for Exploration and Space Science (NESS)

2018-06-01

A radio observatory on the lunar surface will provide the capability to image solar radio bursts and other sources. Radio burst imaging will improve understanding of radio burst mechanisms, particle acceleration, and space weather. Low-frequency observations (less than ~20 MHz) must be made from space, because lower frequencies are blocked by Earth’s ionosphere. Solar radio observations do not mandate an observatory on the farside of the Moon, although such a location would permit study of less intense solar bursts because the Moon occults the terrestrial radio frequency interference. The components of the lunar radio observatory array are: the antenna system consisting of 10 – 100 antennas distributed over a square kilometer or more; the system to transfer the radio signals from the antennas to the central processing unit; electronics to digitize the signals and possibly to calculate correlations; storage for the data until it is down-linked to Earth. Such transmission requires amplification and a high-gain antenna system or possibly laser comm. For observatories on the lunar farside a satellite or other intermediate transfer system is required to direct the signal to Earth. On the ground, the aperture synthesis analysis is completed to display the radio image as a function of time. Other requirements for lunar surface systems include the power supply, utilizing solar arrays with batteries to maintain the system at adequate thermal levels during the lunar night. An alternative would be a radioisotope thermoelectric generator requiring less mass. The individual antennas might be designed with their own solar arrays and electronics to transmit data to the central processing unit, but surviving lunar night would be a challenge. Harnesses for power and data transfer from the central processing unit to the antennas are an alternative, but a harness-based system complicates deployment. The concept of placing the antennas and harnesses on rolls of polyimide and

The Virtual Solar Observatory and the Heliophysics Meta-Virtual Observatory

NASA Technical Reports Server (NTRS)

Gurman, Joseph B.

2007-01-01

The Virtual Solar Observatory (VSO) is now able to search for solar data ranging from the radio to gamma rays, obtained from space and groundbased observatories, from 26 sources at 12 data providers, and from 1915 to the present. The solar physics community can use a Web interface or an Application Programming Interface (API) that allows integrating VSO searches into other software, including other Web services. Over the next few years, this integration will be especially obvious as the NASA Heliophysics division sponsors the development of a heliophysics-wide virtual observatory (VO), based on existing VO's in heliospheric, magnetospheric, and ionospheric physics as well as the VSO. We examine some of the challenges and potential of such a "meta-VO."

The Solar-Stellar Connection (NAG5-6124: SOHO Guest Investigator Program)

NASA Technical Reports Server (NTRS)

Ayres, Thomas R.

1997-01-01

The following is a final report from the SOHO Guest Investigator program to use the SUMER far-UV spectrometer to obtain imaging spectroscopy in support of the goals of the so-called "solar-stellar connection." In particular, a major emphasis was utilization of the long-slit time-resolved maps of the solar surface in bright far-UV emission lines to deduce how particular aspects of the temporally and spatially averaged line profiles trace back to individual structural features of the magnetically disturbed outer atmosphere; to help interpret the unresolved line profiles from high quality stellar observations (say, with the Space Telescope Imaging Spectrograph). The researchers served two tours of duty in the SOHO Operations Center as SUMER planners, during which time we conducted an extensive series of observing programs. These can be divided into three general categories: surface mapping, translimb spectroscopy, and active region diagnostics. We have analyzed some of the large volumes of data to the point where we have presented them in poster papers, and in invited papers at national and international meetings. Listed below are the titles of the preliminary publications we have written, including brief abstracts to indicate the main results. (1) Chromospheric structure and Dynamics-- Observations -- The chromosphere is a highly structured dynamic 'layer' of the solar outer atmosphere. Here, not only are the effects of mechanical heating first evident (moving upward in altitude from the deep photosphere), but also the amount of nonradiative energy deposited is far greater than in the albeit much hotter overlying transition region and corona. Further, the chromosphere is by far the thickest zone of the solar atmosphere with respect to the pressure scale height. A major goal of stellar astrophysics is to understand how the chromosphere is heated and why it adopts its peculiar structure. A cursory examination of solar filtergrams and high-resolution movies demonstrates

Wide and Narrow CMEs and Their Source Explosions Observed at the Spring 2003 SOHO-Sun-Ulysses Quadrature

NASA Technical Reports Server (NTRS)

Suess, Steven; Corti, G.; Poletto, G.; Sterling, A.; Moore, R.

2006-01-01

At the time of the spring 2003 Ulysses-SOHO-Sun quadrature, Ulysses was off the East limb of the Sun at 14.5 degrees north latitude and 4.91 AU. LASCO/C2 images show small transient events that originated from near the limb on May 25, 26 and 27 in the north-east quadrant, along with a large Coronal Mass Ejection (CME) that originated from an active region near disk center on May 26. Ulysses data bear clear signatures of the large CME, specifically including an enhanced abundance of highly ionized Fe. SOHO/UVCS spectra at 1.75 solar radii, near the radial direction to Ulysses, give no evidence of emission from high temperature lines, even for the large CME: instead, for the small events, occasional transient high emission in cool lines was observed, such as the CIII 977 Angstrom line usually absent at coronal levels. Each of these events lasted ca. 1 hour or less and never affected lines from ions forming above ca. 106K. Compact eruptions in Helium 304 Angstrom EIT images, related to the small UVCS transients, were observed at the limb of the Sun over the same period. At least one of these surge events produced a narrow CME observed in LASCO/C2. Most probably all these events are compact magnetic explosions (surges/jets, from around a small island of included polarity) which ejected cool material from lower levels. Ulysses data have been analyzed to find evidence of the cool, narrow CME events, but none or little was found. This puzzling scenario, where events seen by UVCS have no in situ counterparts and vice versa, can be partially explained once the region where the large CME originated is recognized as being at the center of the solar disk so that the CME material was actually much further from the Sun than the 1.7 Rsun height of the UVCS slit off the limb. Conversely, the narrow events may simply have missed Ulysses or been too brief for reliable signatures in composition and ionization state. A basic feature demonstrated by these observations is that large

Magnetic field experiment on the SUNSAT satellite

NASA Astrophysics Data System (ADS)

Kotzé, P. B.; Langenhoven, B.; Risbo, T.

2002-03-01

On Tuesday 23 February 1999, at 10:29 UTC, SUNSAT was launched into an 857×655 km, 96.47° polar orbit on a Boeing-Delta II rocket from Vandenberg Air Force Base in California, USA. Both SUNSAT and Ørsted were NASA-sponsored secondary payloads accompanying the USA Air Force Argos satellite. In the process it became South Africa's (and Africa's) first satellite in space. Although sponsored by several private industrial organisations, it is essentially a student project with more than 96 graduate students in the Department of Electronic and Electrical Engineering at the University of Stellenbosch providing the majority of SUNSAT's engineering development and operation since 1992. This paper reports on the magnetic field experiment on board the Sunsat satellite, consisting of two fluxgate magnetometers, called Orimag and Scimag, both built and calibrated by the Hermanus Magnetic Observatory. Orimag is mainly used for orientation control purposes on SUNSAT, while Scimag, mounted on a boom of 2.2 m is designed to perform geomagnetic field observations, employing standard navigation fluxgate technology.

NASA Announces Contest to Name X-Ray Observatory

NASA Astrophysics Data System (ADS)

1998-04-01

NASA is searching for a new name for the Advanced X-ray Astrophysics Facility (AXAF), currently scheduled for launch Dec. 3, 1998, from the Space Shuttle Columbia. AXAF is the third of NASA's Great Observatories, after the Hubble Space Telescope and the Compton Gamma Ray Observatory. Once in orbit around Earth, it will explore hot, turbulent regions in the universe where X-rays are produced. Dr. Alan Bunner, director of NASA's Structure and Evolution of the universe science program, will announce April 18 at the National Science Teacher's Association meeting in Las Vegas, NV, the start of a contest, open to people worldwide, to find a new name for the observatory. Entries should contain the name of a person (not living), place, or thing from history, mythology, or fiction. Contestants should describe in a few sentences why this choice would be a good name for AXAF. The name must not have been used before on space missions by NASA or other organizations or countries. The grand prize will be a trip to NASA's Kennedy Space Center in Cape Canaveral, FL, to see the launch of the satellite aboard the Space Shuttle. Ten runner-up prizes will be awarded and all entrants will receive an AXAF poster. The grand prize is sponsored by TRW Inc., AXAF's prime contractor. The AXAF Science Center in Cambridge, MA, will run the contest for NASA. NASA will announce the final selection of the winning name later this year. Entries also can be mailed to: AXAF Contest, AXAF Science Center, Office of Education and Public Outreach, 60 Garden Street, MS 83, Cambridge, MA 02138. Mailed entries must be postmarked no later than June 30, 1998. All entries must state a name for the mission, along with the reason the name would make a good choice. The observatory, now in the final stages of assembly and testing at TRW's facility in Redondo Beach, CA, is more than 45 feet long and weighs 10,500 pounds. AXAF is the largest and most powerful X-ray observatory ever constructed, and its images will be

NASA's Great Observatories: Paper Model.

ERIC Educational Resources Information Center

National Aeronautics and Space Administration, Washington, DC.

This educational brief discusses observatory stations built by the National Aeronautics and Space Administration (NASA) for looking at the universe. This activity for grades 5-12 has students build paper models of the observatories and study their history, features, and functions. Templates for the observatories are included. (MVL)

The NASA Earth Science Program and Small Satellites

NASA Technical Reports Server (NTRS)

Neeck, Steven P.

2015-01-01

Earth's changing environment impacts every aspect of life on our planet and climate change has profound implications on society. Studying Earth as a single complex system is essential to understanding the causes and consequences of climate change and other global environmental concerns. NASA's Earth Science Division (ESD) shapes an interdisciplinary view of Earth, exploring interactions among the atmosphere, oceans, ice sheets, land surface interior, and life itself. This enables scientists to measure global and climate changes and to inform decisions by Government, other organizations, and people in the United States and around the world. The data collected and results generated are accessible to other agencies and organizations to improve the products and services they provide, including air quality indices, disaster prediction and response, agricultural yield projections, and aviation safety. ESD's Flight Program provides the spacebased observing systems and supporting infrastructure for mission operations and scientific data processing and distribution that support NASA's Earth science research and modeling activities. The Flight Program currently has 21 operating Earth observing space missions, including the recently launched Global Precipitation Measurement (GPM) mission, the Orbiting Carbon Observatory-2 (OCO-2), the Soil Moisture Active Passive (SMAP) mission, and the International Space Station (ISS) RapidSCAT and Cloud-Aerosol Transport System (CATS) instruments. The ESD has 22 more missions and instruments planned for launch over the next decade. These include first and second tier missions from the 2007 Earth Science Decadal Survey, Climate Continuity missions to assure availability of key climate data sets, and small-sized competitively selected orbital missions and instrument missions of opportunity belonging to the Earth Venture (EV) Program. Small satellites (500 kg or less) are critical contributors to these current and future satellite missions

Everyday astronomy @ Sydney Observatory

NASA Astrophysics Data System (ADS)

Parello, S. L.

2008-06-01

Catering to a broad range of audiences, including many non-English speaking visitors, Sydney Observatory offers everything from school programmes to public sessions, day care activities to night observing, personal interactions to web-based outreach. With a history of nearly 150 years of watching the heavens, Sydney Observatory is now engaged in sharing the wonder with everybody in traditional and innovative ways. Along with time-honoured tours of the sky through two main telescopes, as well as a small planetarium, Sydney Observatory also boasts a 3D theatre, and offers programmes 363 days a year - rain or shine, day and night. Additionally, our website neversleeps, with a blog, YouTube videos, and night sky watching podcasts. And for good measure, a sprinkling of special events such as the incomparable Festival of the Stars, for which most of northern Sydney turns out their lights. Sydney Observatory is the oldest working observatory in Australia, and we're thrilled to be looking forward to our 150th Anniversary next year in anticipation of the International Year of Astronomy immediately thereafter.

Development of a Full Ice-cream Cone Model for Halo Coronal Mass Ejections

NASA Astrophysics Data System (ADS)

Na, Hyeonock; Moon, Y.-J.; Lee, Harim

2017-04-01

It is essential to determine three-dimensional parameters (e.g., radial speed, angular width, and source location) of coronal mass ejections (CMEs) for the space weather forecast. In this study, we investigate which cone type represents a halo CME morphology using 29 CMEs (12 Solar and Heliospheric Observatory (SOHO)/Large Angle and Spectrometric Coronagraph (LASCO) halo CMEs and 17 Solar Terrestrial Relations Observatory (STEREO)/Sun-Earth Connection Coronal and Heliospheric Investigation COR2 halo CMEs) from 2010 December to 2011 June. These CMEs are identified as halo CMEs by one spacecraft (SOHO or one of STEREO A and B) and limb ones by the other spacecraft (One of STEREO A and B or SOHO). From cone shape parameters of these CMEs, such as their front curvature, we find that the CME observational structures are much closer to a full ice-cream cone type than a shallow ice-cream cone type. Thus, we develop a full ice-cream cone model based on a new methodology that the full ice-cream cone consists of many flat cones with different heights and angular widths to estimate the three-dimensional parameters of the halo CMEs. This model is constructed by carrying out the following steps: (1) construct a cone for a given height and angular width, (2) project the cone onto the sky plane, (3) select points comprising the outer boundary, and (4) minimize the difference between the estimated projection speeds with the observed ones. By applying this model to 12 SOHO/LASCO halo CMEs, we find that 3D parameters from our method are similar to those from other stereoscopic methods (I.e., a triangulation method and a Graduated Cylindrical Shell model).

Natural Satellite Ephemerides at JPL

NASA Astrophysics Data System (ADS)

Jacobson, Robert Arthur; Brozovic, Marina

2015-08-01

There are currently 176 known natural planetary satellites in the solar system; 150 are officially recognized by the IAU and 26 have IAU provisional designations. We maintain ephemerides for all of the satellites at NASA's Jet Propulsion Laboratory (JPL) and make them available electronically through the On-Line Solar System Data Service known as Horizons(http://ssd.jpl.nasa.gov/horizons) and in the form of generic Spice Kernels (SPK files) from NASA's Navigation and Ancillary Information Facility (http://naif.jpl.nasa.gov/naif). General satellite information such as physical constants and descriptive orbital elements can be found on the JPL Solar System Dynamics Website (http://ssd.jpl.nasa.gov). JPL's ephemerides directly support planetary spacecraft missions both in navigation and science data analysis. They are also used in general scientific investigations of planetary systems. We produce the ephemerides by fitting numerically integrated orbits to observational data. Our model for the satellite dynamics accounts for the gravitational interactions within a planetary system and the external gravitational perturbations from the Sun and planets. We rely on an extensive data set to determine the parameters in our dynamical models. The majority of the observations are visual, photographic, and CCD astrometry acquired from Earthbased observatories worldwide and the Hubble Space Telescope. Additional observations include optical and photoelectric transits, eclipses, occultations, Earthbased radar ranging, spacecraft imaging,and spacecraft radiometric tracking. The latter data provide information on the planet and satellite gravity fields as well as the satellite position at the times of spacecraft close encounters. In this paper we report on the status of the ephemerides and our plan for future development, specifically that in support of NASA's Juno, Cassini, and New Horizons missions to Jupiter, Saturn, and Pluto, respectively.

Stratospheric Observatory for Infrared Astronomy

NASA Astrophysics Data System (ADS)

Hamidouche, M.; Young, E.; Marcum, P.; Krabbe, A.

2010-12-01

We present one of the new generations of observatories, the Stratospheric Observatory For Infrared Astronomy (SOFIA). This is an airborne observatory consisting of a 2.7-m telescope mounted on a modified Boeing B747-SP airplane. Flying at an up to 45,000 ft (14 km) altitude, SOFIA will observe above more than 99 percent of the Earth's atmospheric water vapor allowing observations in the normally obscured far-infrared. We outline the observatory capabilities and goals. The first-generation science instruments flying on board SOFIA and their main astronomical goals are also presented.

CM5, a Pre-Swarm Comprehensive Geomagnetic Field Model Derived from Over 12 Yr of CHAMP, Orsted, SAC-C and Observatory Data

NASA Technical Reports Server (NTRS)

Sabaka, Terence J.; Olsen, Nils; Tyler, Robert H.; Kuvshinov, Alexey

2014-01-01

A comprehensive magnetic field model named CM5 has been derived from CHAMP, Ørsted and SAC-C satellite and observatory hourly-means data from 2000 August to 2013 January using the Swarm Level-2 Comprehensive Inversion (CI) algorithm. Swarm is a recently launched constellation of three satellites to map the Earth's magnetic field. The CI technique includes several interesting features such as the bias mitigation scheme known as Selective Infinite Variance Weighting (SIVW), a new treatment for attitude error in satellite vector measurements, and the inclusion of 3-D conductivity for ionospheric induction. SIVW has allowed for a much improved lithospheric field recovery over CM4 by exploiting CHAMP along-track difference data yielding resolution levels up to spherical harmonic degree 107, and has allowed for the successful extraction of the oceanic M2 tidal magnetic field from quiet, nightside data. The 3-D induction now captures anomalous Solar-quiet features in coastal observatory daily records. CM5 provides a satisfactory, continuous description of the major magnetic fields in the near-Earth region over this time span, and its lithospheric, ionospheric and oceanic M2 tidal constituents may be used as validation tools for future Swarm Level-2 products coming from the CI algorithm and other dedicated product algorithms.

Investigation of Quasi-periodic Solar Oscillations in Sunspots Based on SOHO/MDI Magnetograms

NASA Astrophysics Data System (ADS)

Kallunki, J.; Riehokainen, A.

2012-10-01

In this work we study quasi-periodic solar oscillations in sunspots, based on the variation of the amplitude of the magnetic field strength and the variation of the sunspot area. We investigate long-period oscillations between three minutes and ten hours. The magnetic field synoptic maps were obtained from the SOHO/MDI. Wavelet (Morlet), global wavelet spectrum (GWS) and fast Fourier transform (FFT) methods are used in the periodicity analysis at the 95 % significance level. Additionally, the quiet Sun area (QSA) signal and an instrumental effect are discussed. We find several oscillation periods in the sunspots above the 95 % significance level: 3 - 5, 10 - 23, 220 - 240, 340 and 470 minutes, and we also find common oscillation periods (10 - 23 minutes) between the sunspot area variation and that of the magnetic field strength. We discuss possible mechanisms for the obtained results, based on the existing models for sunspot oscillations.

Bus Vent Design Evolution for the Solar Dynamics Observatory

NASA Technical Reports Server (NTRS)

Woronowicz, Michael

2010-01-01

As a spacecraft undergoes ascent in a launch vehicle, its pressure environment transitions from one atmosphere to high vacuum in a matter of minutes. Venting of internal cavities is necessary to prevent the buildup of pressure differentials across cavity walls. Opposing the need to vent these volumes freely into space are thermal, optical, and electrostatic requirements for limiting or prohibiting the intrusion of unwanted energy into the same cavities. Bus vent design evolution is discussed for the Solar Dynamics Observatory. Design changes were influenced by a number of factors and concerns, such as contamination control, electrostatic discharge, changes in bus material, and driving fairing ascent pressure for a launch vehicle that was just entering service as this satellite project had gotten underway.

LISN: A distributed observatory to image and study ionospheric irregularities

NASA Astrophysics Data System (ADS)

Sheehan, R.; Valladares, C. E.

2013-05-01

During nighttime the low-latitude ionosphere commonly develops plasma irregularities and density structures able to disrupt radio wave signals. This interference produces an adverse impact on satellite communication and navigation signals. For example, EM signals originated from satellites can suffer fading as deep as 20 dB even at UHF frequencies. In addition, civil aviation is increasingly dependent upon Global Navigation Satellite Systems and disruption of the navigation capability from ionospheric irregularities poses a clear threat to passengers and crews. To monitor and specify the conditions of the ionosphere over South America, the Low-latitude Ionospheric Sensor Network (LISN) was established as a permanent array of scientific instruments that operate continuously and transmit their observables to a central server in a real-time basis. Presently, the LISN observatory includes 3 different types of instruments: (1) 47 GPS receivers, (2) 5 flux-gate magnetometers and (3) 2 Vertical Incidence Pulsed Ionospheric Radar (VIPIR) ionosondes. In addition to providing a nowcast of the disturbed state of the ionosphere over South America, LISN permits detailed studies of the initiation and development of plasma irregularities. By using data assimilation and tomography techniques, LISN provides continuous estimates of several important geophysical parameters that are indispensable to a program aimed at forecasting the plasma electrodynamics and the formation of density structures in the low-latitude ionosphere.

The precision of today's satellite laser ranging systems

NASA Astrophysics Data System (ADS)

Dunn, Peter J.; Torrence, Mark H.; Hussen, Van S.; Pearlman, Michael R.

1993-06-01

Recent improvements in the accuracy of modern satellite laser ranging (SLR) systems are strengthened by the new capability of many instruments to track an increasing number of geodetic satellite targets without significant scheduling conflict. This will allow the refinement of some geophysical parameters, such as solid Earth tidal effects and GM, and the improved temporal resolution of others, such as Earth orientation and station position. Better time resolution for the locations of fixed observatories will allow us to monitor more subtle motions at the stations, and transportable systems will be able to provide indicators of long term trends with shorter occupations. If we are to take advantage of these improvements, care must be taken to preserve the essential accuracy of an increasing volume of range observations at each stage of the data reduction process.

The precision of today's satellite laser ranging systems

NASA Technical Reports Server (NTRS)

Dunn, Peter J.; Torrence, Mark H.; Hussen, Van S.; Pearlman, Michael R.

1993-01-01

Recent improvements in the accuracy of modern satellite laser ranging (SLR) systems are strengthened by the new capability of many instruments to track an increasing number of geodetic satellite targets without significant scheduling conflict. This will allow the refinement of some geophysical parameters, such as solid Earth tidal effects and GM, and the improved temporal resolution of others, such as Earth orientation and station position. Better time resolution for the locations of fixed observatories will allow us to monitor more subtle motions at the stations, and transportable systems will be able to provide indicators of long term trends with shorter occupations. If we are to take advantage of these improvements, care must be taken to preserve the essential accuracy of an increasing volume of range observations at each stage of the data reduction process.

Constraint-based integration of planning and scheduling for space-based observatory management

NASA Technical Reports Server (NTRS)

Muscettola, Nicola; Smith, Steven F.

1994-01-01

Progress toward the development of effective, practical solutions to space-based observatory scheduling problems within the HSTS scheduling framework is reported. HSTS was developed and originally applied in the context of the Hubble Space Telescope (HST) short-term observation scheduling problem. The work was motivated by the limitations of the current solution and, more generally, by the insufficiency of classical planning and scheduling approaches in this problem context. HSTS has subsequently been used to develop improved heuristic solution techniques in related scheduling domains and is currently being applied to develop a scheduling tool for the upcoming Submillimeter Wave Astronomy Satellite (SWAS) mission. The salient architectural characteristics of HSTS and their relationship to previous scheduling and AI planning research are summarized. Then, some key problem decomposition techniques underlying the integrated planning and scheduling approach to the HST problem are described; research results indicate that these techniques provide leverage in solving space-based observatory scheduling problems. Finally, more recently developed constraint-posting scheduling procedures and the current SWAS application focus are summarized.

NASA's Earth Observatory and Visible Earth: Imagery and Science on the Internet

NASA Technical Reports Server (NTRS)

King, Michael D.; Simmon, Robert B.; Herring, David D.

2003-01-01

The purpose of NASA s Earth Observatory and Visible Earth Web sites is to provide freely-accessible locations on the Internet where the public can obtain new satellite imagery (at resolutions up to a given sensor's maximum) and scientific information about our home planet. Climatic and environmental change are the sites main foci. As such, they both contain ample data visualizations and time-series animations that demonstrate geophysical parameters of particular scientific interest, with emphasis on how and why they vary over time. An Image Composite Editor (ICE) tool will be added to the Earth Observatory in October 2002 that will allow visitors to conduct basic analyses of available image data. For example, users may produce scatter plots to correlate images; or they may probe images to find the precise unit values per pixel of a given data product; or they may build their own true-color and false-color images using multi- spectral data. In particular, the sites are designed to be useful to the science community, public media, educators, and students.

Satellite Data for Geomagnetic Field Modeling

NASA Technical Reports Server (NTRS)

Langel, R. A.; Baldwin, R. T.

1992-01-01

Satellite measurements of the geomagnetic fields began with the launch of Sputnik 3 in May of 1958 and have continued sporadically. Spacecraft making significant contributions to main field geomagnetism will be reviewed and the characteristics of their data discussed, including coverage, accuracy, resolution and data availability. Of particular interest are Vanguard 3; Cosmos 49, Ogo's -2, -4, and -6; Magsat; DE-2; and POGS. Spacecraft make measurements on a moving platfrom above the ionosphere as opposed to measurements from fixed observatories and surveys, both below the ionosphere. Possible future missions, such as Aristoteles and GOS are reviewed.

NASA X-Ray Observatory Completes Tests Under Harsh Simulated Space Conditions

NASA Astrophysics Data System (ADS)

1998-07-01

the Operations Control Center after launch. "As is usually the case, we identified a few issues to be resolved before launch," said Wojtalik. "Overall, however, the observatory performed exceptionally well." The observatory test team discovered a mechanical problem with one of the primary science instruments, the Imaging Spectrometer. A door protecting the instrument did not function when commanded by test controllers. "We do these tests to check and double check every aspect of satellite operation that could affect the ultimate success of the science mission," said Craig Staresinich, TRW Advanced X-ray Astrophysics Facility program manager. "Discovering a problem now is a success. Discovering a problem later, after launch, would be a failure." A team of NASA and contractor engineers are studying the mechanical problem and developing a plan to correct it. The instrument will be sent back to its builder, Lockheed-Martin Astronautics in Denver, Colo., where it will be repaired while the rest of the observatory continues other testing. This should still allow an on-time delivery of the observatory to NASA's Kennedy Space Center, Fla., in August, where it will be readied for launch in January. With a resolving power 10 times greater than previous X-ray telescopes, the new X-ray observatory will provide scientists with views of previously invisible X-ray sources, including black holes, exploding stars and interstellar gasses. The third of NASA's Great Observatories, it will join the Compton Gamma Ray Observatory and the Hubble Space Telescope in orbit. The Advanced X-ray Astrophysics Facility program is managed by the Marshall Center for the Office of Space Science, NASA Headquarters, Washington, D.C. TRW Space & Electronics Group is assembling the observatory and doing verification testing. The Advanced X-ray Astrophysics Facility Operations Control Center is operated by the Smithsonian Astrophysical Observatory. Using glass purchased from Schott Glaswerke, Mainz, Germany

Soho Ultraviolet Coronograph Spectrometer (UVCS) Mission Operations and Data Analysis

NASA Technical Reports Server (NTRS)

Kohl, John L.; Gurman, Joseph (Technical Monitor)

2002-01-01

The scientific goal of UVCS is to obtain detailed empirical descriptions of the extended solar corona as it evolves over the solar cycle and to use these descriptions to identify and understand the physical processes responsible for coronal heating, solar wind acceleration, coronal mass ejections (CMEs), and the phenomena that establish the plasma properties of the solar wind as measured by 'in situ' solar wind instruments. This report covers the period from 01 December 2000 to 31 January 2002. During that time, UVCS observations have consisted of three types: (1) standard synoptic observations comprising, primarily, the H I Ly(alpha) line profile and the O VI 103.2 and 103.7 nm intensity over a range of heights from 1.5 to about 3.0 solar radii and covering 360 degrees about the sun; (2) sit and stare watches for CMEs; and (3) special observations designed by the UVCS Lead Observer of the Week for a specific scientific purpose. The special observations are often coordinated with those of other space-based and ground-based instruments and they often are part of SOHO joint observation programs and campaigns. Lead observers have included UVCS Co-Investigators, scientists from the solar physics community and several graduate and undergraduate level students.

Shuttle Astronauts Visit NASA's X-Ray Observatory Operations Control Center in Cambridge to Coordinate Plans for Launch

NASA Astrophysics Data System (ADS)

1998-06-01

CAMBRIDGE, MASS.-- June 25, 1998 Eileen Collins, the first U.S. woman commanderof a Space Shuttle mission and her fellow astronauts for NASA s STS-93 mission toured the Operations Control Center (OCC) for the Advanced X-ray Astrophysics Facility (AXAF) today. AXAF is scheduled for launch on January 26, 1999 aboard the Space Shuttle Columbia. They met with the staff of the OCC and discussed how the status of the observatory will be monitored while in the shuttle bay and during deployment. "We are honored to have this historic shuttle crew visit us and familiarize themselves with the OCC," said Harvey Tananbaum, director of the AXAF Science Center, which operates the OCC for the Smithsonian Astrophysical Observatory through a contract with NASA's Marshall Space Flight Center. "It is appropriate that a pathbreaking shuttle mission will deploy the premier X-ray observatory of this century." AXAF is the third of NASA s Great Observatories along with the Hubble Space Telescope and the Compton Gamma Ray Observatory. It will observe in greater detail than ever before the hot, violent regions of the universe that cannot be seen with optical telescopes. Exploding stars, black holes and vast clouds of gas in galaxy clusters are among the fascinating objects that AXAF is designed to study. The satellite is currently in the final stages of testing at TRW Space and Electronics Group,the prime contractor, in Redondo Beach, California. In late August it will be flown aboard a specially-outfitted Air Force C-5 aircraft to Kennedy Space Center in Florida where it will be integrated with a Boeing booster and then installed in the Shuttle bay. The shuttle crew that will take AXAF into space includes Collins (Col., USAF), Jeffrey Ashby (Cmdr., USN), pilot; Steven Hawley, Ph.D., mission specialist; Catherine Cady Coleman, Ph.D. (Major, USAF), mission specialist; and Michel Tognini (Col., French Air Force), mission specialist. While visiting the OCC the crew learned how critical data

Studying the Light Pollution around Urban Observatories: Columbus State University’s WestRock Observatory

NASA Astrophysics Data System (ADS)

O'Keeffe, Brendon Andrew; Johnson, Michael

2017-01-01

Light pollution plays an ever increasing role in the operations of observatories across the world. This is especially true in urban environments like Columbus, GA, where Columbus State University’s WestRock Observatory is located. Light pollution’s effects on an observatory include high background levels, which results in a lower signal to noise ratio. Overall, this will limit what the telescope can detect, and therefore limit the capabilities of the observatory as a whole.Light pollution has been mapped in Columbus before using VIIRS DNB composites. However, this approach did not provide the detailed resolution required to narrow down the problem areas around the vicinity of the observatory. The purpose of this study is to assess the current state of light pollution surrounding the WestRock observatory by measuring and mapping the brightness of the sky due to light pollution using light meters and geographic information system (GIS) software.Compared to VIIRS data this study allows for an improved spatial resolution and a direct measurement of the sky background. This assessment will enable future studies to compare their results to the baseline established here, ensuring that any changes to the way the outdoors are illuminated and their effects can be accurately measured, and counterbalanced.

New Evidence for the Role of Emerging Flux in a Solar Filament's Slow Rise Preceding its CME-Producing Fast Eruption

NASA Technical Reports Server (NTRS)

Sterling, Alphonse C.; Harra, Louis K.; Moore, Ronald L.

2007-01-01

We observe the eruption of a large-scale (approx.300,000 km) quiet-region solar filament, leading to an Earth-directed "halo" coronal mass ejection (CME). We use coronal imaging data in EUV from the EUV Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO) satellite, and in soft X-rays (SXRs) from the Soft X-ray Telescope (SXT) on the Yohkoh satellite. We also use spectroscopic data from the Coronal Diagnostic Spectrometer (CDS), magnetic data from the Michelson Doppler Imager (MDI), and white-light coronal data from the Large Angle and Spectrometric Coronagraph Experiment (LASCO), all on SOHO. Initially the filament shows a slow (approx.1 km/s projected against the solar disk) and approximately constant-velocity rise for about 6 hours, before erupting rapidly, reaching a velocity of approx. 8 km/s over the next approx. 25 min. CDS Doppler data show Earth-directed filament velocities ranging from < 20 km/s (the noise limit) during the slow-rise phase, to approx. 100 km/s-1 early in the eruption. Beginning within 10 hours prior to the start of the slow rise, localized new magnetic flux emerged near one end of the filament. Near the start of and during the slow-rise phase, SXR microflaring occurred repeatedly at the flux-emergence site, in conjunction with the development of a fan of SXR illumination of the magnetic arcade over the filament. The SXR microflares, development of the SXR fan, and motion of the slow-rising filament are all consistent with "tether-weakening" reconnection occurring between the newly-emerging flux and the overlying arcade field containing the filament field. The microflares and fan structure are not prominent in EUV, and would not have been detected without the SXR data. Standard "twin dimmings" occur near the location of the filament, and "remote dimmings" and "brightenings" occur further removed from the filament.

CM5, a pre-Swarm comprehensive geomagnetic field model derived from over 12 yr of CHAMP, Ørsted, SAC-C and observatory data

NASA Astrophysics Data System (ADS)

Sabaka, Terence J.; Olsen, Nils; Tyler, Robert H.; Kuvshinov, Alexey

2015-03-01

A comprehensive magnetic field model named CM5 has been derived from CHAMP, Ørsted and SAC-C satellite and observatory hourly-means data from 2000 August to 2013 January using the Swarm Level-2 Comprehensive Inversion (CI) algorithm. Swarm is a recently launched constellation of three satellites to map the Earth's magnetic field. The CI technique includes several interesting features such as the bias mitigation scheme known as Selective Infinite Variance Weighting (SIVW), a new treatment for attitude error in satellite vector measurements, and the inclusion of 3-D conductivity for ionospheric induction. SIVW has allowed for a much improved lithospheric field recovery over CM4 by exploiting CHAMP along-track difference data yielding resolution levels up to spherical harmonic degree 107, and has allowed for the successful extraction of the oceanic M2 tidal magnetic field from quiet, nightside data. The 3-D induction now captures anomalous Solar-quiet features in coastal observatory daily records. CM5 provides a satisfactory, continuous description of the major magnetic fields in the near-Earth region over this time span, and its lithospheric, ionospheric and oceanic M2 tidal constituents may be used as validation tools for future Swarm Level-2 products coming from the CI algorithm and other dedicated product algorithms.

High Energy Astronomy Observatory (HEAO)

NASA Image and Video Library

1978-11-13

The launch of an Atlas/Centaur launch vehicle is shown in this photograph. The Atlas/Centaur, launched on November 13, 1978, carried the High Energy Astronomy Observatory (HEAO)-2 into the required orbit. The second observatory, the HEAO-2 (nicknamed the Einstein Observatory in honor of the centernial of the birth of Albert Einstein) carried the first telescope capable of producing actual photographs of x-ray objects.

Compositional Analyses and Implications of Visible/Near-Infrared Spectra of Outer Irregular Jovian Satellites

NASA Astrophysics Data System (ADS)

Vilas, Faith; Hendrix, Amanda

2017-10-01

The existence of a visible-near infrared absorption feature attributed to aqueous alteration products has been suggested in both grey and reddened broadband photometry of some outer irregular jovian satellites. Moderate resolution VNIR narrowband spectroscopy was obtained of the jovian irregular satellites JVI Himalia, JVII Elara, JVIII Pasiphae, JIX Sinope, JX Lysithea, JXI Carme, JXII Ananke and JXVII Callirrhoe in 2006, 2008, 2009, and 2010 using the MMT Observatory facility Red Channel spectrograph to confirm the presence of this feature. The spectra are centered near 0.64 μm in order to cover the 0.7-μm feature entirely (generally ranging from 0.57 to 0.83 μm). The spectra generally have a dispersion/element of ~0.6 nm (6Å) some spectra are smoothed. These spectra sample three prograde (i = 28o), four retrograde (i = 149o, 165o) and one independent satellite.We observe these findings among the spectra:- An absorption feature centered near 0.7 µm exists in the spectra of the three prograde (i = 28o) satellites. This feature is spectrally broader than the 0.7-µm feature observed in C-complex asteroids. None appears spectrally reddened. This suggests that these prograde satellites have a common parent body.- A different absorption feature appears in the spectra of the three retrograde (i = 149o) satellites, also suggesting a common parent body. Varying reddening is observed. This feature is similar in spectral location and width to the 0.7-µm feature.- Reddening is observed in the individual observation of JXI Carme (i = 165o), and independent satellite JIX Sinope, similar to the D-class asteroid spectra dominating the Trojan population. A suggested absorption feature is being investigated.Mixing modeling of combinations of both expected and proposed compositions including carbonaceous materials, phyllosilicates, mafic silicates, and other opaque materials, is currently underway. Results will be reported and discussed at the meeting.Acknowledgments: The

Systematic Variability of the He+ Pickup Ion Velocity Distribution Function Observed with SOHO/CELIAS/CTOF

NASA Astrophysics Data System (ADS)

Taut, A.; Drews, C.; Berger, L.; Wimmer-Schweingruber, R. F.

2015-12-01

The 1D Velocity Distribution Function (VDF) of He+ pickup ions shows two distinct populations that reflect the sources of these ions. The highly suprathermal population is the result of the ionization and pickup of almost resting interstellar neutrals that are injected into the solar wind as a highly anisotropic torus distribution. The nearly thermalized population is centered around the solar wind bulk speed and is mainly attributed to inner-source pickup ions that originate in the inner heliosphere. It is generally believed that the initial torus distribution of interstellar pickup ions is rapidly isotropized by resonant wave-particle interactions, but recent observations by Drews et al. (2015) of a torus-like VDF strongly limit this isotropization. This in turn means that more observational data is needed to further characterize the kinetic behavior of pickup ions. In this study we use data from the Charge-Time-Of-Flight sensor on-board SOHO. As this sensor offers unrivaled counting statistics for He+ together with a sufficient mass-per-charge resolution it is well-suited for investigating the He+ VDF on comparatively short timescales. We combine this data with the high resolution magnetic field data from WIND via an extrapolation to the location of SOHO. With this combination of instruments we investigate the He+ VDF for time periods of different solar wind speeds, magnetic field directions, and wave power. We find a systematic trend of the short-term He+ VDF with these parameters. Especially by varying the considered magnetic field directions we observe a 1D projection of the anisotropic torus-like VDF. In addition, we investigate stream interaction regions and coronal mass ejections. In the latter we observe an excess of inner-source He+ that is accompanied by a significant increase of heavy pickup ion count rates. This may be linked to the as yet ill understood production mechanism of inner-source pickup ions.

Measuring CO2 from Space: The NASA Orbiting Carbon Observatory-2

NASA Technical Reports Server (NTRS)

Crisp, D.

2010-01-01

The Orbiting Carbon Observatory (OCO) was the first NASA satellite designed to measure atmospheric carbon dioxide (CO2) from space with the precision, resolution, and coverage needed to detect CO2 surface fluxes. OCO was designed to collect 0.5 to 1 million soundings each day. Typical measurements over land were expected to have precisions of 0.3% within surface footprints smaller less than 3 square km. This project suffered a major setback in February 2009 when the OCO launch vehicle failed to achieve orbit and the satellite was lost. The U.S. Congress has since authorized a restart of the OCO project, and the President's 2010 budget proposal includes funding to develop and fly a replacement for OCO that could be ready for launch no later than February 2013. This mission has been designated OCO-2. While this mission will be a near "carbon copy" of OCO, some changes were needed to replace components that were no longer available. Here, we describe the capabilities, of the OCO-2 mission, highlighting its differences from OCO.

Hawaiian Volcano Observatory

USGS Publications Warehouse

Venezky, Dina Y.; Orr, Tim R.

2008-01-01

Lava from Kilauea volcano flowing through a forest in the Royal Gardens subdivision, Hawai'i, in February 2008. The Hawaiian Volcano Observatory (HVO) monitors the volcanoes of Hawai'i and is located within Hawaiian Volcanoes National Park. HVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Kilauea and HVO at http://hvo.wr.usgs.gov.

Solar Radiation and Climate Experiment (SORCE) Satellite

NASA Technical Reports Server (NTRS)

2003-01-01

This is a close-up of the NASA-sponsored Solar Radiation and Climate Experiment (SORCE) Satellite. The SORCE mission, launched aboard a Pegasus rocket January 25, 2003, will provide state of the art measurements of incoming x-ray, ultraviolet, visible, near-infrared, and total solar radiation. Critical to studies of the Sun and its effect on our Earth system and mankind, SORCE will provide measurements that specifically address long-term climate change, natural variability and enhanced climate prediction, and atmospheric ozone and UV-B radiation. Orbiting around the Earth accumulating solar data, SORCE measures the Sun's output with the use of state-of-the-art radiometers, spectrometers, photodiodes, detectors, and bolo meters engineered into instruments mounted on a satellite observatory. SORCE is carrying 4 instruments: The Total Irradiance Monitor (TIM); the Solar Stellar Irradiance Comparison Experiment (SOLSTICE); the Spectral Irradiance Monitor (SIM); and the XUV Photometer System (XPS).

NASA Investigating the Life of Comet ISON

NASA Image and Video Library

2013-12-02

Comet ISON comes in from the bottom right and moves out toward the upper right, growing more faint, in this time-lapse image from the ESA/NASA Solar and Heliospheric Observatory. The image of the sun at the center is from NASA's Solar Dynamics Observatory. Credit: ESA/NASA/SOHO/SDO/GSFC After several days of fading, scientists continue to work to determine and to understand the fate of Comet ISON: There's no doubt that the comet shrank in size considerably as it rounded the sun and there's no doubt that something made it out on the other side to shoot back into space. The question remains as to whether the bright spot seen moving away from the sun was simply debris, or whether a small nucleus of the original ball of ice was still there. Regardless, it is likely that it is now only dust. Comet ISON, which began its journey from the Oort Cloud some 3 million years ago, made its closest approach to the sun on Nov. 28, 2013. The comet was visible in instruments on NASA's Solar Terrestrial Relations Observatory, or STEREO, and the joint European Space Agency/NASA Solar and Heliospheric Observatory, or SOHO, via images called coronagraphs. Coronagraphs block out the sun and a considerable distance around it, in order to better observe the dim structures in the sun's atmosphere, the corona. As such, there was a period of several hours when the comet was obscured in these images, blocked from view along with the sun. During this period of time, NASA's Solar Dynamics Observatory could not see the comet, leading many scientists to surmise that the comet had disintegrated completely. However, something did reappear in SOHO and STEREO coronagraphs some time later – though it was significantly less bright. Read more: 1.usa.gov/18hGYag NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments

Satellite laser ranging using superconducting nanowire single-photon detectors at 1064  nm wavelength.

PubMed

Xue, Li; Li, Zhulian; Zhang, Labao; Zhai, Dongsheng; Li, Yuqiang; Zhang, Sen; Li, Ming; Kang, Lin; Chen, Jian; Wu, Peiheng; Xiong, Yaoheng

2016-08-15

Satellite laser ranging operating at 1064 nm wavelength using superconducting nanowire single-photon detectors (SNSPDs) is successfully demonstrated. A SNSPD with an intrinsic quantum efficiency of 80% and a dark count rate of 100 cps at 1064 nm wavelength is developed and introduced to Yunnan Observatory in China. With improved closed-loop telescope systems (field of view of about 26^''), satellites including Cryosat, Ajisai, and Glonass with ranges of 1600 km, 3100 km, and 19,500 km, respectively, are experimentally ranged with mean echo rates of 1200/min, 4200/min, and 320/min, respectively. To the best of our knowledge, this is the first demonstration of laser ranging for satellites using SNSPDs at 1064 nm wavelength. Theoretical analysis of the detection efficiency and the mean echo rate for typical satellites indicate that it is possible for a SNSPD to range satellites from low Earth orbit to geostationary Earth orbit.

First Simultaneous Views of the Axial and Lateral Perspectives of a Coronal Mass Ejection

NASA Astrophysics Data System (ADS)

Cabello, I.; Cremades, H.; Balmaceda, L.; Dohmen, I.

2016-08-01

The different appearances exhibited by coronal mass ejections (CMEs) are believed to be in part the result of different orientations of their main axis of symmetry, consistent with a flux-rope configuration. There are observational reports of CMEs seen along their main axis (axial perspective) and perpendicular to it (lateral perspective), but no simultaneous observations of both perspectives from the same CME have been reported to date. The stereoscopic views of the telescopes onboard the Solar-Terrestrial Relations Observatory (STEREO) twin spacecraft, in combination with the views from the Solar and Heliospheric Observatory (SOHO) and the Solar Dynamics Observatory (SDO), allow us to study the axial and lateral perspectives of a CME simultaneously for the first time. In addition, this study shows that the lateral angular extent ( L) increases linearly with time, while the angular extent of the axial perspective ( D) presents this behavior only from the low corona to {≈} 5 R_{⊙}, where it slows down. The ratio L/D ≈ 1.6 obtained here as the average over several points in time is consistent with measurements of L and D previously performed on events exhibiting only one of the perspectives from the single vantage point provided by SOHO.

Griffith Observatory: Hollywood's Celestial Theater

NASA Astrophysics Data System (ADS)

Margolis, Emily A.; Dr. Stuart W. Leslie

2018-01-01

The Griffith Observatory, perched atop the Hollywood Hills, is perhaps the most recognizable observatory in the world. Since opening in 1935, this Los Angeles icon has brought millions of visitors closer to the heavens. Through an analysis of planning documentation, internal newsletters, media coverage, programming and exhibition design, I demonstrate how the Observatory’s Southern California location shaped its form and function. The astronomical community at nearby Mt. Wilson Observatory and Caltech informed the selection of instrumentation and programming, especially for presentations with the Observatory’s Zeiss Planetarium, the second installed in the United States. Meanwhile the Observatory staff called upon some of Hollywood’s best artists, model makers, and scriptwriters to translate the latest astronomical discoveries into spectacular audiovisual experiences, which were enhanced with Space Age technological displays on loan from Southern California’s aerospace companies. The influences of these three communities- professional astronomy, entertainment, and aerospace- persist today and continue to make Griffith Observatory one of the premiere sites of public astronomy in the country.

Observatory Improvements for SOFIA

NASA Technical Reports Server (NTRS)

Peralta, Robert A.; Jensen, Stephen C.

2012-01-01

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a joint project between NASA and Deutsches Zentrum fuer Luft- und Raumfahrt (DLR), the German Space Agency. SOFIA is based in a Boeing 747 SP and flown in the stratosphere to observe infrared wavelengths unobservable from the ground. In 2007 Dryden Flight Research Center (DFRC) inherited and began work on improving the plane and its telescope. The improvements continue today with upgrading the plane and improving the telescope. The Observatory Verification and Validation (V&V) process is to ensure that the observatory is where the program says it is. The Telescope Status Display (TSD) will provide any information from the on board network to monitors that will display the requested information. In order to assess risks to the program, one must work through the various threats associate with that risk. Once all the risks are closed the program can work towards improving the observatory.

Spectroscopic Characterization of GEO Satellites with Gunma LOW Resolution Spectrograph

NASA Astrophysics Data System (ADS)

Endo, T.; Ono, H.; Hosokawa, M.; Ando, T.; Takanezawa, T.; Hashimoto, O.

The spectroscopic observation is potentially a powerful tool for understanding the Geostationary Earth Orbit (GEO) objects. We present here the results of an investigation of energy spectra of GEO satellites obtained from a groundbased optical telescope. The spectroscopic observations were made from April to June 2016 with the Gunma LOW resolution Spectrograph and imager (GLOWS) at the Gunma Astronomical Observatory (GAO) in JAPAN. The observation targets consist of eleven different satellites: two weather satellites, four communications satellites, and five broadcasting satellites. All the spectra of those GEO satellites are inferred to be solar-like. A number of well-known absorption features such as H-alpha, H-beta, Na-D,water vapor and oxygen molecules are clearly seen in thewavelength range of 4,000 - 8,000 Å. For comparison, we calculated the intensity ratio of the spectra of GEO satellites to that of the Moon which is the natural satellite of the earth. As a result, the following characteristics were obtained. 1) Some variations are seen in the strength of absorption features of water vapor and oxygen originated by the telluric atmosphere, but any other characteristic absorption features were not found. 2) For all observed satellites, the intensity ratio of the spectrum of GEO satellites decrease as a function of wavelength or to be flat. It means that the spectral reflectance of satellite materials is bluer than that of the Moon. 3) A characteristic dip at around 4,800 Å is found in all observed spectra of a weather satellite. Based on these observations, it is indicated that the characteristics of the spectrum are mainly derived from the solar panels because the apparent area of the solar cell is probably larger than that of the satellite body.

Solar Polar Field Observed by SOHO/MDI and Hinode

NASA Astrophysics Data System (ADS)

Liu, Y.

2009-12-01

Using 1-minute cadence time-series full disk magnetograms taken by SOHO/MDI in 2007 March, and the corresponding Hinode/SOT vector magnetograms, I have studied evolutionary characteristics of magnetic elements in Sun's south polar region in solar minimum. It is found that the lifetime of magnetic elements is 17.0 hours on average with an average lifetime of 21.8 hours for elements with positive field, the dominant polarity in the south pole, and 1.6 hours for elements with negative field. The elements with positive field are dominant in the south pole with a percentage of 76% in element number and 90.5% in magnetic flux. The lifetime and magnetic flux of the elements is found to be highly related. This agrees with some previous studies for the elements in low latitude quiet regions. Using an image cross correlation method, I also measure solar rotation rate at high latitude, up to 85° in latitude, which is ω = 2.914-0.342 × sin2φ-0.482×sin4φ μrad/s sidereal. It agrees with previous studies using spectroscopic and image cross correlation methods, and also agrees with the results from some work using the element tracking method in which the sample of tracked elements is large. The consistency of those results from different data and methods strongly suggests that this rate at high latitude is reliable.

Iranian National Observatory

NASA Astrophysics Data System (ADS)

Khosroshahi, H. G.; Danesh, A.; Molaeinezhad, A.

2016-09-01

The Iranian National Observatory is under construction at an altitude of 3600m at Gargash summit 300km southern Tehran. The site selection was concluded in 2007 and the site monitoring activities have begun since then, which indicates a high quality of the site with a median seeing of 0.7 arcsec through the year. One of the major observing facilities of the observatory is a 3.4m Alt-Az Ritchey-Chretien optical telescope which is currently under design. This f/11 telescope will be equipped with high resolution medium-wide field imaging cameras as well as medium and high resolution spectrographs. In this review, I will give an overview of astronomy research and education in Iran. Then I will go through the past and present activities of the Iranian National Observatory project including the site quality, telescope specifications and instrument capabilities.

Development of a Full Ice-cream Cone Model for Halo Coronal Mass Ejections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Na, Hyeonock; Moon, Y.-J.; Lee, Harim, E-mail: nho0512@khu.ac.kr, E-mail: moonyj@khu.ac.kr

It is essential to determine three-dimensional parameters (e.g., radial speed, angular width, and source location) of coronal mass ejections (CMEs) for the space weather forecast. In this study, we investigate which cone type represents a halo CME morphology using 29 CMEs (12 Solar and Heliospheric Observatory (SOHO) /Large Angle and Spectrometric Coronagraph (LASCO) halo CMEs and 17 Solar Terrestrial Relations Observatory ( STEREO )/Sun–Earth Connection Coronal and Heliospheric Investigation COR2 halo CMEs) from 2010 December to 2011 June. These CMEs are identified as halo CMEs by one spacecraft ( SOHO or one of STEREO A and B ) and limbmore » ones by the other spacecraft (One of STEREO A and B or SOHO ). From cone shape parameters of these CMEs, such as their front curvature, we find that the CME observational structures are much closer to a full ice-cream cone type than a shallow ice-cream cone type. Thus, we develop a full ice-cream cone model based on a new methodology that the full ice-cream cone consists of many flat cones with different heights and angular widths to estimate the three-dimensional parameters of the halo CMEs. This model is constructed by carrying out the following steps: (1) construct a cone for a given height and angular width, (2) project the cone onto the sky plane, (3) select points comprising the outer boundary, and (4) minimize the difference between the estimated projection speeds with the observed ones. By applying this model to 12 SOHO /LASCO halo CMEs, we find that 3D parameters from our method are similar to those from other stereoscopic methods (i.e., a triangulation method and a Graduated Cylindrical Shell model).« less

Farside Halo

NASA Image and Video Library

2017-12-08

There's no way to tell from this SOHO image whether the halo CME on March 5, 2013, originated from the front or far of the sun. But the STEREO spacecraft were watching the sun from the sides and showed it was from the far side. The bright planet is Venus. Credit: NASA/SOHO CME WEEK: What To See in CME Images Two main types of explosions occur on the sun: solar flares and coronal mass ejections. Unlike the energy and x-rays produced in a solar flare – which can reach Earth at the speed of light in eight minutes – coronal mass ejections are giant, expanding clouds of solar material that take one to three days to reach Earth. Once at Earth, these ejections, also called CMEs, can impact satellites in space or interfere with radio communications. During CME WEEK from Sept. 22 to 26, 2014, we explore different aspects of these giant eruptions that surge out from the star we live with. When a coronal mass ejection blasts off the sun, scientists rely on instruments called coronagraphs to track their progress. Coronagraphs block out the bright light of the sun, so that the much fainter material in the solar atmosphere -- including CMEs -- can be seen in the surrounding space. CMEs appear in these images as expanding shells of material from the sun's atmosphere -- sometimes a core of colder, solar material (called a filament) from near the sun's surface moves in the center. But mapping out such three-dimensional components from a two-dimensional image isn't easy. Watch the slideshow to find out how scientists interpret what they see in CME pictures. The images in the slideshow are from the three sets of coronagraphs NASA currently has in space. One is on the joint European Space Agency and NASA Solar and Heliospheric Observatory, or SOHO. SOHO launched in 1995, and sits between Earth and the sun about a million miles away from Earth. The other two coronagraphs are on the two spacecraft of the NASA Solar Terrestrial Relations Observatory, or STEREO, mission, which

Snowy CME

NASA Image and Video Library

2017-12-08

A solar flare associated with the coronal mass ejection seen in this image generated a flurry of fast-moving solar protons. As each one hits the CCD camera on SOHO, it produces a brief snow-like speckle in the image. Credit: NASA/SOHO CME WEEK: What To See in CME Images Two main types of explosions occur on the sun: solar flares and coronal mass ejections. Unlike the energy and x-rays produced in a solar flare – which can reach Earth at the speed of light in eight minutes – coronal mass ejections are giant, expanding clouds of solar material that take one to three days to reach Earth. Once at Earth, these ejections, also called CMEs, can impact satellites in space or interfere with radio communications. During CME WEEK from Sept. 22 to 26, 2014, we explore different aspects of these giant eruptions that surge out from the star we live with. When a coronal mass ejection blasts off the sun, scientists rely on instruments called coronagraphs to track their progress. Coronagraphs block out the bright light of the sun, so that the much fainter material in the solar atmosphere -- including CMEs -- can be seen in the surrounding space. CMEs appear in these images as expanding shells of material from the sun's atmosphere -- sometimes a core of colder, solar material (called a filament) from near the sun's surface moves in the center. But mapping out such three-dimensional components from a two-dimensional image isn't easy. Watch the slideshow to find out how scientists interpret what they see in CME pictures. The images in the slideshow are from the three sets of coronagraphs NASA currently has in space. One is on the joint European Space Agency and NASA Solar and Heliospheric Observatory, or SOHO. SOHO launched in 1995, and sits between Earth and the sun about a million miles away from Earth. The other two coronagraphs are on the two spacecraft of the NASA Solar Terrestrial Relations Observatory, or STEREO, mission, which launched in 2006. The two STEREO spacecraft

Aeronautics and Space Report of the President, Fiscal Year 2002 Activities

NASA Technical Reports Server (NTRS)

2002-01-01

Fiscal Year (FY) 2002 brought advances on many fronts in support of NASAs new vision, announced by Administrator Sean OKeefe on April 12, to improve life here, to extend life to there, to find life beyond. NASA successfully carried out four Space Shuttle missions, including three to the International Space Station (ISS) and one servicing mission to the Hubble Space Telescope (HST). By the end of the fiscal year, humans had occupied the ISS continuously for 2 years. NASA also managed five expendable launch vehicle (ELV) missions and participated in eight international cooperative ELV launches. In the area of space science, two of the Great Observatories, the Hubble Space Telescope and the Chandra X-Ray Observatory, continued to make spectacular observations. The Mars Global Surveyor and Mars Odyssey carried out their mapping missions of the red planet in unprecedented detail. Among other achievements, the Near Earth Asteroid Rendezvous (NEAR) Shoemaker spacecraft made the first soft landing on an asteroid, and the Solar and Heliospheric Observatory (SOHO) monitored a variety of solar activity, including the largest sunspot observed in 10 years. The education and public outreach program stemming from NASAs space science missions continues to grow. In the area of Earth science, attention focused on completing the first Earth Observing Satellite series. Four spacecraft were successfully launched. The goal is to understand our home planet as a system, as well as how the global environment responds to change.

The Space Telescope Observatory

NASA Technical Reports Server (NTRS)

Bahcall, J. N.; Odell, C. R.

1979-01-01

A convenient guide to the expected characteristics of the Space Telescope Observatory for astronomers and physicists is presented. An attempt is made to provide enough detail so that a professional scientist, observer or theorist, can plan how the observatory may be used to further his observing programs or to test theoretical models.

Orbiting Carbon Observatory Briefing

NASA Image and Video Library

2009-01-29

Anna Michalak, an Orbiting Carbon Observatory science team member from the University of Michigan, Ann Arbor, speaks during a media briefing to discuss the upcoming Orbiting Carbon Observatory mission, the first NASA spacecraft dedicated to studying carbon dioxide, Thursday, Jan. 29, 2009, at NASA Headquarters in Washington. Photo Credit: (NASA/Paul E. Alers)

Testing of Environmental Satellite Bus-Instrument Interfaces Using Engineering Models

NASA Technical Reports Server (NTRS)

Gagnier, Donald; Hayner, Rick; Nosek, Thomas; Roza, Michael; Hendershot, James E.; Razzaghi, Andrea I.

2004-01-01

This paper discusses the formulation and execution of a laboratory test of the electrical interfaces between multiple atmospheric scientific instruments and the spacecraft bus that carries them. The testing, performed in 2002, used engineering models of the instruments and the Aura spacecraft bus electronics. Aura is one of NASA s Earth Observatory System missions. The test was designed to evaluate the complex interfaces in the command and data handling subsystems prior to integration of the complete flight instruments on the spacecraft. A problem discovered during the flight integration phase of the observatory can cause significant cost and schedule impacts. The tests successfully revealed problems and led to their resolution before the full-up integration phase, saving significant cost and schedule. This approach could be beneficial for future environmental satellite programs involving the integration of multiple, complex scientific instruments onto a spacecraft bus.

Morphology of the southern African geomagnetic field derived from observatory and repeat station survey observations: 2005-2014

NASA Astrophysics Data System (ADS)

Kotzé, P. B.; Korte, M.

2016-02-01

Geomagnetic field data from four observatories and annual field surveys between 2005 and 2015 provide a detailed description of Earth's magnetic field changes over South Africa, Namibia and Botswana on time scales of less than 1 year. The southern African area is characterized by rapid changes in the secular variation pattern and lies in close proximity to the South Atlantic Anomaly (SAA) where the geomagnetic field intensity is almost 30 % weaker than in other regions at similar latitudes around the globe. Several geomagnetic secular acceleration (SA) pulses (geomagnetic jerks) around 2007, 2010 and 2012 could be identified over the last decade in southern Africa. We present a new regional field model for declination and horizontal and vertical intensity over southern Africa (Southern African REGional (SAREG)) which is based on field survey and observatory data and covering the time interval from 2005 to 2014, i.e. including the period between 2010 and 2013 when no low Earth-orbiting vector field satellite data are available. A comparative evaluation between SAREG and global field models like CHAOS-5, the CHAMP, Orsted and SAC-C model of the Earth's magnetic field and International Geomagnetic Reference Field (IGRF-12) reveals that a simple regional field model based on a relatively dense ground network is able to provide a realistic representation of the geomagnetic field in this area. We particularly note that a global field model like CHAOS-5 does not always indicate similar short-period patterns in the field components as revealed by observatory data, while representing the general secular variation reasonably well during the time interval without near-Earth satellite vector field data. This investigation further shows the inhomogeneous occurrence and distribution of secular variation impulses in the different geomagnetic field components and at different locations in southern African.

Laser Communication Experiments with Artemis Satellite

NASA Astrophysics Data System (ADS)

Kuzkov, Sergii; Sodnik, Zoran; Kuzkov, Volodymyr

2013-10-01

In November 2001, the European Space Agency (ESA) established the world-first inter-satellite laser communication link between the geostationary ARTEMIS satellite and the low Earth orbiting (LEO) SPOT-4 Earth observation satellite, demonstrating data rates of 50 Mbps. In 2006, the Japanese Space Agency launched the KIRARI (OICETS) LEO satellite with a compatible laser communication terminal and bidirectional laser communication links (50 Mbps and 2 Mbps) were successfully realized between KIRARI and ARTEMIS. ESA is now developing the European Data Relay Satellite (EDRS) system, which will use laser communication technology to transmit data between the Sentinel 1 and 2 satellites in LEO to two geostationary satellites (EDRS-A and EDRS-C) at data rates of 1.8 Gbps. As the data handling capabilities of state-of-the-art telecommunication satellites in GEO increase so is the demand for the feeder-link bandwidth to be transmitted from ground. This is why there is an increasing interest in developing high bandwidth ground-to-space laser communication systems working through atmosphere. In 2002, the Main Astronomical Observatory (MAO) started the development of its own laser communication system for its 0.7m AZT-2 telescope, located in Kyiv, Ukraine. The work was supported by the National Space Agency of Ukraine and by ESA. MAO developed a highly accurate computerized tracking system for AZT-2 telescope and a compact laser communication package called LACES (Laser Atmosphere and Communication Experiments with Satellites). The LACES instrument includes a camera of the pointing and tracking subsystems, a receiver module, a laser transmitter module, a tip/tilt atmospheric turbulence compensation subsystem, a bit error rate tester module and other optical and electronic components. The principal subsystems are mounted on a platform, which is located at the Cassegrain focus of the AZT-2 telescope. All systems were tested with the laser communication payload on-board ARTEMIS and

INTERMAGNET and magnetic observatories

USGS Publications Warehouse

Love, Jeffrey J.; Chulliat, Arnaud

2012-01-01

A magnetic observatory is a specially designed ground-based facility that supports time-series measurement of the Earth’s magnetic field. Observatory data record a superposition of time-dependent signals related to a fantastic diversity of physical processes in the Earth’s core, mantle, lithosphere, ocean, ionosphere, magnetosphere, and, even, the Sun and solar wind.

Astronomical Archive at Tartu Observatory

NASA Astrophysics Data System (ADS)

Annuk, K.

2007-10-01

Archiving astronomical data is important task not only at large observatories but also at small observatories. Here we describe the astronomical archive at Tartu Observatory. The archive consists of old photographic plate images, photographic spectrograms, CCD direct--images and CCD spectroscopic data. The photographic plate digitizing project was started in 2005. An on-line database (based on MySQL) was created. The database includes CCD data as well photographic data. A PHP-MySQL interface was written for access to all data.

Data Collection, Access and Presentation Technologies in the National Ecological Observatory (NEON) Design (Invited)

NASA Astrophysics Data System (ADS)

Aulenbach, S. M.; Berukoff, S. J.

2010-12-01

The National Ecological Observatory Network (NEON) will collect data across the United States on the impacts of climate change, land use change and invasive species on ecosystem functions and biodiversity. In-situ sampling and distributed sensor networks, linked by an advanced cyberinfrastructure, will collect site-based data on a variety of organisms, soils, aquatic systems, atmosphere and climate. Targeted airborne remote sensing observations made by NEON as well as geographical data sets and satellite resources produced by Federal agencies will provide data at regional and national scales. The resulting data streams, collected over a 30-year period, will be synthesized into fully traceable information products that are freely and openly accessible to all users. We provide an overview of several collection, access and presentation technologies evaluated for use by observatory systems throughout the data product life cycle. Specifically, we discuss smart phone applications for citizen scientists as well as the use of handheld devices for sample collection and reporting from the field. Protocols for storing, queuing, and retrieving data from observatory sites located throughout the nation are highlighted as are the application of standards throughout the pipelined production of data products. We discuss the automated incorporation of provenance information and digital object identifiers for published data products. The use of widgets and personalized user portals for the discovery and dissemination of NEON data products are also presented.

WFIRST Observatory Performance

NASA Technical Reports Server (NTRS)

Kruk, Jeffrey W.

2012-01-01

The WFIRST observatory will be a powerful and flexible wide-field near-infrared facility. The planned surveys will provide data applicable to an enormous variety of astrophysical science. This presentation will provide a description of the observatory and its performance characteristics. This will include a discussion of the point spread function, signal-to-noise budgets for representative observing scenarios and the corresponding limiting sensitivity. Emphasis will be given to providing prospective Guest Observers with information needed to begin thinking about new observing programs.

Relationships between U.S. Naval Observatory, LORAN-C and the Defense Satellite Communication System

NASA Technical Reports Server (NTRS)

Charron, L. G.

1982-01-01

The methods used in forming time scales for distant sites monitoring LORAN-C are addressed. The time transfers obtained via the defense satellite communication system (DSCS) and the data provided by this system used to calibrate these remote time scales are emphasized. The errors involved are discussed.

Archive interoperability in the Virtual Observatory

NASA Astrophysics Data System (ADS)

Genova, Françoise

2003-02-01

Main goals of Virtual Observatory projects are to build interoperability between astronomical on-line services, observatory archives, databases and results published in journals, and to develop tools permitting the best scientific usage from the very large data sets stored in observatory archives and produced by large surveys. The different Virtual Observatory projects collaborate to define common exchange standards, which are the key for a truly International Virtual Observatory: for instance their first common milestone has been a standard allowing exchange of tabular data, called VOTable. The Interoperability Work Area of the European Astrophysical Virtual Observatory project aims at networking European archives, by building a prototype using the CDS VizieR and Aladin tools, and at defining basic rules to help archive providers in interoperability implementation. The prototype is accessible for scientific usage, to get user feedback (and science results!) at an early stage of the project. ISO archive participates very actively to this endeavour, and more generally to information networking. The on-going inclusion of the ISO log in SIMBAD will allow higher level links for users.

Sofia Observatory Performance and Characterization

NASA Technical Reports Server (NTRS)

Temi, Pasquale; Miller, Walter; Dunham, Edward; McLean, Ian; Wolf, Jurgen; Becklin, Eric; Bida, Tom; Brewster, Rick; Casey, Sean; Collins, Peter;

In Brief: Deep-sea observatory

NASA Astrophysics Data System (ADS)

Showstack, Randy

2008-11-01

The first deep-sea ocean observatory offshore of the continental United States has begun operating in the waters off central California. The remotely operated Monterey Accelerated Research System (MARS) will allow scientists to monitor the deep sea continuously. Among the first devices to be hooked up to the observatory are instruments to monitor earthquakes, videotape deep-sea animals, and study the effects of acidification on seafloor animals. ``Some day we may look back at the first packets of data streaming in from the MARS observatory as the equivalent of those first words spoken by Alexander Graham Bell: `Watson, come here, I need you!','' commented Marcia McNutt, president and CEO of the Monterey Bay Aquarium Research Institute, which coordinated construction of the observatory. For more information, see http://www.mbari.org/news/news_releases/2008/mars-live/mars-live.html.

An astronomical observatory for Peru

NASA Astrophysics Data System (ADS)

del Mar, Juan Quintanilla; Sicardy, Bruno; Giraldo, Víctor Ayma; Callo, Víctor Raúl Aguilar

2011-06-01

Peru and France are to conclude an agreement to provide Peru with an astronomical observatory equipped with a 60-cm diameter telescope. The principal aims of this project are to establish and develop research and teaching in astronomy. Since 2004, a team of researchers from Paris Observatory has been working with the University of Cusco (UNSAAC) on the educational, technical and financial aspects of implementing this venture. During an international astronomy conference in Cusco in July 2009, the foundation stone of the future Peruvian Observatory was laid at the top of Pachatusan Mountain. UNSAAC, represented by its Rector, together with the town of Oropesa and the Cusco regional authority, undertook to make the sum of 300,000€ available to the project. An agreement between Paris Observatory and UNSAAC now enables Peruvian students to study astronomy through online teaching.

Ghana's experience in the establishment of a national digital seismic network observatory

NASA Astrophysics Data System (ADS)

Ahulu, Sylvanus; Danuor, Sylvester Kojo

2015-07-01

The Government of Ghana has established a National Digital Seismic Network Observatory in Ghana with the aim of monitoring events such as earthquakes, blasts from mining and quarrying, nuclear tests, etc. The Digital Observatory was commissioned on 19 December 2012, and was dedicated to Geosciences in Ghana. Previously Ghana did not have any operational, digital seismic network acquisition system with the capability of monitoring and analysing data for planning and research purposes. The Ghana Geological Survey has been monitoring seismic events with an analogue system which was not efficient and does not deliver real-time data. Hence, the importance of setting up the National Digital Seismic Network System which would enable the Geological Survey to constantly monitor, manage and coordinate both natural and man-made seismic activities in the country and around the globe, to some extent on real-time basis. The Network System is made up of six remote digital stations that transmit data via satellite to the central observatory. Sensors used are 3× Trillium Compact and 3× Trillium 120PA with Trident digitizers. The department has also acquired strong motion equipment: Titan accelerometers with Taurus digitizers from Nanometrics. Three of each of these instruments have been installed at the Akosombo and Kpong hydrodams, and also at the Weija water supply dam. These instruments are used to monitor dams. The peak ground acceleration (PGA) values established from the analysed data from the accelerometers will be used to retrofit or carry out maintenance work of the dam structures to avoid collapse. Apart from these, the observatory also assesses and analyses seismic waveforms relevant to its needs from the Global Seismographic Network (GSN) system operated by the US Geological Survey. The Ghana Geological Survey, through its Seismic Network Observatory makes data available to its stakeholder institutions for earthquake disaster mitigation; reports on all aspects of

New Opportunities for Cabled Ocean Observatories

NASA Astrophysics Data System (ADS)

Duennebier, F. K.; Butler, R.; Karl, D. M.; Roger, L. B.

2002-12-01

With the decommissioning of transoceanic telecommunications cables as they become obsolete or uneconomical, there is an opportunity to use these systems for ocean observatories. Two coaxial cables, TPC-1 and HAW-2 are currently in use for observatories, and another, ANZCAN, is scheduled to be used beginning in 2004 to provide a cabled observatory at Station ALOHA, north of Oahu. The ALOHA observatory will provide several Mb/s data rates and about 1 kW of power to experiments installed at Station ALOHA. Sensors can be installed either by wet mateable connection to a junction box on the ocean floor using an ROV, or by acoustic data link to the system. In either case real-time data will be provided to users over the Internet. A Small Experiment Module, to be first installed at the Hawaii-2 Observatory, and later at Station ALOHA, will provide relatively cheap and uncomplicated access to the observatories for relatively simple sensors. Within the next few years, the first electro-optical cables installed in the 1980's will be decommissioned and could be available for scientific use. These cables could provide long "extension cords" (thousands of km) with very high bandwidth and reasonable power to several observatories in remote locations in the ocean. While they could be used in-place, a more exciting scenario is to use cable ships to pick up sections of cable and move them to locations of higher scientific interest. While such moves would not be cheap, the costs would rival the cost of installation and maintenance of a buoyed observatory, with far more bandwidth and power available for science use.

Daily variation characteristics at polar geomagnetic observatories

NASA Astrophysics Data System (ADS)

Lepidi, S.; Cafarella, L.; Pietrolungo, M.; Di Mauro, D.

2011-08-01

This paper is based on the statistical analysis of the diurnal variation as observed at six polar geomagnetic observatories, three in the Northern and three in the Southern hemisphere. Data are for 2006, a year of low geomagnetic activity. We compared the Italian observatory Mario Zucchelli Station (TNB; corrected geomagnetic latitude: 80.0°S), the French-Italian observatory Dome C (DMC; 88.9°S), the French observatory Dumont D'Urville (DRV; 80.4°S) and the three Canadian observatories, Resolute Bay (RES; 83.0°N), Cambridge Bay (CBB; 77.0°N) and Alert (ALE, 87.2°N). The aim of this work was to highlight analogies and differences in daily variation as observed at the different observatories during low geomagnetic activity year, also considering Interplanetary Magnetic Field conditions and geomagnetic indices.

History of Satellite Observations of East Pacific Atmospheric Rivers

NASA Astrophysics Data System (ADS)

Vonder Haar, T. H.; Forsythe, J. M.; Seaman, C.

2017-12-01

The terms "Atmospheric River" or "Tropospheric River" were not used in refereed literature until the 1990's, although earlier works hinted at the existence of narrow corridors of moisture transport. With the advent of satellite observations in the 1960's, meteorologists began to discover the fingerprints of these phenomena via cloud observations. Early geostationary satellites depicted "cloud rivers" or "pipeline cirrus" impacting the U.S. west coast, with only indirect evidence of large water vapor transport. Routine use of passive microwave imagery to retrieve total column water vapor began in the late 1980's with the launch of the Special Sensor Microwave / Imager instrument, whose descendants continue to provide realtime monitoring of atmospheric rivers today. Passive microwave data opened the door to quantitative studies of atmospheric rivers, by providing the water vapor measurements needed to compute integrated moisture flux. Atmospheric rivers are detected in near-realtime from passive microwave water vapor products. In recent years, dedicated coastal observatories, multidecadal global water vapor data sets, cloud radars, and satellite sounding systems have begun to probe the 4-dimensional moisture structure of atmospheric rivers. The timeline of our understanding of atmospheric rivers will be presented from the standpoint of evolving satellite observing systems.

Observatories of Sawai Jai Singh II

NASA Astrophysics Data System (ADS)

Johnson-Roehr, Susan N.

Sawai Jai Singh II, Maharaja of Amber and Jaipur, constructed five observatories in the second quarter of the eighteenth century in the north Indian cities of Shahjahanabad (Delhi), Jaipur, Ujjain, Mathura, and Varanasi. Believing the accuracy of his naked-eye observations would improve with larger, more stable instruments, Jai Singh reengineered common brass instruments using stone construction methods. His applied ingenuity led to the invention of several outsize masonry instruments, the majority of which were used to determine the coordinates of celestial objects with reference to the local horizon. During Jai Singh's lifetime, the observatories were used to make observations in order to update existing ephemerides such as the Zīj-i Ulugh Begī. Jai Singh established communications with European astronomers through a number of Jesuits living and working in India. In addition to dispatching ambassadorial parties to Portugal, he invited French and Bavarian Jesuits to visit and make use of the observatories in Shahjahanabad and Jaipur. The observatories were abandoned after Jai Singh's death in 1743 CE. The Mathura observatory was disassembled completely before 1857. The instruments at the remaining observatories were restored extensively during the nineteenth and twentieth centuries.

The Pierre Auger Cosmic Ray Observatory

DOE PAGES

Aab, Alexander

2015-07-08

The Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world's largest cosmic ray observatory. The objectives of the Observatory are to probe the origin and characteristics of cosmic rays above 1017 eV and study the interactions of these, the most energetic particles observed in nature. The Auger design features an array of 1660 water Cherenkov particle detector stations spread over 3000 km 2 overlooked by 24 air fluorescence telescopes. Additionally, three high elevation fluorescence telescopes overlook a 23.5 km 2, 61-detector infilled array with 750 m spacing. The Observatory has been in successful operationmore » since completion in 2008 and has recorded data from an exposure exceeding 40,000 km 2 sr yr. This paper describes the design and performance of the detectors, related subsystems and infrastructure that make up the Observatory.« less

Byurakan Astrophysical Observatory as Cultural Centre

NASA Astrophysics Data System (ADS)

Mickaelian, A. M.; Farmanyan, S. V.

2017-07-01

NAS RA V. Ambartsumian Byurakan Astrophysical Observatory is presented as a cultural centre for Armenia and the Armenian nation in general. Besides being scientific and educational centre, the Observatory is famous for its unique architectural ensemble, rich botanical garden and world of birds, as well as it is one of the most frequently visited sightseeing of Armenia. In recent years, the Observatory has also taken the initiative of the coordination of the Cultural Astronomy in Armenia and in this field, unites the astronomers, historians, archaeologists, ethnographers, culturologists, literary critics, linguists, art historians and other experts. Keywords: Byurakan Astrophysical Observatory, architecture, botanic garden, tourism, Cultural Astronomy.

Golden legacy from ESA's observatory

NASA Astrophysics Data System (ADS)

2003-07-01

'milestone number' of 1000 scientific papers was reached. Even now ISO's data archive remains a valuable source of new results. For example, some of the latest papers describe the detection of water in 'protostars', which are stars in the process of being born, and studies of numerous nearby galaxies. "Of course we were confident ISO was going to do very well, but its actual productivity has been far beyond our expectations. The publication rate does not even seem to have peaked yet! We expect many more results," Salama says. Note for editors ISO's data archive contains scientific data from about 30 000 observations. Astronomers from all over the world have downloaded almost eight times the equivalent of the entire scientific archive. As much as 35% of all ISO observations have already been published at least once in prestigious scientific journals. ESA is now preparing to continue its infrared investigation of the Universe. The next generation of infrared space observatories is already in the pipeline. ISO is to be followed by the NASA SIRTF observatory to be launched later this year. Then, in 2007, ESA will follow up the pioneering work of ISO with the Herschel Space Observatory, which will become the largest imaging telescope ever put into space. ISO The Infrared Space Observatory (ISO) was launched in 1995 and operated from November that year to May 1998, when it ran out of the coolant needed to keep its detectors working. At the time it was the most sensitive infrared satellite ever launched and made particularly important studies of the dusty regions of the Universe, where visible light telescopes can see nothing. ESA will reopen its examination of the infrared Universe when Herschel is launched in 2007. Herschel Herschel will be the largest space telescope when, in 2007, it is launched on an Ariane-5 rocket, together with ESA’s cosmology mission, Planck. Herschel’s 3.5-metre diameter mirror will collect longwave infrared radiation from some of the coolest and most

An international network of magnetic observatories

USGS Publications Warehouse

Love, Jeffrey J.; Chulliat, A.

2013-01-01

Since its formation in the late 1980s, the International Real-Time Magnetic Observatory Network (INTERMAGNET), a voluntary consortium of geophysical institutes from around the world, has promoted the operation of magnetic observatories according to modern standards [eg. Rasson, 2007]. INTERMAGNET institutes have cooperatively developed infrastructure for data exchange and management ads well as methods for data processing and checking. INTERMAGNET institute have also helped to expand global geomagnetic monitoring capacity, most notably by assisting magnetic observatory institutes in economically developing countries by working directly with local geophysicists. Today the INTERMAGNET consortium encompasses 57 institutes from 40 countries supporting 120 observatories (see Figures 1a and 1b). INTERMAGNET data record a wide variety of time series signals related to a host of different physical processes in the Earth's interiors and in the Earth's surrounding space environment [e.g., Love, 2008]. Observatory data have always had a diverse user community, and to meet evolving demand, INTERMAGNET has recently coordinated the introduction of several new data services.

OSO-6 Orbiting Solar Observatory

NASA Technical Reports Server (NTRS)

1972-01-01

The description, development history, test history, and orbital performance analysis of the OSO-6 Orbiting Solar Observatory are presented. The OSO-6 Orbiting Solar Observatory was the sixth flight model of a series of scientific spacecraft designed to provide a stable platform for experiments engaged in the collection of solar and celestial radiation data. The design objective was 180 days of orbital operation. The OSO-6 has telemetered an enormous amount of very useful experiment and housekeeping data to GSFC ground stations. Observatory operation during the two-year reporting period was very successful except for some experiment instrument problems.

The Farid & Moussa Raphael Observatory

NASA Astrophysics Data System (ADS)

Hajjar, R.

2017-06-01

The Farid & Moussa Raphael Observatory (FMRO) at Notre Dame University Louaize (NDU) is a teaching, research, and outreach facility located at the main campus of the university. It located very close to the Lebanese coast, in an urbanized area. It features a 60-cm Planewave CDK telescope, and instruments that allow for photometric and spetroscopic studies. The observatory currently has one thinned, back-illuminated CCD camera, used as the main imager along with Johnson-Cousin and Sloan photometric filters. It also features two spectrographs, one of which is a fiber fed echelle spectrograph. These are used with a dedicated CCD. The observatory has served for student projects, and summer schools for advanced undergraduate and graduate students. It is also made available for use by the regional and international community. The control system is currently being configured for remote observations. A number of long-term research projects are also being launched at the observatory.

VLBI clock synchronization tests performed via the ATS-1 and ATS-3 satellites

NASA Technical Reports Server (NTRS)

Ramasastry, J.; Rosenbaum, B.; Michelini, R. D.; Kuegler, G.

1971-01-01

Clock synchronization experiments were carried out May 10 to June 10, 1971, by the NASA/Goddard Space Flight Center and the Smithsonian Astrophysical Observatory via the ATS-1 and 3 geostationary satellites at the NASA tracking stations Rosman and Mojave, during a VLBI (Very Long Baseline Interferometer) experiment in order to determine the clock-offset between the two stations. Ten microsecond pulses at C-band with very sharp risetime were exchanged by the two stations through the dual transponders of the satellites. At each station, a time-interval counter was started by the transmitted pulse and stopped by the received pulse. The probable error of the difference in the mean values of the clock-offset is 10 nanoseconds.

The European Virtual Observatory EURO-VO | Euro-VO

Science.gov Websites

: VOTECH EuroVO-DCA EuroVO-AIDA EuroVO-ICE The European Virtual Observatory EURO-VO The Virtual Observatory news Workshop on Virtual Observatory Tools and their Applications, Krakow, Poland June 16-18, organized present the Astronomical Virtual Observatory at the Copernicus (European Earth Observation Programme) Big

Mechanical Overview of the International X-Ray Observatory

NASA Technical Reports Server (NTRS)

Robinson, David W.; McClelland, Ryan S.

2009-01-01

The International X-ray Observatory (IXO) is a new collaboration between NASA, ESA, and JAXA which is under study for launch in 2020. IXO will be a large 6600 kilogram Great Observatory-class mission which will build upon the legacies of the Chandra and XMM-Newton X-ray observatories. It combines elements from NASA's Constellation-X program and ESA's XEUS program. The observatory will have a 20-25 meter focal length, which necessitates the use of a deployable instrument module. Currently the project is actively trading configurations and layouts of the various instruments and spacecraft components. This paper will provide a snapshot of the latest observatory configuration under consideration and summarize the observatory from the mechanical engineering perspective.

Entry Debris Field Estimation Methods and Application to Compton Gamma Ray Observatory Disposal

NASA Technical Reports Server (NTRS)

Mrozinski, Richard B.

2001-01-01

For public safety reasons, the Compton Gamma Ray Observatory (CGRO) was intentionally deorbited on June 4, 2000. This deorbit was NASA's first intentional controlled deorbit of a satellite, and more will come including the eventual deorbit of the International Space Station. To maximize public safety, satellite deorbit planning requires conservative estimates of the debris footprint size and location. These estimates are needed to properly design a deorbit sequence that places the debris footprint over unpopulated areas, including protection for deorbit contingencies. This paper details a method for estimating the length (range), width (crossrange), and location of entry and breakup debris footprints. This method utilizes a three degree-of-freedom Monte Carlo simulation incorporating uncertainties in all aspects of the problem, including vehicle and environment uncertainties. The method incorporates a range of debris characteristics based on historical data in addition to any vehicle-specific debris catalog information. This paper describes the method in detail, and presents results of its application as used in planning the deorbit of the CGRO.

Laser experiments in light cloudiness with the geostationary satellite ARTEMIS

NASA Astrophysics Data System (ADS)

Kuzkov, V.; Kuzkov, S.; Sodnik, Z.

2016-08-01

The geostationary satellite ARTEMIS was launched in July 2001. The satellite is equipped with a laser communication terminal, which was used for the world's first inter-satellite laser communication link between ARTEMIS and the low earth orbit satellite SPOT-4. Ground-to-space laser communication experiments were also conducted under various atmospheric conditions involving ESA's optical ground station. With a rapidly increasing volume of information transferred by geostationary satellites, there is a rising demand for high-speed data links between ground stations and satellites. For ground-to-space laser communications there are a number of important design parameters that need to be addressed, among them, the influence of atmospheric turbulence in different atmospheric conditions and link geometries. The Main Astronomical Observatory of NAS of Ukraine developed a precise computer tracking system for its 0.7 m AZT-2 telescope and a compact laser communication package LACES (Laser Atmosphere and Communication experiments with Satellites) for laser communication experiments with geostationary satellites. The specially developed software allows computerized tracking of the satellites using their orbital data. A number of laser experiments between MAO and ARTEMIS were conducted in partial cloudiness with some amount of laser light observed through clouds. Such conditions caused high break-up (splitting) of images from the laser beacon of ARTEMIS. One possible explanation is Raman scattering of photons on molecules of a water vapor in the atmosphere. Raman scattering causes a shift in a wavelength of the photons.In addition, a different value for the refraction index appears in the direction of the meridian for the wavelength-shifted photons. This is similar to the anomalous atmospheric refraction that appears at low angular altitudes above the horizon. We have also estimated the atmospheric attenuation and the influence of atmospheric turbulence on observed results

110th Anniversary of the Engelhardt Astronomical Observatory

NASA Astrophysics Data System (ADS)

Nefedyev, Y.

2012-09-01

The Engelhardt Astronomical Observatory (EAO) was founded in September 21, 1901. The history of creation of the Engelhard Astronomical Observatory was begun in 1897 with transfer a complimentary to the Kazan University of the unique astronomical equipment of the private observatory in Dresden by known astronomer Vasily Pavlovichem Engelgardt. Having stopped astronomical activity owing to advanced years and illnesses Engelgardt has decided to offer all tools and library of the Astronomical observatory of the Kazan University. Vasily Pavlovich has put the first condition of the donation that his tools have been established as soon as possible and on them supervision are started. In 1898 the decree of Emperor had been allocated means and the ground for construction of the Astronomical observatory is allocated. There is the main historical telescope of the Engelhard Astronomical Observatory the 12-inch refractor which was constructed by English master Grubbom in 1875. The unique tool of the Engelhard Astronomical Observatory is unique in the world now a working telescope heliometer. It's one of the first heliometers, left workshops Repsolda. It has been made in 1874 and established in Engelgardt observatory in 1908 in especially for him the constructed round pavilion in diameter of 3.6 m. Today the Engelhard Astronomical Observatory is the only thing scientifically - educational and cultural - the cognitive astronomical center, located on territory from Moscow up to the most east border of Russia. Currently, the observatory is preparing to enter the protected UNESCO World Heritage List.

Kitt Peak National Observatory | ast.noao.edu

Science.gov Websites

National Observatory (KPNO), part of the National Optical Astronomy Observatory (NOAO), supports the most diverse collection of astronomical observatories on Earth for nighttime optical and infrared astronomy and NOAO is the national center for ground-based nighttime astronomy in the United States and is operated

Modified Homogeneous Data Set of Coronal Intensities

NASA Astrophysics Data System (ADS)

Dorotovič, I.; Minarovjech, M.; Lorenc, M.; Rybanský, M.

2014-07-01

The Astronomical Institute of the Slovak Academy of Sciences has published the intensities, recalibrated with respect to a common intensity scale, of the 530.3 nm (Fe xiv) green coronal line observed at ground-based stations up to the year 2008. The name of this publication is Homogeneous Data Set (HDS). We have developed a method that allows one to successfully substitute the ground-based observations by satellite observations and, thus, continue with the publication of the HDS. For this purpose, the observations of the Extreme-ultraviolet Imaging Telescope (EIT), onboard the Solar and Heliospheric Observatory (SOHO) satellite, were exploited. Among other data the EIT instrument provides almost daily 28.4 nm (Fe xv) emission-line snapshots of the corona. The Fe xiv and Fe xv data (4051 observation days) taken in the period 1996 - 2008 have been compared and good agreement was found. The method to obtain the individual data for the HDS follows from the correlation analysis described in this article. The resulting data, now under the name of Modified Homogeneous Data Set (MHDS), are identical up to 1996 to those in the HDS. The MHDS can be used further for studies of the coronal solar activity and its cycle. These data are available at http://www.suh.sk.

Worldwide R&D of Virtual Observatory

NASA Astrophysics Data System (ADS)

Cui, C. Z.; Zhao, Y. H.

2008-07-01

Virtual Observatory (VO) is a data intensive online astronomical research and education environment, taking advantages of advanced information technologies to achieve seamless and uniform access to astronomical information. The concept of VO was introduced in the late 1990s to meet the challenges brought up with data avalanche in astronomy. In the paper, current status of International Virtual Observatory Alliance, technical highlights from world wide VO projects are reviewed, a brief introduction of Chinese Virtual Observatory is given.

History of Chandra X-Ray Observatory

NASA Image and Video Library

1999-07-01

A crew member of the STS-93 mission took this photograph of the Chandra X-Ray Observatory, still attached to the Inertial Upper Stage (IUS), backdropped against the darkness of space not long after its release from Orbiter Columbia. Two firings of an attached IUS rocket placed the Observatory into its working orbit. The primary duty of the crew of this mission was to deploy the 50,162-pound Observatory, the world's most powerful x-ray telescope.

VISAGE Visualization for Integrated Satellite, Airborne and Ground-Based Data Exploration

NASA Technical Reports Server (NTRS)

Conover, Helen; Berendes, Todd; Naeger, Aaron; Maskey, Manil; Gatlin, Patrick; Wingo, Stephanie; Kulkarni, Ajinkya; Gupta, Shivangi; Nagaraj, Sriraksha; Wolff, David;

VizieR Online Data Catalog: 2007-2016 Pulkovo Uranian satellites obs. (Ershova+, 2017)

NASA Astrophysics Data System (ADS)

Ershova, A. P.; Roshchina, E. A.; Izmailov, I. S.

2016-11-01

Observations of the main Uranian satellites were made with the 26-inch refractor (D/F=65cm/1041.3cm) at the Pulkovo Observatory in 2007-2016. The CCD camera FLI Pro Line was used (3056x3056px, each pixel of 12-microns). The field of view -- 12'x12', focal plane scale -- 19.8"/mm, scale on the CCD frames -- 0.24"/px. The UCAC4 catalog was used as a reference. Coordinates' epoch is the J2000.0. Average values of Standart Error of the Mean (SEM) of RA and DEC for each satellite are shown in table below. Satellite RASEM DECSEM ------------------------------------------------ Ariel (U1) 0.06" 0.06" Umbriel (U2) 0.05" 0.07" Titania (U3) 0.02" 0.02" Oberon (U4) 0.02" 0.02" ------------------------------------------------ Coordinates with their errors are shown in the "obsperr.dat" file. The "obs.dat" file was made according to MPC format and contains data in the same order as "obsperr.dat". Both files contain date of observation and satellite index so sit is easy to compare strings. (2 data files).

Early German plans for southern observatories

NASA Astrophysics Data System (ADS)

Wolfschmidt, G.

2002-07-01

As early as the 18th and 19th centuries, French and English observers were active in South Africa. Around the beginning of the 20th century, Heidelberg and Potsdam astronomers proposed a southern observatory. Then Göttingen astronomers suggested building an observatory in Windhoek for photographing the sky and measuring the solar constant. In 1910 Karl Schwarzschild (1873-1916), after a visit to observatories in the United States, pointed out the usefulness of an observatory in South West Africa, in a climate superior to that in Germany, giving German astronomers access to the southern sky. Seeing tests were begun in 1910 by Potsdam astronomers, but WW I stopped the plans. In 1928 Erwin Finlay-Freundlich (1885-1964), inspired by the Hamburg astronomer Walter Baade (1893-1960), worked out a detailed plan for a southern observatory with a reflecting telescope, spectrographs and an astrograph with an objective prism. Paul Guthnick (1879-1947), director of the Berlin observatory, in cooperation with APO Potsdam and Hamburg, made a site survey to Africa in 1929 and found the conditions in Windhoek to be ideal. Observations were started in the 1930s by Berlin and Breslau astronomers, but were stopped by WW II. In the 1950s, astronomers from Hamburg and The Netherlands renewed the discussion in the framework of European cooperation, and this led to the founding of ESO in 1963.

Al Gore attends Fall Meeting session on Earth observing satellite

NASA Astrophysics Data System (ADS)

Richman, Barbara T.

2011-12-01

Former U.S. vice president Al Gore, making unscheduled remarks at an AGU Fall Meeting session, said, "The reason you see so many pictures" of the Deep Space Climate Observatory (DSCOVR) satellite at this session is "that it already has been built." However, "because one of its primary missions was to help document global warming, it was canceled. So for those who are interested in struggling against political influence," Gore said, "the benefits have been documented well here." Gore made his comments after the third oral presentation at the 8 December session entitled "Earth Observations From the L1 (Lagrangian Point No. 1)," which focused on the capabilities of and progress on refurbishing DSCOVR. The satellite, formerly called Triana, had been proposed by Gore in 1998 to collect climate data. Although Triana was built, it was never launched: Congress mandated that before the satellite could be sent into space the National Academies of Science needed to confirm that the science it would be doing was worthwhile. By the time the scientific validation was complete, the satellite "was no longer compatible with the space shuttle manifest," Robert C. Smith, program manager for strategic integration at the NASA Goddard Space Flight Center, told Eos.

Application of Compressive Sensing to Gravitational Microlensing Data and Implications for Miniaturized Space Observatories

NASA Technical Reports Server (NTRS)

Korde-Patel, Asmita (Inventor); Barry, Richard K.; Mohsenin, Tinoosh

2016-01-01

Compressive Sensing is a technique for simultaneous acquisition and compression of data that is sparse or can be made sparse in some domain. It is currently under intense development and has been profitably employed for industrial and medical applications. We here describe the use of this technique for the processing of astronomical data. We outline the procedure as applied to exoplanet gravitational microlensing and analyze measurement results and uncertainty values. We describe implications for on-spacecraft data processing for space observatories. Our findings suggest that application of these techniques may yield significant, enabling benefits especially for power and volume-limited space applications such as miniaturized or micro-constellation satellites.

Telescopes in Education: the Little Thompson Observatory

NASA Astrophysics Data System (ADS)

Schweitzer, A. E.; Melsheimer, T. T.

2003-12-01

The Little Thompson Observatory is the first community-built observatory that is part of a high school and accessible to other schools remotely, via the Internet. This observatory is the second member of the Telescopes in Education (TIE) project. Construction of the building was done completely by volunteer labor, and first light occurred in May 1999. The observatory is located on the grounds of Berthoud High School in northern Colorado. We are grateful to have received an IDEAS grant to provide teacher training workshops for K-12 schools to make use of the observatory, including remote observing from classrooms. Students connect to the observatory over the Internet, and then receive the images back on their local computers. A committee of teachers and administrators from the Thompson School District selected these workshops to count towards Incentive Credits (movement on the salary schedule) because the course meets the criteria: "Learning must be directly transferable to the classroom with students and relate to standards, assessment and/or technology." Our program is also accredited by Colorado State University.

Cyberinfrastructure for the NSF Ocean Observatories Initiative

NASA Astrophysics Data System (ADS)

Orcutt, J. A.; Vernon, F. L.; Arrott, M.; Chave, A.; Schofield, O.; Peach, C.; Krueger, I.; Meisinger, M.

2008-12-01

The Ocean Observatories Initiative (OOI) is an environmental observatory covering a diversity of oceanic environments, ranging from the coastal to the deep ocean. The physical infrastructure comprises a combination of seafloor cables, buoys and autonomous vehicles. It is currently in the final design phase, with construction planned to begin in mid-2010 and deployment phased over five years. The Consortium for Ocean Leadership manages this Major Research Equipment and Facilities Construction program with subcontracts to Scripps Institution of Oceanography, University of Washington and Woods Hole Oceanographic Institution. High-level requirements for the CI include the delivery of near-real-time data with minimal latencies, open data, data analysis and data assimilation into models, and subsequent interactive modification of the network (including autonomous vehicles) by the cyberinfrastructure. Network connections include a heterogeneous combination of fiber optics, acoustic modems, and Iridium satellite telemetry. The cyberinfrastructure design loosely couples services that exist throughout the network and share common software and middleware as necessary. In this sense, the system appears to be identical at all scales, so it is self-similar or fractal by design. The system provides near-real-time access to data and developed knowledge by the OOI's Education and Public Engagement program, to the physical infrastructure by the marine operators and to the larger community including scientists, the public, schools and decision makers. Social networking is employed to facilitate the virtual organization that builds, operates and maintains the OOI as well as providing a variety of interfaces to the data and knowledge generated by the program. We are working closely with NOAA to exchange near-real-time data through interfaces to their Data Interchange Facility (DIF) program within the Integrated Ocean Observing System (IOOS). Efficiencies have been emphasized through

Refuting S 825AB System Classification through Astrometry and Gaia Satellite Data

NASA Astrophysics Data System (ADS)

Lyman, Noah; Musegades, Lila; Davis, Edward; Briney, Micah; Francis, Aaron; Niebuhr, Cole; Rowe, David; Harshaw, Richard; Genet, Russell

2018-04-01

A student-led team of researchers studied double star S 825AB (WDS 23100+3651). Analysis of ten CCD images obtained by the Sierra Research Observatory yielded an average position angle of 318.37º and an average separation of 67.38". Comparing these results to published findings in the Washington Double Star Catalog and measurements taken from the European Space Agency's Gaia astrometry satellite, the team concluded that S 825AB is not a binary system.

Satellite Sees Holiday Lights Brighten Cities - Atlanta

NASA Image and Video Library

2017-12-08

City lights shine brighter during the holidays in the United States when compared with the rest of the year, as shown using a new analysis of daily data from the NASA-NOAA Suomi NPP satellite. Dark green pixels are areas where lights are 50 percent brighter, or more, during December. Because snow reflects so much light, the researchers could only analyze snow-free cities. They focused on the U.S. West Coast from San Francisco and Los Angeles, and cities south of a rough imaginary line from St. Louis to Washington, D.C. Credit: Jesse Allen, NASA’s Earth Observatory Read more: www.nasa.gov/content/goddard/satellite-sees-holiday-light....NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Satellite Sees Holiday Lights Brighten Cities - Florida

NASA Image and Video Library

2017-12-08

City lights shine brighter during the holidays in the United States when compared with the rest of the year, as shown using a new analysis of daily data from the NASA-NOAA Suomi NPP satellite. Dark green pixels are areas where lights are 50 percent brighter, or more, during December. Because snow reflects so much light, the researchers could only analyze snow-free cities. They focused on the U.S. West Coast from San Francisco and Los Angeles, and cities south of a rough imaginary line from St. Louis to Washington, D.C. Credit: Jesse Allen, NASA’s Earth Observatory Read more: www.nasa.gov/content/goddard/satellite-sees-holiday-light....NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

SOFIA - Stratospheric Observatory for Infrared Astronomy

NASA Technical Reports Server (NTRS)

Kunz, Nans; Bowers, Al

2007-01-01

This viewgraph presentation reviews the Stratospheric Observatory for Infrared Astronomy (SOFIA). The contents include: 1) Heritage & History; 2) Level 1 Requirements; 3) Top Level Overview of the Observatory; 4) Development Challenges; and 5) Highlight Photos.

COMPARISON OF SEISMIC SIGNATURES OF FLARES OBTAINED BY SOHO/MICHELSON DOPPLER IMAGER AND GONG INSTRUMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zharkov, S.; Matthews, S. A.; Zharkova, V. V.

2011-10-01

The first observations of seismic responses to solar flares were carried out using time-distance (TD) and holography techniques applied to SOHO/Michelson Doppler Imager (MDI) Dopplergrams obtained from space and unaffected by terrestrial atmospheric disturbances. However, the ground-based network GONG is potentially a very valuable source of sunquake observations, especially in cases where space observations are unavailable. In this paper, we present an updated technique for pre-processing of GONG observations for the application of subjacent vantage holography. Using this method and TD diagrams, we investigate several sunquakes observed in association with M- and X-class solar flares and compare the outcomes withmore » those reported earlier using MDI data. In both GONG and MDI data sets, for the first time, we also detect the TD ridge associated with the 2001 September 9 flare. Our results show reassuringly positive identification of sunquakes from GONG data that can provide further information about the physics of seismic processes associated with solar flares.« less

NASA capabilities roadmap: advanced telescopes and observatories

NASA Technical Reports Server (NTRS)

Feinberg, Lee D.

2005-01-01

The NASA Advanced Telescopes and Observatories (ATO) Capability Roadmap addresses technologies necessary for NASA to enable future space telescopes and observatories collecting all electromagnetic bands, ranging from x-rays to millimeter waves, and including gravity-waves. It has derived capability priorities from current and developing Space Missions Directorate (SMD) strategic roadmaps and, where appropriate, has ensured their consistency with other NASA Strategic and Capability Roadmaps. Technology topics include optics; wavefront sensing and control and interferometry; distributed and advanced spacecraft systems; cryogenic and thermal control systems; large precision structure for observatories; and the infrastructure essential to future space telescopes and observatories.

Global Precipitation Measurement (GPM) Core Observatory Falling Snow Estimates

NASA Astrophysics Data System (ADS)

Skofronick Jackson, G.; Kulie, M.; Milani, L.; Munchak, S. J.; Wood, N.; Levizzani, V.

2017-12-01

Retrievals of falling snow from space represent an important data set for understanding and linking the Earth's atmospheric, hydrological, and energy cycles. Estimates of falling snow must be captured to obtain the true global precipitation water cycle, snowfall accumulations are required for hydrological studies, and without knowledge of the frozen particles in clouds one cannot adequately understand the energy and radiation budgets. This work focuses on comparing the first stable falling snow retrieval products (released May 2017) for the Global Precipitation Measurement (GPM) Core Observatory (GPM-CO), which was launched February 2014, and carries both an active dual frequency (Ku- and Ka-band) precipitation radar (DPR) and a passive microwave radiometer (GPM Microwave Imager-GMI). Five separate GPM-CO falling snow retrieval algorithm products are analyzed including those from DPR Matched (Ka+Ku) Scan, DPR Normal Scan (Ku), DPR High Sensitivity Scan (Ka), combined DPR+GMI, and GMI. While satellite-based remote sensing provides global coverage of falling snow events, the science is relatively new, the different on-orbit instruments don't capture all snow rates equally, and retrieval algorithms differ. Thus a detailed comparison among the GPM-CO products elucidates advantages and disadvantages of the retrievals. GPM and CloudSat global snowfall evaluation exercises are natural investigative pathways to explore, but caution must be undertaken when analyzing these datasets for comparative purposes. This work includes outlining the challenges associated with comparing GPM-CO to CloudSat satellite snow estimates due to the different sampling, algorithms, and instrument capabilities. We will highlight some factors and assumptions that can be altered or statistically normalized and applied in an effort to make comparisons between GPM and CloudSat global satellite falling snow products as equitable as possible.

The Malaysian Robotic Solar Observatory (P29)

NASA Astrophysics Data System (ADS)

Othman, M.; Asillam, M. F.; Ismail, M. K. H.

2006-11-01

Robotic observatory with small telescopes can make significant contributions to astronomy observation. They provide an encouraging environment for astronomers to focus on data analysis and research while at the same time reducing time and cost for observation. The observatory will house the primary 50cm robotic telescope in the main dome which will be used for photometry, spectroscopy and astrometry observation activities. The secondary telescope is a robotic multi-apochromatic refractor (maximum diameter: 15 cm) which will be housed in the smaller dome. This telescope set will be used for solar observation mainly in three different wavelengths simultaneously: the Continuum, H-Alpha and Calcium K-line. The observatory is also equipped with an automated weather station, cloud & rain sensor and all-sky camera to monitor the climatic condition, sense the clouds (before raining) as well as to view real time sky view above the observatory. In conjunction with the Langkawi All-Sky Camera, the observatory website will also display images from the Malaysia - Antarctica All-Sky Camera used to monitor the sky at Scott Base Antarctica. Both all-sky images can be displayed simultaneously to show the difference between the equatorial and Antarctica skies. This paper will describe the Malaysian Robotic Observatory including the systems available and method of access by other astronomers. We will also suggest possible collaboration with other observatories in this region.

High Energy Astronomy Observatory (HEAO)

NASA Image and Video Library

1977-08-01

This picture is of an Atlas/Centaur launch vehicle, carrying the High Energy Astronomy Observatory (HEAO)-1, on Launch Complex 36 at the Air Force Eastern Test Range prior to launch on August 12, 1977. The Kennedy Space Center managed the launch operations that included a pre-aunch checkout, launch, and flight, up through the observatory separation in orbit.

Satellite monitoring of remote volcanoes improves study efforts in Alaska

NASA Astrophysics Data System (ADS)

Dean, K.; Servilla, M.; Roach, A.; Foster, B.; Engle, K.

Satellite monitoring of remote volcanoes is greatly benefitting the Alaska Volcano Observatory (AVO), and last year's eruption of the Okmok Volcano in the Aleutian Islands is a good case in point. The facility was able to issue and refine warnings of the eruption and related activity quickly, something that could not have been done using conventional seismic surveillance techniques, since seismometers have not been installed at these locations.AVO monitors about 100 active volcanoes in the North Pacific (NOPAC) region, but only a handful are observed by costly and logistically complex conventional means. The region is remote and vast, about 5000 × 2500 km, extending from Alaska west to the Kamchatka Peninsula in Russia (Figure 1). Warnings are transmitted to local communities and airlines that might be endangered by eruptions. More than 70,000 passenger and cargo flights fly over the region annually, and airborne volcanic ash is a threat to them. Many remote eruptions have been detected shortly after the initial magmatic activity using satellite data, and eruption clouds have been tracked across air traffic routes. Within minutes after eruptions are detected, information is relayed to government agencies, private companies, and the general public using telephone, fax, and e-mail. Monitoring of volcanoes using satellite image data involves direct reception, real-time monitoring, and data analysis. Two satellite data receiving stations, located at the Geophysical Institute, University of Alaska Fairbanks (UAF), are capable of receiving data from the advanced very high resolution radiometer (AVHRR) on National Oceanic and Atmospheric Administration (NOAA) polar orbiting satellites and from synthetic aperture radar (SAR) equipped satellites.

The Plate Boundary Observatory Cascadia Network: Development and Installation of a Large Scale Real-time GPS Network

NASA Astrophysics Data System (ADS)

Austin, K. E.; Blume, F.; Berglund, H. T.; Feaux, K.; Gallaher, W. W.; Hodgkinson, K. M.; Mattioli, G. S.; Mencin, D.

2014-12-01

The EarthScope Plate Boundary Observatory (PBO), through a NSF-ARRA supplement, has enhanced the geophysical infrastructure in in the Pacific Northwest by upgrading a total of 282 Plate Boundary Observatory GPS stations to allow the collection and distribution of high-rate (1 Hz), low-latency (<1 s) data streams (RT-GPS). These upgraded stations supplemented the original 100 RT-GPS stations in the PBO GPS network. The addition of the new RT-GPS sites in Cascadia should spur new volcano and earthquake research opportunities in an area of great scientific interest and high geophysical hazard. Streaming RT-GPS data will enable researchers to detect and investigate strong ground motion during large geophysical events, including a possible plate-interface earthquake, which has implications for earthquake hazard mitigation. A Mw 6.9 earthquake occurred on March 10, 2014, off the coast of northern California. As a response, UNAVCO downloaded high-rate GPS data from Plate Boundary Observatory stations within 500 km of the epicenter of the event, providing a good test of network performance.In addition to the 282 stations upgraded to real-time, 22 new meteorological instruments were added to existing PBO stations. Extensive testing of BGAN satellite communications systems has been conducted to support the Cascadia RT-GPS upgrades and the installation of three BGAN satellite fail over systems along the Cascadia margin will allow for the continuation of data flow in the event of a loss of primary communications during in a large geophysical event or other interruptions in commercial cellular networks. In summary, with these additional upgrades in the Cascadia region, the PBO RT-GPS network will increase to 420 stations. Upgrades to the UNAVCO data infrastructure included evaluation and purchase of the Trimble Pivot Platform, servers, and additional hardware for archiving the high rate data, as well as testing and implementation of GLONASS and Trimble RTX positioning on the

Observatory Bibliographies as Research Tools

NASA Astrophysics Data System (ADS)

Rots, Arnold H.; Winkelman, S. L.

2013-01-01

Traditionally, observatory bibliographies were maintained to provide insight in how successful a observatory is as measured by its prominence in the (refereed) literature. When we set up the bibliographic database for the Chandra X-ray Observatory (http://cxc.harvard.edu/cgi-gen/cda/bibliography) as part of the Chandra Data Archive ((http://cxc.harvard.edu/cda/), very early in the mission, our objective was to make it primarily a useful tool for our user community. To achieve this we are: (1) casting a very wide net in collecting Chandra-related publications; (2) including for each literature reference in the database a wealth of metadata that is useful for the users; and (3) providing specific links between the articles and the datasets in the archive that they use. As a result our users are able to browse the literature and the data archive simultaneously. As an added bonus, the rich metadata content and data links have also allowed us to assemble more meaningful statistics about the scientific efficacy of the observatory. In all this we collaborate closely with the Astrophysics Data System (ADS). Among the plans for future enhancement are the inclusion of press releases and the Chandra image gallery, linking with ADS semantic searching tools, full-text metadata mining, and linking with other observatories' bibliographies. This work is supported by NASA contract NAS8-03060 (CXC) and depends critically on the services provided by the ADS.

Science Enabled by Ocean Observatory Acoustics

NASA Astrophysics Data System (ADS)

Howe, B. M.; Lee, C.; Gobat, J.; Freitag, L.; Miller, J. H.; Committee, I.

2004-12-01

Ocean observatories have the potential to examine the physical, chemical, biological, and geological parameters and processes of the ocean at time and space scales previously unexplored. Acoustics provides an efficient and cost-effective means by which these parameters and processes can be measured and information can be communicated. Integrated acoustics systems providing navigation and communications for mobile platforms and conducting acoustical measurements in support of science objectives are critical and essential elements of the ocean observatories presently in the planning and implementation stages. The ORION Workshop (Puerto Rico, 4-8 January 2004) developed science themes that can be addressed utilizing ocean observatory infrastructure. The use of acoustics to sense the 3-d/volumetric ocean environment on all temporal and spatial scales was discussed in many ORION working groups. Science themes that are related to acoustics and measurements using acoustics are reviewed and tabulated, as are the related and sometimes competing requirements for passive listening, acoustic navigation and acoustic communication around observatories. Sound in the sea, brought from observatories to universities and schools via the internet, will also be a major education and outreach mechanism.

Reconciling CME Kinematics using Radio and White-light Observations from STEREO and SOHO

NASA Astrophysics Data System (ADS)

Gopalswamy, Nat; Yashiro, Seiji; Xie, Hong; Makela, Pertti; Akiyama, Sachiko; Reiner, Michael; MacDowall, Robert

2014-05-01

We study the characteristics of nonthermal radio emission associated with coronal mass ejections (CMEs) observed by STEREO, SOHO, and Wind spacecraft. In particular, we examine three backside CMEs associated with type II radio bursts at frequencies below 16 MHz. These bursts are known to be excellent indicators of solar energetic particle events. We use the universal drift rate spectrum of type II radio bursts and the inferred density scale heights in the corona and interplanetary medium o estimate the speed of the shock waves that produce the type II radio bursts. We find that the radio bursts can provide an accurate estimate of the CME speeds. We consider three backside events and a cannibalism event to show the usefulness of radio dynamic spectrum in inferring CME kinematics. We use radio direction finding technique to show that CME-CME interaction results in enhanced nonthermal radio emission. The radio data also provide constraints on the particle acceleration mechanisms and the reason for the energetic particles observed at wide-ranging longitudes. Finally we infer the shape and extent of the shock associated with one of the biggest solar energetic particle events in the space era.

Byurakan Astrophysical Observatory as Cultural Centre

NASA Astrophysics Data System (ADS)

Mickaelian, A. M.; Farmanyan, S. V.

2016-12-01

NAS RA V. Ambartsumian Byurakan Astrophysical Observatory is presented as a cultural centre for Armenia and the Armenian nation in general. Besides being scientific and educational centre, the Observatory is famous for its unique architectural ensemble, rich botanical garden and world of birds, as well as it is one of the most frequently visited sightseeing of Armenia. In recent years, the Observatory has also taken the initiative of the coordination of the Cultural Astronomy in Armenia and in this field, unites the astronomers, historians, archaeologists, ethnographers, culturologists, literary critics, linguists, art historians and other experts.

The SPLASH Survey: Spectroscopy of 15 M31 Dwarf Spheroidal Satellite Galaxies

NASA Astrophysics Data System (ADS)

Tollerud, Erik J.; Beaton, Rachael L.; Geha, Marla C.; Bullock, James S.; Guhathakurta, Puragra; Kalirai, Jason S.; Majewski, Steve R.; Kirby, Evan N.; Gilbert, Karoline M.; Yniguez, Basilio; Patterson, Richard J.; Ostheimer, James C.; Cooke, Jeff; Dorman, Claire E.; Choudhury, Abrar; Cooper, Michael C.

2012-06-01

We present a resolved star spectroscopic survey of 15 dwarf spheroidal (dSph) satellites of the Andromeda galaxy (M31). We filter foreground contamination from Milky Way (MW) stars, noting that MW substructure is evident in this contaminant sample. We also filter M31 halo field giant stars and identify the remainder as probable dSph members. We then use these members to determine the kinematical properties of the dSphs. For the first time, we confirm that And XVIII, XXI, and XXII show kinematics consistent with bound, dark-matter-dominated galaxies. From the velocity dispersions for the full sample of dSphs we determine masses, which we combine with the size and luminosity of the galaxies to produce mass-size-luminosity scaling relations. With these scalings we determine that the M31 dSphs are fully consistent with the MW dSphs, suggesting that the well-studied MW satellite population provides a fair sample for broader conclusions. We also estimate dark matter halo masses of the satellites and find that there is no sign that the luminosity of these galaxies depends on their dark halo mass, a result consistent with what is seen for MW dwarfs. Two of the M31 dSphs (And XV, XVI) have estimated maximum circular velocities smaller than 12 km s-1 (to 1σ), which likely places them within the lowest-mass dark matter halos known to host stars (along with Boötes I of the MW). Finally, we use the systemic velocities of the M31 satellites to estimate the mass of the M31 halo, obtaining a virial mass consistent with previous results. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Main field and secular variation modeling with Defense Meteorological Satellite Program magnetic measurements

NASA Astrophysics Data System (ADS)

Alken, P.; Olsen, N.; Finlay, C. C.; Chulliat, A.

2017-12-01

In order to investigate the spatial structure and development of rapid (sub-decadal) changes in the geomagnetic core field, including its secular variation and acceleration, global magnetic measurements from space play a crucial role. With the end of the CHAMP mission in September 2010, there has been a gap in high-quality satellite magnetic field measurements until the Swarm mission was launched in November 2013. Geomagnetic main field models during this period have relied on the global ground observatory network which, due to its sparse spatial configuration, has difficulty in resolving secular variation and acceleration at higher spherical harmonic degrees. In this presentation we will show new results in building main field models during this "gap period", based on vector magnetic measurements from four Defense Meteorological Satellite Program (DMSP) satellites. While the fluxgate instruments onboard DMSP were not designed for high-quality core field modeling, we find that the DMSP dataset can provide valuable information on secular variation and acceleration during the gap period.

The Solar Dynamics Observatory

NASA Technical Reports Server (NTRS)

Pesnell, William D.

2008-01-01

The Solar Dynamics Observatory (SDO) is the first Space Weather Mission in NASA's Living With a Star Program. SDO's main goal is to understand, driving towards a predictive capability, those solar variations that influence life on Earth and humanity's technological systems. The past decade has seen an increasing emphasis on understanding the entire Sun, from the nuclear reactions at the core to the development and loss of magnetic loops in the corona. SDO's three science investigations (HMI, AIA, and EVE) will determine how the Sun's magnetic field is generated and structured, how this stored magnetic energy is released into the heliosphere and geospace as the solar wind, energetic particles, and variations in the solar irradiance. SDO will return full-disk Dopplergrams, full-disk vector magnetograms, full-disk images at nine EIUV wavelengths, and EUV spectral irradiances, all taken at a rapid cadence. This means you can 'observe the database' to study events, but we can also move forward in producing quantitative models of what the Sun is doing today. SDO is scheduled to launch in 2008 on an Atlas V rocket from the Kennedy Space Center, Cape Canaveral, Florida. The satellite will fly in a 28 degree inclined geosynchronous orbit about the longitude of New Mexico, where a dedicated Ka-band ground station will receive the 150 Mbps data flow. How SDO data will transform the study of the Sun and its affect on Space Weather studies will be discussed.

Monitoring volcanic threats using ASTER satellite data

USGS Publications Warehouse

Duda, K.A.; Wessels, R.; Ramsey, M.; Dehn, J.

2008-01-01

This document summarizes ongoing activities associated with a research project funded by the National Aeronautics and Space Administration (NASA) focusing on volcanic change detection through the use of satellite imagery. This work includes systems development as well as improvements in data analysis methods. Participating organizations include the NASA Land Processes Distributed Active Archive Center (LP DAAC) at the U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS), the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Science Team, the Alaska Volcano Observatory (AVO) at the USGS Alaska Science Center, the Jet Propulsion Laboratory/California Institute of Technology (JPL/CalTech), the University of Pittsburgh, and the University of Alaska Fairbanks. ?? 2007 IEEE.

Biggest Solar Flare on Record

NASA Technical Reports Server (NTRS)

2002-01-01

View an animation from the Extreme ultraviolet Imaging Telescope (EIT). At 4:51 p.m. EDT, on Monday, April 2, 2001, the sun unleashed the biggest solar flare ever recorded, as observed by the Solar and Heliospheric Observatory (SOHO) satellite. The flare was definitely more powerful than the famous solar flare on March 6, 1989, which was related to the disruption of power grids in Canada. This recent explosion from the active region near the sun's northwest limb hurled a coronal mass ejection into space at a whopping speed of roughly 7.2 million kilometers per hour. Luckily, the flare was not aimed directly towards Earth. Solar flares, among the solar system's mightiest eruptions, are tremendous explosions in the atmosphere of the Sun capable of releasing as much energy as a billion megatons of TNT. Caused by the sudden release of magnetic energy, in just a few seconds flares can accelerate solar particles to very high velocities, almost to the speed of light, and heat solar material to tens of millions of degrees. Solar ejections are often associated with flares and sometimes occur shortly after the flare explosion. Coronal mass ejections are clouds of electrified, magnetic gas weighing billions of tons ejected from the Sun and hurled into space with speeds ranging from 12 to 1,250 miles per second. Depending on the orientation of the magnetic fields carried by the ejection cloud, Earth-directed coronal mass ejections cause magnetic storms by interacting with the Earth's magnetic field, distorting its shape, and accelerating electrically charged particles (electrons and atomic nuclei) trapped within. Severe solar weather is often heralded by dramatic auroral displays, northern and southern lights, and magnetic storms that occasionally affect satellites, radio communications and power systems. The flare and solar ejection has also generated a storm of high-velocity particles, and the number of particles with ten million electron-volts of energy in the space near

The Little Thompson Observatory's Astronomy Education Programs

NASA Astrophysics Data System (ADS)

Schweitzer, Andrea E.

2007-12-01

The Little Thompson Observatory is a community-built E/PO observatory and is a member of the Telescopes in Education (TIE) project. The observatory is located on the grounds of Berthoud High School in northern Colorado. Annually we have approximately 5,000 visitors, which is roughly equal to the population of the small town of Berthoud, CO. This past year, we have used the funding from our NASA ROSS E/PO grant to expand our teacher workshop programs, and included the baseball-sized meteorite that landed in Berthoud three years ago. Our teacher programs have involved scientists from the Southwest Research Institute and from Fiske Planetarium at CU-Boulder. We thank the NASA ROSS E/PO program for providing this funding! We also held a Colorado Project ASTRO-GEO workshop, and the observatory continues to make high-school astronomy courses available to students from the surrounding school districts. Statewide, this year we helped support the development and construction of three new educational observatories in Colorado, located in Estes Park, Keystone, and Gunnison. The LTO is grateful to have received the recently-retired 24-inch telescope from Mount Wilson Observatory as part of the TIE program. To provide a new home for this historic telescope, we have doubled the size of the observatory and are building a second dome (all with volunteer labor). During 2008 we plan to build a custom pier and refurbish the telescope.

Construction/Application of the Internet Observatories in Japan

NASA Astrophysics Data System (ADS)

Satoh, T.; Tsubota, Y.; Matsumoto, N.; Takahashi, N.

2000-05-01

We have successfully built two Internet Observatories in Japan: one at Noda campus of the Science University of Tokyo and another at Hiyoshi campus of the Keio Senior High School. Both observatories are equipped with a computerized Meade LX-200 telescope (8" tube at the SUT site and 12" at the Keio site) with a CCD video camera inside the sliding-roof type observatory. Each observatory is controlled by two personal computer: one controls almost everything, including the roof, the telescope, and the camera, while another is dedicated to encode the real-time picture from the CCD video camera into the RealVideo format for live broadcasting. A user can operate the observatory through the web-based interface and can enjoy the real-time picture of the objects via the RealPlayer software. The administrator can run a sequence of batch commands with which no human interaction is needed from the beginning to the end of an observation. Although our observatories are primarily for educational purposes, this system can easily be converted to a signal-triggered one which may be very useful to observe transient phenomena, such as afterglows of gamma-ray bursts. The most remarkable feature of our observatories is that it is very inexpensive (it costs only a few tens of grands). We'll report details of the observatories in the poster, and at the same time, will demonstrate operating the observatories using an internet-connected PC from the meeting site. This work has been supported through the funding from the Telecommunicaitons Advancement Foundation for FY 1998 and 1999.

The MicroObservatory Net

NASA Astrophysics Data System (ADS)

Brecher, K.; Sadler, P.

1994-12-01

A group of scientists, engineers and educators based at the Harvard-Smithsonian Center for Astrophysics (CfA) has developed a prototype of a small, inexpensive and fully integrated automated astronomical telescope and image processing system. The project team is now building five second generation instruments. The MicroObservatory has been designed to be used for classroom instruction by teachers as well as for original scientific research projects by students. Probably in no other area of frontier science is it possible for a broad spectrum of students (not just the gifted) to have access to state-of-the-art technologies that would allow for original research. The MicroObservatory combines the imaging power of a cooled CCD, with a self contained and weatherized reflecting optical telescope and mount. A microcomputer points the telescope and processes the captured images. The MicroObservatory has also been designed to be used as a valuable new capture and display device for real time astronomical imaging in planetariums and science museums. When the new instruments are completed in the next few months, they will be tried with high school students and teachers, as well as with museum groups. We are now planning to make the MicroObservatories available to students, teachers and other individual users over the Internet. We plan to allow the telescope to be controlled in real time or in batch mode, from a Macintosh or PC compatible computer. In the real-time mode, we hope to give individual access to all of the telescope control functions without the need for an "on-site" operator. Users would sign up for a specific period of time. In the batch mode, users would submit jobs for the telescope. After the MicroObservatory completed a specific job, the images would be e-mailed back to the user. At present, we are interested in gaining answers to the following questions: (1) What are the best approaches to scheduling real-time observations? (2) What criteria should be used

The Coronal Solar Magnetism Observatory

NASA Astrophysics Data System (ADS)

Tomczyk, S.; Landi, E.; Zhang, J.; Lin, H.; DeLuca, E. E.

2015-12-01

Measurements of coronal and chromospheric magnetic fields are arguably the most important observables required for advances in our understanding of the processes responsible for coronal heating, coronal dynamics and the generation of space weather that affects communications, GPS systems, space flight, and power transmission. The Coronal Solar Magnetism Observatory (COSMO) is a proposed ground-based suite of instruments designed for routine study of coronal and chromospheric magnetic fields and their environment, and to understand the formation of coronal mass ejections (CME) and their relation to other forms of solar activity. This new facility will be operated by the High Altitude Observatory of the National Center for Atmospheric Research (HAO/NCAR) with partners at the University of Michigan, the University of Hawaii and George Mason University in support of the solar and heliospheric community. It will replace the current NCAR Mauna Loa Solar Observatory (http://mlso.hao.ucar.edu). COSMO will enhance the value of existing and new observatories on the ground and in space by providing unique and crucial observations of the global coronal and chromospheric magnetic field and its evolution. The design and current status of the COSMO will be reviewed.

The Astrophysical Multimessenger Observatory Network (AMON)

NASA Technical Reports Server (NTRS)

Smith. M. W. E.; Fox, D. B.; Cowen, D. F.; Meszaros, P.; Tesic, G.; Fixelle, J.; Bartos, I.; Sommers, P.; Ashtekar, Abhay; Babu, G. Jogesh;

The Phase Curve Survey of the Irregular Saturnian Satellites: A Possible Method of Physical Classification

NASA Technical Reports Server (NTRS)

Bauer, James M.; Grav, Tommy; Buratti, Bonnie J.; Hicks, Michael D.

2006-01-01

During its 2005 January opposition, the saturnian system could be viewed at an unusually low phase angle. We surveyed a subset of Saturn's irregular satellites to obtain their true opposition magnitudes, or nearly so, down to phase angle values of 0.01 deg. Combining our data taken at the Palomar 200-inch and Cerro Tololo Inter-American Observatory's 4-m Blanco telescope with those in the literature, we present the first phase curves for nearly half the irregular satellites originally reported by Gladman et al. [2001. Nature 412, 163-166], including Paaliaq (SXX), Siarnaq (SXXIX), Tarvos (SXXI), Ijiraq (SXXII), Albiorix (SXVI), and additionally Phoebe's narrowest angle brightness measured to date. We find centaur-like steepness in the phase curves or opposition surges in most cases with the notable exception of three, Albiorix and Tarvos, which are suspected to be of similar origin based on dynamical arguments, and Siarnaq.During its 2005 January opposition, the saturnian system could be viewed at an unusually low phase angle. We surveyed a subset of Saturn's irregular satellites to obtain their true opposition magnitudes, or nearly so, down to phase angle values of 0.01 deg. Combining our data taken at the Palomar 200-inch and Cerro Tololo Inter-American Observatory's 4-m Blanco telescope with those in the literature, we present the first phase curves for nearly half the irregular satellites originally reported by Gladman et al. [2001. Nature 412, 163-166], including Paaliaq (SXX), Siarnaq (SXXIX), Tarvos (SXXI), Ijiraq (SXXII), Albiorix (SXVI), and additionally Phoebe's narrowest angle brightness measured to date. We find centaur-like steepness in the phase curves or opposition surges in most cases with the notable exception of three, Albiorix and Tarvos, which are suspected to be of similar origin based on dynamical arguments, and Siarnaq.

Early German Plans for a Southern Observatory

NASA Astrophysics Data System (ADS)

Wolfschmidt, Gudrun

As early as the 18th and 19th centuries, French and English observers were active in South Africa. Around the beginning of the 20th century the Heidelberg astronomer Max Wolf (1863-1932) proposed a southern observatory. In 1907 Hermann Carl Vogel (1841-1907), director of the Astrophysical Observatory Potsdam, suggested a southern station in Spain. His ideas for building an observatory in Windhuk for photographing the sky and measuring the solar constant were taken over by the Göttingen astronomers. In 1910 Karl Schwarzschild (1873-1916), after having visited the observatories in America, pointed out the usefulness of an observatory in South West Africa, where it would have better weather than in Germany and also give access to the southern sky. Seeing tests were begun in 1910 by Potsdam astronomers, but WW I stopped the plans. In 1928 Erwin Finlay-Freundlich (1885-1964), inspired by the Hamburg astronomer Walter Baade (1893-1960), worked out a detailed plan for a southern observatory with a reflecting telescope, spectrographs and an astrograph with an objective prism. Paul Guthnick (1879-1947), director of the Berlin observatory, in cooperation with APO Potsdam and Hamburg, made a site survey to Africa in 1929 and found the conditions in Windhuk to be ideal. Observations were started in the 1930s by Berlin and Breslau astronomers, but were stopped by WW II. In the 1950s, astronomers from Hamburg and The Netherlands renewed the discussion in the framework of European cooperation, and this led to the founding of ESO in 1963, as is well described by Blaauw (1991). Blaauw, Adriaan: ESO's Early History. The European Southern Observatory from Concept to Reality. Garching bei München: ESO 1991.

The Virtual Solar Observatory and the Heliophysics Meta-Virtual Observatory

NASA Astrophysics Data System (ADS)

Gurman, J. B.; Hourclé, J. A.; Bogart, R. S.; Tian, K.; Hill, F.; Suàrez-Sola, I.; Zarro, D. M.; Davey, A. R.; Martens, P. C.; Yoshimura, K.; Reardon, K. M.

2006-12-01

The Virtual Solar Observatory (VSO) has survived its infancy and provides metadata search and data identification for measurements from 45 instrument data sets held at 12 online archives, as well as flare and coronal mass ejection (CME) event lists. Like any toddler, the VSO is good at getting into anything and everything, and is now extending its grasp to more data sets, new missions, and new access methods using its application programming interface (API). We discuss and demonstrate recent changes, including developments for STEREO and SDO, and an IDL-callable interface for the VSO API. We urge the heliophysics community to help civilize this obstreperous youngster by providing input on ways to make the VSO even more useful for system science research in its role as part of the growing cluster of Heliophysics Virtual Observatories.

Terrestrial Planet Finder Coronagraph Observatory summary

NASA Technical Reports Server (NTRS)

Ford, Virginia; Levine-Westa, Marie; Kissila, Andy; Kwacka, Eug; Hoa, Tim; Dumonta, Phil; Lismana, Doug; Fehera, Peter; Cafferty, Terry

2005-01-01

Creating an optical space telescope observatory capable of detecting and characterizing light from extra-solar terrestrial planets poses technical challenges related to extreme wavefront stability. The Terrestrial Planet Finder Coronagraph design team has been developing an observatory based on trade studies, modeling and analysis that has guided us towards design choices to enable this challenging mission. This paper will describe the current flight baseline design of the observatory and the trade studies that have been performed. The modeling and analysis of this design will be described including predicted performance and the tasks yet to be done.

Project on Chinese Virtual Solar Observatory

NASA Astrophysics Data System (ADS)

Lin, Gang-Hua

2004-09-01

With going deep into research of solar physics, development of observational instrument and accumulation of obervation data, it urges people to think such things: using data which is observed in different times, places, bands and history data to seek answers of a plenty science problems. In the meanwhile, researcher can easily search the data and analyze data. This is why the project of the virtual solar observatory gained active replies and operation from observatories, institutes and universities in the world. In this article, how we face to the development of the virtual solar observatory and our preliminary project on CVSO are discussed.

Telescopes in Education: the Little Thompson Observatory

NASA Astrophysics Data System (ADS)

Schweitzer, A. E.; Melsheimer, T. T.; Sackett, C.

2001-12-01

The Little Thompson Observatory is believed to be the first observatory built as part of a high school and accessible to other schools remotely, via the Internet. This observatory is the second member of the Telescopes in Education (TIE) project. Construction of the building was done completely by volunteer labor, and first light occurred in May 1999. The observatory is located on the grounds of Berthoud High School in northern Colorado. We are grateful to have received an IDEAS grant to provide teacher training workshops for K-12 schools in Colorado to make use of the observatory, including remote observing from classrooms. Students connect to the observatory over the Internet, and then receive the images back on their local computers. We are honored that a committee of teachers and administrators from the Thompson School district have selected these workshops to count towards Incentive Credits (movement on the salary schedule) because the course meets the criteria: "Learning must be directly transferable to the classroom with students and relate to standards, assessment and/or technology." Also in the past year, our training materials have been shared with NASA Goddard and Howard University, which are working together to develop a similar teacher education program.

Assessing Surface BRDF-related Biases Using Target Mode Retrievals from the Orbiting Carbon Observatory-2 (OCO-2)

NASA Astrophysics Data System (ADS)

Natraj, V.; McDuffie, J. L.; O'Dell, C.; Eldering, A.; Fu, D.; Wunch, D.; Wennberg, P. O.

2015-12-01

The Orbiting Carbon Observatory-2 (OCO-2) is NASA's first dedicated Earth remote sensing satellite to study atmospheric carbon dioxide from space, and was launched successfully on July 2, 2014. In the target mode of observation, the Observatory will lock its view onto a specific surface location, and will scan back and forth over that target while flying overhead. A target track pass can last for up to 9 minutes. Over that time period, the Observatory can acquire as many as 12,960 samples at local zenith angles that vary between 0° and 85°. Here, we analyze target track measurements over several of the OCO-2 validation sites where ground-based solar-looking Fourier Transform Spectrometers are located. Preliminary analysis of target mode retrievals using the operational algorithm show biases that appear to be due to not accounting for bidirectional surface reflection (BRDF) effects, i.e., the non-isotropic nature of surface reflection. To address this issue, we implement a realistic BRDF model. The column averaged CO2 dry air mole fraction (XCO2) results using this new model show much less variation with scattering angle (or airmass). Further, the retrieved aerosol optical depth (AOD) is in much better agreement with coincident AERONET values. We also use information content analysis to evaluate the degrees of freedom with respect to BRDF parameters, and investigate cross-correlations between the parameters.

A Survey of Geosynchronous Satellite Glints

NASA Astrophysics Data System (ADS)

Vrba, F.; Hutter, D.; Shankland, P.; Armstrong, J.; Schmitt, H.; Hindsley, R.; Divittorio, M.; Benson, J.

Artificial satellites have characteristic diffuse reflected-light signatures as they are illuminated at varying phase angles by the Sun and are viewed at differing orientations by an observer. At times of favorable alignment between the satellite, observer and Sun, specular reflection off of relatively flat surfaces, such as solar panels, can cause brief increases in reflected light of several hundred times that of the nominal diffuse signature. Such events are commonly referred to as "glints". In the case of geosynchronous satellites, favorable glint alignments are due to changes in the Sun-Vehicle-Observer angle which are primarily due to the apparent motion of the Sun as the observer-satellite vector remains nearly stationary. These occur near in time to the vernal and autumnal equinoxes. While the most favorable geosynchronous satellite glint alignments are precluded by the fact that the satellites are at that time most likely to be in Earth shadow, observations of several glints have been reported in the literature. While such studies note the peak brightnesses, durations, and phase angles of individual glints, to our knowledge, no extended study of geosynchronous glint characteristics exists. Beginning with the autumnal equinox glint season of 2007 we have built on our earlier studies using the U.S. Naval Observatory, Flagstaff Station 40-inch Ritchey telescope to provide near-real-time astrometric and photometric information for use by the Navy Prototype Optical Interferometer (NPOI) team in its efforts to obtain interferometric fringes of geosynchronous satellites during a glint episode. The combined observations culminated in successful fringe measurements of DirecTV-9S during the vernal equinox 2008 and 2009 seasons (see Armstrong, et al. 2009, this conference). For our 40-inch telescope observations we used an LN2-cooled 2048x2048 CCD with standard R-band and H-alpha photometric filters, covering an area of the sky of approximately 22x22 arcmin with each

The Cincinnati Observatory as a Research Instrument for Undergraduate Research

NASA Astrophysics Data System (ADS)

Abel, Nicholas; Regas, Dean; Flateau, Davin C.; Larrabee, Cliff

2016-06-01

The Cincinnati Observatory, founded in 1842, was the first public observatory in the Western Hemisphere. The history of Cincinnati is closely intertwined with the history of the Observatory, and with the history of science in the United States. Previous directors of the Observatory helped to create the National Weather Service, the Minor Planet Center, and the first astronomical journal in the U.S. The Cincinnati Observatory was internationally known in the late 19th century, with Jules Verne mentioning the Cincinnati Observatory in two of his books, and the Observatory now stands as a National Historic Landmark.No longer a research instrument, the Observatory is now a tool for promoting astronomy education to the general public. However, with the 11" and 16" refracting telescopes, the Observatory telescopes are very capable of collecting data to fuel undergraduate research projects. In this poster, we will discuss the history of the Observatory, types of student research projects capable with the Cincinnati Observatory, future plans, and preliminary results. The overall goal of this project is to produce a steady supply of undergraduate students collecting, analyzing, and interpreting data, and thereby introduce them to the techniques and methodology of an astronomer at an early stage of their academic career.

ADDOSS: Autonomously Deployed Deep-ocean Seismic System - Communications Gateway for Ocean Observatories

NASA Astrophysics Data System (ADS)

Laske, Gabi; Berger, Jon; Orcutt, John; Babcock, Jeff

2014-05-01

We describe an autonomously deployable, communications gateway designed to provide long-term and near real-time data from ocean observatories. The key features of this new system are its abilities to telemeter sensor data from the seafloor to shore without cables or moorings, and to be deployed without a ship, thereby greatly reducing life-cycle costs. The free-floating surface communications gateway utilizes a Liquid Robotics wave glider comprising a surfboard-sized float towed by a tethered, submerged glider, which converts wave motion into thrust. For navigation, the wave glider is equipped with a small computer, a GPS receiver, a rudder, solar panels and batteries, and an Iridium satellite modem. Acoustic communications connect the subsea instruments and the surface gateway while communications between the gateway and land are provided by the Iridium satellite constellation. Wave gliders have demonstrated trans-oceanic range and long-term station keeping capabilities. The acoustics communications package is mounted in a shallow tow body which utilizes a WHOI micro modem and a Benthos low frequency, directional transducer. A matching modem and transducer is mounted on the ocean bottom package. Tests of the surface gateway in 4350 m of water demonstrated an acoustic efficiency of approximately 396 bits/J. For example, it has the ability to send 4 channels of compressed, 1 sample per second data from the ocean bottom to the gateway with an average power draw of approximately 0.15 W and a latency of less than 3 minutes. This gateway is used to send near real-time data from a broadband ocean bottom seismic observatory, first during short week-to-months long test deployments but will ultimately be designed for a two-year operational life. Such data from presently unobserved oceanic areas are critical for both national and international agencies in monitoring and characterizing earthquakes, tsunamis, and nuclear explosions. We present initial results from a two short

The Little Thompson Observatory's Astronomy Education Programs

NASA Astrophysics Data System (ADS)

Schweitzer, Andrea E.

2008-05-01

The Little Thompson Observatory is a community-built E/PO observatory and is a member of the Telescopes in Education (TIE) project. The observatory is located on the grounds of Berthoud High School in northern Colorado. Annually we have approximately 5,000 visitors, which is roughly equal to the population of the small town of Berthoud, CO. In spring 2008, we offered a special training session to boost participation in the GLOBE at Night international observing program. During 2005-2007 we used the funding from our NASA ROSS E/PO grant to expand our teacher workshop programs, and included the baseball-sized meteorite that landed in Berthoud four years ago. Our teacher programs are ongoing, and include scientists from the Southwest Research Institute and from Fiske Planetarium at CU-Boulder. We thank the NASA ROSS E/PO program for providing this funding! Statewide, we are a founding member of Colorado Project ASTRO-GEO, and the observatory offers high-school astronomy courses to students from the surrounding school districts. We continue to support the development and construction of three new educational observatories in Colorado, located in Estes Park, Keystone and Gunnison. The LTO is grateful to have received the retired 24-inch telescope from Mount Wilson Observatory as part of the TIE program. To provide a new home for this historic telescope, we have doubled the size of the observatory and are building a second dome (almost all construction done with volunteer labor). During 2008 we will be building a custom pier and refurbishing the telescope.

Climatology at the Roque de LOS Muchachos Observatory

NASA Astrophysics Data System (ADS)

Varela, Antonia M.; Muñoz-Tuñón, Casiana

2009-09-01

The Roque de los Muchachos Observatory (ORM) at La Palma (Canary Islands) is one of the two top pre-selected sites for hosting the future European Extremely Large Telescope (E-ELT), the other ones are Ventarrones (Chile), Macon (Argentine) and Aklim (Maroc). Meteorological and seeing conditions are crucial both for the site selection and for telescope design and feasibility studies for adaptive optics. The ELTs shall be very sensitive to wind behavior when operating in open air, therefore ground level wind velocity and wind gust are also required for the feasibility of the telescope construction. Here we analyze the wind speed and wind direction, the air temperature, the relative humidity and the barometric pressure statistical results obtained from data recorded at different sites at the ORM by several Automatic Weather Stations (AWS) since 1985, day and night time separately. Ground wind speed regimes (775mbar) are compared with those provided by satellites from 200 to 700mbar. There exists also observational evidence of the correlation between the seeing and the wind speed and wind direction that will be discussed in this work.

Alaska Volcano Observatory

USGS Publications Warehouse

Venezky, Dina Y.; Murray, Tom; Read, Cyrus

2008-01-01

Steam plume from the 2006 eruption of Augustine volcano in Cook Inlet, Alaska. Explosive ash-producing eruptions from Alaska's 40+ historically active volcanoes pose hazards to aviation, including commercial aircraft flying the busy North Pacific routes between North America and Asia. The Alaska Volcano Observatory (AVO) monitors these volcanoes to provide forecasts of eruptive activity. AVO is a joint program of the U.S. Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). AVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Augustine volcano and AVO at http://www.avo.alaska.edu.

Automated observatory in Antarctica: real-time data transfer on constrained networks in practice

NASA Astrophysics Data System (ADS)

Bracke, Stephan; Gonsette, Alexandre; Rasson, Jean; Poncelet, Antoine; Hendrickx, Olivier

2017-08-01

In 2013 a project was started by the geophysical centre in Dourbes to install a fully automated magnetic observatory in Antarctica. This isolated place comes with specific requirements: unmanned station during 6 months, low temperatures with extreme values down to -50 °C, minimum power consumption and satellite bandwidth limited to 56 Kbit s-1. The ultimate aim is to transfer real-time magnetic data every second: vector data from a LEMI-25 vector magnetometer, absolute F measurements from a GEM Systems scalar proton magnetometer and absolute magnetic inclination-declination (DI) measurements (five times a day) with an automated DI-fluxgate magnetometer. Traditional file transfer protocols (for instance File Transfer Protocol (FTP), email, rsync) show severe limitations when it comes to real-time capability. After evaluation of pro and cons of the available real-time Internet of things (IoT) protocols and seismic software solutions, we chose to use Message Queuing Telemetry Transport (MQTT) and receive the 1 s data with a negligible latency cost and no loss of data. Each individual instrument sends the magnetic data immediately after capturing, and the data arrive approximately 300 ms after being sent, which corresponds with the normal satellite latency.

Flight Results of the Chandra X-ray Observatory Inertial Upper Stage Space Mission

NASA Technical Reports Server (NTRS)

Tillotson, R.; Walter, R.

2000-01-01

Under contract to NASA, a specially configured version of the Boeing developed Inertial Upper Stage (IUS) booster was provided by Boeing to deliver NASA's 1.5 billion dollar Chandra X-Ray Observatory satellite into a highly elliptical transfer orbit from a Shuttle provided circular park orbit. Subsequently, the final orbit of the Chandra satellite was to be achieved using the Chandra Integral Propulsion System (IPS) through a series of IPS burns. On 23 July 1999 the Shuttle Columbia (STS-93) was launched with the IUS/Chandra stack in the Shuttle payload bay. Unfortunately, the Shuttle Orbiter was unexpectantly inserted into an off-nominal park orbit due to a Shuttle propulsion anomaly occurring during ascent. Following the IUS/Chandra on-orbit deployment from the Shuttle, at seven hours from liftoff, the flight proven IUS GN&C system successfully injected Chandra into the targeted transfer orbit, in spite of the off-nominal park orbit. This paper describes the IUS GN&C system, discusses the specific IUS GN&C mission data load development, analyses and testing for the Chandra mission, and concludes with a summary of flight results for the IUS part of the Chandra mission.