... If I need to observe a field containing bright stars, do I risk damage to the NICMOS detector by saturating it? ... NICMOS . ... Detectors . ... Observing Strategies . ... A.: The NICMOS Instrument Science Reports Number 24 and Number 23 present results of the analysis of persistence from On-Orbit data and Thermal Vacuum data. ...

... The great variety of star colors in this open cluster underlie its name: The Jewel Box. One of the bright central stars is a red supergiant, in contrast to the many blue stars that surround it. The cluster, also known as Kappa Crucis contains just over 100 stars, and is about 10 million years old. ... APOD is Six Years Old Today . ... The most compact cluster of stars known in our galaxy, the Arches cluster, boasts 100 or so massive, young stars contained within a diameter of one light-year. ...

You Can Make Stellar Images Brighter . Articles | ... A few months ago I wrote an article titled "You Can’t Make Them Brighter". So why am I now writing that you can make them brighter. ... The image of a focused star is actually a small disk called the Airy disk, named after the 19 th century scientist Sir George Airy. ... For a given aperture, a smaller Airy disk means that the light is focused to a smaller disk and is therefore brighter. ... www.astronomy.net . About Astronomy Net | ...

... 2006 July 7 . Bright Galaxy M81 . ... Explanation: Big and beautiful spiral galaxy M81 lies in the northern constellation Ursa Major . One of the brightest galaxies in planet Earth's sky, M81 is also home to the second brightest supernova seen in modern times. This superbly detailed view reveals M81's bright yellow nucleus, blue spiral arms, and sweeping cosmic dust lanes with a scale comparable to the Milky Way . ... About APOD | ... NASA Web Site Statements, Warnings, and Disclaimers . ...

In this gallery are many images of Low Surface Brightness Galaxies which have recently been discovered and analyzed. ... The central surface brightness of this galaxy is 24.28 . Malin 2 This galaxy is another huge disk galaxy with a scale length of 15 kpc and a redshift of 15000 km/a. The high surface brightness knot in one of its spiral arms actually has the same color, luminosity and H-alpha equivalent width as the entire Large Magellanic Cloud . ... Truly it is a Low Surface Brightness Galaxy. ...

... Stars . ... Straight away the three stars in his belt will grab your attention, followed by the glittering white star Rigel in his left foot and the bright orangish star Betelgeuse in his right shoulder (assuming Orion is standing facing us and not with his back to us). ... Orion Belt?s with the stars Alnitak, Alnilam and Mintaka. ... In short, Orion was a big, loud giant of a man and indeed a mighty hunter, he also inherited some aquatic superpowers from his father who was the sea god Neptune. ...

The CHIANTI database consists of 4 primary ASCII files for each ion in the database. contains the energy levels in cm^(-1) It includes both experimental data and theoretical values of the levels energies. References: %Theoretical energy levels: Zhang, Sampson, ADNDT, 1992 , 52, 143 %Experimental energy levels: Edlen, B., Phys. Scr., 1983, 28, 51. %produced as part of the Arcetri/Cambridge/NRL 'CHIANTI' atomic data base collaboration % % Enrico Landi 1997 . ...

XMM-Newton observation of the core of the massive cluster Cyg OB2 located in the constellation Cygnus, 4,700 light-years from Earth. The cluster contains massive O-type stars that shine brightly in X-rays. Cyg OB2 #9 is seen as the bright star just below the central star, and in 2008 was determined to be a binary system. ... Hundreds of lower mass stars also fill the field of view, which spans nearly 22 x 16 arcminutes. ...

Next: Feed Polarisation Up: Calibration Previous: Calibration Index . RPFITS files do not contain any information as to whether the telescope calibration was in units of Kelvin or Janskys. On reading the data a default value is set depending on the telescope and frequency of observation. ... ASAP>scans = scantable('2004-11-23_1841-P484.rpf', unit='Jy') # Or in two steps ASAP>scans = scantable('2004-11-23_1841-P484.rpf') ASAP>scans.set_fluxunit('Jy') . ...

... We present the ROSAT All-Sky Survey Bright Source Catalogue (RASS-BSC, revision 1RXS) derived from the all-sky survey performed during the first half year of the ROSAT mission in 1990/91. 18,811 sources are catalogued, with a limiting ROSAT PSPC countrate of 0.05 cts/s in the 0.1-2.4 keV energy band. ... Broad band images are available for a subset of the flagged sources. ... Retrieving the full catalogue The ROSAT All-Sky Survey Bright Source Catalogue can be retrieved via your WWW browser: 1. ...

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... To make it easier to "read" this celestial calendar, they grouped the brighter stars into readily recognizable shapes, the constellations. ... From Star Maps , [AS 289] a constellation slide set, available from the ASP . Our modern constellation system comes to us from the ancient Greeks. ... The ancient Greek tradition was to name stars by their position within a constellation. ... And it explains why we have a system of Greek constellations with Latin names containing stars with Arabic names. ...