... Infrared observations of RCBs show that, even at maximum light, there are copious amounts of dust surrounding the star ([ Kilkenny & Whittet 1984 ], [ Walker 1985 ]). A very interesting result is that during a decline, when the V-band brightness is plummeting, the infrared L-band brightness shows no significant change and continues to show pulsational variations [ Feast et al. ... Therefore the obscuring dust can only cover a fraction of the stellar surface. ...

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. ...

... Near Infrared Camera and Multi-Object Spectrometer Instrument Handbook for Cycle 17 > Appendix C: Bright Object Mode > C.1 Bright Object Mode . ... The time taken to read through a quadrant on the array sets a fundamental limit on the fastest electron collection rate which can be achieved by resetting all the pixels. ... In BRIGHTOBJ mode, an ACCUM sequence of operations is performed on one pixel in each quadrant at a time. ... The time required to take a BRIGHTOBJ mode exposure can be rather long. ...

... The Galactic low-mass X-ray binary GS 2023+338 was discovered during the burst on May 22, 1989 with the Japanise satellite Ginga (aka Galaxy). The flux reached 17 crabs (this unit of flux measurement is an bright X-ray source, Crab Nebula) at 10-35 keV. ... No other radio telescope worldwide carried out multi-frequency measurements. ... Upon 14 days the radio flux fell below the detection level at the RATAN-600 in relation to the decrease of the X-ray flux. ...

... Orion s Belt Continued . ... Yesterday's skyscape featured Alnitak, Alnilam, and Mintaka, the stars of Orion's Belt. ... Orion s Belt . ... Otherwise known as the Belt of Orion, these three blue supergiant stars are hotter and much more massive than the Sun. Anemic Galaxy NGC 4921 at the Edge . ... Comet Lulin Tails . ... Recent changes in Lulin's lovely greenish coma and tails are featured in this two panel comparison of images taken on January 31st (top) and February 4th. ... February 2010 . ...

. Please standby and you will be automatically connected to the new location of the unframed Supernova page. Or, click on the link above. If you have questions or problems, please email me at David Bishop dbishop@vhdl.org . Last modified: Mon Aug 27 12:40:15 EDT 2001

ATNF Annual Report 2000 (submitted) . ... One of the first products is the HIPASS {\it Bright Galaxy Catalogue}, which is a catalogue of the 1000 apparently brightest HI galaxies in the southern hemisphere. ... In Figure 1 we show the spatial distribution of the brightest HIPASS galaxies. ... Figure 4 shows the velocity distribution of the 1000 brightest HIPASS galaxies (orange) compared to the 1000 brightest optical galaxies (selected from the Lyon/Meudon Extragalactic Database using blue magnitude). ...

The night sky brightness, together with number of clear nights, seeing, transparency, photometric stability and humidity, are some of the most important parameters that qualify a site for front-line ground--based astronomy. ... Night sky at ESO-Paranal (Chile). ... Night sky brightness data . ... UBVRI night sky brightness at ESO-Paranal during sunspot maximum (A 2003, PDF) . ... The Dancing Sky: six years of night sky observations at Cerro Paranal (Starlight 2007 conference proceedings, PDF) . ...

... 2001 December 6 . Comet Linear (WM1) Brightens . ... Explanation: A comet bright enough to be seen with binoculars is swooping into southern skies. Comet C/2000 WM1 (LINEAR) continues to brighten and develop tails as it nears its closest approach of the Sun in late January 2002. ... In the above picture from the Curtis Schmidt 0.6-meter Telescope in Chile , a 30-second exposure in red on December 4 captured detail in Comet LINEAR WM1's emerging dust tail . ... About APOD | ...

Check out the new images (Jan 18-25) and (Jan 26-Feb 05) of the comet by Rob McNaught. ... Every few years a comet becomes bright enough to be easily seen with the naked eye but only every decade or so are these comparable with comets like Halley. ... Before Jan 13, the comet is not visible in the Australian sky after sunset. ... SOHO images . ... On Jan 12 at approximately 09:00 UT (8pm NSW time), comet C/2006 P1 McNaught appears at the 11 o'clock position in the images. ... STEREO images . ...

... STScI-PRC98-11A STARING INTO THE WINDS OF DESTRUCTION: HST/NICMOS IMAGES OF THE PLANETARY NEBULA NGC 7027 The Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) has captured a glimpse of a brief stage in the burnout of NGC 7027, a medium-mass star like our sun. ... The material settles into a wind of gas and dust blowing away from the dying star. ... During this phase, intense ultraviolet radiation from the central star lights up a region of gas surrounding it. ...

[ CATS home ] [ Back to CATS list ] [ ftp ] . 2000ApJS..131..335Rutledge+ . Division of Physics, Mathematics and Astronomy MS 220-47, California Institute of Technology, Pasadena, CA 91107 rutledge@srl.caltech.edu, rb@astro.caltech.edu, prince@srl.caltech.edu

... Luminosity (L) · · · · A source's luminosity is the power that it emits in radiation. ... NB Astronomers often say `flux' when they mean `flux density' · SI units are Wm-2Hz -1 -26 filter · Also used are Jy 10 Wm-2Hz -1 E= РРРF d dA dt Specific Intensity, Surface Brightness (I) · Specific intensity (or surface brightness) is the power received (or emitted) per unit area per unit frequency per unit solid angle. ч F at surface of a spherical source = I · · Specific intensity is independent of distance...

... Usually, H I is seen as bright emission against a darker background, but under the right viewing conditions, it can also be seen as dark absorption against a brighter background. In the case where the background is itself H I emission, the hydrogen is said to be self-absorbed, and the radiative transfer process is termed H I self-absorption (HISA). ... Shown below is a single CGPS H I 21cm spectral line channel at a radial velocity of -41 km/s in the Local Standard of Rest, at l =140њ, b =+1њ. ...

Subject, Problems and Objects of Theoretical Astrophysics. ... Stellar Photospheres, Their Features. ... Physics of Continuous Radiation Absorption in Stellar Photospheres. ... Continuous Radiation Absorption in Stellar Photospheres of Various Spectral Classes. Solar Type Photospheres. ... Characterisics of Absorption Lines. ... Interstellar Absorption Lines, Their Features. ... Physical and Dynamic Features of Interstellar Medium, Which Follows from Observations of Interstellar Absorption Lines. ...

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 | ...

... Tonight's Sky . ... The Magazine . ... Observing . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Astronomy for Kids . ... Observing springtime deep-sky objects with a large telescope . ... Bright planets meet at dusk . ... Astronomy magazine subscribers can read the full article for free. ... Get instant access to subscriber content on Astronomy.com! ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter....

... Solar System . ... Milky Way . Stars . ... Blue-white Vega is of course one of the brightest stars in our night sky lying about 25 light years from us in Lyra. ... Also in Lyra is the double star Beta Lyrae (Sheliak). This is in fact a close eclipsing pair of B-class stars about 960 light years from the Sun and was only the second eclipsing binary system to be discovered after Algol. ... Planet of Beta Lyrae (from The New Challenge of the Stars by Patrick Moore & David Hardy 1977) . ...

THE THERMAL RADIATION OF THE LUNAR SURFACE IN THE IR RANGE OF THE SPECTRUM (10-12 µm). ... 0.80 0.60 0.40 0.20 0.00 -0.20 -0.40 -0.60 -0.80 -0.80 -0.60 -0.40 -0.20 0.00 0.20 0.40 0.60 0.80 Fig.1 0.80 0.60 0.40 0.20 0.00 -0.20 -0.40 -0.60 -0.80 -0.80 -0.60 -0.40 -0.20 0.00 0.20 0.40 0.60 0.80 Fig.2 0.60 0.40 0.20 -0.00 -0.20 -0.40 -0.60 -0.60 -0.40 -0.20 -0.00 0.20 0.40 0.60 0.80 Fig.3 Indicatrix of the thermal radiation of the Moon (10.5-12.5 µ). ...

... Bad Astronomy . ... Bitesize Astronomy . ... Keep Bad Astronomy close to your heart, and help make me filthy rich. ... When Venus is on the far side of the Sun, we see the entire near side lit by the Sun. ... When it is on the near side of the Sun, it shows a beautiful thin crescent, because it is between us and the Sun and we see the mostly unlit dark half. ... To see this for yourself, draw a circle one centimeter across, then, next to it, draw a circle 6 centimeters across. ... 2008 Phil Plait. ...