. Images of the position of GRB080319B before the burst (left) and at the moment of maximal optical brightness (right). The transient position is marked with an arrow. Peak optical brightness made the burst visible by a naked human eye (5.3 stellar magnitude). To view high temporal resolution video of the transient seen by TORTORA camera, click here (avi).

The WFPC2 cameras have significant geometric distortion which not only affects astrometry, but also affects photometry (because it induces an apparent variation in surface brightness across the field, and hence impacts the flat fields). ... The pixel scale can be estimated from the commanded offsets between the frames (relying on the FGS scale and distortion calibrations). ... The cubic distortion coefficients can be used to derive effective pixel areas as presented in Figure 5.16 . ...

Astronomy Picture of the Day . Vela Supernova Remnant in Optical . ... 13.06.1996 . ... This bright supernova may have been visible to the first human farmers . Today the Vela supernova remnant marks the position of a relatively close and recent explosion in our Galaxy. ... Publications with keywords: Vela - supernova remnant - supernova . Publications with words: Vela - supernova remnant - supernova . ... Vela Supernova Remnant in Visible Light . Keplers Supernova Remnant in X Rays . ...

... 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....

... R-band images obtained at 0.8 arcsec seeing conditions have allowed us to separate foreground star from point-like extragalactic source and estimate their brightness separately. ... To study the nature and properties of the source, we observed it under high spatial resolution. ... CONCLUSION RTT150 optical observations with sub-arcsecond seeing and low resolution spectra confirm the hypothesis of superposition of a radio source onto a `normal' F/G galactic star proposed by [1]. ...

Photograph quality The photographs must be: I no more than 6-months old 35­40mm in width close up of your head and top of your shoulders so that your face takes up 70­80% of the photograph in sharp focus and clear of high quality with no ink marks or creases too close too far away I I I I blurred ink marked/creased I The photographs must: show you looking directly at the camera ...

... astro-ph/0003002 We cross-identified the ROSAT Bright Source Catalog (RBSC) and the NRAO VLA Sky Survey (NVSS) to construct the RBSC-NVSS sample of the brightest X-ray sources (~0.1 counts s^{-1} ~= 10^{-12} ergs cm^-2s^-1 in the 0.1--2.4 keV band) that are also radio sources (S ~= 2.5 mJy at 1.4 GHz) in the 7.8 sr of extragalactic sky with |b| > 15deg and DEC > -40deg. ... We used the more accurate radio positions to make reliable X-ray/radio/optical identifications down to the POSS plate limits. ...

... all new HIPASS galaxies (Table 2.4) that have no yet been observed with the ATCA . ... Table : Remaining ATCA target list (sorted by RA) -------------------------------------------------------------------------------- Name RA DEC ID Max mom0 mom1 mom2 w50 w20 -------------------------------------------------------------------------------- ZSS 13 07:33:16 -28:41:07 new -HIZSS013 0.151 9.2 2077.6 21.6 52.8 144.6 HIP 358 07:44:56 -41:47:02 ESO311-G006/7 0.262 30.9 1049.4 34.5 127.1 149.5 ...

... Moon . ... Monthly Sky Notes . ... The Moon remains of interest in January as this month also marks the first of six тАШsupermoonsтАЩ to grace our skies in 2015. ... The Winter Circle, also known as the Winter Hexagon is an asterism or recognisable pattern of bright stars in the south east of the sky at sunset. ... At the start and end of the month the moon will travel through the Winter Circle but its glare will have no effect on the bright stars in this pattern as they are all first magnitude...

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. ...

NMW survey overview . Access image archive . ... The New Milky Way survey aims to detect bright (V<13.5) optical transients near the Galactic plane using an automated wide-field (8x6 deg.) system capable of surveying the whole Milky Way area visible from the observing site in one night. ... All images obtained during the transient search survey are available online (please use the image archive access form ). ... Images per field: . ... Images per night: . ... Milky Way imaging time: . ...

... In principle, two observers on the ground can tell, by comparing the position of the same auroral arc against the background stars. ... The display stretches across Canada; just below it, in the middle of the picture, are the lights of Chicago, next to Lake Michigan. ... The Canadian scientific satellite Isis-2 (1971) carried an auroral imaging camera and discovered the diffuse aurora, a broad ribbon around the auroral oval, too spread-out to be noticed from the ground. ... Auroral Acceleration . ...

... PISTON piston . ... this command is not used by the TCC The guide camera mechanical controller sets the filter, focus and other mechanical functions, but not the position of the guide camera in the focal plane. Positioning, if available, is handled by one or two guider position axes controllers , one per axis of motion. ... Notifies the controller that subsequent commands apply to the guider mechanical controller. ... Sets the piston of the guider to the specified value (in decimal microns). ...

... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . See also images taken on November 22nd . Image taken by Andy McCrea who says, . To me the comet appears yellowish and it has gone from star-like to a . ... More images from Andy McCrea here . ... The true explanation is that a very faint comet, known as periodic comet Holmes, produced a massive outburst of material and became a million times brighter than it was just a day earlier. ... More images from Andy McCrea . ...

... Using a simple 2-D Gaussian Point Spread Function (PSF) on a constant (flat) sky background, I derive a theoretical photometric and astrometric performance model for analytical and digital PSF-fitting stellar photometry. ... The photometric performance is maximized when either the effective background area or the effective-background-level measurement error is minimized. ... An important, but frequently ignored, noise source is the uncertainty of the measurement of the effective background level ( )...

Finding Himalia, The Fifth Brightest Moon Of Jupiter . Articles | ... Himalia is the only moon other than the Galilean moons of Jupiter that is visible in an amateur size telescope. ... I normally use “The Sky” from Software Bisque for planning my observing sessions and in helping me find objects, but it only has the Galilean moons for Jupiter so I used Red Shift (version 3 at the time) which I also had on my computer. ... www.astronomy.net . ... dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" . ...

SN 1999aa - A Third Supernova Discovery . Just 9 weeks after the discovery of SN 1998ey a suspect was found 1" east and 28" north from the centre of NGC 2595 on Feb.11.0166 U.T.. ... Further inspection of 6 images of NGC 2595 taken during Feb. and March 1998 showed no object at the position of the suspect. ... Beijing Astronomical Observatory recorded SN 1999aa on Feb. 11.6 and 12.6 UT, the first obervation being only 14 hours after the discovery. ... Back to Supernova 1999aa in NGC 2595 . ...

I-GALFA Reveals Dynamic Events in Our Galaxy . S. J. Gibson, J.-h. Kang, B.-C. Koo, June 2009 . ... The white stripe marks the Galactic equator ( b=0 ). ... I-GALFA three-color H I image for FVW40.0+0.5, integrated over v lsr = -100 to -90 km/s ( red ), -90 to -80 km/s ( green ), and -80 to -70 km/s ( blue ). ... I-GALFA data reveal a complex tracery of loops, filaments, and blobs hundreds of parsecs above and below the Galactic plane, with isolated compact clouds extending even higher. ...

... This can be used to overlay the position of fiducial stars onto an image, for example. Positions can be input manually or from a list. To position marks interactively display the image and then cl> noao no> images im> tv tv> tvmark 1 STDIN interactive+ type . to put dot at cursor position type + to put cross at cursor position type c to put circle at cursor position (must specify hidden parameter ``radii'') <ctrl>d to exit . ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. July 13, 1997 . Vela Supernova Remnant in Optical . ... Today the Vela supernova remnant marks the position of a relatively close and recent explosion in our Galaxy . ... As gas flies away from the detonated star , it reacts with the interstellar medium , knocking away closely held electrons from even heavy elements . ... About APOD > . ...