This page gives the name and meaning of the various parameters which can be queried in HyperLeda through SQL requests . ... real . ... actual error on t . ... log 10 of apparent major axis diameter d25 at 25 mag.arcsec -2 (d25 in 0.1') . ... actual error on logd25 . ... Apparent maximum rotation velocity of gas . ... log 10 of apparent corrected diameter (dc in 0.1') . ... total apparent corrected B-magnitude . ... total apparent corrected U-B color . ... Questions: leda@univ-lyon1.fr ...

... To be read in conjunction with Section 4.11 of the WFPC2 Instrument Handbook , -Version 4.0. ... 1 The second study found evidence that CTE loss for faint stars has increased with time (Whitmore, 1998). The primary observational consequence of CTE loss is that a point source at the top of the chip appears to be fainter than if observed at the bottom of the chip, due to the loss of electrons as the star is read out down the chip (see Figure 1 ). ... Last updated: 06/16/98 10:38:00 . ...

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. ...

... 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 ( )...

... Impact on source motion in Galactic coordinate system is given by Kovalevsky (2003), Malkin (2011) l cos b = -A sin l, b = -A cos l sin b, where A = R0 02 /c is the galactocentric acceleration called hereafter the GA constant. ... We just have to return to the traditional many-centuries-old astrometric practice of modelling the position of a celestial object as a linear trend with two parameters: the position at the initial (conventional) epoch and the apparent (proper) motion. ... 2011). ...

HIPASS Name RA, DEC(J2000) l, b NED ID peak rms mom0 vsys w50 w20 vLG MHI Ref. ... Col(1,2) = HIPASS name (HIPASS Jhhmm-dd; A,B,C if needed) . Col(3,4) = HIPASS center position in RA, DEC (J2000) . ... NGC6822 0.490 Mpc (Mateo 1998) . DDO210 0.880 Mpc (Mateo 1998) . NGC0055 1.480 Mpc (Mateo 1998) . ... ESO594-G004 1.060 Mpc (Mateo 1998) . IC5152 1.590 Mpc (Mateo 1998) . WLM 0.925 Mpc (Mateo 1998) . NGC3109 1.250 Mpc (Mateo 1998) . SextansA 1.440 Mpc (Mateo 1998) . ...

... They worked out that first magnitude was on average 100 times brighter than the 6th magnitude star. ... This formed an equation of apparent magnitude Mv which is: Mv = -2.5 log f + constant were f is the flux of that star f = ( counts/ exposure) The images that we worked on were taken by the Polar Bear Telescope. ... One of these being that it will be combined with standard stars, which will be used to identify the area of stars and to also help identify other stars within the image. ...

Measurement of Sky Brightness at the Iranian National Observatory Davoud Afshari1 and Sadollah Nasiri1,2 1Physics Department, Zanjan University, Zanjan 45195-313, Iran; Institute for Advanced studies in Basic Science (IASBS), Zanjan 45195-1159, Iran; Measurement of light pollution 2 Introduction Among 34 candidate sites at the central part of the country, 5 sites namely Garkesh (in Kashan ), Kolahbarfi(in Kashan ), Deynava (in ... One of these is light pollution. ...

I was wondering what conditions should be met to have the "darkest" sky .. ... Upon the above publication of the Southern Galactic hemisphere, TunГ Tezel started seeking opportunities to create the Northern counterpart image. ... So, the initial quest of having the darkest possible sky have delivered us these two all-sky images of the two galactic hemispheres as seen from Planet Earth. Zoomable and 'full-screenable' fisheye view of the "darkest sky" Southern Galactic Hemisphere image. ...

On April 14, 2000 UT a series of Shack-Hartmann measurements were made at varying altitudes. ... The tilts and sags shown are those given by the normal Shack-Hartmann analysis. ... Without this feedback, off-telescope tests showed positioning errors on the order of 10 arcseconds in the secondary mirror position. ... Tilt M2 Bk by X" . ... The coefficients m1 through m3 need to be added to those that are currently in the TCC to correct for the secondary translation with respect to the primary. ...