... Flight qualified ADCs with higher dynamic range (>12 bits) were not available, so WFPC2 operates the two available ADCs at different gain factors, to take partial advantage of both the low read noise and large available full well depth. One channel has a gain of 14e - DN -1 , which significantly undersamples the CCD read noise (5 e - pixel -1 RMS), and gives a digital full well of about 53,000e - . ... The choice of gain factor will be determined by the scientific objective. ...

... 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 ( )...

... This calibration approach is recommended when dealing with high frequency data from the old ATCA correlator, especially at 3mm wavelengths. ... The approach described here exploits the dual frequency bands that were available with the old correlator. ... Rather the current approach assumes that you have a single Miriad dataset containing bandpass calibrator, phase calibrator, flux density calibrator and program source. ... MFCAL . ... Input multi-source, dual-band dataset. select=source(1921-293) . ...

Compilation of Surface Brightness . HyperLeda home | Documentation | Search by name | ... Search an object in the surface brightness catalogue . The surface brightness in magnitudes per square arcsec (mag arcsec -2 ) . ... Surface brightness at effective radius . ... Effective mean surface brightness within the effective radius (equivalent radius in which half the total flux is emitted). ... Quality Flag The quality flag has the following meaning: . ... regular measurement . ...

XMM-Newton Science Analysis System . ... A different approach is done via the setting withctisrcpos =Y: all event energy corrections do not use the actual RAWY coordinate but the corresponding RAWY location of the source ( SRCPOS ) as determined by the task epframes (either automatically or via setting withsrccoords =Y). ... The task epchain may be used with the setting ccds =4 withctisrcpos =Y to process only the CCD 4 where usually the bright source is located that causes the Out-of-Time events. ...

Problem Set 2 - Cosmology­A3002 ­Due on or before November 7th. Can be sent via internal mail (Brian Schmidt, RSAA) use H0=70 km/s/Mpc, M=0.27, =0.73, w=-1 for all problems. ... Finish off your Monte Carlo simulation by selecting objects at random redshifts from 0<z<0.1, assuming that they have a mean absolute magnitude of M=-19.5 with a dispersion 0.2 magnitudes. ... Problem 2.1 (2 pt): In class we described the scale at which material can collapse in the Universe as the Jeans' length. ...

Peremennye Zvezdy", . ... Star Name: . GSC 3710-00312, USNO-A2.0 1425-04252279 . ... Variability type: . ... USNO-A2.0 1425-04252279 is located at the distance of 15?.7 from the X-ray source 1RXS J031707.9+572942, which is larger than the position error of the source (12?), but its hardness ratio HR1 = 0.03 0.29, typical of chromospherically active stars, and its character of variability allow us to assume that the star is related to the X-ray source. ... Eclipsing variability . Sine wave 1 . ...

... HIPASS results . ... Of the BGC galaxies, 138 have redshifts for the first time. ... We really need ALFA to address that faint end. ... This estimate accounts for the smaller beam size, the number of pixels, and the available solid angle. ... HIPASS (with an integration time of 250 sec per pixel) was complete only for M * galaxies at cz ALFA (with the same intergration time) would be complete to 15,000 km/s . ... The integration time would be only 1 sec per beam for a total time of about 2.6 hours. ...

... The effect of the normal star on the compact magnetized component is largely determined by the rate and velocity of stellar wind at infinity . ... For Be-stars (i.e. those stars at the stage ``I'' whose mass increased during the first mass exchange), the wind velocity at infinity is taken to be equal to the Keplerian velocity   at the stellar surface . Thus, the lower stellar wind velocity leads to an effective increase of the captured mass rate by a secondary companion to such Be-stars. ...

Physical and dynamical parameters of particles in outbursting Comet 17 P/Holmes . ... The time depending offset between the center of brightness and center of mass of the comet nucleus has been determined on the ground of positional observations of the comet. ... The motion of these particles allowed subsequent offset between the center of brightness and center of mass of the comet nucleus to be obtained from positional observations. ... comet, dynamical model, outburst, brightness. ...

... Lucas (2000) also mentions the possibility of using the 183 GHz Water-Vapour Radiometers (WVRs) to correct for the emission. A correction based on the WVRs would largely remove the noise due to atmospheric emission, but would also add thermallike noise due to the noise within the radiometer itself. ... 125 100 K /m m K /m m 3 CORRECTING ALMA TOTAL-POWER OBSERVATIONS Each of the 12-m ALMA antennas will have a 183 GHz water vapour radiometer fed from the centre of the focal plane of the antenna. ...

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. ...

Channel ops are one of the most powerful and simple tools available to you with the GIMP. ... Channel ops are operations that typically involve two images. Each channel operation compares and does some sort of manipulation based on the pixels in two images. ... Add takes two images, and adds the RGB or greyscale values of the pixels. ... If you have a completely black canvas, all the values are zero. ... This channel operation compares two images and results in the darkest values from each image. ...

... Einstein data for SNR are available as images on magnetic tape or diskette and as tables of counting rates. ... In seven cases, with coverage from 35% to 90%, we have calculated an HRI rate for the entire SNR by using the observed IPC data and assuming the ratio of HRI to IPC rates was the same for the observed and the unobserved parts of the remnant. ... Positions of the bright bulge sources and remnants in the galactic plane are known and the rates in table 2 are free of the effects of these. ...

... References: %Observed energy levels (2-5): Kucera et al., 2000, ApJ , 538, 424 % Observed energy levels (6-15): Edlen, B., 1984, Pysica Scripta, 30, 135 % Observed energy levels (n=3): identifications from the X-ray line list by Landi Phillips 2005 , ApJ , in press % Observed energy levels (n=4,5): Shirai,T., Sugar,J., Musgrove,A., Wiese,W.L., 2000, J.Phys.Chem.Ref.Data, Monograph 8 % Observed energy ...

... In brief: the frequency-dependent radiative transfer equation is solved for a dust under assumption of spherically-symmetric geometry for its distribution taking into account particle size distribution and quantum heating effects for the very small dust particles. ... Table: Model parameters for IRAS04296+3429. ... parameter . ... hot dust shell) . ... The best fit to the spectral energy distribution of IRAS04296 is shown by heavy solid line (see Table2 for details concerning parameters of the model...

The ESA/ESO Astronomy Exercise Series 2 . The Distance to Messier 100 as Determined by Cepheid Variable Stars . ... The small variations in distance to the individual Cepheid variable stars in the Cloud are negligible compared with the much larger distance to the SMC. ... In this way Cepheid variable stars can be used as one of the 'standard candles' in the Universe that act either as distance indicators themselves or can be used to calibrate (or set the zero point for) other distance indicators. ...

... Status of the numerical solutions and validation 2. ... Coupling of "solid" Earth components, e.g. core ­ mantle (Dehant et al.) ... Consistent relativistic formulation of Earth rotation (Gerlach, Klioner, Soffel) Status of the numerical solutions - 2 · The results from numerical solutions suffer from ­ Simplified solid Earth models ­ Incomplete Earth system models or neglecting of certain parts or neglecting of certain coupling mechanisms ­ Methodological limitations of computations...

... Telescopes ћ Binoculars ћ Microscopes . Meade Ultra-High Transmission coatings (UHTC ) Group . ... Meade Standard Coatings: The optical surfaces of all Meade telescopes include high-grade optical coatings fully consistent in quality with the precision of the optical surfaces themselves. ... These specialized, and extremely advantageous, coatings are offered here as the Meade Ultra-High Transmission Coatings (UHTC) group, a coatings group available optionally on many Meade telescope models. ...

ARCSAT ID NUMBER: AS01 DESCRIPTIVE TITLE: Search for Short-Period Planets Orbiting Bright White Dwarfs PI: Brett Morris (UW) OBSERVER(S): Brett Morris (UW), Doug Branton (UW) UNCERTIFIED/UNTRAINED OBSERVERS: Undetermined Pre-MAP students ... In addition, since typical white dwarfs are roughly Earth-sized, the transit of an Earth-sized planet can cause changes in brightness on the order of several tens of percent for durations on the order of one minute (Agol 2011). ...