Target Acquisition Reference Information . ... In almost all cases where an onboard acquisition will not work (because the object is in a crowded field, or is variable, or is a moving target), it is sufficient to use an early acquisition to get a WFPC2 or FOC image a few weeks in advance of the GHRS observation. ... Explicit BRIGHT and FAINT limits may be specified if you desire, although there is an increased risk of a failed acquisition unless you are confident of those fluxes. ... MAPs . ...

... Although it is possible to solve for nonlinearity (e.g., dead-time) corrections in both pulse-counting and DC photometry, extreme care should be used in doing so. ... A common error is to include standard-star values in the solution; this aliases conformity errors for the 2 or 3 brightest stars into the nonlinearity parameter. ... To determine nonlinearity accurately, a neutral attenuator should be used to observe a considerable number (say, 15 or 20) of the brightest stars. ...

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. ...

... true false . A boolean switch determining whether the list of to be considered HK parameters shall be explicitly specified with parameter parameters . ... blank separated list of HK parameter names . ... If set to true overrideparameters must contain a list of HK parameter names and overrideparametervalues a corresponding list of validity ranges for those parameters (see below). overrideparameters . ... If withoverrideparameters is set to true the list must contain valid HK parameter names. ...

THE PHOTOMETRIC RESEARCHS OF THE MERCURY'S SURFACE BY MEANS OF DIGITAL MODELS. ... The surface brightness of Mercury was measured Danjon (1933, 1949, 1953) and Harris (1961) in phase angle 3o-123o. The analysis of the various data of the integral photometric gives the results of determination of the main photometric constants for Mercury. ... THE PHOTOMETRIC RESEARCHS OF THE MERCURY'S SURFACE: S.G. Pugacheva The surface brightness of the Mercurian images was established on the geologic map Mercury. ...

Old subtables of the extended ``HIPASS Bright Galaxy Catalog'' . ... Koribalski, Staveley-Smith, Kilborn, + HIPASS/ZOA teams 2004, AJ 128, 16 . The 1000 Brightest HIPASS Galaxies: HI Properties . ... The 1000 Brightest HIPASS Galaxies: The HI Mass Function . ... The 1000 Brightest HIPASS Galaxies: Newly Cataloged Galaxies . ... To download the gzipped ps-file click here . ... The Brightest Galaxies from HIPASS . Presented is the distribution of the 700 brightest HIPASS galaxies. ...

... Guider functions . ... Guide Sensor Performance . ... Guide Sensor Sky Coverage/ Star Availability . Guide Star Selection Criteria . ... Guide fiber organization and reach at plug plate . ... Plug plate holes for guide stars are identical to those for science FO . ... FOV for each of 9 guide stars is 7.4 arcsec dia. (0.45 mm FO, Sumitomo IGN-05/10) . ... Selected guide stars must have no neighbor stars within TBD (5 arcsec) radius that have a brightness within TBD (5 mag.) of guide stars . ...

... Bad Astronomy . ... Mad Science . ... Universe Today . ... Keep Bad Astronomy close to your heart, and help make me filthy rich. ... type 1a supernovae seem most useful . ... This is a bright, massive star that explodes after fusing all the light elements in its core. ... That means we can calculate how far away it is. ... This is exactly what we are trying to do with these supernovae; look far enough away that any deviations from flatness of the Universe can be seen. ... Phil Plait . ...

Russian SHAREABLE DATA CENTER Institute of Solar-Terrestial Physics SB RAS . ... Although their determination is based on the scattering process model, independent check-ups by rocket experiments have shown their correctness in experimental applications. ... Ionospheric data analysis, especially during strong disturbances, cannot be without some other kinds of diagnostic tools. ... The lack of data has always been a challange in this case. ...

Next: Mass change Up: Evolutionary Scenarios of Binary Previous: Stellar Winds From Normal . As mentioned earlier, the duration of the binary evolutionary stage (say, I+I) is determined by the faster evolving component , where is the time each component spends at the corresponding evolutionary stage. ... Next, we should calculate the mass change for the slower evolving companion, the orbital semi-major axis and the eccentricity. Mass change . Semi-major axis change . ...

... We demonstrate through numerical simulations that model parameters estimated with our technique are essentially bias-free, even when the average number of counts per bin is 1. ... The IW technique avoids such biases by estimating through successive iterations, where for each iteration, j, , and the best-fit parameters are determined by minimization of . ... In our sample, we find that the minimum values and best-fit parameters converge after about 6 iterations. ...

The determination of the detector parameters is based on sets of images of a spatially uniform-illumination scene (flatfield frames) and without any illumination (dark frames), putting a plug in place of the filter, taken at a series of exposure times. ... We interleave before and after each exposure time in the series of flatfield frames a set of reference images at an exposure time of 1 sec to determine the possible temporal variation of the illumination level. ...

... 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...

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) . ...

tranback -- Transform an X,Y position from output to input pixel position using the same conventions as drizzle tranback xout yout . xout = 400 [real] . ... The X dimension of the input image (this is used to determine the centre which is the origin of the transformations). (nyin = 800) [real] . ... If "output" the input image center is mapped to the center of the output grid, rotated about that center and then shifted along the grid of the output image. ...

... Star formation requires interstellar clouds that are cold and dense enough for self-gravity to overcome internal pressure from gas thermal motions and other factors, thus leading to cloud contraction and eventual collapse to stellar densities. ... Absorption has all of these parameters plus one more describing the fraction of the emission (p) that is behind the absorbing cloud. ... Obser ving Interstellar Hydrogen Clouds Clouds in the ISM can produce either emission or absorption spectra. ...

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. ...

... IRAF supports two kinds of parameters, auto parameters and hidden parameters, which are treated differently. auto parameters are updated every time a task is run. ... Parameters for each task are contained in `parameter files' in the uparm sub-directory in `myiraf'. ... im > imhead.longheader=yes # explicitly setting <task.param>=<value> im > eparam imhead # Edit the parameter file to update one or more # parameters at the same time # see next section . ...

... We cannot use for this purpose equivalent widths and profiles of HI lines (well known criteria of atmospheric conditions for normal supergiants), since these lines are strongly distorted in the spectrum of IRAS04296 as seen in Fig. ... Figure: Upper: iron abundance FeI (circles) and FeII (crosses) calculated for IRAS04296+3429 with model parameters , and using lines with different excitation potentials EP of a low level; bottom: the same as a function of the equivalent width W . ...

... Future seminars . P a s t seminars . Seminar council . The emission time of Gamma-Ray Bursts" . A. Sanin (IKI) . ... The three new parameters of cosmic gamma-ray bursts are introduced: the emission time, the peak energy of the emission time spectrum and the cosmological invariant parameter. ... Using this distribution the "collective estimation" of the best fitting redshifts for the group of long bright gamma-ray bursts detected by BATSE experiment was found. ...