CCD Performance . ... The dark current appears to have two components: one from electronic sources in the CCD, and a second component whose strength correlates with the cosmic ray flux. ... As of this writing, the " DARKTIME" keyword in the WFPC2 image headers does not reflect correctly the actual time during which the CCD collects dark current. ... External exposures of 180s or longer made with the serial clocks off (CLOCKS=NO; the default setting) suffer an additional 60s of darktime (restart=1). ...

... 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...

GALFACTS MEMO: # 10 ALFA RFI Saturation Problem J. S. Dever 20 Decemb er 2006 1 Overview Observations made with ALFA can be partially or completely lost due to strong RFI saturating a component in the receiver chain. ... A determination of where the saturation is occuring should be made, and the problem solved. ... 1 Radar RFI 1.35 1.3 1.25 Power 1.2 1.15 1.1 16750 16800 16850 16900 Time 16950 17000 17050 Figure 1: Band average plot for 135 seconds showing the effect of Radar RFI in the continuum. ...

The Crab : the absorption model and consequences for absolute effective area calibration Jelle S. Kaastra SRON Using the Crab nebula as calibration source · Good calibration sources should obey: 1) Simple continuum 2) Known continuum 3) Constant in time 4) Point source 5) No dust scattering halo Crab only obeys rule 1 and 3 partially, but except for White dwarf spectra there is nothing better Extended emission · ... Caveat: curved continuum spectrum nebula? ...

Median Twilight Image . all frames normalized by their median before averaging and corrected for 4-port structure) . Median of Normalized Twilight Images at Rotator Angle 0 . Median of Normalized Twilight Images at Random Rotator Angle . Time Frame and Rotator Angle Distribution . B_UT2_2CCD: 134 frames . ... distribution of rotator angles) . U_UT2_2CCD: 106 frames . ... uncorrected median twilight image) . B_UT2: 298 frames . ... U_UT2: 246 frames . ... B_UT3: 266 frames . ...

Magnetic Fields around Radio Galaxies Robert Laing (ESO) Laing et al. ... 2008) Negligible depolarization and 2 rotation Almost all Faraday effects must be due to foreground material How to fit depolarization caused by foreground Faraday rotation Complex polarization Rotation measure Integrate over a beam Observed RM for 0 2 rotation and depolarization Faraday rotation and depolarization 5.5 arcsec FWHM Faraday effects at high resolution FWHM = 1.5 ...

... User Guide ] Task: atfix Purpose: Apply various miscellaneous corrections to ATCA visibility data Categories: uv analysis ATFIX performs various miscellaneous offline corrections appropriate for ATCA 3mm data. ... Correct antenna table (when some antennas were off-line) NOTE: This task will usually be used very early in the data reduction process. ... Key: vis The names of the input uv data sets. ... Leave the Tsys calibration as is. constant Apply a constant Tsys between successive Tsys...

Detection technique . We are using ISIS , the optimal image subtraction method developed by C. Alard & R.H. Lupton, to search for SNe in our images. ... The second image shows the same subtraction, but after the convolution of the best image with ISIS: . ... For this reason, we are suggested to search for nuclear SNe with NICMOS on HST, to exploit its stable PSF, sensitivity and angular resolution to detect from space nuclear obscured SNe which might have been missed by ground-based surveys. ...

... In spite of the good potential possibilities, some of the station "Dnepr" design characteristics did not allow us to apply the usual special IS radar measurement methods. ... Thus for IS signal measurements at the "Dnepr" station, we have developed special methods for recording and processing IS signals in order to determine plasma ionospheric parameters. ... Equations (4-5) from the basis for data post processing to obtain ionosphere parameters. ...

Next: ZGSC (Compressed GSC) and XSKYMAP . ... This is a preliminary report on an investigation of the quality and properties of plates digitized during creation of the Guide Star Catalog (GSC). The results will be vital for reclassifying GSC objects. ... Many objects are measured on more than one plate, and thus have multiple catalog entries. ... Among the shortcomings of the GSC are: biased magnitudes and incorrect classifications for certain objects, presence of artifact objects. ...

Next: Reduction procedure Up: Extinction and transformation Previous: Strategy . Standard stars can be included in the extinction solution, if one is careful. The problem is that there are usually appreciable ``conformity errors'' due to mismatch between the instrumental and the standard passbands [ 16 ]. ... Thus, it is wrong to assume that the transformation between the instrumental system and the standard system is exact, even if there were no measurement error in either system [ 1 ]. ...

We have analyzed the UV continuum light curves of 2535 pixels obtained during fifteen separate observations of active regions with the Ultraviolet Spectrometer and Polarimeter (UVSP) on board the solar maximum mission in 1989. ... The distribution N(v), which describes the number of pixels having maximum power at frequency v, is strongly concentrated in the 2 - 5 mHz band with a distinct maximum at 3 - 3.5 mHz. ... No clear correlation is found between the maximum power and the count rate in a pixel. ...

... The variability of the spectrum of the optical component of the IR-source IRAS01005+7910 was discovered for the first time in the BTA spectra [1]. ... The spectral features include absorptions that form in near-photospheric layers, narrow envelope emissions, and emission-absorption profiles that form in photosphere-to-envelope transition layers (the wind). ... Discovery of spectral variation in the optical counterpart of IRAS01005+7910. ... Dashed line - envelope curve of all the SiII 5979 profiles ...

... Lake Effect Snow on Earth . ... Credit Copyright: SeaWiFS Project , NASA Explanation: What are those strange clouds stretching out from these lakes? The clouds are caused by cold air moving over a warm water and result in bands of lake-effect snow . The rising bands of moistened, warmed air that drop lake-effect snow alternate with clear bands of falling cold air. ... During this lake-effect snowfall of 2000 December 5, practically all of the state of Michigan , USA got covered. ...

... COMPUTER SIMULATION OF RADIOWAVE MULTIPLE SCATTERING EFFECTS IN IONOSPHERE USING MONTE-CARLO METHOD . ... Distribution of reflected radiation on the ground is computed. ... Such influence can be remarkable if the scattering is multiple, i.e. the optical thickness for the scattering process is considerably greater than a unit. ... Radiation energy transfer in the slab is modeled by distribution of some particles carring small portions of radiation energy. ... The isotropic plasma approximation is...

... 2.3 Establishing the Extragalactic Distance Scale . ... 2.3.2 The Second Rung: Distances to stellar clusters . ... 2.3.4 Distances to Local Group Galaxies . ... The Luminosity Function of Planetary Nebulae . ... 3.2.2 Clusters of Galaxies . ... 4.2 Evidence for Dark Matter as a Function of Scale Size . ... 4.3 Other Dark Matter Indicators for Galaxies . ... What is the nature of the large-scale distribution of matter in the universe as traced by the three-dimensional galaxy distribution? ...

Next: Rapidly Rotating Stars Up: Discussion Previous: Relations . ... They attributed this to a mechanism which regulated stellar angular momentum through the accretion disk. ... While some of this may be due to sampling effects, the data seem to indicate that after a star loses its disk, either it continues its slow rotation for a period of time and then a rapid increase in rotation rate commences or spin up does not necessarily follow the loss of the disk. ...

... Product details: . ... 2 Composition/Data on components: . ... Information pertaining to particular dangers for man and environment . ... 4 First aid measures . ... Use fire fighting measures that suit the surrounding fire. ... Measures for environmental protection: . ... This information is furnished without warranty, and any use of the product not in conformance with this Material Safety Data Sheet, or in combination with any other product or process, is the responsibility of the user. ...

... The FIG element is used for figures. ... It also allows graphical hypertext links to be specified in the markup and interpreted by the user agent rather than the server. The anchor elements in the figure description text play a dual role: Non-graphical user agents show conventional hypertext links, while for graphical user agents, the same anchor elements specify graphical hypertext links, with the SHAPE attribute designating the hotzones. ... CLEAR . ... Specifies the figure's graphical content. ...

... Stellar magnitudes, provided by observations in an optical band, are reduced to the units of erg/cm /s as follows: . ... Table: `Zero-points', central wavelengths, and effective widths of optical bands (Zombeck's Handbook, 1990). - the corrected value (the handbook value is given in parentheses). ... We have achieved coincidence between theoretical values by Bochkarev et al (1991) and ours, obtained with rectangular shapes of transmission band of optical filters. ... 1991, V. 1, P. 41. ...