... subroutine omlcbuild read parameters loop i=0, nSources get handle on source rates file get handle on source region file if (exposure IDs are different) issue warning get handle on background rates file get handle on background region file if (exposure IDs are different) issue warning if (exposure ID source != exposure ID background ) call fatal get source extraction radius = s_radius get ...

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ACS Insturment Handbook for Cycle 24 . ... Advanced Camera for Surveys Instrument Handbook for Cycle 24 > Chapter 9: Exposure-Time Calculations > 9.3 Computing Exposure Times . ... The detector background ( B det ) or dark count in units of counts/second/pixel and the read noise ( R) in counts of the CCD. ... As a consequence, in order to obtain correct estimated count rates for red targets, observers are advised to use the synphot package in IRAF /STSDAS (or Pyraf), or the pysynphot package in Pyraf. ...

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• WFPC-2 ETC Help
• Space Telescope Imaging Spectrograph Instrument Handbook
• ACS Instrument Handbook for Cycle 20

... My source shows only 5 counts in a short 5 ksec Chandra exposure. ... We calculated the significance of observing 5 counts given the expected background counts of 0.1 using spfunc.gammp(5,0.1) =8e-8. ... I believe more fine tuning in computing this p-value is necessary but I wish to address that computing the p-value assuming Ho: background counts=0.1 vs. ... For a given rescaled background (b/50), the p-value is the probability that the counts in the source region can exceed the observed counts. ...

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• The AstroStat Slog error propagation
• The AstroStat Slog background
• The AstroStat Slog Blog Archive Background Subtraction [EotW]

... This paper describes the main algorithms used by the Einstein Level One processing to create the exposure masks and the background maps for Einstein IPC images, and how these algorithms were recreated in the IRAF environment. Our goal was to recreate the algorithms used by the Level One Processing to create exposure masks and background maps for Einstein Image Proportional Counter (IPC) data (cf. sections 2.5 and 2.7 of Harnden et al. ...

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• A New PROS Task for Calculating HRI Source Intensities or Upper Limits
• A Method for Minimizing Background Offset Errors When Creating Mosaics
• ADASS 2003 Conference Proceedings

Next: Combining Bias Frames Up: Preparing Your Calibration Previous: Input and Output . Except for summing the frames together, combining frames may require correcting for variations between the frames due to different exposure times, sky backgrounds, extinctions, and positions. ... The input frames are combined by applying a sigma clipping algorithm at each pixel. ... The input frames are combined with a variant of the sigma clipping algorithm which works well with only a few frames. ...

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• Search Algorithms
• Alternative construction
• Averaging and Merging Frames

The beam pattern and the polarization characteristics . of the radio telescope RATAN-600 . The Mueller matrix elements was computed via formulas [1]: . ... The BP were computed by the aperture method, proceeding from the fild distribution in the aperture of the primary mirror. The components of the main and cross-polarization components of the electric field in the vertical aperture of the primary mirror was computed in Frenel diffraction approximation. ...

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• shmidt_e

The aim of this section of the course is to enable you to use simple computer programs to solve a variety of common astronomical tasks. ... I have (somewhat arbitrarily) decided to use Python for this course, because it seems to be gaining popularity fast for astronomical data handling, and because some of you will have encountered it at the ATNF course. ... We've put Python (plus all relevant libraries) on the Stromlo Linux computers moron and maggot. ... Now log in to moron (or maggot). ...

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... Bojan Nikolic web pages (r. 329) . ... Atmospheric Modelling for ALMA . This is a short and simple illustration of how to use (A)ATM to calculate the dispersive path delay introduced by the atmosphere as well as the non-dispersive parts. ... Compute dispersive delay in the atmosphere This program is part of AATM version 0.06 GPL license -- you have the right to the source code. ... Computing dispersive atmospheric delay with AATM . ... Computing atmospheric absorption with AATM . ...

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• Computing dispersive atmospheric delay with AATM

The original files with the data were in different formats. ... Such files were named "standard data files" and linked to the database. They can be easily transformed to any desirable format by a code. Here we present two simple computer programs of this kind. ... When running the code, you can specify columns in the output file: wavelength, energy (eV) or wavenumber (cm -1 ) as the first column, and complex refractive index or dielectric function as the second and third columns. ...

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• AI SPbU library of scattering codes

asncombine -- Process and combine images in one or two NICMOS associations asncombine association . ... set to yes to include error planes in co-added images error. background . ... This is useful to use different background subtractions for different images. fheader . set to yes in order to multiply the background by the value of keyword "factor" in the image header. ... Set to yes to use quadrants statistics save in the image header from previous runs of asncombine. regquad1 . ...

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• ST-ECF Grism Spectrum Software for NICMOS Grism Data
• HSTPOLPOINTS (V1.00) --- May99 --- HSTPOLPOINTS (V1.00)

This diagram shows the six superimposed "layers" of the CSS table model. This diagram illustrates the algorithm for calculating a cell's final background. ... The diagram shows how, looking down on the six rectangles, one may compute the background color of each cell. ... A cell without a background color in the top layer is depicted as a "window" onto the lower layers, which give its final background color. ...

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• Long description of example illustrating background calculation
• Explanations for solar physics computing page
• Thomson's method of spectral estimation

... March 9, 1997 . COBE Hotspots: The Oldest Structures Known . Credit: DMR , COBE , NASA , Four-Year Sky Map . ... These spots are the oldest, most distant structures known. ... By studying the size and distribution of the spots found with COBE and future missions , astronomers hope to le