. This diagram shows a small table with three transparent cells and illustrates how their final background is determined. The table consists of two rows. Four (labeled) cells lie in the first row, but the second cell spans the first and second row. The first, third, and fourth cells of the second row are "empty". Each non-empty cell has a red background and a double black border. Each empty cell has the table's background color (specified as #ff0) as its own. Return to image.

... Near Infrared Camera and Multi-Object Spectrometer Instrument Handbook for Cycle 17 > Chapter 9: Exposure TimeCalculations > 9.1 Overview: Web based NICMOS ETC . 9.1 Overview: Web based NICMOS ETC . ... The imaging NICMOS WWW ETC is documented in an Instrument Science Report (Arribas, NICMOS ISR-2004-002 ). ... Additional information on the ETC and its structure can be found in the Instrument Science Reports (ISRs) posted on the STScI NICMOS Instrument Web page. http://www.stsci.edu/hst/nicmos/ . ...

... This example uses an error array to determine the errors in the radial profile. task: imcnts . ... xs imcnts err=vigsnr_err expo=xdata$snr_exp.pl expthr=95.0 bkgdex=xdata$snr_exp bkgdth=95.0 bkgderr=vigsnr_err # Run the imcnts task with the appropriate parameters source image file : vigsnr # vigsnr.imh source region descriptor: a 300 300 0 50 n=5 # 5 annuli centered at 300 , 300 , 0 and 50 pixels min/max radius background image file or cts/pixel: cr # From the same ...

... 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. ...

XMM-Newton Science Analysis System Page: 1 esensmap July 1, 2008 Abstract Calculate EPIC sensitivity map 1 Instruments/Modes Instrument Mode EPIC MOS: IMAGING EPIC PN: IMAGING 2 Use pipeline processing yes interactive analysis yes 3 Description This task creates a sensitivity map giving point source detection upper limits (vignetting corrected source count rate corresponding to the likelihood of detection as speci ed in the parameter le) for each image pixel. ...

BACKGROUND . ... Electron bombarded silicon (EBS) gain makes the CCD interesting for keV electron detection. Ionizing particles absorbed in silicon create electron-hole pairs at the average rate of one per 3.64 eV incident energy. ... The variance in the number of electron-hole pairs created is given by the Fano factor for silicon (.1-.2) times the number of pairs created. When we use a CCD as a detector of ionizing particles, we would like to collect all of the electrons created. ...

Program: HIFLUX Purpose: derive fluxes and standard deviations from HIRAS images File: hiflux.src Category: IRAS Author: Do Kester Keywords: *** MAPS= Max number of maps to be processed simultaneously [4] All maps should be of the same size, and presumably of the same field. ... COLIND= Color index for plot colours [standard] *** LOCAL= Calculate local background [No] The background is determined as the median of the points within the form selected with SELECT=. ... But see also RADIUS=). ...

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. ...

... The formation of spectral disturbances of Cosmic Background Radiation (CBR) during the period of hydrogen recombination at redshift is considered. Special attention is paid to the decimeter and meter wavelength band. ... In this paper we will return to the question on the spectral lines caused by recombination of hydrogen discussed by Dubrovich (1975) , in the longer wavelength part of spectrum of the CBR. ... A synthesis of recombination radiolines spectra is divided into several stages. ...

Next: Imaging Polarimetry with NICMOS Up: NICMOS Data Calibration and Previous: The Photometric Performance of . ... NICMOSlook and Calnic C . ... Extracting spectra from a large number of NICMOS grism images requires a convenient interactive tool which allows a user to manipulate direct/grism image pairs. ... NICMOSlook and Calnic-C are two programs that were designed to take advantage of the fact that the NICMOS grism mode typically consists of taking both a direct and a grism image. ...

These are very prominent absorption lines is most all galaxies. ... These pair of absorption lines will appear in all the spectra and they should be your principle source for determining the redshift. ... When this applet opens you will see an iconic representation of galaxies in the left hand side of the applet and a target area in the right side of the applet. ... Note: What you are doing in this excercise is identical to what Hubble did in the 1920's and you are using the same galaxies. ...