... Posts tagged ?spectra? ... Leccardi & Molendi (2007) have a paper in A&A ( astro-ph/0705.4199 ) discussing the biases in parameter estimation when spectral fitting is confronted with low counts data. Not surprisingly, they find that the bias is higher for lower counts, for standard chisq compared to C-stat, for grouped data compared to ungrouped. ... Tags: bias , C-stat , chi-square , chisq , Cstat , Fitting , parameter estimation , Peter Freeman , spectra . ... 1 Comment . ... Entries RSS . ...

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... Purpose: To measure changes to the properties of the data when the spectra are moved over a range of cross-dispersion and dispersion positions. Description: This program will obtain COS FUV spectra of external targets at a range of cross-dispersion and dispersion positions in order to evaluate the optical performance of the spectrograph at different lifetime positions. ... Link to Cycle 17 Science # Use the GO + GTO Phase 1 exposure listing and derived statistics # posted on WWW. ...

... NB The next 2 columns will only be present if the parameter usecat has been set to true . ... Source parameters such as count-rates, magnitudes and semi-major axes, are given in sub-tables-eg the column CORR_RATE is actually a vector column containing the values for each filter. ... QUALITY FLAGS Each source has an associated ``quality flag''. ... 0 1 Source lies above one or more bad pixels . ... QFLAG The quality flag for each source in each filter obtained from the input source-lists. ...

. Comment on J1842+7946 . Comparing the brightnesses of the two main features seen in our 5 GHz image with higher frequency VLBI images available in the literature (at 8.4 GHz from the USNO database and at 15 GHz by Kellermann et al. (1998)), one can conclude that the NW component has a steeper spectrum since the SE one becomes relatively stronger as the observing frequency increases. VLBApls home page . Last modified: 16 Oct 2000

... Submitted by Paul Benni on 11/27/2013 18:38:14 . Comet C/2013 R1 Lovejoy (November 8) . Morning image (Nov. 8) of Comet Lovejoy. ... C8 EdgeHD SCT with Hyperstar (f/2.1) and ST-8300C ccd. Image is uncropped from the Hyperstar setup. Compare to my Comet ISON image with the same image scaling. Interesting how much brighter and larger Comet Lovejoy is now compared to ISON. ... Copyright (c) Amateur Telescope Makers of Boston, Inc. ...