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: http://www.naic.edu/alfa/performance/spectral-scans/Tcal/wide/about-out.shtml
Дата изменения: Unknown Дата индексирования: Wed Feb 6 03:40:05 2013 Кодировка: Поисковые слова: hst |
The .out files contain the data displayed in plots of the wide spectral scans of High-CAL and the respective bets-fits obtained. Each of the 14 pipelines has a separate file.
What to expect inside this file ?
The top line has numbers of samples sets (rows) to follow, and the number of columns in addition to the frequency listing.
The first column in the subsequent rows contains frequency, and other columns have the corresponding best fit high-CAL values for a given polarization channel as well as the raw estimates for the same, in that order.
The subsequent lines in that file may contain some plot/data details that you may ignore.
These files are made available for interested people to download.
A fortran code fetch_from_best_fit_model.f is also made available, for use with ALFA_TCAL_POLY_FIT.PARAMETERS containing the best-fit model coefficients.
Note: Since the measurements for the beam0-pol_1, beam 5 (both pol.s) were missed from the set on tJD:53228 (due to the pre-amp and WAPP problems respectively), the corresponding fits & .out files missing. However, the subsequent measurements on tJD:53278 have provided the full set of TCAL for the 14 pipelines. The Tsys & Gain scans of all channels do show less undue modulation compared to when an appropriate model of Tcal is not available for the mentioned pipelines. The residual modulations is possibly a result of spectral variation in the apparent TCAL that is not modelled well enough (even by a 100-order fit), or due to standing waves that donot get calibrated out.