This page gives information relevant for the March 2008 run only. The first version of Upena, v0.1, was used in March. After March, Upena 1.0 is used, and is a little bit different than v0.1.
Upena v0.1 provides reduced data in FITS format only; a Linux tool (upena_LE_table) was developed to extract from the FITS file the ASCII table usually provided with Libre-ESpRIT, and take as input one FITS file at a time. All data for the March run has already been converted to the *.s format. Each FITS processed data is associated with 2 *.s files, with the same odometer number. One file has a 'n' in its name, for the reduction with the continuum normalized to 1; the other file has a 'u' in its name for the reduction done without any continuum normalization.
For example, the file 987123i.fits was converted to produce 987123in.s and 987123iu.s, and the file 912345p.fits produces 912345pn.s and 912345pu.s.
FITS format of reduced spectra [Back to Top]
To increase the legacy value of the reduced spectra produced by Libre-ESpRIT, FITS keywords are added to the file than contains the reduced data. The FITS keywords from the original raw FITS files are copied over. The reduced spectra with its continuum normalized to 1 follows; a few FITS keywords report on the reduction (see an example), and the table follows. The file ends with the reduced spectra with its continuum not normalized, again with FITS keywords and data.
The following Linux tool
upena_read_table can be used to browse
through a file, for example, by typing
upena_read_table 978123p.fits | more
Standard Libre-ESpRIT *.s file are also provided to PIs.
Data reduction for PIs [Back to Top]
The final reduction component re-reduces all the data with additional flats taken in the morning (if available), and performs the polarimetric calculations if appropriate. All data are reduced, whether the exposures were validated or not (except for the first 5 nights of the first run where the 4th exposure of a polarimetric sequence is useless); if Libre-ESpRIT can reduce an exposure, regardless of Image Quality or extinction by clouds, the exposures are reduced. All data are reduced with the continuum normalized to 1, and also not normalized; PIs do not need to make a special request regarding continuum normalization. In QSO mode, the only option available to PIs is to not use the telluric lines to correct the wavelengths (the w option); in that case, an additional set of reduced data will be provided to PIs. For Stokes U measurements, the sign of the Stokes parameter (column 3) needs to be flipped (inverted). A comment in the FITS header indicates this.
The naming scheme for the reduced files is the following: regardless
of the Observing Mode used, each single FITS raw file ( For PIs who have requested the w option, the additional set of
spectra will be called Files distributed and their
content
Filename Raw/Processed File type Note
b.fits Raw Bias c.fits Raw Comparison a.fits Raw Fabry-Perot f.fits Raw Flast x.fits Raw Focus Not needed by PIs o.fits Raw Object i.fits Processed Intensity Continuum
normalised (first table) and not normalized (second table) in.s Processed Intensity Libre-ESpRIT
format, continuum normalised to 1 iu.s Processed Intensity Libre-ESpRIT
format, continuum not (un) normalised p.fits Processed Polarization Continuum
normalised (first table) and not normalized (second table) pn.s Processed Polarization Libre-ESpRIT
format, continuum normalised to 1 pu.s Processed Polarization Libre-ESpRIT
format, continuum not (un) normalised j.fits Processed Intensity with w
option Continuum normalised (first table) and not normalized
(second table) jn.s Processed Intensity with w
option Libre-ESpRIT format, continuum normalised to 1 ju.s Processed Intensity with w
option Libre-ESpRIT format, continuum not (un) normalised r.fits Processed Polarization with w
option Continuum
normalised (first table) and not normalized (second table) rn.s Processed Polarization with w
option Libre-ESpRIT format, continuum normalised to 1 ru.s Processed Polarization with w
option Libre-ESpRIT format, continuum not (un) normalised i/p/j/r.out output file from the Libre-ESpRIT
reduction Contains useful information on S/N ratios, radial
velocity corrections, etc. ff Processed Average flat
field th*.s Processed Comparison exposure (1D), not
calibrated in wavelength th*.ws Processed Comparison exposure (1D),
calibrated in wavelength geom*dat geometric calibration
data geom*out geometric calibrations output file
wcal*dat wavelength calibration
data wcal*out wavelength calibrations output file
http://www.cfht.hawaii.edu/Instruments/Spectroscopy/Espadons/
This CFHT Web page is maintained by Nadine Manset (manset
-=AT=-
cfht.hawaii.edu)