FOCAS IFU

20220817 => 20230831

bias_overscan.py was modified. The previous version showed a systematic error of a few counts after the bias subtraction.
The new option -bo was added to bias_overscan.py to use an upper overscan region for a bias subtraction instead of template bias files. See the detail here.

20210818 => 20220817

New scripts (objecterr.py and errestimate.py) were introduced for creating an error data cube thanks to Isobe-san's contribution.
Some scripts were modified for the error estimation.
rmidpoints.py was newly implemented. This automatically eliminates most of bad data points identified by identify_dispersion.py.
In the sky subtraction process, object.py uses the old script for old data before August 2021 because they used the old sky slit.

20200210 => 20210818

This version was adapted to the new sky slit.
The option“ql” was implemented in some scripts.
This version was adapted to VPH680+SY47.
From this version, a data cube is trimmed after sky subtraction, and the wavelength range becomes the one which is cov ered in the whole field of view.

20201003 => 20210210

zero_padding.py is now executed at the end of object.py when users demand it.
In mkedgeimage.py, neighboring spectrum areas are not padded with 0 to avoid slight uncertainty (< 1 spatial pixel ~ 0.2 arcsec by default) of defining spectrum edges.
Explanations of comp_emis_position.py and show_skyshift.py are added in this manual.

20200213 => 20201003

Sky subtraction method has been modified to decrease residuals of sky emission lines. In the new method, wavelength deviations between a sky spectrum and object spectra of each spaxel are derived from a comparison data. For this purpose, a comparison data cube is created.
Previously, blank pixels around spectrum edges are padded with NaN in transform.py. Now this function is moved to the separate script, zero_padding.py.

No version number change

Incorrect descriptions about the arguments for standardstar.py and object.py have been corrected. There was no description about the required argument, "Comparison ID for dome flat", in the previous manual.

20200210 => 20200213

In transform.py, blank pixels are padded with NaN. In the previous version, they are padded with 0.
After flux calibration, unit has been changed from ergs/s/cm2/A to 1E-20 ergs/s/cm2/A. Because of this change, Auto Plot 3D function of SAO image ds9 works well.

20190621 => 20200210

"os.path.join" has been used to add a path to a file name.
In fitcoord_dispersion.py, xorder and yorder have been changed from 7,7 to 5,3.
In terms of WCS, only the CD matrix has been used. In the previous version, both the CD matrix and the CDELT keywords were included in the FITS header.
Some minor bugs have been fixed.
In Section 4.2.6 of the manual, the explanation has been slightly changed, and Figure 10 and Figure 11 have been changed.
In the manual, figure numbers have been corrected.

Reduction software