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General :
Observations :
Operations :

Procedure:	Image Quality of SOFI
Updated : Created:	January 2004 - Malvina Billeres October 2001 - Malvina Billeres

1- The Observations you need

For SOFI you can use the template Image_Quality_SOFI.obx (click on the link to retreive it if you need).
You will have 36 positions on the detector (36 fits files).

If you prefer you always can do manually the offset to have the 36 positions on the detector. The main advantage of this method is that you won't have any problem of elongation due to the telescope motion. You can pick the offset values in the template above.

2- The programs you need

All SOFI scripts and plot programs are ready:

- imagequality.cl : a iraf script to reduce your data;

- image_quality_3.0.py : a python script that processes the data;

- plot_mac.f : a fortan program with smongo inserts to plot the results;

3- The reduction of the data

The iraf script named imagequality.cl simply substracts the median sky and divides by flat. (so you need flats !!!). The script needs as input a list of the raw data (liste*.lis), some flats and it asks to you the prefix you want to give to the reduced files (ex: LF_J). The final files must be called LF_J_001.fits to LF_J_036.fits. You have to run it inside iraf, of course.....

4- The determination of the image quality

Now you have to use the python program imagequal_3.0.py to extract the star, calculate the ellipticity and plot some graphs. imagequal_3.0.py needs as input:

liste.txt:
example of liste.txt:

./SOFI_first_try/DATA/Small_Field/images_reduites/	liste_J.txt	SMALL	small_J
./SOFI_first_try/DATA/Large_Field_FE/images_reduites/	liste_FE.txt	LARGE	FE

First column: directory where the reduced images are
Second column: name of the list of all the fits files
Third column: instrument/configuration : SUSI - EMMI - LARGE - SMALL - FE _ SO (the last 4 choices are for SOFI)
Fourth column: the prefix for the final files <prefix>

plot_mac.x: the executable file of the plot_mac.f program. A fortran/Smongo program who plots the final results.BE sure that the plot_mac.x is already compile on the machine you are working on: problems of uniformity of the machines in La Silla, the librairies are not updated.......... If the program is not compiled on the machine you are working, compile it using the command :

f77 -g -o plot_mac.x plot_mac.f /home/scisoft/sm/sm2_4_2/src/libplotsub.a
/home/scisoft/sm/sm2_4_2/src/libdevices.a /home/scisoft/sm/sm2_4_2/src/libutils.a
/usr/X11R6/lib/libX11.a -lm

be sure that the path for the librairies correspond to what you have on your computer.

The python program reads inside the list file the name of all the fits files and do an extraction of all the objects in the field with SEXTRACTOR. The extraction parameters are in default.sex(they can be modified). For each file, a sex*.cat file is created with all the positions encountered by SEXTRACTOR (here are the other files needed by SEXTRACTOR default.conv and default.param).
imagequal_3.0.py selects inside each sex*.cat file THE position that corresponds to the number of the file and the predefined position (where the star you are looking for should be according to the template). The numerotation of the files from 001 to 036 is really important to do the link between the fits file and the position of the star.A file smongo.dat is created with the needed parameters for the 36 files : ximage, yimage, A, B, rotational angle.
When the extraction is done, imagequal_3.0.py calls plot_mac.x to plot the final graph : there are 3 options 1- xterm 2-printer 3-ps file. It's important to know which option is wanted because the plot cannot be repeated whitout star again the complete procedure.

At the end you have a <prefix>.dat file and <prefix>.ps file.

To start the python program, just enter %> python imagequal_3.0.py

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Last Update: January , 2004 (Billeres Malvina)