Last revision April 8, 2019, T. Pribulla

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The data are ALWAYS reduced on per-night and instrument basis, several
   chip temperatures, different binning, various filter and exposures
   are allowed
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1. Copy all [dark, flat, object] FITS frames from ONE night to 

   REDUCE/raw/

   [N.B. IMAGETYP must be either "DARK", "LIGHT", "FLAT"]

2. start IRAF "cl" in "REDUCE/" 

3. Check if the "INSTRUME" FITS header keyword equals to 
   one of the allowed values:

   "G1_50cm_SBIG"   =  new SBIG since 2010
   "G1_60cm_FLI2"   =  new FLI since July 2012
   "G2_15cm_SBIG"   =  old SBIG (2003) in the Maksutov focus
   "G2_60cm_CTK1"   =  old FLI (CTK1 from Jena) since July 2009 
   "G2_60cm_MIG4"   =  Moravian Instruments G4-9000
   "G1_60cm_SBIG"   =  new SBIG since 2010
   "G1_18cm_MIG4"   =  Moravian Instruments G4-9000 in the Meniskas focus 
   "G1_18cm_FLI2"   =  new FLI since July 2012 in the Meniskas focus
   "G1_18cm_SBIG"   =  new SBIG since 2010 in the Meniskas focus
   "G1_60cm_Eshl"   =  eShel spectrograph 


   If not, use "hedit raw/*fits" in cl and set value of "INSTRUME", e.g.:

   hedit raw/* fields="INSTRUME" value="G1_60cm_SBIG" verify=no

4. Make master darks and master flats frames in cl:

   red12
 
   [Notes: Flats require corresponding dark files. Good master 
    frames (the user prompted to check) are written to directory 
    /data3/FLAT and /data3/DARK and subdirectory depending on the 
    instrument. Only multiples of 5 K, of the CCD temp are allowed. 
    Flats have predefined ADU levels to be accepted. Both flats and
    darks are median combined. Previous master calibration files for the 
    given night are clobbered. Minimum number of good 
    darks/flats was set to 5. Raw dark/flat frames used to produced 
    masters are automatically archived in /data3/YYYYMMDD.GX directory]

    [N.B. # of darks/flats coming into the median is given 
    in "NCOMBINE" keyword added to the master flatfield.]

5. Dark and Flat correction of the object frames and searching 
   for stars in the frames

   red34

   [Note: reduced frames are stored in directory "/tmp/$USER/reduced/"]
   [N.B.: Searching for stars in big frames requires lot of CPU and
    typical runtime is 2-3 sec/frame]
   [Note: Object frames must contain IMAGETYP="LIGHT" in the
    headers to be selected]

6. Check if catalog file at 

   https://www.sto.astro.sk/uploads/files/katalog.dat

   contains your field - for e.g., DV Psc there must be file "dvpsc" 
   [5 starting characters of the filename]. If not, ask me [=Pribulla]
   to add it.

7. Check if the directory "../STARS" contains file with the coordinates
   of the variable and comparison stars. They must be given in degrees.
   The filename for DV Psc must be "dvpsc.reg". The contents should 
   look like (RA2000, DEC2000):

   3.2881572 5.5948720
   3.2658680 5.5821691
   3.2710961 5.6317022

   The first line is for the variable, the second for the comparison, 
   the third for the check star. In the case of simple ensamble photometry
   (more than three stars listed), first stars is variable, all other are 
   comparisons.

   [N.B.: coordinates can be saved using ds9 (Saoimage) using an astrometrically 
    reduced FITS CCD frame (with the WCS written to the header). Click on the 
    targets (autocenter must be on) in the above order and go to Region/Save, 
    then give the output file and select Format "xy" and Coordinate system 
    "WCS".] 

8. Astrometry and photometry of the reduced CCD frames

   red56 hs223

   where hs223 is the field to be reduced
   
   After the astrometric reduction the light curve is plotted. You can select 
   the optimum aperture ("a" and "s" keys), set low and upper limit to determine
   standard deviation ("l" and "u"), remove bad points (pressing 'd' while on 
   the point); "q" continues to the next filter. "r" re-scale the plot). 
   Further possibilities are shown in the terminal window.

   The reduced frames (folder "/tmp/$USER/reduced/") are automatically 
   moved to e.g. "/data3/20120926.G1/". 
   Frames astrometrically, dark and flat corrected have now suffix "adf_".
  
   [Note:  Raw object frames resulting in good astrometric plate solution 
    are automatically archived in /data3/YYYYMMDD.GX directory]

   [Note: Resulting aperture photometry is written to files in folder according 
    to the object, night and dome, e.g. ../DATA/BSUMa/20120912.G1/V.dat]

   [Note: The process results in temporary files in the "/tmp/$USER/temp/" 
    directory. Files with extension "str" contain lists of detected stars (maximum
    40 brightest), files with extension "mat" give matched frame and catalogue
    objects used to perform astrometric (plate) solution.]

   [Note:  The output photometry files (U.dat, B.dat, V.dat, R.dat, I.dat, C.dat)
    contain: HJD, V-C1, error V-C1, C1-C2, error C1-C2, airmass, x and y-pixel coordinates
    of V, FITS filename]

   [Note:  In the case of ensamble photometry (with comparison stars C1, C2,
    ...Cn and corresponding plate comparison Cp) the files contain HJD, V-Cp, error
    V-Cp, C1-Cp, error C1-Cp, C2-Cp, error C2-Cp,...., Cn-Cp, error Cn-Cp, 
    airmass, x and y-pixel coordinates of V, FITS filename]
    
9. After browsing and saving the light curves for all objects in given night
    you can clean the working directory. 
   [You must be in the "REDUCE/" folder]

   ./clean