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Combine Example

As an example let us create a master flat frame by combining all calibration flat field associated to a science frame. As an example we take the science frame susi0100.bdf. Suppose the association table contains 4 flat field associated with susi0100.bdf. To do these into the master flat field we enter:

COMBINE/CCD FF susi0100

The command will first go the association table and select all rows that have the science frame susi0100.bdf in the column :SC. From this subtable it will store all frames in the column :FF in a temporary MIDAS catalogue called susi0100_ff.cat. This catalogue will be used as input for the final combining. Since we didn't specify the output frame name, the default naming convention will be used: the output flat will be susi0100_ff.bdf. The output on the screen and stored in the MIDAS log file will look like ( VERBOSE=YES):

    Combining FLAT frames: Input=susi0100_ff.cat; output=susi0100_ff.bdf 
 
    Statistics of frame no. 0: 
    area [@60,@10:@1070,@1020] of frame 
    minimum, maximum:                  5.560000e+02   8.654000e+03
    mean, standard_deviation:          6.101316e+03   1.913127e+02
 
    Statistics of frame no. 1: 
    area [@60,@10:@1070,@1020] of frame 
    minimum, maximum:                  8.390000e+02   1.276900e+04
    mean, standard_deviation:          8.313817e+03   2.569877e+02
 
    Statistics of frame no. 2: 
    area [@60,@10:@1070,@1020] of frame 
    minimum, maximum:                  4.220000e+02   1.046500e+04
    mean, standard_deviation:          5.622723e+03   1.722370e+02

    Method=avsigclip, low=  0.00, high=  0.00
    lowclip=  3.00, highclip=  3.00
        frame #        Ncomb   Exp_time   Mode   Scale   Offset   Weight
    susi0142.bdf         1       1.00 571.878   1.093       -0    0.333
    susi0140.bdf         1       5.00 862.392   0.725       -0    0.333
    susi0143.bdf         1       5.00 441.692   1.416       -0    0.333
    --------------------------------------------------------------------
    Statistics of output frame susi0100_ff    : 
    area [@60,@10:@1070,@1020] of frame 
    minimum, maximum:                  6.045866e+02   1.023942e+04
    mean, standard_deviation:          6.886717e+03   2.060752e+02

                       Ncomb   Exp_time   Mean    Mode  N_undef
    susi0100_ff          3      3.933 6886.72 623.478        0
    Undefined pixels, set to `null value' (=     0.000000)
    --------------------------------------------------------------------



Pascal Ballester
Tue Mar 28 16:52:29 MET DST 1995