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Extracting the Spectrum

The limits of the object are defined in the keyword \fbox{OBJECT}. A simple row average is performed by:

Midas...> SET/LONG OBJECT=189,196
Midas...> EXTRACT/AVERAGE corr56 ext56

which is equivalent to the general MIDAS command:

Midas...> AVERAGE/ROW ex56 = corr56 @189,@196

An optimal extraction algorithm is also available, requiring the knowledge of the CCD detector parameters, a preliminary definition of the sky background, as well as the values of a polynomial order \fbox{ORDER} and a number of iterations \fbox{NITER}. The command:

Midas...> EXTRACT/LONG ccd0056 ext56 sky56

applies the Horne's optimal extraction algorithm to the image ccd0056.bdf and performs the sky subtraction to generate the output image ext56.bdf.

Petra Nass