The limits of the object are defined in the keyword 
. 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 
and a number of iterations
. 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.