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##

Extracting the Spectrum

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**.

*Petra Nass*

*1999-06-15*