Combining two spectra from two different epochs

rohit wrote on Dec 01, 2009

I would like to combine two spectra taken on the same instrument with the same setup of the same star but at two different epochs (particularly 5 months apart). How do I combine them?

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Mike Fitzpatrick wrote on Dec 01, 2009

SCOMBINE is normally used to combine spectra. I assume you mention the time difference because you need to remove some the velocity components, see the RVCORRECT task to compute the heliocentric velocity for the time of observation and the DOPCOR task to apply a correction so the data are both in the rest frame.

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Last post on Dec 01, 2009