Notes

• A suitable flat-field spectrum, arc spectrum and standard-star spectrum should previously have been reduced and filed with the calibration system.

• Sky-object pairs may be observed in any sequence (for example sky-object-object-sky or object-sky-object-sky). Any observations with telescope offsets greater than 30 arcsec will be assumed to be a sky position. It is recommended that the observation types are set to OBJECT and SKY as appropriate (this is essential if your offsets to sky are smaller than 30 arcsec).

• Variances are propagated if KAPPA 1.0 or later is available. A warning is displayed if variances are lost.

• A variant of this recipe, EXTENDED_SOURCE_NOSTD, is available which does not divide the spectrum by a standard-star or flux calibrate the spectrum. It may be useful to specify this recipe on the command line when running ORAC-DR if you choose to defer observation of your standard until after you have observed your object.