3 A error

Dr Andrew Smith

Simple answer  is I don’t know.

Can you process a calibration frame as if it were a star? Rename it so ISIS is not confused. Are the lines in the right place? 

If they are then I can only think it is the fact that the calibration light is not illuminating the spectrograph in the same way as the star.

If the are not then it may be other issues like undersampling.

Regards Andrew