Dithering spectra

[Andrew Smith]

Hi, I am writing a script to automate the collection of spectra and have the option of moving the star along the slit for each sub exposure. This is a bit like dithering the image as done by astrophotographers to eliminate artifacts due to hot or cold pixels etc. Does anyone have a view on the value of doing this for spectra? Can ISIS manage a shift in the spectra of say 10 to 15 pixels along the slit?

Thanks Andrew

[Terry Bohlsen]

I wouldn't do it.
If your slit isn't perfectly vertical then it will affect the calibration as well.
It is easier just to use good dark frames.
Terry

[Olivier GARDE]

With ISIS, you can eliminate bads pixels with the cosmetique fonction and that's work well.

Dithering isn't the solution to process spectra.

[Andrew Smith]

Thanks for the advice - regards Andrew