Nigel Evans has derived the dispersion equation for my system so I can calculate the wavelength for any pixel value in the spectrum.
Hi Mike,
I used a mix of Visual Spec and ISIS to process your spectrum (VSpec to remove the sky background and digitise, ISIS to derive the dispersion equation and rectify) See
https://britastro.org/forums/topic/variable-star-section-circular-for-september-2026-number-209#post-642748
but there are other packages around which could do this eg RSpec, BASS and others. The steps are the same and essentially those I describe here
https://britastro.org/document_folder/baa-document-store/past-talks/spectroscopy-workshop-at-the-nlo-oct-2015
specifically “Low resolution slitless spectroscopy”
You still need a reference point in the spectrum to be able to do an absolute wavelength calibration though, hence my question about the possibility of including an image of the star in the same image.
We are off topic here though so we could either continue this in spectroscopy section of the forum or off line if you like
Cheers
Robin
