ISIS non eShel echelle

[Andrew Smith]

I have been building an echelle spectrograph similar to the eSchel and would like to know if I can use ISIS to process its spectra. It looks like I can but one problem is I don't have ( and can't afford at present) a ThAr calibration lamp. Is it possible to extract the spectra without wave length calibration?

Thanks Andrew

[Martin Dubs]

Hi Andrew,

I have built my own echelle and I use a FeAr hollow cathode lamp. ISIS works well with this, you have to create your own line list (see eg here: http://iraf.noao.edu/specatlas/) and adjust the geometrical and optical parameters of the echelle, which is a bit tricky, but once you have found the correct settings it works perfectly. Instead of a HCL you can also use another lamp, e.g. from a fluorescent starter, which contains a lot of Ar lines. The problem is then to assign the proper lines. You can always use the uncalibrated spectra of each order for a start.

Regards, Martin

[Andrew Smith]

Hi Martin, that is encouraging! I don't seem to be able to find the ISIS ThAr line list could you point me at it? I have Richard Walkers RELCO line list so could start there.

I may be back for more help!!

Thanks Andrew

[Martin Dubs]

Andrew,

it should be in the subfolder calib, named lines.lst.

Martin

[Andrew Smith]

Thanks Martin, I think I understand now. In reality where it talks about the ThAr calibration you can use any calibration source you have as long as it has enough lines and you provide the list. I think with your help and Richard Walkers SC480 emission line atlas I am on my way!

The only tricky bit for me is adjusting the camera angle because at present my square FLI camera is firmly bolted to the optical table (plywood base).

I eventually released I need to rotate my camera 180 to get the correct orientation of the spectra for processing and using the atlas fully identified all the lines in order 34. I know it seems a small step but it looked a long way off this morning

Thanks again Andrew

[Martin Dubs]

Hi Andrew,

I do not know which camera and recording software you use, but I use Audela for spectra recording. There you have the possibility to mirror or rotate the image while recording, in addition the numbering is compatible with ISIS. So you do not have to change the mounting of your camera. There is even the possibility to process the echelle spectra in Audela, but this I cannot really recommend. I have not used it for years. With Maxim e.g. you can run a batch process to rotate or flip your images into the correct orientation. So you have several choices.

Regards, Martin