Star Analyser and Rainbow Optics comparison Spectra

[Jack Martin]

Any comments?

Jack

Comparison Spectra.pdf

[andrew s]

I guess it is what I would have expected - greater dispersion with the 200l/mm v 100l/mm but without more info it is hard to comment. For example I assume they are in a the convergent beam and processed in exactly the same way?

Andrew

[Jack Martin]

Andrew,

Your comments are correct although processed in the same way it is easier to obtain spectra of fainter stars with the Star analyser because of its lower dispersion.

Regards,

Jack

[phxjeff]

I have used both the Star Analyser and Rainbow optics. The dispersion for the Star Analyser can be changed by putting the cell further from the detector to make it larger. I use the Star Analyser for both visual work, with an eyepiece and with a DSI Pro II for imaging with an 8" LX90. I also use a Lhires III with 2400 l/mm grating with a 12" LX200 for high resolution work. I process the spectra with RSpec. After struggling with the French freeware RSpec is a refreshing change.

For use with the DSI Pro II I have two configurations. I have the low profile adapter on the camera with a dark slid. One configuration I screw the Star Analyser into the nose piece. This gives me both the star (zero order spectrum) and first order spectrum. By screwing the Star Analyser in the nose of a star diagonal the DSI Pro II fills the window with the spectrum.

I have attached an image with two line profiles of Vega I took last night. The top is a 0.03 second exposure with the Star Analyser in the nose of the DSI Pro ii. The second is 0.18 second exposure with the Star Analyser in the nose of a Star Diagonal. Both were taken with an 8" LX90 and processed with RSpec. No calibration has been performed on the profiles yet.

Jeff

[phxjeff]

It appears the attachment didn't work so here is another try.

Jeff

[Merlin66]

Jeff,

The TransSpec spreadsheet, available on the Rspec group will help determine the resolution and plate scale for the various gratings.

The resolution of a grating is around 30A. Getting a bit more dispersion, depending on the CCD pixel size can make the analysis of the spectrum a little easier.

Good results. Well done.

[Jack Martin]

Jeff,

I use the French freeware Iris + V Spec and find it OK what problems are you having?

How do you observe with the SA?

What is a dark slid?

Nice spectra of Vega well done.

Regards,

Jack