spectro-aras.com

Une page consacrée au test du spectrographe UVEX (UltraViolet EXplorer spectrograph) :

http://www.astrosurf.com/buil/UVEX/index.html

A page devoted to the description and tests of UVEX spectrograph(sorry in french but easy
to translate):

http://www.astrosurf.com/buil/UVEX/index.html



Exemples de spectre (comparaison avec un spectre CALSPEC (StSci)) :





Christian Buil

Hello Christian,

Very interesting - thanks for posting your information and results.

As the width of the spectral trace increases (due to astigmatism), you can see a distinct 'separation' start to appear. I'm curious to know if you think this is the shadow of the comparatively large secondary in your fast Newtonian. I've conducted similar tests using a fast RC with the Lhires and see a similar artefact, which seems more obvious with fast reflecting telescopes with large secondaries than it is with 'slower' SCT designs.

Regards,

Paul

I confirm Paul, the separation is induced by the secondary mirror on a defocused image
(along one axis, here spatial direction).

Christian

Hello Christian:

What impact has the spherical aberration of the two mirrors?
It could improve the results with two parabolic mirrors?

Regards, Joan.

Joan, use of high aspherical mirror can significantly improve the spectra qualities, but simple paraboloid figures have not
real impacts. The aspherisation increase also the cost of the spectrograph (no standard optics) - a real problem.

Christian