UVEX (1800 l/mm grating)

[Christian Buil]

UVEX optical configuration if you use a 1800 l/mm grating and a F/10 input beam (ThorLabs grating, blaze 500 nm) :



It is nearly the max. spectral resolution configuration for UVEX.

The incidence angle on the grating is 24,3°, the diffraction angle (for Halpha) is 51,3°. The anamorphic factor is cos(24,3) / cos(51,3) = 1,46, so the wide of the 23 microns slit (physical) is 1,46 x 23 = 34 microns. The measured spectral resolution power at Halpha level is R=7200 (just half of a Lhires III 2400 lines/mm spectrograph).

Some spectra (H2O telluric lines removed) :











Christian B.

[Christian Buil]

Test of the 1800 l/mm grating for the UV/blue spectral region.
By using a 23 microns slit and a F/10 telescope, the spectral resolution is about R = 4200 at 400 nm.

Aspect of the classical Vega profile:



Deneb (sharp spectral lines):



Be stars:


(note resolved emission lines on the Balmer jump)





Symbiotic stars (of course, very faint UV continuum):





(Note: by comparison with a RC telescope of a old C8, the C9.25 StarLight optic absorb significantly the UV flux (specific AR coating)).

Christian

[etienne bertrand]

Merci pour ces reports Christian.

Pour les comètes tu penses que l'UVEX est meilleur que l'Alpy ? (je ne sais pas si le terme est bon mais permet il de résoudre mieux les spectres que l'Alpy dans les bandes de Swan avec une résolution meilleure ?)