I made a 3D printed version of the UVEX spectrograph, a first for me. UVEX (UltaViolet Explorer) is a Czerny-Turner design
(see http://www.astrosurf.com/buil/UVEX/index.html). Here the actual optical definition:
Low cost and light spectrograph (300 grams without the camera, 670 grams with an Atik414EX camera), no guidance system integrated, no slit at this stage (!)... designed to be operated only on small telescopes (apochromatic refractor, small Newton telescope). Some view of the first 3D printing prototype (more optimized version is coming, thanks Pierre Thierry and Franck Vaissiere for the help):
The first light on a Kepler 200 mm f/5 telescope:
(note use of a CMOS camera, a ASI1600MM cooled model).
A Vega spectrum by orienting the grating to capture the entire visible spectrum onto the ASI1600MM large CMOS sensor :
The great advantage of the system is the high degree of achromaticity, which allows to capture a correct spectrum over a very broad spectral range (R = 700 approximately). It is also possible to orient the grating to optimize the observation of ultraviolet (the primary goal!). Nothing else is changed in the spectrograph (it is also possible to obtain a good spectrum of the infrared part with the same definition). Here the UV spectrum of Vega:
A significant signal is detected down to 3200 A with an Atik414EX / 460EX camera, and from a city observatory - no an altitude observatory. The "lines" observed near 3200-3300 A are the stratospheric ozone (O3) Huggins band. It is the proof of a valuable signal detection, not a noise.
Another example, wide spectral range spectrum of beta Lyrae (Shelyak), and a high SNR close look of ultraviolet part :
Same concerning CH Cyg star :
(with my polluted sky, the absence of slit is here a real problem, but in a good sky, the result would be more correct in the UV).
A hot star, gamma Cas (note structure near 3200 A, i.e. ozone Huggins band):
a more coldest star, gamma Cyg :
Finally, a modest spectrograph for the discovery of spectroscopy and explore the domain, but with which it is possible to do some science and study regions of the spectrum rarely explored by the amateurs.
Christian Buil
