Hi Grant,
Dont get me wrong, it would be good to have some competition for Shelyak who dominate the market currently and reflective optics are indeed a big advantage, mainly due to the lack of chromatism (ask David Boyd about his LISA) than the extended UV response, but designing one suitable for astronomy rather than for bench use is tough. The one Maurice reviewed was far from free of astigmatism though which limits its use. The field distortion looks suspect too in that video. The length of the slit is very short but the calibration lines were significantly curved even over that short distance, fine for a bench instrument but you are going to struggle to produce spectroscopic images of comets like this for example with this instrument
https://britastro.org/comment/8942#comment-8942
Availability of calibration lamps and guider modules is a given these days. The calibration lamp is just the same fluorescent lamp starter discovered by Swiss amateur Richard Walker and adopted by Shelyak for all their instruments and all other other offerings currently use a mirror slit guider rather than a beam splitter which has practical alignment issues and was abandoned by other manufacturers (This was touched on in the video where it was said that the user would be expected to tweak the guide position to position the star on the slit, critical for throughput and potentially challenging when you cannot actually see the slit in beam splitter designs so it remains to be seen how this will work in practise)
I did not intend criticising the instrument. Difficult really since I have not used one, though I do see some potential issues and did ask various questions about it when it came out which remain unanswered because of the lack of experienced users publishing results. (The limited knowledge of the dealer/customer? in the video was embarrassing). I agree with Eric, we are lacking an in depth practical appraisal by experienced spectroscopists. Contrast this with how much we already know about the design and performance of its direct competitor out in commercial form later this year.
http://www.spectro-aras.com/forum/viewtopic.php?f=45&t=2577
For example
https://www.shelyak.com/wp-content/uploads/SMSW2_Buil_UVEX.pdf
http://www.spectro-aras.com/forum/viewforum.php?f=45
Cheers
Robin