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Originally Posted by
Maurice
I have in mind some planetary spectroscopy (hence the resolution), possibly
Titan If I can coax my old C14 back into life.
As a start, just to see how the device performs, I'll probably do the old
rotational velocity experiment using the D lines on the E-W solar limbs.
Further down the line I may have a look at the Mid IR (my day job involves
working in that region of the spectrum, so a sensor may be available). Have
to look at new gratings though.
I'll post a photo / link once I've sorted out these last bugs with the feed.
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That sound good Iain - the beauty slit/ fibreoptic feed spectroscopy aligned in RA, small scope miss tracks still record data.
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Incidentally, did you ever pursue commercializing your own compact hi res
spectroscope - you mentioned the possibility a few years ago when we last
spoke?
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Maybe three years back Starlight Xpress were talking of say 100 units which I said was wholly unrealistic for the amateur market. Terry Platt raised it again with me as London Astrofest. His image-shift system [rocking glass plate] has a pickoff prism for the autoguider essentially identical to my WPO Littrow spectrograph and he will reinvestigate the possibilities and maybe make a mockup. Essentially he has all the components to hand except off-the-shelf grating and imaging [camera] lens.
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All the best Iain
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Been rethinking your defocus problem. If I recall the SBIG SGS CzT is an Ebert arrangement
http://home.freeuk.com/m.gavin/ebert.htm with two extra flats to align the input-output beams to a common axis. The slit is imaged full size onto the detector [just like the Littrow]. Are you confident these two beams are of equal length? If not light projected onto the grating will not be parallel and the image scale at slit and detector will be of dissimilar scale.
I have a Sivo fibreoptic feed spectrograph
http://www.astroman.fsnet.co.uk/sivo.htm and frankly the throughput and resolution was initially very poor where the 30[?] stacked fibres form a virtual slit and where the collimator and image [camera] lens were of similar focal length the result was gross oversampling. I suggested incorporating a barlow between virtual slit and collimator [eg doubling its focal length] so slit image onto detector half size and so much sharper - see footnote to about 'review'. Reimaging may be the route with fibreoptics to improve resolution but does little to help throughput with those horrendous numeric[?] apertures.
best regards
Nytecam