After completing my current oil painting blitz, I spent some time today completing 'Spectrometer Mark2' in the 'clean room' or the kitchen as my wife likes to call it. The primary reason for the redesign is my desire to use either my QHY5v or QHY5-11 as the imaging camera, without dedicating either camera to capturing spectra. So a modular approach seemed sensible and the ability to experiment with different diffraction gratings was also an objective. Mark1 was virtually built for 'nowt', Mark2 has required the expenditure of a few quid mainly on purchasing an extra mounting bracket for the QHY5 (I already had one in my bag of astro bits and bobs). I made the base from hardwood samples handed down from my late and great mate Barry Shulver. The tilt and turn mechanism, for holding the diffraction transmission grating, was fashioned from a camera holder and tripod obtained from everyones favourite country 'Poundland'.
I used an on-line transmission grating calculator to work out the diffraction angles for different gratings and basic trigonometry to calculate the distance between the gratings and the cameras chips to fit the first order spectrum on the chip. Hopefully, if I've got it right , it should work ok - so watch this space for my continuing 'Chad Valley' exploits in 'Off World Spectra'!