Making a Lhires III lightproof
Posted: Sat Nov 05, 2011 11:11 pm
A few weeks ago, I finally isolated my LhiresIII spectrograph from outside light!
It was no exceptional challenge, but I wanted to do it in a way that did not force me to re-do it every time I changed grating. This is why I think this idea may be useful for others..
I used the iconic black ducktape for most of the seams. But for the rear part of the grating holder, I decided to use a different strategy.
I used a packaging for chicken wings from the supermarket, made of some interesting type of Styrofoam, or poly-something-tane plastic, that is very easy to cut, light, and resistant to humidity. Very handy!.. It also looks very promising for making rear-illuminated diffusers for flatfield screens. This plastic was then wrapped in black tape to make it dark and lightproof..
I've cut the packaging in a way that would make a cover over all hopes on the back of the spectrograph, and punctured holes in the places the screws hold the grating holder. You can see the idea in the images!
I can now take spectra of calibration lamps in daylight that looks indistinguishable from night time
No more lightleaks!
I have also cut a part that fits around the colimator/objective holder, a bit like a suggestion here. But I think this extra baffling is not needed if the holes on the rear of the spectrograph are well covered.
It was no exceptional challenge, but I wanted to do it in a way that did not force me to re-do it every time I changed grating. This is why I think this idea may be useful for others..
I used the iconic black ducktape for most of the seams. But for the rear part of the grating holder, I decided to use a different strategy.
I used a packaging for chicken wings from the supermarket, made of some interesting type of Styrofoam, or poly-something-tane plastic, that is very easy to cut, light, and resistant to humidity. Very handy!.. It also looks very promising for making rear-illuminated diffusers for flatfield screens. This plastic was then wrapped in black tape to make it dark and lightproof..
I've cut the packaging in a way that would make a cover over all hopes on the back of the spectrograph, and punctured holes in the places the screws hold the grating holder. You can see the idea in the images!
I can now take spectra of calibration lamps in daylight that looks indistinguishable from night time
No more lightleaks!I have also cut a part that fits around the colimator/objective holder, a bit like a suggestion here. But I think this extra baffling is not needed if the holes on the rear of the spectrograph are well covered.