Making a Lhires III lightproof

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Filipe Dias
Posts: 13
Joined: Thu Sep 29, 2011 7:33 am
Location: Lisboa, Portugal

Making a Lhires III lightproof

Post by Filipe Dias »

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.
Attachments
The original Chicken packaging
The original Chicken packaging
SP_A0115.jpg (11.78 KiB) Viewed 3358 times
Cut into pieces; and tools needed
Cut into pieces; and tools needed
SP_A0116.jpg (20.47 KiB) Viewed 3358 times
Placed on the back of the spectrograph
Placed on the back of the spectrograph
SP_A0117.jpg (34.9 KiB) Viewed 3358 times
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Christian Buil
Posts: 1431
Joined: Mon Sep 26, 2011 6:59 pm
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Re: Making a Lhires III lightproof

Post by Christian Buil »

Excellent suggestion !

Christian
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