Saturday, July 24, 2010

Eyepiece case


I've found it a nuisance to take eyepieces in and out of bolt cases.  Moreover, the amount of time it takes to pack up everything at the end of an observing session limits the length of the session.  So I decided to make one of those eyepiece cases where the eyepieces sit naked and can be used right out of the box.  I initially planned to make a plywood box, but decided that would be too heavy.  Instead, I picked up a Harbor Freight steel and plastic toolcase (like this one, but maybe slightly smaller) for a low price, and made a plywood insert.  Unfortunately, the case was stinky.  The plastics in it were off-gassing.  It took about seven weeks of ventilation until it became usable (obviously, I don't want off-gassing onto optics).  Finally, today, I put the insert in--gluing it in place with silicone glue and putting some screws in.

It includes space for 1.25" and 2" eyepieces (the laser collimator occupies one of the 1.25" slots).  In the middle there is room for filters.  I drilled two holes through all my slide-mounted Rosco gel filters, and put machine screws pointing upwards on the insert for the filters to sit on.  The fit is good.  My ND and OIII filters are in a plastic box attached with Velcro (or maybe a generic hook and loop fastener) to the insert.  Finally, on the right side, there is room for my battery box (for driving fans or giving extra power to PDA), geen laser, flashlights and spare batteries.  I am quite pleased.  But since the silicone is still off-gassing, I took everything out after taking the photo.

9 comments:

  1. Nice! Now, the question is, how much longer will it take before the silicone is done off-gassing?

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  2. In my experience, I can't smell silicone after 24 hours. :-)

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  3. I was wrong--it took more than 24 hours.

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  4. It smells a bit if I keep it closed. But so did my old case, I now realized. This one smells a bit more, but I am giving in and using it--it is just so much more convenient.

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  5. As long as it doesn't damage the eyepieces. Also, if a few people shun you away, you'll know why. lol

    Hey, Alex, I thought of you when I saw this article on a blog. It's titled 'To Infinity and Beyond: The Struggle to Save Arithmetic.' http://www.newscientist.com/article/mg20727731.300-to-infinity-and-beyond-the-struggle-to-save-arithmetic.html?full=true

    In gist, it speaks about how infinities causes problems, and it seems the best way to avoid these problems is to become a 'finitist.' So, I guess, the debate is whether infinities actually exist. Just thought I'd show you the article, even though there's probably nothing new in there.

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  6. I am worried about eyepiece damage. I've taken to keeping the box uncovered, with a cotton cloth over it to keep out the dust. Maybe a cheesecloth would be best.

    As for infinity, I am not sure I see the worry in this case. So there are things you can't prove from small extensions of Peano's axioms. But that doesn't even strike me as counterintuitive. There are infinitely many numbers. Why would one expect a small number of axioms (or recursive axiom schemas) would capture all of arithmetical truth? Prima facie, wouldn't one expect the opposite result?

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  7. I wonder if there is some kind of product (some sort of sealer - oiled based paint, for example) you could buy and spread onto the case that would stop the off-gassing.

    As for the infinities, one should certainly expect that a small number of axioms cannot capture ALL arithmetical truth. However, I believe, I recall you saying you didn't find Hilbert's Hotel counter-intuitive, or something along those lines. I don't know, but when dealing with infinities, for me, it's so abstract that it's hard for me to wrap my head around the concept. Surly, I'm not the only one!

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  8. There is a sealant, but it's expensive. (Of course, so are the eyepieces.) Right now, I put some cloth on the bottom, hoping that the nasties will deposit on it. At least, it'll be a good experiment. After a couple of days, I'll take the cloth out and smell it.

    Right now, I don't know what to say about infinity. Maybe eventually I'll have something...

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