seek thermal infront of parabolic mirror and housing repair job - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: November 30, 2020, 03:47:17 am
content: So I was playing with my lens and the camera split in half on the glue seam. It looks like it came back together and still works, but it basically split into 3 parts that are now lightly held together by failed glue. (bottom cover, pcb, and optics assembly). The shutter seems to work fine (I put it back together and it only opened a a few mm for a few seconds)I have a parabolic mirror from a telescope. If I take just the CCD without the lens and position it in the correct place infront of the mirror, will it work like a thermal telescope? If I just put it infront of the mirror, I can see the camera in the reflection. Is the parabola of a telescope mirror made with the oval shape of the reflector mirror in mind.. would it work better if I found the missing mirror (or made one out of polished stainless or titanium ) and put the camera at a right angle, as the original eyepiece. My telescope has the adjustment, but is missing the mini-periscope mirror, but has the main reflector mirror.Also, what glue is good for fixing this up? I read some where superglue can fume, and I am not sure what to use to fix it, because its too easy to split apart now. I thought to just wrap it in thin wire and put a drop of glue on the exterior wire knot, so I can take it apart in the future if need be, without figuring out what glue is good for future repairs?.

author: Vipitis
author_rank: Frequent Contributor
timestamp: November 30, 2020, 07:53:45 am
content: first of all it is not a CCD but a microbolometer. And as you can see the reflection of your camera in the primary mirror, you should be able to get to use it otherwise as well. But using a parabolic primary with no secondary mirror is really difficult. For best reflection in the LWIR spectrum you likely want to have a goal coated mirror. But a Newtonian design is slow anyway, so expect no or only a really noisy signal. example by a forum member:https://www.flickr.com/photos/ultrapurple/16524885978/in/pool-therm-app-users/

author: coppercone2
author_rank: Super Contributor
timestamp: November 30, 2020, 08:23:37 am
content: can you polish gold leaf if you glue it down with good glue? or does it need to be a thin film and not actually polished gold

author: Vipitis
author_rank: Frequent Contributor
timestamp: November 30, 2020, 08:49:41 am
content: a normal first surface secondary mirror for your newtonian telescope will do fine enough.for a coated mirror you are probably better off buying one, if you don't have a sputtering setup at homehttps://www.edmundoptics.eu/knowledge-center/application-notes/optics/metallic-mirror-coatings/

author: Ultrapurple
author_rank: Super Contributor
timestamp: November 30, 2020, 10:39:45 am
content: As Viptis says, a normal telescope mirror will work just fine - as long as everything is done with first surface mirrors and there is no glass in the way, you can expect to get images.But - and it's a big but - don't expect to be able to see anything dimmer than the Moon.The amount of thermal radiation reaching us from other planets and the stars is so minute that you have absolutely no chance of seeing anything with anything affordable on an amateur budget.As far as glues are concerned, epoxy resin is usually a decent bet, although some of the UV-cure adhesives may be worth a look. If you're (rightly) concerned about it messing up your optics, do a test where you put something like a sliver of mirror close to a bit of the glue as it dries. Any outgassing that condenses will be easily visible. It's not foolproof of course - mirror glass isn't a delicate optical coating - but it may let you weed out the worst offenders.

author: Uho
author_rank: Frequent Contributor
timestamp: December 01, 2020, 06:37:46 am
content: It is really impossible to glue with cyanide-based superglue. I glue with fast curing epoxy.

author: coppercone2
author_rank: Super Contributor
timestamp: December 01, 2020, 06:49:21 am
content: it will fume and cover the lens? mechanically it would be the best bet with a primer given how tight the seam is etci am not sure how good epoxy is either because it smells so much. not sure what will effect thermal optics. i only have this setmaybe a low offgassing epoxy? the UV stuff I have smells alot too, and I doubt it will cure well in the seam of the camera.actually its made from metalI will try low outgassing electronics epoxy

author: coppercone2
author_rank: Super Contributor
timestamp: December 02, 2020, 12:51:54 am
content: I glued it back together with DP460. I mixed it for 15 seconds on top of a little plastic cup and carefully applied the glue using a pick into the seam. It has pretty much cured now and I don't see any problems with the imager. I wiped it down with denatured alcohol after I pressed it together, but I was very careful putting the glue on it.https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Scotch-Weld-Epoxy-Adhesive-DP460/?N=5002385+3293241275&rt=rud