Products > Thermal Imaging
3D print help for germanium telescope (apologies if slightly OT)
Ultrapurple:
Apologies if this is off-topic but...
For a long time I have been trying to construct a decent mount for my Therm-App cameras to an Inframetrics x3 telescope (like Fraser's, pictured below - I have shamelessly stolen his photo for this post).
The problem is that the Therm-App (and Therm-App Pro, on the right) don't have a flat front surface:
It's not just that it has a conical section surrounding the lens, the two sides are about 3 or 4mm different heights. This makes it (for me) a very difficult task to make anything fit.
If you haven't come across these telescopes before, they're wonderful - you just place your thermal imager behind it, focused at infinity, and you get an image three times the size (and inverted).
I have done some work previously using a precision-crafted water bottle, gaffer tape and rubber bands:
but this is not a particularly rigid (or professional) approach. The results, however were encouraging, even with the 384x288 sensor
(larger version here)
I have tested the setup, hand-held, with the 640x480 Therm-App Pro and 35mm lens with very heartening results.
(original file here).
I figure it would probably be fairly simple for someone with 3D design and print experience to come up with something that will interface mechanically between the two devices, including perhaps a tripod mount so I can attach the whole caboodle to a Gigapan head and make some really high resolution thermal images.
Has anyone got the necessary skills, or can you point me in the direction to go? For various reasons I'm not really able to rise up the necessary learning curve to do this entirely for myself, even though 35 years ago I did scrape a pass in my Technical Drawing CSE.
Vipitis:
hey Ultrapurple,
I am rather jealous of your scopes and imagers. I followed the whole process, I wanted to mention a few of your project in the lepton fov post as well. A 3D Printed solution is possible. Although an augmented one, for example a tripod mount.... won't really print in a usable manner. But you can embed a quater inch nut into a 3D print with some tricks like friction fit or heat.
For your project, be sure to google around a little or look on websites like thingiverse.com, to see if anybody has already done something like you want, or something similar. If you are going to do a custom model, or ask for somebodies help. It really helps to do some sketches, like a cross section form different axis. Annotate with exact measurements. Try to find a 3D (CAD) model of the therm app or a technical drawing, or measure the important parts with calipers and provide annotated pictures. A 3D printed solution is always a process of iterating and prototyping, there are many things that can go bad during the print or some design flaws which might have been overlooked during designing and only come apparent when the model is printed out.
Not every model can be printed on an FDM system - sometimes support is needed and sometimes models are impossible, but a lot of things are possible if design correctly. Professional power printing can get expensive really quick.
I own a printed and I have access to good CAD software. I have done some really basic custom adapters for optical systems before. I would love to help --- and I got the whole week to finally design and print again. Share some sketches and measurements, and I will see what I can do.
IwuzBornanerd:
Nice kluge! :-+
As an interim, perhaps more stable kluge, and something that might help you visualize what you need from the printer, you might try what I do in such situations: I roll tubes out of thin (easy bending) cardboard such as that used for file folders, gluing as I go (you could use 2-sided tape if you want to avoid glue near the lens). I would cut a strip a bit wider than the height of the collar on the lens holder & wrap it around until it is at the same diameter as the top part of the camera housing. Then I would cut a strip of cardboard a bit wider than the sum of the first one and the height of that top part of the housing and wrap that on top of the first strip, gluing it to the first strip first (assuming the top of the housing is circular; this is probably no good if it is not circular). You would wrap that out to some convenient diameter & make another tube long enough to span the required distance to your telescope. You would use the same technique to match diameters at the other end. The tubes naturally keep things aligned. A piece of PVC pipe could also be used to span the distance between the camera & telescope & would provide something solid to mount to the tripod.
Ultrapurple:
--- Quote from: Vipitis on October 29, 2017, 06:59:13 pm ---hey Ultrapurple,
For your project ... It really helps to do some sketches, like a cross section form different axis. Annotate with exact measurements.
--- End quote ---
Yes, no problem. I will ask Opgal if they are prepared to release any dimensioned drawings; failing that I'll dust off my calipers.
--- Quote ---I own a printed and I have access to good CAD software. I have done some really basic custom adapters for optical systems before. I would love to help --- and I got the whole week to finally design and print again. Share some sketches and measurements, and I will see what I can do.
--- End quote ---
That would be absolutely brilliant - thanks! I'll be in touch via PM as soon as I have any details.
Ultrapurple:
--- Quote from: IwuzBornanerd on October 30, 2017, 12:08:52 am ---Nice kluge! :-+
--- End quote ---
Thank you!
Actually, great minds think more-or-less alike. Instead of being smart and using cardboard I bought some carefully-chosen sample lengths of Perspex tube, added some Sugru, and came up with the version in the photos. It doesn't solve the issue with the non-flat front of the camera, but I used some more Sugru to attach a spare Therm-App (!) to the assembly so I could do some initial experiments. My Tower Bridge panoramic image was done with that rig and a small Gigapan head, but it wasn't what I consider very successful because I had problems with wobble (too heavy for the head) and drift (sensor calibration changing with ambient temperature), not to mention time pressure (as always) and flat batteries. And I believe I attracted the attention of a couple of plain-clothes officials who wanted to know what I was doing - but that may just be paranoia on my part. Certainly, several 'normal' people expressed an interest too.
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