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Post by Deleted on May 7, 2017 2:58:48 GMT
Moon’s back so it’s tinkering time. There are lots of ways to do this but I haven’t seen anyone do it this way before. 1. Take your basic finder and unscrew the eyepiece and objective lens. Push out the baffle/stop by inserting a smaller tube into the finder tube. 2. Glue a lens onto the baffle – this converts it to a focal reducer. See Ken’s video for details. ballaratman.wixsite.com/mallincamimages/videosThe lens I used was 42mm diameter, 145mm FL coated achromat from the Surplus Shed ($4 on special). www.surplusshed.com/lens.cfm3. You need a camera that will fit into the finder tube. If you have a security box camera, it should fit snugly into the tube and require no further modification. If you have a smaller camera you will need to make an adapter. 4. You can adjust the amount of focal reduction by changing the lens to sensor distance within the finder tube. I set mine to about 30mm. When you are satisfied put some glue on the baffle tabs – it’s heavier now with lens attached – so it doesn’t move around inside the tube. 5. For more precision in your design you can use this calculator. www.wilmslowastro.com/software/formulae.htm#FRThis modification produced a video finder with a field of view of about 3.5° x 3.0° on a 1/3” sensor.
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Post by Dragon Man on May 7, 2017 9:59:22 GMT
Interesting Robert! The camera fits in nicely.
Where did you get the FOV of 3.5° x 3.0° from? Looking at your Moon view it is a tad under half a degree. Probably about 25 arcminutes.
Or is it the view on the large TV on the wall?
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Post by Deleted on May 7, 2017 11:04:18 GMT
Yes - TV is the finder. Telescope camera is the laptop.
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Post by Dragon Man on May 7, 2017 11:14:11 GMT
Yes - TV is the finder. Telescope camera is the laptop. Ahhhhh OK, now it makes sense LOL! Yes, that is a fantastic FOV! God work Robert. I might have to try this with my spare finderscope.
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