First serious project kicks off. A 60mm f1.33 (fl 800mm) achromatic refractor telescope. Got the objective lens from Aliexpress for $12.32. Tube is 2 cardboard tubes from Saran Wrap rollls from recent move. Step 1: half of the thing to hold the lenspic.twitter.com/9rzVdPdSg3
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Venkatesh Rao Retweeted Venkatesh Rao
Will print the mating part tomorrow. The lens will go between these 2.https://twitter.com/vgr/status/1301295126791163904?s=21 …
Venkatesh Rao added,
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Then will come the hard part: putting the lens together. An achromatic lens is 2 lenses made of different materials (crown and flint glass typically). They can be just held clamped together (easy way) or cemented together with optical epoxy (hard way). Am trying easy way first.pic.twitter.com/TLeJkSeUJK
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Decimal point typo... f13.33 not 1.33. For the record I have *no* idea how to do cemented lens assembly and it seems to be a super finicky thing. Will build an eyepiece focusing assembly, but probably won’t try to assemble eyepiece lens myself. Eyepieces seem much harder.
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The Aliexpress page has some very unclear instructions and talk about blue tape and green film. The package only came with the 2 lenses. No film. Unless they mean coating. Gonna have to figure this out. Tips and suggestions welcome.pic.twitter.com/AhALqq3X7q
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I’m assuming dangerously that this will work with or without cementing. Gonna do experiments with the eyepieces I have first to make sure I have actual telescope optics going before finishing the mechanical design.
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For mount, I plan to design something that will attach to a standard camera tripod. If this thing works out, I should have something similar to a typical small, cheap entry-level refractor. The kind that you can get at Walmart for $80-120. But for ~$40-50 in materials.
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