Aaron, I'm home now and have time for a more thoughtful reply, thanks for your patience. Posting from work is a love-hate thing, I love to post but rarely have the time to do it justice when I'm actually at the computer and most of the time wish I could have stated something better after I've read the digest. 20-20 hindsight. My little home-made refractors use surplus lenses, either real achromats or projection lenses. The 50mm spotter I mentioned in the post uses a WW2 vintage Kodak lens of 450mm focal length(f/9) that I bought from Paul Rini about five years ago for ten dollars. Gold is where you find it, they say; many of my old sources have dried-up, but Apogee Inc. still lists a lot of usable achromats, albeit at prices a little higher than surplus. Surplus Shed has some appropriate ones every now and then. It depends on how big a scope you want to make. Generally the copy lenses are heavy triplets with short focal lenghts and can't be used at higher powers since they are not true achromats and weren't designed for an infinity focus. They work well for low power finders and RFT's. A binocular objective works well at low to medium powers, sometimes broken or mis-aligned binos can be found at pawn shops for only a few dollars and yield a wealth of parts. Half a binocular by itself (monocular) is a great little fixed-power spotter by itself. I prefer to make a tailpiece that allows 1.25" or 2" eyepieces and accessories to be used. My 50mm uses a correct-image diagonal and focuses by sliding either the diagonal or eyepiece and tightening a setscrew. I use the mini-lathe to turn fittings such as cells and tailpieces from sheet PVC plastic and PVC pipe fittings, but with some ingenuity the lathe can be dispensed with, at the expense of a more rustic appearance. I also like to add tripod-mounting blocks, with a 1/4-20 tapped hole, so I can attach my scopes to standard tripods or my "Weightless" mount mentioned here recently. Small scopes for viewing sunspots usually don't need to magnify more than about 40-60x to bring out plenty of small sunspots. In my office at work, I can set it up to look out the window, and by removing the solar filter, can project it on the wall or ceiling for group viewing, yeilding a large, bright solar image, without having folks have to line up at the eyepiece. I'll bring a few home-brewed spotters and finders to the swap-meet for inspection and to hopefully give some folks some ideas. I have a few suitable achromats that I'll bring, for sale, for those ready to take the plunge. I also will be selling a "Chuckified" Meade 60mm refractor/guidescope tube assembly, retrofitted with a metal, 1.25" rack and pinion, as well as (drum roll, please,) a whopping 5" f/9 doublet refractor tube assembly from Apogee, both at fantastic discounts, but these are really commercial telescopes, not homebrewed. Aaron Lambert wrote:
How do you go about making a home-made spotter? I had a lot of fun last summer showing my kids and some scouts the sun using my binos and a cardboard box, but it was a little awkward. Searching around I found a Keplarian(?) one for sale on the net but it was over $300. Is there a way to build a cheap spotter that gives you a decent image? I had wondered If I could buy one of those little ~$30 radio shack 50mm plastic scopes and take it apart to see if I could build my own, but I really have no idea what I am doing.
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