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Rusted

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Rusted last won the day on November 9 2020

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About Rusted

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    http://fullerscopes.blogspot.dk/

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    ATM, imaging, solar, Solar system, photography, blogging, cycling, walking, birdwatching, digiscoping, audio, DIY, clocks.
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    Exiled to sunniest and darkest, rural Denmark!

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  1. Given a suitable, ring form support, it would be quite possible to bolt a sturdy stud [all thread] to the centre of the upper moving platform surface. A compact, lead weight on the stud, placed well below the platform, would lower the C of G quite nicely. The platform base plate would need a slot to clear the counterweight bar. Some commercial equatorial platforms use open frames. While the lead weight would make portability an issue it would greatly improve stability. For larger instruments [Dobs] I could imagine the platform's baseplate or frame mounted on a concrete pipe buried in
  2. A Dobsonian reflector can be mounted on top of a "driven equatorial platform." There are several commercial versions, different varieties & different sizes. A number of Dob users have made their own. Search here and online for <equatorial platform> for far more information.
  3. A foolish amateur astronomer and his money are soon parted. Brand new, car brake disks for popular models are absolute peanuts. Mark where you want your holes with a sharpie / magic marker. Don't have a power drill? Take your disk brake to a local engineering firm to drill a few holes. Ten minutes tops! Price of a beer? Probably.
  4. Almost inevitably. Your glasses will have individual power correction and for the astigmatism in each eye. Remove your glasses and you have instantly lost the individual eye compensation. Careful focusing of each eye helps with the power issues but [probably] not with astigmatism. Most binos have individual eye correction. Or both, plus one EP with adjustable, diopter correction. Many modern binos have fold down eye cups to allow glasses wearers to enjoy the instrument along with their prescription glasses. A chat with your optician about bino use might be helpful. It must be a
  5. Checking binocular alignment is fairly easy if you can rest them on something solid. A tripod with binocular adapter is probably safer than resting on a post or a wall. Focus the binoculars on a distant object at roughly your own viewing height. [Horizontal.] Get any dark card [playing card size] and wave it quickly from side to side in front of the bino objectives. You can wave your hand back and forth but risk knocking binos off an unsafe rest! The card will block your view through each side of the binocular in turn. If the image "jumps" back and forth then binocular alignment
  6. Given the number of PSTs for sale with badly rusted ITFs I wouldn't hold anybody to that high ideal. Not even images will protect you from some private sellers when they know exactly what they are doing. There are scammers on the popular astro sales website who deliberately misuse their inside knowledge to fleece the innocent buyer.
  7. Nobody could afford a "real" one. After 60 years of telescope making I'm still puzzled by my handmade to measure, OO "band" tube rings with their curved bases. Is there a commercial mounting somewhere with a matching curve machined on the dovetail? I just use them as "stop rings" to ensure instant OTA balance when I refit the 'scope.
  8. Some rambling thoughts on pier isolation: The "jigsaw" soft flooring must help to reduce a lot of potential problems with footfall transference to the pier. Haven't tried it myself but it would be in my first thoughts on inheriting a finished slab. It would be an awful job for an amateur making a large enough hole in concrete and then removing "the plug." Strictly for "heavy duty" professionals with specialist diamond tipped hole saws and pro hammer drills. Factory ventilation contractors are good at that sort of thing. They can "drill" concrete up to 60cm or more in Ø. The pr
  9. Snow has arrived with NE-Easterly winds. About 100mm/4" accumulated on flat surfaces by lunch time. It is interesting to see how the snow is attached downwind but remains clear on the windward side.
  10. Interesting idea. Heavy wall plastic pipe is certainly sturdy but would rely entirely on the load applied and how well the pipe itself was supported. You cannot assume that your pipe's base is dead flat and likely to remain so. How would you "restrain" the pipe? Bolts through the middle? How would you ensure a true, level circle? I used large, 180mm/7", industrial truck wheels with roller bearings on my heavy, plywood, 3m/10' dome. The base ring of the dome itself, on which they ran, was laminated marine plywood but did NOT remain flat. While watching the base ring rotation
  11. Was the 24" substrate the real problem? Astigmatism can easily be caused by a poorly annealed blank. A thin, 24" blank would need to be very well supported for working and testing. Otherwise the blank will distort under its own weight. Mirror blank support is a steadily developing "art." I once worked flats onto three 8.75" Monax blank to find one was hideously twisted. So badly, that it couldn't even be used for cold pressing the pitch lap. It made the other two flats worse when used for figuring in rotation. The aforementioned "tester" also gave a damning report on one iSta
  12. My bulb blower lost its plastic tip in a drawer closing accident. So I slipped a bit of a silicone tubing over it. Now it's soft in the head. I bought a rouge mop from the make-up department at the chemist as my lens brush insurance prior to using the microfibre cloth.
  13. Thanks for all the interest. It was never truly sprung. For most of the time. I tried various springs to pull the worm into the wheel and then [usually] locked the pivot screws. That didn't work well. Nor did it work with the springs and loosened pivots. It would have needed a very firm pivot with no play at all. I just used a fixing bolt shank as the pivot. Sloppy! The latest mods are a great improvement but I still want to make a new, rear worm bearing steady. We are enjoying extensive frosts so working with metal is painful or clumsy due to wearing gloves. My workshop
  14. This company must be aware that their units are being discussed on the specialised astronomy forums. About as focused a potential as you can get when it comes to word of mouth "advertising". Which is the only advertising I am prepared to listen to in a trans-global sewer of [enter your derogotory term here.] This company no longer cares about the specialist solar observer and imager. IMO. It is happy to trash its reputation on sales to those who are far less likely to "do their homework" before purchase. Any company willing to sell such expensive lottery tickets has even less respect
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