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About Alan64

  • Rank
    Sub Dwarf

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  • Gender
  • Interests
    ...astronomy, naturally.
  • Location
    Mid-South, U.S.
  1. The telescope in question is a 76mm f/4 Newtonian. The design has been around since 1668. This is how it works... ...the light from an object enters the tube and travels all the way down to the big mirror at the bottom. Since the surface of the big mirror is curved, the light of the image begins to form a cone once it leaves that surface. After the light gathered by the big mirror leaves that surface, the light heads back up to the front of the tube, and to the little mirror. By the time the cone of light reaches the little mirror near the front of the tube, the cone is much narrower. The little mirror then sends the tip of the cone of light to the eyepiece, and the image formed to the eye and mind of the observer. Being that the telescope is an f/4, it will require a more precise collimation, the alignment of the mirrors inside the tube in relation to the focusser, and in order to enjoy sharp and pleasing images. Don't automatically assume that the telescope was collimated upon its arrival. Collimation instructions... http://www.astro-baby.com/astrobaby/help/collimation-guide-newtonian-reflector/ https://garyseronik.com/a-beginners-guide-to-collimation/ In addition, the focal-length of the telescope is awfully short, at 300mm. If a barlow did not come with the kit, you might want one if you want to see any details of the objects you're looking at; for example... https://www.365astronomy.com/GSO-2x-Barlow-2-Element-Achromatic-Barlow.html Without a barlow, that 10mm will give you a power of 30x, and rather low; with the 2x-barlow, 60x, yet still a bit low. Now, with a 3x-barlow and the 10mm, you'd get a power of 90x.
  2. Time-consuming, but it is what it is if you want it...
  3. Lovely brass, although not quite as lovely as bronze...
  4. The cut-outs have been shaped, and all the pieces sanded down. Here they are in the same box within which they were stripped... Now to cut out the brass...
  5. The first, actually second, set of legs has been prepared further, sanded down, numbered, and in preparation for the brass, then the dye...
  6. Indeed, and as they fall off the barge from overseas. Aside from the need to finish it, the trick is not to overload it, and then to enjoy an ultimate in grab 'n' go.
  7. The off-setting, which occurs automatically during a normal collimation procedure, looks to be correct, however the center-spot should be centered within the light-grey circle, but it's off a bit. Here's the collimation scene from my 150mm f/5... ...and well collimated. In the past, I had made a mock-up, using that scene, and to simulate how the scene of the AWB "OneSky", and the same as your own, should appear... Incidentally, you did well in choosing an f/5 Newtonian, and the shortest I would suggest for those first starting out.
  8. The mount-head is done for the most part; just a few odds and ends to which to tend... ...like clamp-screws for the saddle, a lock-nut for the latitude bolt, a lock-washer or other for the latitude-clamp; little things like that. My, it certainly is a diminutive, li'l darling... Incidentally, that Coke can is two years out of date, and it seemed swollen a bit, so I took it outside and threw it up into the air onto the road, then threw it in the bin. I didn't want it to explode one night whilst I slept. Now I don't have me prop. Today, I'm working on my legs... I have to get those cut-outs just right, and then epoxy that .010"-thick brass over each, a total of six. I may apply something or other over the outsides as well, and to further strengthen the wood there, since it's now thinner. I wonder if I should dye the legs first before applying the brass...
  9. Thanks all. With the RA-clamp locked, there is only half of a millimeter, if that much, of movement in either direction; not nearly a full measure of same. I may then hold the mount with one hand, and with a little effort twist the worm shaft with the fingers of the other, and round it goes in a complete circle without a hitch; nothing short of marvelous, the motion. I removed the steel washers from the axes' lock-nuts, leaving only the bronze washers, and I must say the improvement was rather noticeable afterwards; those rotten steel washers, they're history now. Also, I feel that I used PTFE as a shim for the stepped RA-bore... ...in a pinch, with the now-obvious and most preferred solution having escaped me at the time. The PTFE shim was .015" in thickness, so I made two shims of .008" phosphor-bronze, and for a total of .016"... I made the inner shim 1mm shorter than the outer... ...a more solid interface, and it shows when testing the axis. Incidentally, PTFE is subject to creeping, spreading out over time, and what amounts to nothing more than deterioration. Hindsight is not only 20/20, but also most fortuitous. I don't think I can add or do a single, solitary thing extra to these axes.
  10. I had to cut down the right-angled portion of a hex-key to batten down the bolts. Anyhoo, I had gotten three of these smaller bronze washers for the worm assembly... ...but I needed only two in the end; one polished only, and one with its O.D. ground down in order to recess into the hole of the threaded yoke... The one that's recessed is barely visible on the right... The motions throughout are most satisfactory, but I do expect that it will need a tweaking here and there once a telescope is mounted upon it.
  11. Earlier, I took the block and the bolt with me. I went straight to the standard nut-checker and...<drum-roll, please>... ...10-32... Being that this is a Chinese clone of Japanese design and manufacture, why isn't everything in metric??? I would like to extend my thanks to Themos for urging caution when working within this area of the mount-head, for it is of the utmost importance not to torque-down the bolts when reassembling.
  12. Drat, the longer bolts will not thread inward. I took the original bolt with me and fed it into the nut-checker. Later today I will take the threaded block itself.
  13. Oh, I'm always careful, save for that one time...
  14. The outing today was successful... The originals are 12mm in length, whilst the next size up at my local hardware is 20mm, so I thought about lock-washers in addition. The bolts turned out to be M5s, and as I had suspected. I may have to cut them down slightly, I don't know yet.
  15. The DEC-control components, before... ...and after... The spring and the actuator are noticeably cleaner. But the insides of the two housings for the spring were rusty, particularly the larger. You can tell by the outside surface of the smaller one. I didn't take photos of what I sanded and scoured out of them, as I'll leave that to your imagination. I did spend at least an hour doing so. The components freshly-lubed and installed...
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