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Alan64

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Everything posted by Alan64

  1. An 8" Schmidt is the "sweet spot" among the varying apertures of the design; good choice.
  2. Don't get an eyepiece/accessory kit. In the long run it may very well end up in the closet. Besides, it doesn't include a 32mm, and you'll want that. Acquire your eyepieces no more than one or two at a time, and after careful research. Choosing eyepieces is somewhat akin to acquiring prescription-eyeglasses, at the eye-doctor. What sort of diagonal will you use at night? Perhaps a 2" star-diagonal, and in tandem with the "1.25" to 2" plus T thread adapter"? You can then choose just one 2" eyepiece; a 32mm, or a 38mm, and for your lowest power and widest field-of-view; to get your bearings there in the night sky, to find your way round. In so far as using a telescope during the day, and at night, a focal-length at, the very least, 600mm, to 900mm, would be ideal. Maksutovs, and Schmidts, are a bit lengthy(>1000mm); with the 72mm ED refractor at the other extreme(420mm), and intended primarily for imaging, for taking pictures. Incidentally, I have this 70mm f/13 achromat, and with a focal-length of 900mm... It was thrown in with the mount I had wanted at the time. I can get a respectably low power of 28x out of it, with a 32mm eyepiece, but it doesn't gather much light from an object; and no, I'm not suggesting that particular telescope, not at all. However, it does demonstrate an ideal focal-length, at or near maximum, which would play quite well with the 4mm-to-40mm range of eyepieces, but the aperture is too dim for my liking. This one has a focal-length of 600mm... https://www.firstlightoptics.com/pro-series/skywatcher-evostar-80ed-ds-pro-ota.html An 80mm aperture is as small as I would choose, for my first refractor, but that's just me.
  3. The current "long" achromats are not that long. This is a long-focus achromat, and with a focal-length similar to that of a Maksutov... https://stargazerslounge.com/uploads/monthly_11_2014/post-33902-0-80153000-1415559339.jpg The current, longish achromats are actually of a medium length, rather. With a 90mm f/10, there would be minimal false-colour, but only when viewing the brighter and brightest objects in the sky. You might see some during the day as well. Given its moderate focal-length, respectably low powers with widish fields-of-view are quite possible; moreso than with a Maksutov, although a Maksutov is a worthy contender nonetheless. If at all possible, if you go with a Maksutov, get a 127mm, as that's the "sweet spot" among the design's varying apertures... https://www.firstlightoptics.com/maksutov/skywatcher-skymax-127-ota.html ...although the focal-length does increase as one goes up in aperture, per the design. You would perhaps not need that much aperture during the day, as the Sun's out, albeit behind the clouds on occasion, but at night, the more aperture the better.
  4. Oh, I had forgotten... Where the DEC clamp-ring fits over its corresponding flange, slop... You can see the gap there trailing around. It's not a lot, but slop nonetheless. It's not that crucial to do anything about it, but that is where most of the action takes place as the telescope is swung to and fro, hence, more bronze to the rescue... At that point, there certainly wasn't any more slop, but it was too tight for my preference. I then thought, "Well, it'll get smoother over time", but in the next moment I had visions of it getting all mucked up in the process, and where I'd have to take it all apart in future and clean it. I didn't want to reduce the I.D. of the aluminum clamp-ring, so I ground, sanded, and polished down the steel flange all around instead. My only other alternative was the use of a thinner brass for the shim, an easier although inferior solution.
  5. Continuing on with the mount-head, the DEC-axis still... I had gone ahead and altered this thicker, sintered-bronze washer, and for the needle-thrust bearing to rest upon... ...but all for naught, as that extra thickness would've created problems at the clamp-ring and the axis' lock-nut. So instead of a total of two thinner washers of phosphor-bronze to craft for the DEC, three instead. So, I made the second one, not knowing that the thicker one wasn't going to pan out... After the revelation, I made the third, and the very last one to make for this entire mount-head... Both the second and third are identical, to sandwich the needle-thrust bearing, and isolating same from the aluminum above and below it... There they are, a total of three I had to make. Do note how the bearing juts out at the side all around, but then how could you not notice. Nonetheless, the bronze washers overlap at least half of the length of the rollers within the bearing, on both sides, and good enough. I might make a protective cover for the bearing in future, depending, and to keep dirt and dust off and out of it. Next, I adjusted and polished a smaller, sintered-bronze washer for the lock-nut... The DEC-axis is completed. Incidentally, I'm using Super Lube throughout this mount... How's the motion?
  6. Just which type of diagonal is predominant within the astronomical marketplace...oh, and vastly so, and why?
  7. Any star-prism diagonal will perform better with a Maksutov than a mirrored one. Maksutovs are known for their superior contrast among reflector telescopes, and a prism will help preserve that very thing. Honestly, three mirrors within a single optical path? Leave that configuration to the Tri-Schiefspiegler.
  8. To make it clear about mirrored-diagonals: they're cheaper to manufacture. That's their only advantage over star-prisms, that and the zero addition of false-colour to fast-achromats. But I'd rather have a wee bit of false-colour than of light-scattering any day, or night. You can read all about the different types and brands of diagonals within this test that was conducted a while back... http://baader-planetarium.de/news/mirror-Prism-Dielectric-Diagonal-Comparison_2014-03-06_v2.pdf Incidentally, I have this Baader T2 Zeiss-prism, and that's mentioned within that article... I had gotten that one back in 2007 or so; perhaps earlier than that, I don't remember exactly. I use it with this telescope only... Know this: there is absolutely no optical advantage in using a diagonal. Observing straight-through, without a diagonal in place, is always going to be best, but diagonals have become, and will remain, a most necessary evil.
  9. Now, about the diagonal that came with your kit. Is it a mirror-type, or a prism? Here's the difference illustrated... In any event, a Maksutov already contains two mirrors. I don't see the logic in adding a third mirror in the form of a diagonal, as mirrors scatter light in the first place. Here, light-scattering illustrated, there on the left... Now, that's not to say that the detriment would be to that extent, but why give it a chance in the first place. Get a good star-prism diagonal, but make certain that it's not an Amici, an erect-image, as those are for daytime/terrestrial viewing. For examples... https://www.rothervalleyoptics.co.uk/celestron-90-degree-star-diagonal-125.html That one is mass-produced on a ten-pence, but I lucked out and got a good one; quite good, but not everyone does, so I've read. It's like playing roulette, at that price. https://www.firstlightoptics.com/diagonals/takahashi-125-diagonal.html Yes, that's a pricey one, but it's a Takahashi. I would suggest the Celestron star-prism diagonal if on a budget.
  10. One of, if not the, problem with using 2" accessories with a Maksutov is the hole in the center of the telescope's primary-mirror, not to mention the baffle that juts outward from the mirror... That's when and where someone was flocking their own, and for improved contrast. The hole of the mirror and the baffle are simply not 2" in diameter, therefore the images would be cut off, vignetted, when viewed through a 2" eyepiece. Many gravitate towards Maksutovs for their short, compact tubes, and oft combined with go-to mounts, understandably given their long focal-lengths. The Maksutov was designed for medium-to-high powers, and for which it is most capable, and with 1.25" eyepieces. It is not a low-power instrument. Quite a few who acquire them find that out after the sale, yet some will attempt to move heaven and earth to make it more versatile, for low-power observations in addition. Now, there is a Sky-Watcher 127mm Maksutov, sold in the U.S., that sports a 2" visual-back, diagonal, and eyepiece... https://www.skywatcherusa.com/products/sky-watcher-skymax-127 But I don't think it can make full use of the 2" format; for example, the full view afforded by a 2" 38mm 70° eyepiece, and certainly not Unk Al's 2" 82° offerings. However, you do have the option of attaching a fast(f/5), short, 80mm achromat with a 2" focusser to your existing mount, and for low-power views, although you would have to fit a 2" focusser onto said achromat first. For example... https://www.firstlightoptics.com/startravel/skywatcher-startravel-80-ota.html Naturally, only one telescope at a time. My 80mm f/6 achromat, a little longer than that one listed above, came with a 2" focusser, and from Canada, but they're no longer available... But don't point one at anything bright, as you'll see "rainbows", and forget about high-powered observing. However that's precisely why one would complement your Maksutov beautifully. One is the antithesis of the other, and in that perfectly matched.
  11. Oxblood is more traditional, than the "Merlot" I had used for my larger wooden tripod; old-school, like a wooden stake.
  12. There's much less drag, resistance, with that washer in place; smooth as butter 'tis.
  13. Whilst waiting on the dye to arrive for my "sticks", as a relative refers to them, the first of two of the .008"-thick phosphor-bronze washers for the DEC-axis has been scribed onto the sheet of same... The I.D. is perfect, but I'll have to trim the O.D. just a little after cutting it out of the sheet. You don't have to drill a perfect hole all the way through the I.D., just as long as it's fairly centered and with enough room to insert the tips of those scissors, then you snip out the bulk of the I.D.... With the washer still within the sheet, you grind and sculpt out the I.D., checking the fit frequently over whichever flange it might be. You want it to just fit over the flange, and with no binding as the sheet is rotated... You then cut the washer from the sheet, trim it close to the O.D.'s scribed line, and there it is in its rough and unpolished state... Next, the edge of the O.D. is ground down to its final diameter, then the edges of the I.D. and O.D. are evened-up and smoothed with 100-grit or finer sandpaper. Lastly, you take #0000 steel-wool with a few drops of lemon-oil and polish the washer, edges and surfaces, throughout... With the DEC-control, and the washer sandwiched between it and the body of the saddle... It's a bit overkill for that area, as only minute movements will be made at that juncture, but nonetheless the washer isolates aluminum from aluminum.
  14. No, the wooden legs are taken off of the surveyor-hub, and then the legs placed on the hub of the kit. As for myself, I wouldn't give a single, badly-tarnished penny for a tripod sporting tubular-steel legs, quite frankly.
  15. The "SkyMax" go-to tripod-hub has traditional yokes jutting out for the attachment of legs... I'd suggest thinking outside the box, although not too far gone, and get a wooden surveyors' tripod, and adapt it... ...or other wooden tripod. Wood is best for dampening vibrations, and it looks good to boot. You can make a spreader of chain for it. I made a spreader of oak for my wooden tripod... In future, the legs can be moved over to the hubs of other kits, including other Sky-Watcher types.
  16. I decided against the burgundy dye, as it has just a bit too much yellow, making it brownish. My late father was a luthier of sorts, in his retirement. He would use leather-dyes for his woods, like this one... He added some black, to where it's a dark purple when I added some denatured alcohol, and the bottle had long since been emptied. It is still sold, but I ordered two bottles of this brand instead... I've seen that particular brand of oxblood dye tested on a neutral piece of wood... Come heck or high-water, it's going to be that, as I'll have two bottles of the stuff. It can be diluted, for a lighter shade if desired, and with denatured-alcohol.
  17. Yes, and then there's this one... https://astronomy.tools/calculators/field_of_view/ ...similar. Enjoy.
  18. I had been looking at the various dyes online, rather than stain, and for these tripod-legs. Some were water-based, but I didn't want that. And there in my own backyard, in a cupboard actually, a bottle of alcohol-based burgundy, and practically full... ...and tested there on a scrap of maple. Incidentally, I still don't know the species of wood of which these legs were made. I'm thinking luan, meranti or "Philippine mahogany"; all the same I think. In any event, it's rather dense, inflexible... ...and quite strong for such small stock.
  19. I don't use a 45° Amici for stargazing. That's simply the diagonal that came with the C90. But upon studying the images more closely, perhaps a RACI would be best, particularly when the telescope is pointed at or near the zenith; my apologies.
  20. An obsessed amateur does what an obsessed amateur must... "Gruelling" was not the word, rather "exhausting", "excruciating", and in stripping those legs. It was absolutely, positively, no fun, and to the point where I don't feel any sense of reward after having done so. But, they are pretty nonetheless. I've decided not to worry it to death in getting every last speck of the old stain out of the pores. The colour to be chosen will be medium-dark, after all. I want this colour...
  21. A Maksutov requires a "seeing-eye-dog", or a seeing-eye owl, when attempting to navigate the sky with the Maksutov's rather long, drinking-straw-like focal-length; in manual mode, on the fly... If a finderscope, get a straight-through 50mm... https://www.firstlightoptics.com/finders/skywatcher-9x50-finderscope.html The RACIs were developed for Newtonians.
  22. I have this Meade 8-24mm. It's bigger than a bread bin... I got my own last year for less than USD$65. The views are not bad, not at all, but I haven't used it much, like once. Some do barlow zooms. I suppose they get some benefit from so doing. Incidentally, whether one uses a Plossl and a barlow, or a BST planetary or "Starguider", no matter, as a barlow is being employed, whether separately, or integrated.
  23. Ah, but you lose the grain of the wood in that. These legs are going to get something special, colour-wise.
  24. Welly well, that worked a charm, a treat... The bulk of the old finish is gone, but traces remain. I may give them a second coat, but outdoors, as this stuff is not particularly nose-friendly, even with a ventilation-fan running, although that did help, and from turning me into a vegetable.
  25. Yes, the legs are practically identical... The tripod-hub of my own has the same split-yokes, but not much of a base for a mount head... Yes, all of these off-shore equatorials, particularly the entry-level, must be loosened throughout, and before even thinking of adding a motor-drive. The greater the level of attention, the better for the drive... https://stargazerslounge.com/topic/319273-meade-large-equatorialeq-2-hyper-tuning/ I still have some more to do to it, however.
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