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About hunterknox

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    Proto Star
  1. Seeing as it’s likely out of warranty it can’t hurt to take a look. The PST uses a 5-sided prism to bounce the light up to the eyepiece. One face should be parallel with the front on the scope, one with the eyepiece. When you’re turning the focuser you’re just screwing the prism holder back and forth within the black box. The holder isn’t a great design. The prism is “pinched”, if you will, at the slides (like a litter picking claw might pinch some rubbish). It’s not a great way of securing something so it’s not unknown for the prism to slip a little which puts the whole optical alignment out of kilter. Have a go at unbolting the hex bolts on the side of the black box and see what you find. They might be a bit stiff - I think mine were loctited. It could just be a case of manually adjusting the the prism so it’s facing the correct way in its cradle. Good luck.
  2. I guess the seeing in York must be fairly stable - flip side of the fog you often get. Anything over 180x is a bonus for me but I don't think you necessarily need the highest magnifications for a reasonable star test. Glad to hear there are no optical horror stories thus far though.
  3. What? Problems appeared as I was typing? Sounds about par for the course. Still got my fingers crossed for you for first light though...
  4. Fortune favours the brave! I'm a sucker for alternative designs of anything. Very interested to see how you get on with this one...
  5. I think the phrase "primarily a visual instrument" comes from the original marketing info. I know a few people who've looked through them, myself included. If you can get excited about seeing a faint, featureless purple circle then it's a visual instrument. If you're a normal person then it's for imaging only. Great scopes, but only for a very small niche. I sold mine when I stopped imaging.
  6. Yep. Never really understood why people do it though, except in very specific circumstances (e.g. using a Daystar filter). If you're struggling to get a perfect circle for your aperture mask there was a guy who used to make Bahrtinov masks who traded on ebay as Morris Engraving. He made me a custom Hartmann mask for a very reasonable price so I'm sure he could do an aperture mask too.
  7. Weirdly my older Solarmax has a red front-end etalon and a red objective, so it might be that the etalons have ERFs up front but that they're not suitable for use without additional energy rejection components.
  8. Here's a solarchat thread on he same topic: http://solarchat.natca.net/viewtopic.php?t=4307&p=43819 In summary, check design specifics with the manufacturer but there doesn't seem to be anything intrinsically bad about using oil-spaced refractors.
  9. I suspect that any glass or oil up front isn't an issue - heat gets concentrated at the back of the scope and if anything the oil im a triplet might help to stabilise any temperature differential betwen lenses. That said I do believe that the earlier TEC 140s aren't recommended for solar viewing - something to do with the collet rings? Later versions had a different design and to say they've been used to impressive effect would be understating it.
  10. I would say no, the 66 is unlikely to be better for solar unless the opticstar's a dog. Aperture still rules for solar refractors and the magnification you can use is more likely to be dictated by seeing than telescope.
  11. Nice one, Stu. you can tell that a mount's a beast when it comes with its own carry handle!
  12. I hate spending money but the Baader wedge is one thing I'd have no hesitation in buying again.
  13. It all comes down to seeing again. You're right that you get the same peering-through-the-atmosphere effect when the sun's very low down but it's usually dominated by ground effects once the sun's heat kicks in and that's worst around mid-day. That's why a lot of land-based solar observatories are up towers and by lakes - it's the best way of ensuring a stable atmosphere. I also find the seeing effects to be wavelength dependent, which would make sense given that red light is refracted to a lesser degree than blue. Back when I was doing imaging I tried to get calcium K done before 9:30, white light before 10:30 and H alpha shortly after. In winter it can be better for observing in some ways due to the lack of a significant temperature differential. One of the best tips I've picked up for white light is that if you switch a continuum filter for a red filter when the atmosphere gets choppy you can get a better view until the seeing breaks up altogether.
  14. Solar's a different kettle of fish when it comes to magnification. I can rarely use magnification over about 60x because the seeing's so affected by the sun's warming effect and I don't think that's uncommon. See how you get on with your existing eyepieces, figure out what your optimal magnification is and if you do feel the need to change try a simple eyepiece like a plossl or an orthoscopic - fewer glass elements is usually better, in my experience.
  15. CA is the last thing that bothers me, as in it does bother me, but it's the last thing on my list of things a scope has to get right. Any kind of perceivable softness (spherical aberration), coma, diffraction spikes usually bug me more. I've tried various ED refractors and have been impressed every time. They do enough of a job on CA that I'd definitely consider them before a Newt or catadiatropic of some kind, but then I'm a refractor guy at heart.
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