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Axunator

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About Axunator

  • Rank
    Nebula

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  • Location
    Helsinki, Finland
  1. Still looking... For clarification, when I wrote ’excellent condition’, I meant mainly optics, normal minor cosmetic signs of use in the barrel etc are ok of course.
  2. Looking for Nagler 16T5 in excellent condition, including box and end caps, shipped to Finland. PayPal payment preferred (I will cover PP fees, of course). Thanks!
  3. Focuser in FC-100D’s is easy to screw off and on without tools for ultra-compact transport if needed - that will shave appr. 10 cm off the length (don’t have my DF now at hand to measure exactly but that’s the ballpark figure), and I presume this will apply also to the DZ. However, with the dew shield screwed off the DF is even shorter than DZ due to its 6 cm shorter f.l. But then you have to protect the lens somehow and pack the dew shield safely to protect it from getting bent out of shape. So I’d feel safer to travel with the new DZ...
  4. Yes, it’s an insulation wrap: two layers of reflecting aluminized bubble wrap with a thin foam layer sandwiched in between. I added it last spring after lot of talk about SCT/MCT insulation on CN, and I have to admit it seems to decrease required cool-down time to effectively zero. Haven’t tried it during really cold winter weather yet, though. I still also use a corrector dew heater band under the insulation (at low power), if I don’t put a dew shield on, since I need battery power for the mount anyway. With an insulated dew shield, insulation is supposed to prevent the cooling of the corrector below dew point, making active dew heating unnecessary.
  5. Tak FC100-DF + C9.25 on AZ-EQ6 and Berlebach Planet:
  6. The max true field of FC-100DF with a 2” EP is 3.6 degrees, quite a bit more than half of NP101...
  7. I see several advantages in these, as compared to standard SCTs: - easier thermal management compared to closed tube SCTs - way easier dew management (no corrector plate) - flatter field due to slower primary - much wider diffraction-limited coma-free field (standard f/10 SCT has coma-free field of ca. f/5 Newt, whereas f/12 Cassegrain equals ca. f/12 Newt, i.e. very wide diffraction-limited field. EdgeHD and ACF SCTs are of course a completely different story in this regard, but come with a price tag to match... yet still have that dew-magnet corrector plate). - no mirror flop during focusing (can be avoided with after market focusers in SCTs as well, albeit with a price) Of course, there are downsides as well: - a bit narrower FOV due to longer focal length (although diffraction-limited field is wider compared to standard SCT, see above) - diffraction spikes from the secondary spider - fixed focal length (back focus in 8" is reported to be 150 mm behind the 2" focuser), which may affect the use of some accessories, like binoviewers - more difficult to collimate because of hyperboloid secondary I guess you can tell that I'm excited ? And yet I'm still quite happy SCT owner as well ?
  8. Remains to be seen. I believe there are several visually oriented amateurs out there (count me in!) who fill find an open tube classical Cassegrain design - even at f/12 - very tempting and interesting... Especially at these prices. Whether it will be sufficiently profitable for GSO/TS/Astronomics, only time will tell. At least their RCs have been going on for years, and they are targeted to quite narrow audience as well.
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