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Louis D

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Everything posted by Louis D

  1. If that level of pincushion distortion bothers you, stay away from the 27mm Panoptic and 28mm RKE as they have even stronger pincushion than Plossls (like the NPL). Notice the bowing of the ruler/yardstick in the last four eyepiece AFOV images below:
  2. Here's Tele Vue's own history table documenting the introduction (but not discontinuation) of each product.
  3. That's in my AT72ED with TSFLAT2 and 8" Dob with GSO CC. The 30mm APM UFF is also dead flat as well in both. By way of comparison, the 30mm Wide-Field III clone has loads of field curvature in either. I once moved it well back from the diagonal in the AT72ED with a 2" extension and racked in my focuser to overcompensate the field flattening, and then the 30mm WFIII had a pretty flat field and just residual astigmatism at the edge. It's a shame it doesn't have a built in field flattening element at the bottom because it would actually make a pretty decent 80 degree eyepiece. I was able
  4. Since the current generation of ES-82s all have recessed eye lenses, I can understand where it would lose about 3mm of eye relief right there. I know I can just take in the whole field of my first-gen mushroom top 30mm ES-82 with eyeglasses on. I've measured it to have 16mm of usable eye relief while the ES spec says 22mm, and that's about how it feels, or possibly 17mm. You have to press in to take in the entire field of view, but it is doable without scratching your glasses. Since the 24mm version has a smaller eye lens, I would expect less usable eye relief in the original gen-1
  5. Interesting. I have one of the original mushroom top 30mm ES-82s, and it is dead flat of field to my presbyopic eyes. What I can't stand about it is the CAEP that causes the ring of fire. It also causes extended objects like planets to split into a red and blue copy slightly separated from one another near the edge. If you simply concentrate on the center, it's hard to notice this, so it is good for sweeping rich star fields. Enjoy your Terminagler/Genesis combination!
  6. Good to hear. Did you buy through AliExpress or directly from Hercules? Any issues with the transaction?
  7. The only time I got tripped up with all these inversions and flips was when I was using both a refractor and a Newtonian at an outreach event on alt-az mounts. As I moved each to reposition the object after letting it drift though the field of view, I kept getting mixed up which way was up/down and left/right in each. The refractor is upright, but reversed left/right. The Newtonian is rotated 180 degrees, so inverted in both directions. I eventually got the hang of it.
  8. @GKADid you ever get a chance to try out your Hercules solar wedge? If so, what are your thoughts on it?
  9. KUO is making some splendid eyepieces like the APM UFFs and likely the Aero ED, WO/Nirvana/TS UWANs, and maybe even the Orion LHD and APM HDC-XWA lines. If any Chinese eyepiece maker can pull it off, they're mostly likely to be able to do it.
  10. It's still quite comfortable to use with eyeglasses. In use, it feels more like the 18mm of eye relief that my Pentax XWs and 14mm Morpheus have.
  11. Maybe I missed it in the video, but how does it compare to the 9mm APM XWA HDC Hyperwide? Is the 9mm ES-100 worth $250 more ($549 vs $299)?
  12. I just remember how long it took for the 17.5mm Morpheus to finally hit store shelves. Wasn't it several years of delays? And that was pre-Covid.
  13. It's a good idea to keep these screws around for other unforeseen needs in the future. They're used in a lot of astro equipment.
  14. Okay, I now understand you're trying this photographically. Can you try it visually to see if a Barlow/eyepiece combination can reach focus? I'm much less familiar with photographic applications. My guess is that you need to rack your focuser inward to reach focus, not add more extensions.
  15. Are you sure you don't need more in-focus? Is a star image getting smaller after inserting the Barlow at the original focus point when moving the Barlow/eyepiece combination toward or away from the visual back?
  16. Generally M4 or M5 screws, depending on the brand.
  17. With slight refocusing near the field stop (last 10% of field, let's say) in all of my scopes, I see a bit of astigmatism in my 14mm Morpheus that is utterly absent from the 9mm Morpheus, 10mm Delos, and 14mm Pentax XL (which has loads of field curvature, but no astigmatism). I look at planets near the field stop as I let them drift across the field to maximize dwell time looking for details. There's no degradation in the 9mm Morpheus or 10mm Delos across the field that I can detect using this technique.
  18. A 2" Barlow will severely vignette/cutoff longer (22mm+) widest field eyepieces. You're better off going with a telecentric magnifier as @johninderby suggests above. If you want to go cheap but good and are willing to deal with loss of field, the GSO/Revelation/etc. 2" 2x ED Barlow is hard to beat, especially used. They typically go for about $60 used here in the states.
  19. Alright, I'll come to the defense of 40mm SWA eyepieces at f/6 under Bortle 6 skies. I enjoy maxing out the field of view while viewing large objects like the Pleiades or Collinder 70. They're bright enough that the brighter sky background isn't distracting at all. They're also enjoyable for sweeping rich star fields. Yes, they're marginally useful for detecting smaller DSOs due to the low contrast with the brighter sky background, so higher power and wider field of view eyepieces are more useful.
  20. Probably an M3, possibly an M4, screw. Take one down to your local big box home improvement store and screw it into their thread sizer mounted on a column in the fasteners aisle to find out for sure.
  21. I've been using a Celestron 94108 90° correct image diagonal for 20+ years in my 60mm finder scope to good effect. I can't seem to locate it at any retailers these days, though.
  22. From what I've read, the 4.5mm and 6.5mm Morpheus have less eye relief than the longer focal length ones. As a result, you need to get your eye closer to the eye lens to take in the entire field of view as you found out. Try removing the extension ring and see if the vignetting goes away. As for the difficulty holding the view in them, it sounds like SAEP (Spherical Aberration of the Exit Pupil) or kidney beaning. I've experienced the same issue with the 12mm and 17mm Nagler T4s. It wasn't until I took images through them using a 127 Mak and a slow, extreme wide angle phone camera tha
  23. I don't think it's possible with the maximum field of view of an 8" SCT being about 1.4 degrees and the Pleiades being about 1.8 degrees. Even in an 8" Dob with a 1200mm FL, it's a bit of a tight fit. You can't combine an F/R with a 2" diagonal and widest field 2" eyepieces without severe vignetting. The cheapest route is generally the F/R if you've already got a 32mm Plossl or 24mm SWA eyepiece.
  24. Of course, in Japan, this might be one reason why straight through viewing is popular.
  25. There's the GSO diagonals sold under the Revelation and iOptron brands in the UK as well. I really like their 2" diagonals, but have no direct experience with their 1.25" diagonals. One advantage to prism diagonals over dielectric diagonals is lower scatter.
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