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Louis D

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About Louis D

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    Brown Dwarf

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    Texas, USA
  1. Louis D

    15mm Panoptic

    I think the short eye relief of the 15mm Panoptic helped to seal its fate. That, and all the affordable 14mm to 16mm 82 degree eyepieces that came on the market over the last 15 years. Any other ideas on why TV discontinued it?
  2. It kind of depends on the folks length of your Dob. I can get down to about 3 degrees with one of my Dobs, but only about 1.5 degrees with the other. Since most RACI finders only go to about 5 degrees, it's marginally helpful for the shorter focal length one, but very helpful for the other. Here in the US, a lot of folks are also adding green laser pointers/sights to aid it getting the tube quickly on target as well without destroying your back or neck. As long as you're mindful of your surroundings and watch out for passing aircraft, I haven't heard of anyone having any legal issues with them here. In Australia, it's my understanding that only card-carrying astronomy club members are allowed to use them for pointing out objects at outreach events and such. I have no idea about Britain or other parts of the world.
  3. Louis D

    BRESSER 40mm Eyepiece 60 ° 5 Elements

    Indeed. The original version of the Bresser 40mm is spec'ed to weigh 560g which is exactly the same as my decloaked 40mm Meade 5000 Plossl (705g with cloak). Decloaked, it has a 43mm eye lens yielding 29mm of usable eye relief. I measured the AFOV to be 60 degrees and the eAFOV to be 61 degrees based on a calculated field stop of 42.3mm from reading off a yardstick at a distance and doing the math. Technically, I should be able to measure the FS directly, but it's too far up inside the barrel for my calipers to reach it without disassembly, and I'm not going to risk it. Interestingly enough, the 30mm ES-82 has a calculated FS from measurements of 42.4mm, so almost identical TFOV, just at a higher power and wider AFOV. It's not bad at f/12 in my Mak, but it's still no Panoptic or even Meade 5000 SWA or ES-68. As Alan says, the outer 25% to 30% starts to fall apart quite badly at f/6. I think it's due to astigmatism more than field curvature because refocusing didn't improve matters at all. Out of focus stars were definitely astigmatic. However, I could not detect any image distortion as the moon was panned from edge to edge. It remained perfectly circular. The fact that the AFOV and eAFOV are nearly identical would seem to confirm this. Edges aside, the center view in it is fantastic. The correction is phenomenal with pinpoint stars on an inky black background. The center is far sharper than the 30mm ES-82 and perhaps sharper than the 40mm Meade 5000 SWA. The exit pupil is easy to find and hold despite the massive eye relief. I never notice any blackouts or finickiness in the view. If you look straight ahead at the center, the edge can be ignored and you'll be happy with the eyepiece. I paid about $60 used for mine some time ago, so 29,99 € is a very reasonable price for one. That's 1.25" 4 element Plossl territory. It would at least make an excellent outreach eyepiece if you find you don't like it. Ultimately, I prefer the decloaked 40mm Meade 5000 SWA because it has a wider TFOV (45.7mm FS), AFOV (71 degrees), eAFOV (65 degrees), and is basically sharp to the edge. It also has 29mm of usable eye relief and has a very stable exit pupil. It does weigh 874g decloaked, but it's worth the rebalancing and price. It does distort the moon into an egg shape quite noticeably at the edge, though.
  4. Louis D

    Alternative to Baader magic fluid?

    Or try to make your own Baader Wonder Fluid based on their MSDS. It's 25% ethanol and 35% Propan-1-ol (an isomer of isopropyl alcohol). I know it sounds terrible, but I've had good luck with Windex window cleaner as well. I'm sure there's a British equivalent.
  5. The 24mm APM UFF is no where near as good as the 30mm. First off, it's not actually flat of field. I have to refocus for the edge, if you can believe it! It is wider than a 32mm plossl at the expense of some edge vignetting and indistinctness (a 27.5mm effective field stop based on my measurements relative to said plossl). It's as if they pushed the design a bit too far. I measured it to have a 63 degree visible AFOV, but an effective AFOV (eAFOV) of 66 degrees due to magnification differing across the field. With the eyecup folded down, it does have 17mm of usable eye relief, so it's quite easy to use with eyeglasses. I haven't encountered blackouts or exit pupil finickiness. There might be some edge astigmatism, but I would need to double check that before I say anything more on that point. Stars definitely don't remain pin sharp to the edge. The last 5% becomes mushy. In the central region, I'm still evaluating it. So far, it's no better or worse than a plossl in that region based on my limited time with it under the stars. I haven't written much about it because I'm still developing my opinions about it. I'm mostly disappointed it isn't flat of field as claimed and yet costs a lot compared to other 24mm options out there. The 30mm APM UFF is definitely flat of field, so I don't know what happened with this eyepiece's design.
  6. Louis D

    Omegon Panorama II eyepieces

    I buy all of my own eyepieces and never get paid for anything I write. I use only my own equipment at outreach events. I'm just disappointed that there are those who would take money in this hobby to write reviews without a disclaimer. I'm sure Steve is a fine person and has to make a living, and does not let payment taint his judgement as he has stated above. I'm just a firm believer in volunteerism and have spent countless hours trying to help folks navigate this hobby and don't like the idea of people being paid to write reviews without full disclosure. Maybe I missed that he did disclose that he was loaned the eyepieces and was compensated for his effort, but I can't find it. Perhaps it was in the original magazine's print version. Full Disclosure: I disclose that I don't have and have never had a financial interest in any astronomy related company, nor have I ever been loaned an eyepiece to review (and probably never will now ), nor have I ever been paid to write anything astronomy related. @rwilkey Sorry to hijack your thread and go off on my soapbox. I hope you get a chance to use your new eyepieces in the near future and report back here on your findings. I'll shut up now.
  7. Louis D

    Omegon Panorama II eyepieces

    Indeed. Upon rereading, they are all there, just toned down.
  8. Louis D

    Omegon Panorama II eyepieces

    Now that's the kind of feedback that should have been in the initial review. Please try to incorporate such details into your future magazine reviews.
  9. If the inverted image really bothers him, just have him stand on the other side of the scope and bend over it looking into the eyepiece upside-down. Sure, it's not very comfortable, but the image will be right-side-up from that perspective.
  10. Louis D

    Omegon Panorama II eyepieces

    I was just used to Popular and Modern Photography magazines in the US performing in-house bench testing of camera lenses as well as field testing them back in the day. Of course, they're both long gone now perhaps because of their objectivity. It's a sad day that magazines have devolved into shills for their advertisers to remain afloat. It would be nice if they posted a disclaimer on their reviews to that effect to warn newbies to take whatever they publish with a healthy dose of skepticism.
  11. Louis D

    Omegon Panorama II eyepieces

    Then why didn't he directly address the online criticisms of these eyepieces and put them to rest once and for all by verifying the manufacturer's AFOV and ER claims 4 years after they were introduced? You're all certain he alone is correct and everyone else who has bought these and been disappointed by them not living up their claims doesn't know what they're talking about? Nor did the reviewer make any effort to see how well it performs in a sub-f/5 scope. I would like someone like Ernest in Russia to bench test these eyepieces. He did test the older Meade XWAs, and they lived up to their marketing hype. All I'm saying is this was not a critical test review by any measure.
  12. Try sweeping your scope manually across the area where it should be. You might be able to detect the slightly brighter patch of sky that is the comet more easily. I find my 15x70 binoculars work fairly well for this. Another trick I've found that helps is to use a moon & skyglow filter to knock down the light pollution just a little bit. 35 miles west of downtown Chicago (near St. Charles, let's say) is still Bortle 7 suburban skies. Try driving 120 miles west toward the Mississippi river and stopping near Massbach, Ill. It appears to have Bortle 3 skies which would be much more conducive to finding a faint comet.
  13. Louis D

    Zoom eyepieces

    Binoviewers are a whole 'nother topic. Basically, the traditional binoviewer adds about 100mm to the optical path. As a result, many scopes won't come to focus with them. SCTs and Maks are the exception because they move the primary to focus and the secondary magnifies how far the focus plane is moved. As a result, they have tremendous potential backfocus. The downside is increased focal length and slightly increased spherical aberration. For other scope types, an OCA/GPC/barlow element needs added to the nose of the binoviewer to reach focus. This generally results in an increase in focal length from 1.25x to 3x thus decreasing the lowest power possible. Maximum field of view is also limited by the clear aperture (CA) of the binoviewer. Entry level ones have about 22mm of CA while high end ones are 27mm or more. Eyepieces with a field stop larger than the CA will vignette somewhat when used in a binoviewer. Larger CA is achieved using larger prisms which increases the path length beyond 100mm and increases the size, weight, and cost of the entire unit. Almost all binoviewers are 1.25"-only. 2" binoviewing is best done with a binoscope (two scopes side-by-side and aligned with eyepieces mounted right across from each other via a series of star diagonals). The amount of light reaching each eye is split in half. This is actually good on solar system objects which tend to be overly bright but bad for faint fuzzies like nebula and galaxies. With two eyes working on the same subject, more detail is generally seen than with one eye. When looking at the full moon, eye strain is basically eliminated because you don't have the dramatic mismatch in brightness between eyes as in mono-viewing. Eyepiece selection is complicated by the fact you have to be able to get them at least as close together as your IPD. This rules out using really fat eyepieces. They also have to allow your nose to fit between them. If you have deep set eyes, this can be a problem.
  14. I would go with the 30mm APM UFF. I replaced my 27mm Panoptic with it.
  15. Louis D

    Omegon Panorama II eyepieces

    I don't know how much trust I'd put in a reviewer who fails to even verify the manufacturer's specs with regard to eye relief and apparent field of view. It wouldn't have taken much effort on his part to project the AFOV onto a wall, measure it, and do the math. Neither would it have taken much effort to measure the eye relief at the same time. He didn't even take the time to compare them to their Ethos, ES, or APM equivalents. If he doesn't have experience with other hyperwide-angle eyepieces, how can he make any sort of comparative analysis? Basically, he says the views look nice over 90% of the field. From the entire review, all we can glean is that there is some abberations in the outer 10%. He also makes no mention of the presence or absence of edge of field brightening. I would expect better from a magazine review. His review sounds like a typical Amazon review posted by someone who was given the eyepieces to use and review.
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