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Ben the Ignorant

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About Ben the Ignorant

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  1. You should have said that to all who mentioned other eyepieces more than 40 times in this thread, and to yourself, 13 times. Same for you.
  2. The Explore 24mm/68° and the maxvision 18mm/82° have the same true field as the Tele Vue 32mm/50° or the 40mm/43° but with a more panoramic view and more magnification. Both have a maximal diameter field lens: (and cleaner lenses inside the Explore but they rest on a powerful torch so the slightest particle looks enormous) And what about eye relief? Do the pupil on paper test and you can compare with your own. This is a ceiling tube lamp so the pupil looks like a line but the pupil on paper test is valid as long as the pupil is focused sharp on the paper.
  3. And recoil even more looking through a window but it can be better, and I have photos to prove it.
  4. What should I be able to see? is the most natural question, and it would be very easy to answer if there were no light pollution, and no personal differences between observers, but these factors are too variable. So the answer is look at everything, starting from the brightest things, and build up your own experience. Light pollution maps are not nearly detailed enough; you might live in a theoretically very bad Bortle zone and have real life decent skies if your site is shielded by walls and trees. The closest lamps are the worst enemies, and just having no direct light in your spot makes it much better. Dry air makes a big improvement, too, so the weather forecast has to be watched, too. Depends on your eyes' sensitivity and what view you find satisfying but that's personal taste so infinite variations. Try viewing the obvious targets like the Pleiades, and then fainter and fainter clusters till you reach your individual don't bother limit. Depending on the night's humidity rate, the scope's magnification (higher is darker), your experience, and the target's height above the horizon, the response will change by two or three magnitudes, so no steadfast answer from others, only your own practical findings.
  5. Yes, this used to be the case but not anymore with recently manufactured windows: To answer your question, Sphenoid, several good scopes can be had for 200£ (230€). The latest nice offers are I've seen are: https://www.teleskop-express.de/shop/product_info.php/language/en/info/p802_Skywatcher-Evostar-90-auf-EQ-2-Refraktor-Teleskop-mit-kompletter-Ausstattung.html https://www.bresser.de/Astronomie/Teleskope/BRESSER-Messier-5-Dobson.html https://www.teleskop-express.de/shop/product_info.php/info/p2705_Skywatcher-Heritage-130P-FlexTube-Dobson---6years--.html https://www.teleskop-express.de/shop/product_info.php/info/p7222_GSO-Dobsonian-Telescope-150C---6-inch-aperture-with-fine-Crayford-focuser.html Good used scopes can be found for that budget but the search would be too long for me to do, however you have one month to look for them so no hurry, learn their basic features and compare. A well-maintained used scope will be larger and better than a new one for the same price, but I suppose you and your husband would prefer some new stuff as a gift.
  6. An ED lens gives optical designers a large advantage, especially with FPL-53 and FPL-55 glass but these are very costly, and the two other lenses matter immensely. I think they have a choice between twenty or thirty glass types, so if a triplet can be great with lenses of less radical properties but lesser cost, they should go that road. It's probably what they did here, the two ED elements have got to be the more affordable type. Straight Ronchi lines and a white star test are all that matter in a triplet apo, anyway, what glasses do it doesn't count a bit. By the way, it's a shame all these new scopes are not advertized with their Ronchi picture and their star test for everyone to see. A Ronchi grating cost 40€ and a star test costs nothing so there is no excuse.
  7. (speaking of TEC's 140mm f/7 triplet) Well, those who say that should know the facts can be found on the internet to prove them wrong. Rohr tested it and found less than 70µ chromatic spread: A Vixen 130SS I looked through has 150µ chromatic spread and no fringe could be detected at all around the Moon, Jupiter and Mars. The W_gesamt 0.9381 value means the scope is an apo because it's under 1. Between 1 and 2 are the semi-apos, and achros are above 2.
  8. They have an official rep in the US now. https://www.outdoorsportoptics.com/shop/telescopes_pw1_6_1.html
  9. Apo binocs with FPL-51 or equivalent glass are nothing new but this one has an air-spaced objective that should be better corrected. Also, the long extensions are not dewshields, they are part of the optical tube so the objectives are far away from the eyepieces, allowing for a longer focal length and another gain in correction. https://www.teleskop-express.de/shop/product_info.php/info/p11809_William-Optics-22x70-ED-APO-Astro-Fernglas.html Too expensive and long and heavy for me, I'm dreaming of the shorter and more affordable APM 16x70 but good to know what everybody makes.
  10. TS asked Sharpstar to make a shortish 140mm triplet (to compete with TEC's 140mm f/7 triplet apparently), and the result is presented in their website today. To keep the stars tight over a large field at the kinda steep for the diameter f/6.5 ratio, they put two low-dispersion lenses in the objective (Takahashi does the same in some large apos). The focuser is a very large 4" unit, and the scope can operate at f/4.8 with a 3" reducer, imagers will love that. https://www.teleskop-express.de/shop/product_info.php/info/p11814_TS-Optics-140-mm-f-6-5-Super-Triplet-Apo-mit-2-ED-Elementen.html I'm visual only but I'm glad these things are being marketed because the more large compact apos they make, the more likely I am to own one one day when I save up enough.
  11. Sky&Telescope's Pocket Star Atlas (20€) if you need compact paper star charts.
  12. Hello, Armando. You must be very experienced after sixty years.
  13. My red and white torches had uneven light... ...but simply rubbing the lens or the red filter with a kitchen sponge made them so: About 25cm away from my APM binoc's white box, would look the same on a star map. The gradients are because the camera does not have enough nuances, visually the spot is totally blended. It took an awful lot of time with the white torch because its lens is a high quality plastic, had to unscrew it, too. It used to project a very detailed and very annoying image of its yellow LED emitter but now its glow is as smooth as can be. It took rubbing both sides of the lens to make it that blended; I just remembered that now. The white pic is from 3/4 of a meter away against a wall. Edit: Didn't work at first but after a few trials messing with the phone's settings this pic of the lit red torch could be made, showing the effect of the red filter and rough sponge on a 9-LED "bicycle" torch. The white one is far too bright to be photographed when it's on.
  14. You don't have to sacrifice aperture to get a more portable scope, the question of portability has been asked by users and tackled by manufacturers, and they came up with 150mm tabletop dobsonians. The most affordable is the Bresser 150 f/5. https://www.teleskop-spezialisten.de/shop/Teleskope/Dobson/bis-150mm/Bresser-Messier-6-Dobson-Newton-Reise-Teleskop-mit-Zubehoer::3462.html It costs about 40€ more than the Sky-Watcher but it has a vastly wider field of view, and it's much shorter and lighter. And for the sake of being complete, Bresser also makes a 130mm f/5 tabletop, but the focuser is a 1.25" unit. https://www.teleskop-spezialisten.de/shop/Teleskope/Dobson/bis-150mm/Bresser-Messier-5-Dobson-Newton-Reise-Teleskop-mit-Zubehoer::3461.html Priced at 199€, so less risk of it becoming a big pile of idle money. (both are parabolic so no worry about optical quality)
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