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@Flame Nebula Hi, yes, I was satisfied with the views visually. Both scopes were good with the binoviewer, which, fwiw, is my preferred way of viewing Moon and planets. The views, of Jupiter and Mars, for example, were not ‘mushy’ and showed good clarity, colour rendition and detail. The MTF curves I’ve seen would suggest that the SCT might have slight advantage over equivalent unobstructed aperture with high frequency detail but be slightly disadvantaged in the mid range, which, other things being equal, might make it a better choice for some sorts of target than others. The 140 apo image is subjectively nicer to look at and probably samples the available UK seeing almost all the time. When I decided to ‘rationalise’ my kit recently, it was the SCT that went - the apo wasn’t going anywhere. I’ll PM you about the bench test, because a third party is involved - suffice to say, it was done for me by someone whose name most users of the forum would recognise as highly expert and who is a friend. As far as I know, there is no option available to test SCTs before purchase. I had it tested purely out of interest. Please bear in mind that while the SCTs I owned turned out to be good - I’ve heard that quality is more consistent these days - there might still be some ‘less thans’ out there. My feeling is that if you have doubts, it would be better to look elsewhere and many helpful suggestions have been made 🙂.
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I’ve owned the 9.25 and the 11 and was pleased with both. I’m a fussy observer and have a TEC140 to compare them with. While the character of views through the apo was (and is) uniquely attractive - there’s no disputing that high quality apos render sweet views - both the SCTs resolved and showed finer detail on, for example, the Moon - not surprising, given their substantial aperture advantage. Both SCTS were good scopes optically and mechanically and this was confirmed for the 9.25 by an expert independent bench test. I’ve had, from memory, 9 Newtonians over the years, from 6 to 14”, including examples with optics by Hinds, Hysom and Grubb Parsons, and would not say that, aperture for aperture, the optically very good Newts generically outperformed the SCTs. There are so many contributory factors, some intrinsic to the design, some to do with the way different sorts of scopes need to be managed in order to perform at their best. And, of course, there’s sky quality to contend with, which doesn’t affect SCTs more or less than any other sort of scope. I liked both of my SCTs. Perhaps I got lucky. Both were rewarding scopes that gave good images and provided decent aperture in a compact package that wasn’t unduly demanding to mount. The AZEQ6 was a good match, incidentally, as was the AZ100.
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Telescope you'd like in your collection within budget.
JTEC replied to Grump Martian's topic in The Astro Lounge
I’m happy with my TEC which is why, several decades and tens of scopes later, it’s one of two I still have. I’ve always wondered about a Mewlon though, I like the sound of those - optical quality, etc, etc, and, of course, its first name begins with ‘T’ 🙄 -
Following a recent cull of scopes that didn't get much use, just 2. I call this ‘rationalisation’ but deep down I know it’s just clearing the decks to speculate about what I might get next. For now it’s: TEC140 apo and Stellalyra 90mm apo. Gone for now are the SCTs and big Dobs, but I know they’re all still out there, waiting …
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Tak 100 dc vs skywatcher 120ed and 150ed
JTEC replied to Flame Nebula's topic in Discussions - Scopes / Whole setups
Just on this point. I’ve owned this combo and would advise against it. The Evo is a nice mount but overstretched with the 9.25 OTA. The C9.25 OTA was excellent but putting it on that mount was definitely imv a step too far. As you say, there are problems with clearance at higher elevations, especially with, for example, a 2” diagonal in place. This makes binoviewers and other attachments at the eyepiece end more or less out of the question unless you’re content to observe only at modest elevations. On top of that, high power viewing that was well within the capabilities of the very good OTA was badly affected by the wobbliness of the combination - Celestron should have stopped at the 8. -
Has anyone layered rainfall and other meteo metrics onto a map of UK Bortle data?
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The skies where I live in Surrey can vary from a (very rare and marginal) 4.5 to a pretty bad 6. So, I think the Bortle Scale has to be viewed as a somewhat useful but very broad brush indicator. Some of the criteria do seem rather arbitrary and situation dependent - the detectability of the Zodiacal Light, for example - and some of the visual tests seem substantially dependent on the characteristics of the observer. Dark Sky maps have some limitations as well because most show light shining upwards and not the appearance of the sky when viewed from the ground with light domes from adjacent towns, etc - though it’s perhaps reasonable to assume that there’s a useful correlation. A simpler way of finding darker skies is to identify population centres and where people live and get as far away from them as possible. Applying this in the UK will take you to places where you usually can’t observe anyway because it will be raining. 🤣
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Which 3 of your eyepieces get the most use, and why?
JTEC replied to F15Rules's topic in Discussions - Eyepieces
13mm Ethos, 10mm Delos and 9mm Tak ortho pair in the bino (if that’s allowed). That said, I don’t remember a session when I only used 3 eyepieces. -
Roland Christen’s advice with regard to binoviewers, choice of eyepieces, GPCs, etc may be of interest - it’s mostly further down the page: http://www.darksights.com/Binoviewers.htm Personally, I don’t go shorter than Tak 6mms. I haven’t got a pair of anything shorter. I think merging anything much shorter might become problematic but also there’s little need - the 6mms with 1.7(more like 1.5) GPC produce about x240 in my refractor which, for almost every application, including lunar and planetary, is enough. I can get more by using a 2x Powermate ahead of the prism with or without the GPC in place, but never feel the need. FWIW, my ‘favourite’ eyepieces in the TEC + Baader Mk V are the 9mm Tak orthos and the 18mm Tak LEs.
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@Mumia, not including various unobtainable, well-nigh mythological eyepieces that I’ve never had the opportunity to try, my vote also goes to the Tak orthos for sharpness, clarity, colour rendition, contrast, etc - I have pairs of the 6,9 and 12.5mm orthos and a pair of 18mm Tak LE orthos for the binoviewer. My shortest fl is now the 4mm TOE but it looks as though @mikeDnight, with his interesting and persuasive review, might have cornered me into forking out for another SV 3-8 😬
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Delighted that you’re happy with the Vixen you bought from me Mike - but does this mean I have to buy another SV 3-8? 🙃
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As @Mark at Beaufort, I bought one of these because it was getting consistently very enthusiastic reviews and was relatively inexpensive. The build quality was instantly very impressive and it was convenient to use - the only handling issue was that the movement, while very smooth, was also fairly firm to the point where twisting it could tug on other bits of the train. But I attributed this to quality fit, and you’d expect it to loosen up with use. In my refractors it gave good images and performed best in the middle of the range. It was not as sharp as fixed focal length eyepieces falling within its range - Tak orthos and a Tak TOE - but that was hardly a fair contest. In my view, it’s not equal in terms of performance to eyepieces like these but, if you like zooms for their intrinsic qualities, I think this is a heck of a bargain.
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Advice on an Ethos for high power observing
JTEC replied to Nicola Fletcher's topic in Discussions - Eyepieces
I’ll just point out that I have an effectively brand new 7mm APM XWA 100 degree eyepiece listed here in the SGL For Sale section 🙂 -
90mm f6 refractor for observing planets is any good?
JTEC replied to aleixandrus's topic in Getting Started With Observing
I speculated that the gradual coming together of colour correction could be explained by progressive, differential cooling/equilibration within the bodies of the lens elements and/or of the 3 elements of the objective in relation to each other - but that could well be complete nonsense 🤣