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Everything posted by Second Time Around
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For further data points, Bill found 20% with a Televue Barlow and an APM 2.7x, 40% with a Klee 2.8x Shorty. I have the 2.7x APM and several other Barlows: 1.3x/1.6x Omegon GPC 1.5/2x shorty 2.25x Baader Hyperion I can see some experiments in my future........
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Author Bill Paolini's tests found that the increase is typically only 20-40%, depending on the focal length of the Barlow, with "shorty" Barlows having a greater increase.
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I note that the only eyepiece supplied with the 12 inch f/5 is a 32mm Plossl. This gives an exit pupil of 5.3mm, that for those in light polluted skies or those older observers whose own pupil size is less than this, won't be able to make full use of all of the 12 inch aperture. Presumably this was chosen to give a wider field of view (1.05 degrees) so that objects that Starsense Explorer found were always visible in the eyepiece. My own experience suggests that this is conservative as this is easily so even for the 0.83 degree field of view I use for a finder eyepiece. Yes, Starsense Explorer is that accurate!
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Welcome additions. As I've often said I reckon Starsense Explorer is a game changer. However, the 6 inch doesn't seem to be good value for money at the moment given that the 8 inch with a full size mount costs just £50 more. At just £549 that's a great price compared with the 6 inch. I'm pleased to see that the mirrors are all parabolic, and the focuser is a rack and pinion rather than a sloppy helical one. By the way there seems to be a discrepancy in the copy of the 130mm. The In the Box section says that the eyepiece focal lengths are 17mm and 10mm. On the other hand in the specifications section it says 25mm and 10mm. @FLOan you please advise?
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Optolong L-eNhance - Worthwhile Upgrade?
Second Time Around replied to Sarek's topic in Imaging - Tips, Tricks and Techniques
Sorry, it's sold now. -
Optolong L-eNhance - Worthwhile Upgrade?
Second Time Around replied to Sarek's topic in Imaging - Tips, Tricks and Techniques
Whoops, the advert is wrong. It is indeed a 2 inch. Ad now corrected. Many thanks indeed! -
Optolong L-eNhance - Worthwhile Upgrade?
Second Time Around replied to Sarek's topic in Imaging - Tips, Tricks and Techniques
If anyone 's interested I recently put a 2 inch L-enhance up on the For Sale forum. I don't take photos so it's surplus to requirements. -
Like Dave I upgraded the scope I gave to my grandkids. I added a Celestron star diagonal, a 32mm Plossl, a 9-27mm zoom eyepiece and a decent 1.5/2x Barlow. I also bought a secondhand AZ Pronto mount and tripod with slow motions and added tube rings. This makes a lot of difference, and it's a nice little package now!
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Excellent and comprehensive write up! Regulars will know I'm a great fan of Starsense Explorer, especially for beginners. Indeed, having bought the 70mm for two of my grandkids I promptly bought another for myself. This was just to get the SSE unit, that I adapted to fit standard Synta finder shoes. I then donated the scope to a pair of beginners. From reading Stu's report I suspect that the 70mm might be better as a scope, purely as the lighter weight and shorter tube makes it less wobbly (the mount's the same it seems). It wouldn't resolve as close doubles of course, but would have a wider field of view - useful for the Pleiades for instance. Thanks again, Stu. 👍
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Help/advice
Second Time Around replied to Kenneth Spackman's topic in Getting Started Equipment Help and Advice
If you bought the scope online you have the legal right to change your mind within 14 days of delivery under the Consumer Contracts Regulations 2013. This is regardless of whether the item is faulty or not. Full details are given at https://www.which.co.uk/consumer-rights/advice/i-want-to-return-something-bought-online-aqsD32m9r5P3 -
Tele Vue Dioptrx Astigmatism Corrector
Second Time Around replied to Grump Martian's topic in Discussions - Eyepieces
Whoops! Sorry, Don is right of course. I'll correct my post. -
1.5× Barlow lens availability (UK)
Second Time Around replied to Paul Manuell's topic in Discussions - Eyepieces
Quite a few 2x Barlows can also be used at 1.5x. On these dual 1.5x/2x Barlows the black lens cell at the bottom of the Barlow can be unscrewed from the body and then screwed into the filter thread at the bottom of an eyepiece to give approx 1.5x. US retailer Agenda Astro say in the specification section of each Barlow they offer whether the lens cell can be removed. Go to https://agenaastro.c...-extenders.htm FLO do a good own brand such 1.5x/2x Barlow that also has a T" camera fitting at the eyepiece end. Go to https://www.firstlightoptics.com/barlows/astro-essentials-125-2x-barlow-with-t-thread.html There's also the Baader 1.3x/2x Barlow Q Barlow, but this can't be used with all eyepieces. This is because if there's a lens near the bottom of the eyepiece there may not be room for the Barlow cell to be inserted. -
Tele Vue Dioptrx Astigmatism Corrector
Second Time Around replied to Grump Martian's topic in Discussions - Eyepieces
Whether or not a Dioptrx will help depends on the degree of astigmatism you have in your observing eye. You can find this on your prescription under cylinder, often abbreviated to CYL. Note that your left eye appears on the right hand side of the prescription and vice versa. The higher the number, the greater the astigmatism. It also depends on the exit pupil of the scope with a given eyepiece. I assume that your Starfield refractor is an f/7, in which case a 5mm eyepiece will give an exit pupil of 5/7, i.e. less than 0.75. As Don has pointed out, with such a small exit pupil your astigmatism would have to be fairly bad to need correction. The graph on the link below will quantify this. From this you'll see that your astigmatism would have to be about 3 dioptres or worse for a Dioptrx to be any use to you with an exit pupil of 0.75. https://www.televue.com/engine/TV3b_page.asp?id=54&Tab=_Choose At bigger exit pupils/lower magnifications you may benefit from a Dioptrx even if your astigmatism isn't very bad. Again the above graph will help here. I'd add that it's not just Televue eyepieces that accept a Dioptrx. Quite a few others do as well such as the Pentax 70 Deg XW and Baader Morpheus ranges. However, that really needs a separate topic. The same applies to whether to observe with glasses or a Dioptrx, for which there are pros and cons. Don prefers the former while I prefer the latter. A search (certainly on Cloudy Nights, but possibly here on SGL as well) should show our reasons and that of others. -
Tele Vue Dioptrx Astigmatism Corrector
Second Time Around replied to Grump Martian's topic in Discussions - Eyepieces
Cheers. Will post tomorrow when back home. -
That's interesting! Support for the latest 32mm series, that's based on new technology, is being withdrawn in 2026. Yet all the current versions of the older 36, 42 and 50mm models are still being supported. I wonder what that tells us? I'm certainly glad that for other reasons I decided to go for the 12x36 III rather than one of the 32mm models.
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Allow me to present an alternative view. It's not better or worse than Jules's, just different Firstly, I have a genetic condition that badly affects my muscles. In fact, on bad days I don't even have the strength to lift a mug of tea. On good days though I have almost full strength. However, even then my back and neck are badly shot to pieces. Like Jules, if I lift the scope or mount in the wrong way I'm out of action for 10-14 days. I wasn't able to attend star parties but instead whilst in Germany visited several telescope shops. There I was able to directly compare a large number of makes, models and sizes. The first thing I decided was that Go-To wasn't for me because of the extra weight. It meant that I'd have to go down a size. I also found that it wasn't just the weight that was important but the footprint of the mount. Having a less bulky mount meant that I could hold it closer to my body, meaning less leverage and less pain. By far the best DOB mounting was the OOUK one. Being made of aluminium it's a lot lighter, plus the footprint is much smaller. Additionally, they have large circular altitude bearings in a ring shape. These make an excellent handle, and I found that I could cope with a mount one size bigger as a result. The Bresser (Explore Scientific in the US) is similar, but not so light as it's not aluminium. This design of bearings also make these two makes particularly smooth. The VX series of Dobs from OOUK also have aluminium tubes, so are lighter than the normal steel. The conclusion I came to was with OOUK Dobs, and to a lesser extent Bresser, I could cope with one size up compared to Skywatcher and GSO (the latter manufacture many of the generic makes on the market). I ended up deciding on a 10 inch OOUK Dob, but couldn't justify a new one. Used models in this size proved very hard to find, but I did get hold of an 8 inch f/6 very quickly. However, it took me over a year to find a 10 inch f/4.8. Since then I've had plenty of opportunity to compare the two sizes. On the planets there's not been much between them because poor seeing in the UK is usually the limiting factor rather than the size of the scope. Only on the rare steady nights has there been much difference. It's on DSOs where the extra aperture really scores. The difference isn't hugely marked though in my Bortle 4 skies, except that is on one class of object. Here there's a very definite improvement with globular clusters - my favourite objects. As a result I wondered whether to go up to a 12 inch. So I asked OOUK to bring a 12 inch f/4 to a show last month. I found the jump in weight from 10 to 12 inches much harder to cope with than from 8 to 10. Additionally, the mount was much bulkier. What I like with the OOUK 10 inch mount is that it fits just over my hips and thus it doesn't move around. I find that this extra steadiness makes a huge difference when walking with the mount rather than just lifting it. I certainly couldn't carry even an OOUK 12 inch very far at all. So for me 10-in is the optimum size.
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I fell on the eyepiece end of my OOUK 10inch f/4.8 and dented it. The end cap was also badly buckled. The local body shop soon fixed the tube for a cost of £50. Spare parts from OOUK are very expensive and a single end cap was £54 + about £6 carriage if I recall correctly. Better than a complete new tube though that would have been £180 + £54 for each end cap + about £34 carriage. Hope that helps.