Louis D

I see that TS Optics sells the range as the TS N-ED flat field eyepiece. Aren't they German?

How about, why doesn't SGL have a proper classifieds area like Cloudy Nights? What advantage is there to the SGL classified method?

I'm assuming based on the title of the thread that it wasn't the Skywatcher EvoStar 120ED. I've often wondered if a long focal ratio 150 achro would outperform such a 120ED on some objects. I wouldn't expect a 127 achro to outperform it in any respect except perhaps mechanically.

If you need portability, the Mak is hard to beat. I have a couple of them, and they're very nice and also gentle on eyepieces due to their long focal ratios. The Startravel-102 is going to be very similar to the Travelscope 70/400, if not a bit worse with regards to violet fringing. It will have slightly better resolution and light grasp The 8" Dob is easily the best of the bunch here. However, it is large and heavy, so be aware of that. The views will be spectacular compared to anything else in this price range.

Read reviews here and on Cloudy Nights. Typically, the 25mm eyepieces aren't too bad while the 10mm eyepieces are generally bad. The eyepieces are basically unchanged since you were a child except that manufacturing has moved to mainland China. Tele Vue, Pentax, Nikon, Zeiss, Leica, Takahashi, and a few others generally produce only high quality eyepieces. Baader and Explore Scientific are a step down from them. Orion, Celestron, Meade, and a bunch of others sell a massive range of eyepieces under their own brands from several different Chinese and Taiwanese optical houses. The quality varies from line to line. Then there are the various astro retailers' house branded eyepieces which typically come from the same suppliers. A GSO/Revelation or similar Plossl would be an improvement over the included eyepieces for not a lot more money. The BST Starguiders offer better eye relief and a wider field of view for a bit more money than those Plossls. After that, it generally takes major jumps in spending to see noticeable improvement in performance. Those jumps come in the areas of resolution, contrast, apparent field of view, and usable eye relief (among others). You generally need at least 18mm of usable eye relief for eyeglasses I've found. It can be less if your eyes aren't set as deeply as mine or more if you wear glasses that don't fit closely to your face. In general, be very skeptical about eye relief numbers quoted by dealers and manufacturers. Many are quoting design eye relief which is measured from the center of the eye lens. If that lens is deeply concave and/or deeply recessed in the housing, the usable eye relief can be much less. I recommend asking on here about specific eyepieces and whether or not they are comfortable for use with eyeglasses. Probably a little, but not a lot. That scope may have a decent objective lens, but it also has loads of violet fringing at higher powers. I have the 70/300 version that I converted into a super-finderscope, and it needs a field flattener due to the very short focal length. However, with a high dollar wide field 2" eyepiece, a 2" 99% dielectric diagonal, and a high dollar field flattener (over $500 together), it does work surprisingly well at 8x for a $25 ebay find.

Orion used to have a very generous return policy that is now down to 30 days for any reason in new condition with no restocking fees. They are also based out of California. Both of these reasons and others have contributed to their higher costs. As for the products, the Orion is basically a retasked GSO 50mm finder scope. It still focuses by the objective end. The SvBony is basically the 50mm version of Orion's 60mm Multi-Use Guide Scope with Helical Focuser which itself appears to be the same as this ebay offering. If you want a helical focuser at 50mm from Orion, you would want their Deluxe Mini 50mm Guide Scope with Helical Focuser which appears to be GSO made. It appears to focus at both ends. It comes down to weight, features, and whether you want to buy Taiwanese (GSO) or Chinese (SvBony) made sold by a US or Chinese retailer. It's been rumored that GSO sources some of their components from Chinese factories, so there is that as well.

Well, technically, 20/20 only refers to distance correction. You're neither near nor far sighted. You could still have undiagnosed astigmatism that you would only notice when viewing bright stars because they are THE acid test of eyesight, telescopes, and eyepieces. Only when all elements in the optical chain are well corrected will you see nice tiny pinpricks of light across the field.

At f/6, the Maxvision 68° or Meade 5000 SWA 40mm work really well to max out your true field of view and your exit pupil without breaking the bank while providing a very well corrected field. They can be found in the astro classifieds at times. You can always put in a "Wanted" to see if someone has one to sell.

You never mention if you need to wear eyeglasses with your EL 42s due to astigmatism in your eyes. If you do, this becomes an important consideration when purchasing eyepieces that operate at larger exit pupils. They will need to have enough eye relief so you can still see the entire field while wearing eyeglasses. There is an alternative called Dioptrx from Tele Vue, but it doesn't fit on all eyepieces, nor do all eyepieces have enough eye relief for it to be used successfully.

I've read that you can request replacement caps directly from Tele Vue, at least in the US.

You could try masking off the broken part and see how objects look when viewing the night sky. It costs nothing to try (except for the cost of some blue masking tape), and it might yield surprising results.

The 30mm APM Ultra Flat Field (UFF) would be my pick for a very well corrected, yet moderately priced, 2" wide field eyepiece.

My 15x70s are excellent for large open clusters such as the Pleiades, Hyades, and Collinder 70. They're also handy for picking out comets near the horizon. In short, they're great for larger objects.

Since you're operating at ~f/6, you'll need eyepieces that do well in moderately fast telescopes. If your budget is tight, I would start with the 12mm, 8mm, and 5mm BST Starguiders. If you only have a 1.25" diagonal, get a 32mm Plossl for lowest power viewing. If you have a 2" diagonal, I'd recommend the 35mm Aero ED SWA for widest field viewing. You might want to add something around 17mm to 22mm in the future, but I tend to skip past that power in scopes near this focal length (900mm). If violet fringing bugs you, you might want to look into a minus violet filter of some sort. The Baader Contrast Booster seems to be well regarded in this capacity. Here's a comparison of the effect various filters have on the view through an achromat:

Probably none if both were recently made in China. I have Chinese made Galileo 15x70s I picked up over a decade ago that look identical. I love the wide field and long eye relief of the eyepieces on them. These binos are heavy and long, so I grab them by the objective ends and wedge the other end into my deep eye sockets while sitting to observe. They were also great for watching the Balloon Fiesta launch field in Albuquerque a couple of years ago from a nearby field over a mile away. I just supported them on the top of the steering wheel while I stayed warm in my car awaiting the morning warm-up. The view was very similar to this telephoto image I shot:

I have some eyepieces with out top caps. I just keep disks of closed cell foam from eyepiece bolt cases over them in the Pelican-style case when stored to avoid the possibility of the case foam from disintegrating onto the eye lens or just plain sticking to it.

Keep in mind that budget wide fields are not known for their excellence when viewing planets, which is what you're after.

Quite the opposite for many types of rubber. It will actually act like a shock absorber and dampen vibrations faster than if the feet were directly on a rigid surface. The best dampening material is probably still Sorbothane from the 80s. I use pads of it under each foot of my tripod to dampen vibrations from 3 seconds to 1/2 second.

Generally, yes. Mounts that are overloaded tend to flex a lot in the breeze and take forever to settle down whenever they're touched in the slightest. That tripod won't be too bad if you don't extend the legs, hang a weight under it in the center, and put anti-vibration pads under each foot. Don't over-tighten the leg locks. On many of these, the bands are made of plastic and will rupture under the strain. I've also heard of people disassembling the legs so they can be filled with packed sand to make them more resistant to vibration.

You might check in on Cloudy Nights as well. There are far more Americans on there than here who might be able to help you out.

If you can spring for a 150mm APO triplet with FPL-53 glass on a very heavy duty EQ mount, it would be very nearly ideal for both imaging and viewing. However, that approach can be cost prohibitive (well over $10,000). Most folks go with a largish reflector of some sort on an alt-az mount of some sort (under $1500 total) for visual work and an 80mm to 100mm ED or APO refractor for imaging on a heavy duty EQ mount (under $2000 total).

Most likely Universal thread M42 mount. Sigma did not make any T-mount lenses to my knowledge during that era (mid-70s by the look of it). They were all dedicated to a particular mount. Get an EOS to M42 adapter. There's plenty of film to flange distance for it to work. I've got several M42 lenses that I've used on my EOS cameras to good effect.

My version from Surplus Shed has between 9mm and 11mm of measured, usable eye relief, a measured AFOV of 33 to 49 degrees, and weighs 180g.

Did you mean does the 8mm have generous eye relief? If so, it has about 12mm of usable eye relief which is very comfortable when not wearing eyeglasses. The 18mm is a decent performer compared to simpler designs such as Konigs, Erfles, Kellners, and low cost SWAs. It isn't as good as the 5mm and 8mm BSTs, however; so temper your expectations.

Both lines reportedly work well at ~f/6. I can personally vouch for the 5mm and 8mm BST Starguiders. They work very well at that f-ratio across the field. Are they as good as my Delos, XWs, and Morpheus, not quite; but they're not far behind. The biggest difference is the quality of the lens polish and stray light suppression which slightly reduces their contrast and ultimate resolving power. However, for ~$60, they are hard to beat.