Louis D

I don't recall it being brought up earlier in this thread, but the rings have been "closing" for several years now, making it harder and harder to make out ring details:

I would have gone with a 32mm GSO Super Plossl to max out the field of view in that case. I have one, and it's a very nicely made eyepiece.

He must have found some really rigid plastic storage containers, then. All the plastic storage bins I've used are made from very flexible plastic that deforms easily. Maybe they're rigid enough for a lightweight scope to sit on top of.

On top of possible tipping, one European user on SGL posted a video review where he complained that the Baader Clicklock pushes the barrel of whatever it's clamping to the side. So, the BCL isn't even self-centering.

To each their own, but I found as stated above that using a 40mm SWA eyepiece with a 46mm field stop increased the linear TFOV from 1.1° to 1.8° and made it a lot easier to get objects centered after getting the telescope in the general vicinity with either an RDF or GLP. Since I already had the 2" diagonal and 2" eyepiece, all it took was adding the step ring and SCT 2" visual back. When I went to buy another one for my daughter to take on her camping trips, it arrived with everything but a max field 2" eyepiece. I'm letting her borrow a couple of mine until she decides what she wants to buy for herself. At f/12, most wide field eyepieces look pretty good. The 1.8° TFOV also makes scanning rich star fields more rewarding. It's obviously not as good as with a short refractor, but it is better.

It's certainly very cool looking in black with that snazzy graphic on its side:

Most eyepieces I've dealt with use the lower base plate to hold the eyepiece lenses in place in lieu of a separate retaining ring, so caveat emptor.

But unless you're in quite dark skies, you won't see much beyond its core. It's surface brightness just isn't enough to overcome most skyglow. You should be able to make out one or both of its two brighter satellite galaxy cores as well.

@Zermelo nailed it. You just screw that adapter onto the existing rear thread, and presto-chango, you have an SCT thread that accepts myriad attachments. Once attached, it does look like the image below from the thread referred to above:

It appears that the TV Apollo 11 also comes with a 2" sleeve: Maybe it would have been $50 cheaper without it?

That "discontinued" 17mm AF70 shown above in my pic has a removable 2" barrel without an undercut. I seriously doubt it added $50 to the cost of that eyepiece. Was TeleVue considering having Starlight Instruments CNC machine them at that price?

And your point is what? I never claimed they were. Besides, the AF70 is available under other brands in Europe. The B&L eyepieces were long since discontinued when I bought them off ebay 15 years ago, so the point is moot with them. They're probably 1960s or 1970s vintage. The 17mm NT4 was just discontinued and is still listed as in stock a few places.

I tried that approach with my 12mm NT4's 2" skirt with extension, but where the parfocalization ring needed to go was right on the lower taper, so it wanted to slide into the taper as I tightened it. I ended up going with rubber O-rings instead:

I had something similar happen when a diagonal tried to unthread itself in a similar manner. All I could do was grouse that this would never happen with a Dob that has it's focuser angled upward.

I was just about to suggest it, but then realized many premium eyepieces have lenses in the lower barrel, so this would only work with an interchangeable 2" skirt on 1.25" eyepieces or on 2" eyepieces that don't need the entire ~46mm inner diameter for lenses. It would be a simple solution for eyepieces that have no lenses in the lower barrel, though.

Ahh, that makes you a Troll (under the bridge dweller), at least according to Yoopers (upper peninsula, above the bridge, dwellers). I'm married to a "Troll" from the Detroit area myself.

My favorites are a pair of vintage 15x wide field B&L microscope eyepieces I originally bought for my AO Series 10 microscope. At f/18 with the 3x Barlow nosepiece on the binos, they are super comfy and sharp.

Since Synta owns both, there's not much to choose between the two on quality. I guess it comes down to features. If you are going with a computerized telescope, I would make sure it maintains alignment even when manually moved without using the motors. That way, it can be used as a push-to as well as a go-to scope.

My basic Arcturus binos' collets tend to tip eyepieces with undercuts. I have to really mash them down in the holders while tightening them to avoid this. However, once tightened, they're solidly in there. However, since there is no way to lock the diopter setting except to snug it all the way up or down, I have to sometimes fight with it while zooming stiff zoom eyepieces.

Having an f/ratio of f5 and f/6, respectively, you'll want a 5mm as your highest power eyepiece for most nights. From there, I would add the 8mm, 12mm, and 25mm Starguider focal lengths. This would give you a nice range of powers in each scope.

You kind of have to with stiff zooming zoom eyepieces, or you have to grab the lower part of the eyepiece to zoom, which is a pain in binoviewers with two of them to zoom.

On a whim, I picked up a 25mm Edscorp Ortho which looks to be the same as other Tani made volcano tops. While sharp in the center at f/6 and flat of field with very little distortion, it is blurry at the edge at f/6 in my field flattened AT72ED. I went so far as to disassemble it and try all 4 orientations of the two groups (singlet and triplet groups) with respect to being possibly flipped by a previous owner, and the original orientation was still best, so it's a design issue with this ortho at f/6. However, at f/12 in my 127mm Mak, all is well for the ortho as well as for the rest of my 25mm 3 or 4 element eyepieces. A similar improvement can be had using a 2x Barlow with an f/6 scope, though I didn't take any photos of that combo yet.

I had one eyepiece holder/eyepiece undercut mismatch so bad that I almost couldn't retrieve the eyepiece from the holder because the brass compression ring got snagged and pulled up out of its groove where it jammed against the eyepiece above its normal position. I was pretty panicked. I'm not sure how I eventually got it freed (it's been years), but I'm more careful now. If there's any snagging, I don't try to brute force the eyepiece out of the holder. The real issue is that compression rings and narrow collet bands don't interact well with eyepiece undercuts. Either by themselves don't generally cause issues.

I was going by the measured AFOV of 44° to 45° as measured by multiple CN users. I can't recall anyone on SGL measuring theirs. I also can't recall anyone accurately measuring the field stop at each focal length. That's what really determines TFOV. As far as converting goes, I just added a step-up ring to bring the native Mak thread up to an SCT thread so I could add a 2" visual back. It's still a 28mm rear aperture, thus the vignetting. Because it is so far ahead of the eyepiece's field stop, the falloff is subtle. If the 28mm opening was at the end of the eyepiece's insertion tube, it would be a hard vignette and would be rather unusable.

The original 13mm Nagler prototype? Look on these webpages for images of the T1's predecessor (I can't link the images because they're not https).