Louis D

I would probably look for a quality Barlow or telecentric magnifier myself and just reuse my existing eyepieces at higher powers.

I have the entire line except for the 3.2mm. The 5mm, 8mm, and 12mm are all very good. The only comment from an experienced observer about the 3.2mm that I've read is from Jon Isaacs over on CN: At F/5-F/7, the 25mm and the 18mm show significant off-axis astigmatism. I still use them but the views are not optimal. Probably better at F/10. The 12mm, 8mm, and 5 mm are quite sharp across the field even at F/5. The 3.2mm, it's a little weird off-axis at F/5, I haven't quite decided about it.

Teeter Telescopes offer(ed) GSO mirrors as the lowest cost mirror option for their telescopes. They must have been pretty good to be putting them into multi-thousand dollar telescopes. Why would you risk your custom telescope business's reputation on crappy mirrors?

Yes, mine is intended for groomed lawns and fields, such as setting up on a soccer field for a star party after driving my van to the edge of the field. Driving on such fields is highly discouraged. 😉

Notice that the high frequency detail is preserved (the pinpoint city lights) while low frequency detail is compromised (the subtle sky and sea tones). I'd guess they're using jpeg compression at a fairly aggressive setting. The jpeg algorithm tries to preserve high frequency detail in a relatively small area at the expense of large swaths of low frequency detail under high compression. There isn't much you can do to change how FB compresses image downloads.

Oh, I just carry my Dob by the handles on each part, but I never carry it more than 100 feet. My 15" Dob has its own flat dolly with heavy duty castors and pull rope to move it about.

What is the diameter of the stock lazy Susan versus the diameter of the ground board and rocker box?

After reviewing your video, the first thing I notice is it seems to wobble on the AZ axis. This is probably a function of the undersized bearing for it. Ideally, the bearings should come all the way out to the edge of the AZ board. You could substitute Teflon pads riding on textured FRP wall board or other nubbly, yet glossy, board. Try separating the rocker box from the ground board and repeat the rocking action again with the rocker box directly on a smooth, solid surface. This would show how much improvement is possible by redesigning the AZ bearings. I can't really tell where the wiggliness in the ALT bearing is coming from. It's hard to tell if it's rocker box flexure or simply the long tube amplifying small flexure at the pivot axis. If that is the case, you'd need to increase the diameter of the side trunnions to reduce the flex coming from that connection point. This is really an engineering problem. Isolate the cause of the "failure" and then try to find a fix, or at the least, a workaround. Even giant, custom Dobs exhibit a bit of wobble sometimes in some orientations and motions. Trying to rotate around Dobson's Hole at zenith comes to mind. This is where the Mag 1 Portaballs had it in spades over the traditional two axis Dob design.

If traveling by car, I'd just wrap a shipping blanket around the tube to protect it from dings and knocks. I suppose the bag would be better for mass transit, though.

Just a wee bit of a price jump there (~$650 or 70%). I'll wait and pick up a used one in a decade like I did with my TS-Optics Photoline 90mm FPL-53 triplet for about 60% of new price.

Sounds like you need to find a used 5-8mm Speers-Waler Zoom (Varifocal). It works quite well as long as you're okay with refocusing during focal length changes and can live with 10mm of usable eye relief; although it's much longer if you don't try to see the entire 78-80 degree AFOV field at once thanks to its 25mm diameter eye lens.

If you were referring to me, I was quite aware of your comprehensive guide. I'm perfectly aware that the LVWs were discontinued years ago, but if you put out a wanted ad on US astro classifieds and offer $300 or so for a used one, quite a few offers will inevitably turn up. I took a pass on them in the late 90s after comparing them to the Pentax XLs and liking the latter better. Perhaps I should have gotten the 22mm LVW back in the day, but it was (and still is) a focal length I rarely use. You pretty much repeated my list of 20mm to 22mm eyepieces if you exclude rebrandings of the same eyepieces. The only other one I though about including was the 22mm Oberwerk since it is uniquely 1.25" and 70°, but typically are only sold in pairs except for their recent remainder sale of the previous version on ebay.

Weight wise, that puts it squarely between its two nearest LER competitors that I own, the 22mm AT AF70 (Omegon Redline SW, etc.) at 494g and the 22mm TV NT4 at 680g. There's also the 20mm Pentax XW at 365g, but it suffers from field curvature, so I've never bothered with it. The 22mm Vixen LVW comes up short in AFOV at 65 degrees. I suppose I could include the 20mm APM XWA HDC which reportedly yields about 70 degrees AFOV with eyeglasses. It weighs 680g, so basically the same as the NT4. Since the Astro Tech version costs $250 right now, it's a very close competitor price wise as well ($12 more once VAT is subtracted). The 17mm ES-92 has a field stop nearly as large as the 22mm AF70, so it could also be included in a LER comparison. Any other 70 to 85 degree LER eyepieces in the 20mm to 22mm range? I keep hoping ES will release a 23mm ES-92, but that seems highly unlikely now. There's the 21mm Ethos, but paying that much for at most 70 degrees AFOV with eyeglasses seems like a total waste of money.

My only concern would be the trunnion supports bowing outward at some point over the next decade. Starmaster telescopes have had this issue despite using red oak plywood. The culprit tends to be moisture intrusion warping the lumber.

I once looked through a 17.5" Coulter Dob at a star party a couple of decades ago, and I can't say that the views were all that impressive. Not bad, but not exceptional like a modern Zambuto or Lockwood mirrored Dob. The fact that the guy kept an ancient 12 passenger van with custom wood cradles in the back to haul it around, and had to get a couple of extra folks to help him extract it and set it up, put me off of getting one. I went with a used 15" Tectron Dob with a Nova Optical mirror instead. It was great until my back got ripped up by a car accident. That 65 pound mirror box is killer.

Sometimes, it comes down to which way you can reach focus and which way looks better corrected. I've heard both ways. TV claims the CC should be kept at the same distance from the eyepiece, so it would slip into the Barlow. Myself, I leave out the CC (a GSO as well) because at higher Barlowed powers, the residual coma doesn't bother me much at all. Your best bet is to get out there under the stars and experiment. It's not like something is going to short circuit and explode in your face. 😁

Had to look that one up since that show hasn't made it to this side of the pond. Good one. 👍

You might try cross posting this question on CN's Classic Telescopes forum as well since you suspect it's an Edmund objective.

You could go cheap with an achromat refractor and image with a green filter like a 56 green possibly combined with a 12 yellow to filter out the unfocused blue and red light. You could then switch to grayscale in post to replicate the green channel to the red and blue channels. Notice below for an achromat (the dotted green line) that if you restrict it to the spectrum range between 500nm and 600nm (hard to see due to the transparent background around the edges, but they're the 2nd and 4th horizontal lines from the bottom), you can get pretty tight focus. That's roughly the color range from teal to orange. Now notice that if you combine a 12 yellow filter with a 56 green filter, you'll do a pretty good job of selecting the 500nm to 600nm range. Since the sun and moon are so bright anyway, you can afford to lose roughly half the light intensity within that range. This would not be a good approach for dim, full spectrum objects. You might not even need to stack the 12 yellow depending on the particular characteristics of the 56 green filter.

You can't use a solar wedge with a Celestron Nexstar 127 SLT. They can only be used with refractors. You'll need to use a full aperture solar filter such as Baader Solar Film unless you either already have a refractor not listed in your signature line or are planning on buying one. The 127 Mak should take fine images of the moon. Given the 1500mm focal length and crop factor of your camera, the full moon (or sun with filter) should just fit on the sensor in one go at prime focus to avoid stitching images together.

Interesting. I just measured the Meade 140 distance from the bottom of the chrome tube to its insertion shoulder and got 85mm. Thus, if I'm seeing 3.0x in my binoviewer, and it takes an additional 45mm extension to get to 3.0x, my binoviewer must have a 130mm optical path length. That's a 30mm longer than I had guessed, probably because I have to screw the nose piece into the BV's insertion barrel filter thread since it uses a nonstandard thread size to attach to the BV body.

There's also the optically-same Meade UHD, Celestron Ultima Edge, Tecnosky Ultraflat, and Altair Ultra Flat versions. Perhaps one of them might be in stock.

I'm an iced tea man myself, it being so hot most of the year here in Texas. I prefer it freshly brewed and strong. In fact, so fresh it melts the ice so I have to add more to cool it to near freezing, thus the need for it to be brewed strong. Nothing offends me more than instant iced tea from a mix served from a beverage fountain. Ugh, disgusting.🤮

I did a write-up here comparing the 30mm APM UFF to the Tele Vue equivalent 27mm Panoptic along with the 30mm ES-82 and a 30mm generic 80 degree Wide Scan III clone. Reportedly, the 28mm ES-68 has better eye relief than the Panoptic, but has poorer edge correction beyond the 80% point. I do have the 40mm Meade 5000 SWA which is the same as the 40mm ES-68, except for eye relief, and really like it a lot. I actually prefer it to my 40mm Pentax XW except its ergonomics being broadly flat topped.

Think Wild West versus Afternoon Tea.