Louis D

It seems folks have been asking about this eyepiece for at least 8 years on both here and on CN, and literally no one has chimed in to offer any sort of report on it. Is the entire original stock of this eyepiece still sitting on dealer shelves?

The OP could also try @John's trick of using a 7.2mm-21.5mm zoom in a Baader Q-Turret 2.25x barlow to get a higher power range (9.55mm to 3.2mm) on the (relatively) cheap:

I can tell you I have a 15" truss Dob that I rarely use since an automotive back injury in 2000 made lifting the 65 pound mirror box a literal pain in the back. I keep it in hopes I'll someday be able to park it in a garage on a wheeled cart with corner jacks at a dark sky vacation/retirement house. That way, I only have to lift it once onto the cart.

I'll have to put a dovetail on my 2000-era ST80 and mount it opposite my 72ED on my DSV-2B mount and compare the views on various targets sometime. The ST80 is limited to 1.25" eyepieces and thus can't accommodate a TSFLAT2 to flatten the field or provide extremely wide field views. That aside, I'm curious how much purple fringing and spherical aberration intrudes into the view through the ST80 relative to the 72ED.

Correct. Discontinued very recently, so you might still find new old stock at some retailers.

Remind us please what you're looking for? Originally you were asking about refractors and now you've expanded to Maks and 12" Dobs in another thread. Tell us what you want to see better, and what limits you have as far as budget, weight, storage, and transport.

Sorry, I just did a quick calculation using the typical 52 degree AFOV of a 32mm Plossl assuming no distortion to get to 2.2°. However, this is a minor quibble because neither value comes close to matching the typical 5° to 10° TFOV of handheld, 6x to 10x binoculars which the OP was trying to match, assuming TFOV and not AFOV was meant by the OP's phrase "they give a similar field of view".

When did this changeover from MDF to OSB occur? 20 years ago, MDF was the go-to wood product for Chinese made scope bases, at least as sold in the US.

Does Baltic plywood ever get dark enough to use in the summer? 😉

Since it has a 1.25" focuser, you're never going to be able to go wider than about 2.2 degrees when using a 32mm Plossl or similar. To use either an 82 degree 32mm or a 62 degree 40mm would require a 2" focuser.

How does the Baader Maxbright compare with the Denkmeier Binotron-27?

Given the super short focal length of your scope, you're probably going to have to either use a Barlow or tele-extender to get the power up to a reasonable level for planetary observations. Alternatively, if you are opposed to adding additional glass to the optical path, you could look for used Vixen HRs which were available in 3.4mm, 2.4mm, 2.0mm, and 1.6mm focal lengths. Tak TOE eyepieces are still available new in 4mm, 3.3mm, and 2.5mm focal lengths.

Why stop there? Start with this nice 20" APO lens from Russia and build your own scope around it. It's a bit of a bummer it's gone up 100,000 Euros in the last couple of years, but you could probably talk them down a bit since it's been sitting on the shelf for a while now.

Although I find it nice to not have to swap out a high power eyepiece for my ~40mm SWA if I step away from the scope to relocate an object that has drifted out of the FOV in the interim. The RACI can get me back on track again pretty quickly. Lately, I've been using my GLP more than either my Rigel QF or my Telrad, though, to get in the general vicinity. It's much less of a struggle to use for someone with a bad neck and back.

Unless you move to a more optimal place to observe to increase your chances.

Absolutely, lots of folks including me. It's probably one of the best uses for them because swapping two eyepieces and making sure they're not tipped is a royal pain. Matching magnification is relative simple. I just rotate the zoom collar on both until my dominant eye sees the best image, and then I fine tune the other zoom's magnification to match. Your brain instinctively knows when they match and you stop zooming then. At that point, you have clear binovision again. They give you the ability to quickly find the optimal magnification for the current seeing conditions relative to the object being viewed.

Keep the finder scope closer to the focuser than the Telrad since you probably ping-pong back and forth between the two as you zero in on an object. I generally only use the Telrad to get me in the vicinity of an object and don't generally look back unless I need to reset my bearings if my fine grained search goes way off the rails. As such, the Telrad can be placed on the other side of the finder scope away from the focuser. However, if there is enough separation between the focuser and the finder scope, you may be able to position the Telrad between the two, but further down the tube away from the end. Just make sure you can bend yourself around to see up through it.

Yes, magnification is proportional to the true field of view. If you halve the TFOV, you must have doubled your magnification if all else is constant. That's the beauty of the ruler method. All that extra optical path length through the BV allows you to reach close focus easier. It's the same as adding an extension tube of equivalent optical length. Give it a try and see if you can reach close focus with the GV without the 1.6x. By close, I mean somewhere between 10 and 50 meters. You're never going to reach focus on something a foot away without an insane amount of extension. 😁

In my experience, the Morpheus line is much better corrected at f/6 than cheaper 70 degree eyepieces like the Omegon Redline and similar. I lump the Hyperions in with the Redline type eyepieces. They're much better than a bare 70 degree Erfle or Konig, but they're not quite there as far as edge correction when compared to the Morpheus, Pentax XW, and Delos lines. It's a matter of how picky you are about edge astigmatism and how far your budget will stretch as to which line to buy.

That's certainly true of observatory class telescopes, but a large Newtonian with a hand figured mirror and Paracorr II is hard to beat dollar for dollar on aperture at the high end of the amateur market. Most folks dropping $20,000+ on catadioptric designs are purely imagers, not visual observers. On the other hand, folks dropping $20,000+ on giant custom Dobs with Zambuto or similar mirrors tend to be visual only observers. It really depends on what you're going to use the telescope for when it comes to deciding on a particular design at a particular price point.

My 20+ year old Dob is made from 3/4" oak plywood and sonotube. Heavy for its size, but both have stood up to being banged into doorways and accidentally kicked without visible injury.

Luckily for you, the Powermate doesn't grow significantly in power with increasing separation. As such, you should just be able to multiply the various magnification values together. As a double-check, setup a ruler or similar and make some field of view measurements without the BV, with the BV and OCA, and with the BV, OCA, and PM. Eyepiece choice shouldn't matter since all you're looking to calculate is the differential magnification between each step. These values will remain more or less constant regardless of eyepiece magnification. This is how I determined that my Meade 140 2x Barlow nosepiece yields exactly 3x in my BV.

I've not used one myself since I'm about 22 degrees latitude south of you, so planets generally get high enough for AD to be a non-issue if I wait for them to be due south. However, I've read many reports that they work really well. Keep in mind that they require a fair amount of in-focus, so check how much you have left with your favorite eyepieces at best focus before buying an ADC.

All I can say is, it's a good thing the Dobsonian mount was invented if that frac is at the top end of an EQ5's capacity. Can you imagine how big of a GEM it would take to mount a 24" Newtonian? It's no wonder all modern giant observatory telescopes have gone to alt-az mounts.

Sounds like you either need to have a serious conversation with your neighbor, or setup a spotlight shining in their bedroom window if they're recalcitrant.