Louis D

Agreed.  My Rigel QuikFinder is still going strong 22 years after buying it new with the original button cell battery.  It works absolutely like new.  I can't say the same for my 3 Telrads (one new, two used).

Yes, probably JOC made.  Just remember, if anything goes wrong (shipping damage, faulty optics or mechanics), you have to deal with China directly, not a local dealer.  Good luck with that.

Is the Orion 2x the Orion Shorty-Plus?  If so, it is the same as the Celestron Ultima and Parks Gold Series which were all 3 element, Japanese made Barlows of very high quality.  If it was the regular vintage Shorty, then it is of decent quality.

I have a 1998 vintage Tele Vue 2x Barlow.  It performs basically the same as the Shorty-Plus and Meade 140 APO 2x Barlow and slightly behind the Orion Deluxe 2x.  All were made in Japan.  All are exceptional performers.  Only the Tele Vue is still available new, though.

On 18/01/2022 at 07:33, Highburymark said:

In terms of high quality zooms which rate alongside fixed eyepieces, I remember a Meade 4000 zoom from the late 1990s which cost around £240 at the time - over twice the price of a case of 8 Meade Plossls. I couldn’t work out why it was so expensive - only later found out it was made by Swarovski.

Did it look like the Japanese made Meade 4000 zoom on the right in the picture below?  If not, you've really piqued my curiosity.

The one on the left is the newer, Chinese made version.

Maximum eye cup metal ring diameters:

12mm/17mm ES-92 = 56.5mm

30mm APM UFF = 45.0mm

22mm TV Nagler T4 = 44.0mm

17mm TV Nagler T4 = 44.0mm

12.5mm APM Hi-FW = 44.0mm

12mm TV Nagler T4 = 43.5mm

27mm TV Panoptic = 43.0mm

24mm APM UFF = 42.9mm

9mm/14mm Baader Morpheus = 42.9mm

Astro-Tech AF70 (13mm/17mm/22mm) = 42.9mm

So I was mistaken. My apologies.  The 30mm APM UFF has an M45 thread.  It is the 24mm APM UFF (and AT AF70s and Morpheus) that have M43 threads.  The 12.5mm APM Hi-FW is spec'ed with an M44.5 thread.

As such, the Dioptrx won't fit the 30mm APM UFF because 44mm is the maximum diameter it will clamp onto.

The 24mm APM UFF is also sold as the Altair Ultraflat, Celestron Ultima Edge, Meade 5000 UHD, and Orion Ultra Flat Field.  I may have missed some European-only versions, so check around.  Point is, there's a good chance someone has it in stock at a decent price.

Short of a 24mm Panoptic, it's about as good as it gets at f/5, especially if long eye relief is important.

3 hours ago, bomberbaz said:

A 26mm ES by 62D FOV gives you x29 by 2.15 TFOV.   So the ES gives you a better magnification, so darker background than a 30mm plossl and at the same time a better tfov than either of the other eyepieces.

How well did the ES-62 work at f/5 for you?  I have it's predecessor, the Meade 5000 Plossl 40mm.  It's a five element super plossl (Zeiss Astroplan) design opened up to 60 degrees from 50 degrees.  At f/6, it falls apart beyond about 50% to the edge, so I can't imagine it's actually better at f/5.  Since it's a scaled design, the ES-62s should all perform the same across focal lengths.  I'll admit it's very sharp in the central 50% with low distortion across the field, so the moon doesn't distort into an egg shape as it drifts across the field.

Here's a comparison image showing the Meade stacked with other eyepieces at f/6 in a field flattened 72ED scope:

It's serviceable for an $80 eyepiece, but not for a $180 eyepiece.  I would just get the 25mm BST Starguider and call it a day:

It's not perfect, but it's no worse than the Meade 5000 Plossl/ES-62, and it's a lot cheaper at £49.

There's also no shame in a 32mm Plossl.  Sure, it won't be perfect to the edge either, but they're only £29.

I ended up buying a couple of used Telrads at $20 a pop that had potentiometers that only switch between full on and off to replace my original one that died after 18 years.  I just didn't have the time to deal with trying to make the dead one work again.  Check the classifieds to see if you can locate a cheap but partially working Telrad.

1 hour ago, Mike Q said:

I will add another vote for a zoom eyepiece.  I use Orion's 8 to 24mm and I have put it in a 2x and 3x barlow.  You can get some wonderful views with this set up.

How well does it work in a helical focuser?  Unless it's super low resistance, it will require two hands to zoom to avoid changing focus.

Buy some rubber O-rings with an inner diameter no bigger than the outer diameter of the 1.25" insertion barrel.  Measure how many millimeters you're off between the 10mm and 25mm eyepieces, divide that by the thickness of each O-ring, and slip that number of O-rings on the 10mm (which seems to focus farther out), pushing them up to the shoulder (wide part) of the eyepiece.  Hopefully, there's still enough lower barrel to secure the eyepiece in the focuser.  Below is an image of how I parfocalized my Tele Vue 12mm Nagler T4.  I needed to add a 20mm long, 2" barrel extension to the 2" skirt to have enough barrel to insert it into the focuser.  Each of the O-rings is 4mm thick times 5 rings to raise the eyepiece 20mm.

52 minutes ago, Doasqa said:

Old and stiff, forget about dobs. I had an 8” and sold it. It was to awkward and heavy to move around and added to my back pain. I sold it and bought a Sky Watcher 100ED. Much easier to deal with. I then added a BT-100ED binocular-telescope. If you have the budget, that’s the way to go. I use my BT five times more than my SW. I’ll probably eventually sell the SW. 

What mount do you use with your SW 100ED and BT-100ED BT, and do you move them around together?

6 hours ago, Second Time Around said:

Louis, can you measure the thread under the 30mm APM?  I'd read that it was a little larger than 43mm, and that a Dioptrx wouldn't fit.

Thanks.

If I get a chance, I'll use my digital caliper on it.  It's quite possible since the way threads are measured, the maximum male thread width could very well exceed 43mm.  Of course, if it's close and you don't need the threads, you could hone them down until it fits. 😉

I don't know that the 27mm Panoptic has enough usable eye relief for comfortable use of a Dioptrx.  I've measured 14mm of usable eye relief, and that matches with my experience with it.  15mm is about the minimum recommended usable eye relief for the Dioptrx.  That eyepiece is too tight on ER to use with eyeglasses.  I actually scratched an eyeglass lens on the eye lens retaining ring years ago trying to push in enough to take in the entire field of view.

I swapped out my 27mm Panoptic for a 30mm APM Ultra Flat Field a couple of years ago.  It is flatter of field, better corrected to the edge, and has plenty of eye relief for eyeglasses.  The Dioptrx might fit since it has a 43mm top thread under the eye cup.  It has a 36mm field stop versus a 30mm FS for the Panoptic.  That's 20% wider which is very noticeably for a mere 10% growth in exit pupil thanks to lower edge distortion.  The APM is available under multiple brandings now, so it should be readily available.

Another option in this price range is the 20mm APM XWA HDC.  It would have about the same true field of view as the 30mm APM at a smaller exit pupil.  It is available under several other brandings, so search for availability and price.

1 hour ago, johninderby said:

Sounds like a project for Rowan. 🤔

If you build it, they will buy. (or something like that)

There were also microscope zoom eyepieces from the ~1970s that could be adapted to telescope usage:

13 hours ago, Dakuwaqa said:

I’ve found when I use my eyepiece I somethings get the field of view shrink but keeps its round shape (if that makes sense). I get a ring of black around the edges.

Are you pulling back too far from the eyepiece to take in the entire field of view?  You might also be too close, but that's less likely, especially with the 10mm.  Try moving your eye position in and out with respect to the eyepiece when you notice this happening.

12 hours ago, Dakuwaqa said:

It’s happened with both my eyepieces. 10mm and 25mm. Could it be condensation?

Not likely because you would see an overall cloudiness of the image, not a black ring.

Aren't there any European made focusers to compete with the Feather Touch?  It seems like there are plenty of high end machine shops over there that could do it.

Here's another test of the two eyepieces.  Move the moon and/or a bright planet or star just outside the field of view.  Which does a better job of suppressing stray light not in the field of view?  Of course, if your scope's tube isn't well baffled/flocked, any eyepiece differences may be drowned out by it.

I have an 8" dovetail on my 72ED and a 14" dovetail on my 90mm APO triplet to get the CG far enough back to use heavy 2" eyepieces and binoviewers with both.  I do have to be careful with the focuser knob's orientation, or it will either touch the dovetail or be behind it, depending on the scope.  I suppose dovetail flex would be an issue for imaging, but it's not an issue for visual observing.

On 28/12/2021 at 07:54, Mr Spock said:

No collimator gets it exactly right. You always need to finish with a star test. I use a laser as it gets it close enough, then finish with a star test.

Not really an option for Dob users with no view of Polaris and no EQ platform like myself.  Unless the star is perfectly centered, you can't easily distinguish decentering from bad collimation; and since it drifts off axis fairly quickly, it doesn't leave much time to adjust collimation.  It's mostly useful as a quick confirmation of decent collimation before the star drifts off axis.

I only use my laser to get my secondary pointed back at the primary's center after loosening everything up and starting over when something seems amiss, but I can't quite nail down where.  I have to be very careful not to lase my own eyeball while looking down the front of the tube to get the laser off the tube wall and back to the mirror.

After that, I mostly use a cheshire sight tube with crosshairs and an Aline cap to finalize everything.

What about something similar to this to keep everything dry?

The Baader Neodymium cuts out a good chunk of the yellow part of the spectrum where there is a lot of light pollution.  This also increases the contrast between blue-green and red-orange planetary features much like a magenta or salmon filter operates.

And if it's the Synta focuser I think it is, don't put the 1.25" adapter in the 2" adapter, you won't be able to reach focus.  Replace the 2" adapter with the 1.25" adapter.  Synta alone uses this scheme.  Every other 2" focuser uses 2" eyepieces natively, and then you insert a 2" to 1.25" adapter into it to step it down for 1.25" eyepieces

As @John points out, 2" eyepieces are best for low power, wide angle views.  I'd recommend picking up something in the 35mm to 42mm widest field range just to help center objects before moving to higher powers.  Of course, with Synta's focuser, this isn't as quick and easy to do as with other focusers.

Take a picture of the primary mirror to help us get an idea of how dusty it is.  It has to be really grungy to warrant a cleaning.  Cleaning microscratches are worse than dust because they cause light scatter.  Dust just tends to attenuate the brightness a bit.

You'll want to at least collimate the primary with something like a Rigel Aline to make sure you're getting decent views.  This assumes the mirror has a center marking ring, which it should have from the factory.

Here's an article with suggestions for more appropriate astro headlamps.