John

Some better pics of my T-Rex with the 130mm F/9.2 on board:

Look forward to your report Peter. So glad that they have sorted things out with these since the problems that I had with the early ones that I was sent. I've seen some amazing lunar images taken with the ED150 on another forum. I always though these scopes had a lot of potential despite the early issues.

One of the the reasons for the price difference is that FPL-53 glass costs about twice as much as FPL-51.

Very true Stu. The eyepiece is actually quite low down on the "wobbly stack" of factors that affect what we actually see.

It's possible that the Nirvana has design changed since I had the 16mm UWAN (which was the version I owned for a while). Also it was now quite a few years ago. I went from the 16mm UWAN to the 16mm Nagler T5 and could not see a lot of difference but that's just my take. I don't wear glasses when observing and back then did not use them at all for anything. I use them for reading now. I think the best we can do is to caveat each report / opinion with "Your Mileage May Vary, and Probably Will" and leave it at that !

I agree. When I used to do them it took hours of observing over several sessions before I would reach any conclusions. And even then it could only be a report of what my eyes, my scopes and my skies and my brain were producing. I did have an advantage that I had the eyepieces loaned to me so I had not paid for them out of my own pocket and also that FLO (who loaned me them) never sought to influence what I reported in any way at all. There is no substitute for finding out for yourself though, if that can be arranged

Very sharp eyepiece, the Nagler T5 16mm. "Honey I shrunk the 31mm"

I've not used the 4mm SLV. I did review the 20mm, 12mm and 6mm for the forum a while back and thought them excellent. I compared the 6mm SLV at some length (ie: over several sessions) and found that it matched the Baader Genuine Ortho 6mm in performance and was more comfortable to use. I was rather surprised at this because the Baader GO 6mm is one of the best 6mm eyepieces that I've owned or used but there was no doubt that the 6mm SLV was providing comparable views: https://stargazerslounge.com/topic/217971-vixen-slv-eyepiece-report-6mm-12mm-and-20mm/

I've seen measured data on the light transmission of various eyepieces and there is some variation (as you might expect) between the designs which might also contribute to the perception of one being dimmer / darker than another. Of course a dark background sky is desirable but not dimming of the intended targets, especially faint ones ! The range was between 88% and 98% of visible wavelengths.

There is the Feathertouch for the Lunt HA scopes. Could that be adapted ?: https://www.firstlightoptics.com/specialist-focusers-borg-tele-vue-lunt-gso-rc/feathertouch-125-dual-speed-focuser-for-lunt-50mm-solar-telescopes.html I think Moonlite might have something similar ?

No, I didn't keep them for long - I caught the "ultra wide" bug shortly after then

OK, thanks. I'm just think that a £380 mount head really ought to be better than a £140 one when compared with the same load on the same tripod. If the AZ-5 managed 2-3 seconds on the 1.75 steel tripod against 1 second for this new mount on a £360 Berlebach Uni then the AZ-5 is not doing too badly

In some ways this is what a smaller sibling of the T-Rex mount might have looked like Do you have an AZ-5 to compare it with on the same tripod ? Or an Ayo Vamo Traveler ?

Looks great I wonder how it would perform with a lighter weight tripod that you might use for travel. The Uni 28 is pretty hefty ! Was your AZ-5 on the Uni 28 when you compared the damping times ?. Tripods can make a substantial difference to a mounts performance.

Yep - thats the "rule of thumb" that I use as well.

The Explorer 200P is F/5. The one they use in the dobsonian, the Skyliner 200P is F/6. An F/7 or F/8 would be a very long and heavy tube which would push even an EQ6 to it's limits. This is an 8 inch F/8:

One interesting thing about the XW's is that they use special coatings on the cemented lens surfaces as well as the glass-to air ones to maximise transmission and minimise scatter. I think some others use this technique now. Not sure if the XL's did or not ?

I've not encountered an XL so I've not had the opportunity to compare one with the XW's. I suppose after finding that the T6 Naglers were a step up in performance from the T1 and T2 Naglers I've thought that the XW's might provide subtle improvements over their predecessor range but I've not had the opportunity to find out for myself as yet. We are up amongst the top tier with all of these I reckon though. Vixen LVW's probably up there as well. Vixen need a really good 70 degree line again IMHO.

https://www.sciencecenter.net/hutech/pentax/ep.htm

The two examples that I was supplied with had packaging issues and arrived well out of collimation. This has been improved upon now and the scopes are arriving with new owners in good order. The scope had a lot of potential I felt even given the issues that I encountered. I'd like to try another someday Edit: Oh I see that Kev has already linked to the above.

Some of the german made mounts (eg: Giros) state that they can accept both threads but I have always assumed that the machining of the thread was specially designed to handle this. Maybe the Skytee II "tolerances" are loose enough to accept either ? The Skytee II is M10 as specified though.

For the cost and trouble of the changed visual back and a decent 2 inch diagonal one could almost have bought a pre-owned a 130mm F/5 newt or 120mm F/5 frac and have a proper wide field scope to compliment the 127 (ish ?) mak-cassegrain rather than going to great length to squeeze a few extra arc minutes of view from a scope who's strengths lie elsewhere. Well that's my take on it anyway

I use the 17.3 and 14 Delos with the 10 thru 3.5mm XW's to make a 1.25 inch set (plus the 24 Panoptic at the lowest power end). The two longest FL Delos reach focus a tiny bit further in then the XW's but close enough. The other Delos, as with the 24 Pan and the Nagler zooms, about 8mm further out. I don't mind focus tweaking at lower magnifications but I like to minimize it at high powers if possible. The 22mm T4 Nagler was my first "big" Tele Vue and I really liked it

Thanks Ant I've got clouds galore here but not, alas, of the noctilucent variety

I think there might be something in that. If the Skytee II was made to the same engineering standards that, say, the Rowan AZ100 uses though, it would not cost £260. And it does work pretty well, with a little tinkering