Tele Vue type 5, 31mm eyepiece.

[Grump Martian]

There is a possibility that I may have the chance if aquiring the above Tele Vue eyepiece. I once owned an ES 30 mm. At around 1.4 kgs it was heavy. The mount used then as was the telescope much larger than my current instruments.The Teleview is 1.4 kgs. My telescopes are an 80 mm and 102 mm ED refractors. So a Skywatcher ST 120. These are used on AZ4 and another Alt/Az mounts. My question is would the Tele Vue 31 mm at 1.4 kgs be too heavy for these telescopes and mounts?

Edited March 18, 2023 by Grump Martian

[GordonD]

If it helps, I think the Tele Vue is closer to 1Kg, rather than 1.4Kg. I haven't weighed it myself, but FLO and Tele Vue themselves list it at 2.2 pounds which is 1Kg. Still a big heavy eyepiece of course, but quite a bit less than the ES 30mm.

[John]

I have a 31mm Nagler. It weighs a touch under 1kg so a little lighter than the ES 30mm. I use it most frequently in my Vixen 102mm refractor which has a Vixen R&P focuser and the scope / focuser seems to cope with it quite well.

I uses to use the Vixen and 31mm Nagler combo with an AZ4 mount as well. 

I'll have to try the mighty Nagler with my newly aquired 70mm F/6 ED refractor - it will give a near-6 degree true field in that !

You might need to move the scope a little bit forward in the tube rings to get a better balance with heavier eyepieces in the diagonal.

 

[Louis D]

I've had trouble with heavy eyepiece/diagonal combos causing my AT72ED focuser to slip downward when used near zenith.  It didn't matter how much I tightened up the central tension screw or roughed up the tube flat (rack).  I eventually bought a 90mm APO with a helical R&P focuser for use with heavy eyepieces or a binoviewer.  It will still unravel if I loosen off on the tube tension, but not otherwise.

I had to buy an 8" dovetail bar and mount the clamp just about even with focuser knobs to reach balance on the AT72ED.  I never had any balance or load issues even with my old DSV-1 mount and certainly none with my DSV-2B mount.  I would think your scopes should be long enough that this won't be such an issue.

You'll just have to try it out and see how it behaves in each focuser.  If you can get the Terminagler for about $525 or less (USD equivalent), then you'll be right in line with typical US used prices and should be able to resell it for no loss.

[Captain Scarlet]

I have the Nagler 31T6 and I _really_ enjoy it, especially on my 105mm f/6.2 . @Stu swears by it on his TV Genesis I believe. Around or slightly under £500 is the going rate in the UK I believe.

Cheers, Magnus

[Stu]

4 minutes ago, Captain Scarlet said:

I have the Nagler 31T6 and I _really_ enjoy it, especially on my 105mm f/6.2 . @Stu swears by it on his TV Genesis I believe. Around or slightly under £500 is the going rate in the UK I believe.

Cheers, Magnus

Certainly do Magnus. It performs noticeably better that the ES 30mm, I was quite surprised.

[Paz]

I've used a 31mm T5 on a 72mm apo and 102mm apo and it was ok. I've used it on a ST120 with an upgraded dual speed crayford focuser and it was fine there also. I have not tried it with the standard focuser on the ST120. I think the 80mm and 102mm EDs with a 31mm T5 would be ok on an AZ4, but an ST120 would be a tougher ask (it might be ok, but I would not want to guess). As well as the scope and mount there is the question of the diagonal being reasonably sturdy.

[F15Rules]

Martin,

If you don't want to spend such a large sum, I can recommend the Axiom LX 31mm..it's an excellent eyepiece which some users claim is c 85 degrees versus the stated 82 degrees..

It's even heavier than the Nagler, at 1.4kg..however, I've decloaked mine and it's now a svelte c 1kg..☺️

As John said, the balancing of the scope is crucial on scopes of 3-4", but they can work really well. I'd always recommend a 2" Clicklock to hold the eyepiece with the utmost confidence.

The photo below shows the Axiom 31mm decloaked on the right, the Axiom 23mm in the middle and a Nagler T2 12mm on the left. All superb EPs..

Dave

Edited March 20, 2023 by F15Rules
Photo added

[rwilkey]

I find using the Nagler 31 T5, with my 102ED is quite satisfactory with a Vixen Porta II mount.

[Don Pensack]

I'm surprised you don't use the 4" refractor on the SkyTee mount.  It is far more stable.

I had issues with shimmy using an 80mm f/6 refractor on the Porta-II.  Are you using the heavier tripod?

[Mr Spock]

I looked through a 31mm T5 once. It was attached to a 16" Dob though, so size didn't seem relevant 

Great view though. The witch's broom from a dark sky looked spectacular.

[John]

Well, nothing broke and the focuser seemed to handle it OK although it did start to creep a bit when I pointed the scope towards the zenith, without the tension knob tightened.

 

[Grump Martian]

 

3 hours ago, Don Pensack said:

I'm surprised you don't use the 4" refractor on the SkyTee mount.  It is far more stable.

I had issues with shimmy using an 80mm f/6 refractor on the Porta-II.  Are you using the heavier tripod?

EQ5 tripod with a Berlebach castor mount

[Don Pensack]

My comment was for RWilkey, though, now that you mention it, the Castor mount looks a bit light for a 4" refractor.

A lot of mounts, though, work OK as long as there is no wind.

[rwilkey]

19 hours ago, Don Pensack said:

I'm surprised you don't use the 4" refractor on the SkyTee mount.  It is far more stable.

I had issues with shimmy using an 80mm f/6 refractor on the Porta-II.  Are you using the heavier tripod?

Hi Don, I don't interchange tripods now as I am partially disabled and can't handle the 200P.  I have the Porta II on the standard aluminium tripod, I have never had a problem with it and find it quite sturdy.  See below:

[cajen2]

A lighter alternative? You could try a Celestron Ultima Edge 2" 30mm (or its APM / StellaLyra UFF equivalents). There's a tendency for people to suppose that if an EP is cheaper and lighter, it'll be worse. My CUE is one of the best EPs I own and it's only 619g. 

[Mr Spock]

If you are willing to accept 70° then there isn't anything better than the 30mm UFF. Easy on the eye - comfortable eye position, no blackouts etc, and sharp to the edge. I've just weighed mine - it's 551g.

[cajen2]

Interesting. The SL is supposed to be the same EP as the CUE, but seems substantially lighter.

 

Edited March 21, 2023 by cajen2
Added pic

[Littleguy80]

Another vote for the APM UFF 30mm or equivalent. I replaced my ES82 30mm with this and have no regrets. I originally went for biggest AFOV when first buying premium eyepieces. After awhile, I found that it was worth sacrificing a bit of FOV for better contrast and sharpness. This worked best for my observing preferences.

[Mr Spock]

3 minutes ago, cajen2 said:

The SL is supposed to be the same EP as the CUE, but seems substantially lighter.

Have you weighed it? Looking on the web it says the CUE is 674.7g...

[cajen2]

3 minutes ago, Mr Spock said:

Have you weighed it? Looking on the web it says the CUE is 674.7g...

Yes, I've weighed it. 619g. Perhaps the official figure includes end caps.

Edited March 21, 2023 by cajen2

[Mr Spock]

Maybe it's all that orange... 

[cajen2]

I like it. None of my other EPs have orange rings, so it's easy to identify.

[cajen2]

Ah, additional. I forgot I left a metal parfocal ring on it, so 608g without.

[Don Pensack]

The Altair Astro version of the UFF is heavier because of a stainless steel lower barrel, but I don't see why the Celestron would be heavier by 57g than the APM.

It's a mystery unless the barrel is a larger outside diameter to accommodate the orange rings.