Converting to 1.25" format

[A McEwan]

So... I have a few 2" eyepieces. 9mm 100 degree ES 2". 23mm Celestron Axiom LX. Nagler 17mm T4. 42mm SWA cheapie. Moonfish 30mm.

I have used and loved 2" eyepieces for many years. However, since acquiring the Takahashi DC100 I find it a bit of a fiddle to switch between 1.25" format and 2" format. It is not that it's impossible to do, but it is tricky to do, as it requires adding an extension tube to the 2" diagonal, aligning everything (the tolerances are pretty tight) in the dark and cold, and then there's the balance issue to be adjusted. I prefer generally to observe in alt-az mode, so balance is usually critical.

I could observe in EQ, and indeed do so sometimes, but generally for planetary. For "general" observing I prefer alt-az.

My other eyepieces are a mix of Plossls, Orthoscopics, 1.25" Nagler and UWA types (TeleVue, Baader, Meade, ES)

Naturally I can use 2" eyepieces in my ED80 as well, but I just get that feeling that if I do go ahead and bring everything back to the same format, it saves weight, space and night-time faff. It would also mean that I could use those long focus wide fields in the Swift 60mm too (which is a lovely scope)

So I guess I'd be thinking about 1.25" alternatives to the 2" eyepieces listed.

I know from experience the Vixen LVW 22mm is a lovely eyepiece that could replace the Axiom LX 23mm.

Nagler 16mm T5 vs Nagler 17mm T4?

Something ultra-wide in the 8-10mm range to replace the 9mm 100-degree?

Something to replace the Moonfish/42mm SWA?

If I did this, I would only want to do it once. I actually haven't changed my eyepiece set up for a few years now, so this is taking some serious thought....

 

[Louis D]

10 minutes ago, A McEwan said:

Something ultra-wide in the 8-10mm range to replace the 9mm 100-degree?

The TV Ethos are all 1.25"-2" hybrids from 13mm and below.

[A McEwan]

2 minutes ago, Louis D said:

The TV Ethos are all 1.25"-2" hybrids from 13mm and below.

Indeed, and thanks for mentioning them, but aren't they in the same sort of weight/bulk bracket as big 2" eyepieces anyway? I haven't handled one so I don't actually know...

[Louis D]

Yes they are.  I misread your intent then.  I thought you wanted to dispense with 2" visual backs and star diagonals.  What you really want to do is stick with lighter weight eyepieces.  There are light weight 2" eyepieces that aren't all that well corrected such as the 36mm Siebert Observatory.  It only weighs 9oz owing to its aluminum barrel.  There's also the Zhummel/Orion 9mm 100 degree at about 15oz that is also not all that well corrected.  When you give up weight and bulk, you often give up correction or eye relief.  You'd probably like the Nagler Type 6 82 series because they only weigh about 8oz.

[Stu]

I guess anything ultra wide will be big, even Delos aren't small.

What are your preferences in terms of afov Ant, and what sort of budget? How about Delites? There is a 9 and 11mm in that range at 62 degree afov. The type 6 Naglers are fairly compact too, again 9 and 11mm available in those at 82 degree afov.

[A McEwan]

Yes, Louis, intention is indeed to have everything in 1.25" format, so no need then for 2" diagonals. One format, similar weights and sizes, fewer balance issues.

Hmmm Stu. Well I have the T6 13mm and I use it every session, so yes I'm familar with them. a 9mm T6 or ES equivelant would be acceptable, and the T6's come up fairly reasonably second hand too.

I like the feel and afov of the 13mm T6. I also have a 4.7mm ES 82-degree, and that is a great eyepiece for me.

I haven't kept up with all the new TeleVue lines. I must read more! Pentax XW's might be an option too. I used to hve several XL's and they were nice too. 

So, afov between 65 and 84 degree would be excellent. I have most focal lengths covered in Plossls and Ortho's already anyway, but it's for the more immersive views I'm thinking of.

Thanks for the advice, guys!

 

 

[F15Rules]

Hi Ant:-)

Hope you're well?

Another worth considering is the new Baader Morpheus range. Bigger than the T6 Nagler to be sure, but a lovely 76deg fov and quite light in weight. Optically very good.

I replaced my Pentax 14mm XW with the Morpheus 14mm and am very happy with it. A bargain new at c £149, some retailers have recently put them up to £169 post Brexit.

The ES 24mm 68 is also a cracking and immersive eyepiece at no too much cost (try www.Bresser.de/uk for ex display bargains).

Good luck:-)

Dave

[A McEwan]

Hi Dave,

Yep pretty good ta! I've seen the 24mm 68-degree being discussed quite a lot recently. Must be quite good? An LVW 22 beater?

Morpheus are new to me too.

I can see tomorrow being a caffiene fuelled browsing and reading marathon! I like Sundays! LOL

 

[Timebandit]

Hello. I have the pentax xw in 7mm and 10mm. Very very good in refractors, around 70 degree fov and so crisp and sharp. Great eye relief as well at around 20mm. ,Nice size and not overly heavy.  I really do think these eyepieces take some beating. I had my best view ever recently of Saturn with the apo on a AZ4 and the pentax xw7mm .

So well worth considering IMO ☺ 

 

 

[F15Rules]

Hi Ant

Checkout Bill Pailini's Morpheus review, just google Baader Morpheus range.

Not used an LVW 22mm, have heard that the 22mm is one of the best of this range. Build of the LVW is slightly above the Morpheus but the wider for of Morpheus and lower cost (slightly) gets my vote at shorter lengths.

The ES 24mm 68 is excellent and is cheaper than the LVW 22 I believe..

Enjoy your research!

Dave

[Stu]

I have the 24mm Panoptic which is about as wide as you can get in 1.25" format. Currently I'm basically 1.25" only too. I imagine the ES 24mm 68 is pretty close, and would make a good lowest power/widest field in your new lineup.

[Dude_with_the_tube]

Hey Ant

what sort of money you plan to spend on each individual Ep? reason why i am asking is that price range is quite substantial.

I would personally go for Pentax XW or older XL in 5mm-10mm,wouldnt actually turn down an ES 82 or Meade 5000 UWA,alternatively TV naglers are light and compact.Delos might be a bit on a heavy side.(balancing purpose), Baaders Morpheus in the 14mm range would be nice,but i wouldnt take them in 4.5mm or 9mm due to critical eye placement , long eye relief it proved difficult.Alternative is Televue Delites in 11 or 18.2mm. In 24mm range a televue Pan 24mm or ES 24mm 68 deg would do the job.Thats my pick.All relatively compact not to upset your balance  

Clear skies.

[Moonshane]

My advice would be a 24mm Panoptic as many Delites as you can afford and a 6-3mm Nagler zoom

I fully empathise with balancing giro type mounts

[John]

I'm tending to use 1.25" format with my Tak 100 as well. Pentax XW''s in 10, 7, 5 and 3.5 plus a 2-4mm Nagler zoom are my mainstays. Up to now I've been using a humble Maxvision 24 / 68 for low and wide with this scope but I may get something nicer in due course. Not that I seem to do "low and wide" that much with the F/9 Tak.

LVW's are very nice and I might fill the focal lengths above 10mm with some of those for use in the Tak.

 

[iPeace]

Hullo Ant - haven't we met before?

I've just about completed my journey in the opposite direction - just sold my 11mm and 3.5mm T6 Naglers and my 1.25" Ethos are fitted with extension rings to use in 2" mode. I will be keeping my Nagler Zooms, so cannot quite do without a 1.25" reducer yet.

Nonetheless, strictly an alt-az man myself, so extra long dovetails etc. are the order of the night when it comes to balancing.

If it had to be 1.25" I would be inclined to go for T6 Naglers, as I have enjoyed them so it's a known quantity. Have never handled a Delos, they seem very nice but cannot tell whether size and form factor are along the lines you envisage.

Then again, it's poverty of experience on my part - get the ones with the green lettering, they said, so I did.

[Mark at Beaufort]

Ant I undertook a similar exercise just over 12 months ago. I sold my 10" Dob and just had an Orion VX8 and a 4" APO both on a SkyTee 2 Alt/Az. I sold all my 2" Ethos EPs because I wanted lighter 1.25" EPs with a wide field. I bought the ES 82 degree range - 4.7mm, 6.7mm, 8.8mm, 11mm, 14mm and a 24mm 68 degree. These are excellent EPs and although my Orion VX8 is f4.5 I still had a sharp image across the FOV.

Now the twist - I missed the bigger scope for DSOs so I bought a 12" Dob. About 6 weeks ago I had the chance to buy a Skywatcher 20mm Myraid and I then appreciated that I missed my 2" Ethos on the bigger scope. I have now added a 9mm Myraid.

Now reviewing my EPs and looking at my 3 different scopes I still love the ES range especially in my Astro Tech APO. I am keeping the 4.7, 6.7, 11 and 14. Even though the 20mm Myraid gives a great FOV I prefer to use the ES 24mm 68 degree in the frac.

Good luck with your decision.

[A McEwan]

Wow - thanks so much for all the replies! And some old friends have chipped in too!

Ok, I'd better give some more back-story, just so you can guage my eperience.

Long ago I had Pentax XL 7mm, 10.5mm, 5mm, XW30mm, so I know how nice these eyepieces are. I have read the excellent review of the Morpheus line, and see that they are so close to the Pentaxes (Pentaxii?) that cost is the deciding factor, and in any given focal length the Morpheus would be an excellent performer.

I don't use wide field eyepieces for planetary viewing. I have excellent Ortho's and Plossls for that.

But I'd better list what I've got. Some focal lengths are more than adequately covered.

Full set of Baader Genuine Ortho's: 18mm, 12.5mm, 9mm, 7mm, 6mm, 5mm. (& a Meade RGO 7mm)

TV Plossls: 20mm, 15mm, 10.4mm, 8mm.

Now, the wider field eyepieces are 23mm Axiom LX, Nagler 17mm T4, Nagler 13mm T6, ES 9mm 100-degree, Meade S4k 6.7mm UWA, ES 4.7mm UWA, Siebert Starsplitter 3.9mm.

Looking just at the focal lengths - 23  -  17  -  13  -  9  -  6.7  -  4.7  -  3.9  all seems well. But the 23 and 17 and 9 are 2" which I'd like to find a replacement for. BUT... I have had to stop using anything 30mm-ish meaningfully as my astigmatism shows when using anything in that sort of focal length. That's why I got the 23mm Axiom (it replaced my XW30 and my astigmatism doesn't show)

So... perhaps move the 23mm and 17mm on and get a single eyepiece that covers that range in 1.25" format? 22 LVW, 24mm 66-degree ES, 24mm Pan, 22mm Pan (is that 1.25?), 19mm Pan, etc, etc, etc! The 9mm could also be replaced. I could go with Nagler T6 or ES 8.8 

Some people may be thinking I should keep the 2" format eyepieces for use with my ED80 instead of moving them on, but the oney from sales can help buy excellent new eyepieces, and if I can get a similar viewing experience in 1.25" instead of 2", then it works for me without having multiple eyepieces in similar focal lengths.

Gaidis, money-wise... well I know that you only pay once for quality!  Mind you, I'd prefer to buy used just to keep costs down, and if I can subsidise costs with sales of my "redundent" eyepieces, then so much the better.

Mike (iPeace) - yep, the Naglers I have and have used were all excellent. I do like the Nagler experience and at the back of the mind there's always the reassurance that technically and from a design and perofrmance standpoint, there is nothing better in that afov range.

Or maybe I'm just overthinking this and should pick up a bundle of EP's and just sell the ones I like least!!!  ;/ 

 

[Stu]

Ant, this page is useful to understand the full range of Televue eyepieces.

http://www.televue.com/mobile/TV5_page.asp?id=214

I guess one question is how you approach things, is it mag, true fov or exit pupil?

Might be worth sticking a load of data into SkySafari and comparing tfov?

[Mark at Beaufort]

Ant what a great collection of quality eyepieces. I agree with your suggestion of selling the 23mm, 17mm and 9mm and replacing with a 1.25" 24mm (either Televue or ES). However, because you have BGO at 9mm and two TeleVue plossls (10.4 and 8) I would sit on the fence until a suitable S/H comes along which you feel might be better.

[John]

2 hours ago, Mark at Beaufort said:

Ant I undertook a similar exercise just over 12 months ago. I sold my 10" Dob and just had an Orion VX8 and a 4" APO both on a SkyTee 2 Alt/Az. I sold all my 2" Ethos EPs because I wanted lighter 1.25" EPs with a wide field. I bought the ES 82 degree range - 4.7mm, 6.7mm, 8.8mm, 11mm, 14mm and a 24mm 68 degree. These are excellent EPs and although my Orion VX8 is f4.5 I still had a sharp image across the FOV.

Now the twist - I missed the bigger scope for DSOs so I bought a 12" Dob. About 6 weeks ago I had the chance to buy a Skywatcher 20mm Myraid and I then appreciated that I missed my 2" Ethos on the bigger scope. I have now added a 9mm Myraid.

Now reviewing my EPs and looking at my 3 different scopes I still love the ES range especially in my Astro Tech APO. I am keeping the 4.7, 6.7, 11 and 14. Even though the 20mm Myraid gives a great FOV I prefer to use the ES 24mm 68 degree in the frac.

Good luck with your decision.

Very interesting to hear your thoughts Mark and the others in this thread.

I'm in 2 minds about my hyper-wides ATM and have been for some time. I do think reasonably often about simplfying things and enjoy using eyepieces of less bulk especially in the smaller refractors but I wonder if I'd miss them after parting with them 

More food for thought !

 

[Stu]

Is this sort of analysis useful Ant?

I suspect that a 24mm Panoptic, 16mm T5 Nag and possibly 9mm T6 Nag would be useful? I've calculated TFOV both ways as at the extremes the Field Stop calculation is more accurate. Obviously other brands could be substituted but Televue rather nicely make all their data available easily.

Scope	Takahashi FC-100D
Aperture	100
Focal Length	740
Focal Ratio	7.4
Eyepiece	Barrel Size	Field stop	Focal Length	AFOV		Magnification	Exit Pupil	TFOV (FS)	TFOV (Mag)
Televue 24mm Panoptic	1.25"	27	24	68		30.9	3.3	2.1	2.21
Televue 16mm Nagler T5	1.25"	22.1	16	82		46.3	2.2	1.72	1.78
Televue 11mm Nagler T6	1.25"	14.9	11	82		67.3	1.5	1.16	1.22
Televue 9mm Nagler T6	1.25"	12.4	9	82		82.3	1.3	0.97	1
Televue 7mm Nagler T6	1.25"	9.7	7	82		105.8	1	0.76	0.78

 

[Moonshane]

I think that balancing issues are a big thing with alt az mounts and it's also scary with a heavy eyepiece in an eq mount when moving around in the sky with a frac (especially when you end up upside down with the eyepiece before revolving something - usually the focuser in my case). These are the reasons I have gone 1.25" only in my fracs although I mitigate the eq issue by mainly using it looking east - west as it's generally planets, moon and solar I use this for and never really need to do a meridian flip. With a dob there's no chance of things dropping out and the longer focal lengths make 2" a boon.

[A McEwan]

Have just finished reading this article: http://www.cloudynights.com/page/articles/cat/user-reviews/24-26-mm-eyepiece-comparison-r2651

Very interesting. And it does indeed show that different eyepieces have different performance priorities, even when in the same "class" and focal length. It is a shame the LVW 22mm wasn't mentioned, but I have hands-on experience with that eyepiece, though it was a long while ago. I remember it fondly...

Stu, I think we're on the same wavelength, in terms of focal length and TeleVue preference anyway! Thanks for the chart - very handy!

Shane, absolutely right! It can be a bit panic-inspiring when changing from heavy to light especially. Get everything out, uncap everything, stick the to-be-inserted stuff together, lock all the axes, half-remove the installed stuff, check the scope isn't going to move, finally remove the stuff and swoop on the new stuff and slot it in as quickly as possible. Loosen the alt axis - catch the inevitable tube-dive!!! Lock it, adjust balance, check balance, .....:O 

 

[Dude_with_the_tube]

 Ant,

i think i might have relatively good solution for you.

for 9mm range to replace ES 100 i would suggest:

1.Might be a straight swap might not,but if you are a TV fan then TV type 6 9mm. 

2.You gain some money if you go for ES 8.8mm or Meade 5000 UWA 8.8 and sell ES9mm 100 deg

for 17mm range.

not really that much of a choice in UWA range for 1.25" as such,best option:

sell Nagler and buy TV Delite in 18.2mm.

As for 24mm range.

Relatively straight forward.

Your pick depending on money:Panoptics 24mm,ExSc 24mm 68deg.

Or alternatively the ultimate option: Leave everything as it is and dont be silly!  not really that much of a hassle to swap out 2" to 1.25" EP. As you have 2" diagonal,get Baader Click lock 2"-1.25" adapter and you are good to go.Will set you back only for about 30-45quid without a hassle of selling/buying new EP`s.

[A McEwan]

An interesting take on things, Gaidis! I completely agree with your first two points - very nice options!

For point three, I see where you're coming from. To explain, the Tak comes with its standard 1.25 twist-grip visual back adapter. Into this I put my Baader prism diagonal. This is the best diagonal I have. It is brighter and shows better image than my other two 2" dielectric diagonals, and is lighter as well. In order to use a 2" diagonal in the Tak, and still have most eyepieces to come to focus, I have to use a 35mm extension (actually the body off a 2x 2" Barlow!). With this in place my 2" eyepieces come to focus, but not all of my 1.25" ones! So then it's a matter of swapping everything around again, depending on what eyepiece I want to use.

I know it doesn't sound like much written down, but in the field (literally) with limited clean space and wanting to Keep It Simple, it adds an extra layer of faff that isn't necessary.

The Tak does come with its own standard 50mm extension, but that doesn't cover everything either! So it comes to yet another matter of compromise.

But... I even now have "in my basket" an ex display 24mm ES 68 degree eyepiece from Breeser.de, at only 75Euros so unless anyone talks me out of it in the time it takes to create an account and complete checkout... I'll get that anyway and be able to compare it with my 23mm Axiom LX (same as Luminos, it turns out)