2" diagonal or not

[Penumbrella]

Hi, 

I'm about to treat myself to a new scope - probably the evolux 82. I'm very much mainly visual (my mount is an az-gtiX) but am thinking about EAA down the road, or switching up to an equatorial mount if/when the AP bug finally hits. I've currently got a 130pds and want to switch to a refractor for easier grabbing and go-ing, and less collimating. 

My question is this - I have an altair 2" 30mm UFF eyepiece which I really enjoy in my 130pds. It's my only 2" eyepiece, but it's probably my favourite. I also (for some reason) have a 1.25" diagonal that I can use on the new scope. Should I sell this diagonal and buy a 2" diagonal, or sell the 30mm UFF and buy the 24mm UFF eyepiece? 

Any advice and thoughts very welcome - but please don't fill my head with 102mm refractor temptations!! It's taken me months to settle on that choice 😂

Edited April 4 by Penumbrella

[Louis D]

Check the classifieds and pick up a used 2" diagonal to see if you use it much, or can come to focus with it.  Here in the US, I've picked up 3 lightly used GSO-made 2" dielectric diagonals over the years for about $80 each off of US astro classifieds.  If you're not picky, you can pick up more traditional 2" diagonals for less.  I'm sure the UK classifieds have similar deals.

You would greatly miss the 30mm UFF if all you have is a 1.25" diagonal.

[Carbon Brush]

Excellent advice from @Louis D.

You are spending >£500 on the scope. Look around SGL Classifieds for a 2" diagonal.
If it works out, great. If you prefer something a little different, sell it on for little loss.

[Stu]

Agreed. One of the joys of these scopes are the widefield views, so having a 30mm eyepiece and 2” diagonal helps you maximise those.

[JTEC]

Always assuming the light path doesn’t raise issues with focus in your scope, the advantages are all with the 2” I think.  First, as Stu and Louis say. And you’d regret getting rid of your favourite eyepiece - why would you do that?  I did that once - it was a 22mm Nagler - regretted it and eventually bought it again.  I’m struggling to think of any disadvantages of the 2” over the 1.25”.  A bit heavier, which really shouldn’t matter. The  2” gives you options. I have had both but only use 2” prisms and mirrors in my scopes now. Those are the Baader prism and the Baader BBHS mirror diagonal, which are, admittedly, high end models - there is no visible performance difference that I can see compared with the 1.25” versions. I like the robustness of the larger model overall and also at the points where it interfaces with the scope and with the eyepiece.

[Mr Spock]

That 30mm UFF is amazing on wide fields, it's just so well corrected.

[mikeDnight]

On 04/04/2024 at 19:31, Penumbrella said:

Hi, 

I'm about to treat myself to a new scope - probably the evolux 82. I'm very much mainly visual (my mount is an az-gtiX) but am thinking about EAA down the road, or switching up to an equatorial mount if/when the AP bug finally hits. I've currently got a 130pds and want to switch to a refractor for easier grabbing and go-ing, and less collimating. 

My question is this - I have an altair 2" 30mm UFF eyepiece which I really enjoy in my 130pds. It's my only 2" eyepiece, but it's probably my favourite. I also (for some reason) have a 1.25" diagonal that I can use on the new scope. Should I sell this diagonal and buy a 2" diagonal, or sell the 30mm UFF and buy the 24mm UFF eyepiece? 

Any advice and thoughts very welcome - but please don't fill my head with 102mm refractor temptations!! It's taken me months to settle on that choice 😂

 I use the Baader/Zeiss BBHS prism. It is the 1.25" version but has an oversized prism. Using this with a 2" nose and 2" click-lock allows me to use my 30mm Ultra Flat without any vignetting. The prism itself is top class!

[Mr Spock]

Same here, but Baader T2 prism with 30mm UFF (SL version). No vignetting with the 30mm UFF - it doesn't like the 42mm LVW though, but you don't have one of those.

[Penumbrella]

Thanks everyone - really appreciate the advice, and the outbreak of unanimity! 

[LondonNeil]

2" diagonals appear in the classifieds.  I know, I bought one new in January then see one I'd have been happy with cheaper in the classifieds.  D'oh!

[LondonNeil]

In fact, it was still there and bumped 2 weeks ago

https://stargazerslounge.com/topic/420289-sky-watcher-2-di-electric-star-diagonal/#comment-4470937

[Highburymark]

11 hours ago, mikeDnight said:

 I use the Baader/Zeiss BBHS prism. It is the 1.25" version but has an oversized prism. Using this with a 2" nose and 2" click-lock allows me to use my 30mm Ultra Flat without any vignetting. The prism itself is top class!

Yep - it’s remarkable how few 2” eyepieces vignette with the Baader T2 diagonals fitted with a 2” clicklock. My two low power widefields are Panoptic 27 and Nagler 22 T4, so there’s no need to buy a 2” diagonal. 
Interesting that the 30mm ultra flat is also fine with the T2 Baader/Zeiss prism Mike. 

[stormioV]

I use SCT version of this. https://www.rothervalleyoptics.co.uk/antares-2-99-dielectric-twist-lock-mirror-diagonals.html 

For me this has been excellent and a fantastic upgrade from where I was at. The twist lock is really very good.