19 replies to this topic

[square_peg]

Man that thing is bright! Last night I had first light with my new 30mm.
Drawbacks:
OK, it's more eyepiece than my 114 can really take advantage of, but the 114 isn't the last scope I'll ever own. Some vignetting on the edges, but less than I expected. Eye relief is kinda long, wouldn't be a problem at a really dark sight.
Advantages:
Jupiter just about ruined my night vision. I saw fields of stars that I had no idea were visible from my light polluted yard. I found M11 and M27 for the first time. They were only the faintest smudges even at higher powers, but I'd have never found them in my other EP's.
Wow!

[erik]

the coatings on the ultrascopic (and ultima's i assume) are among the best i've ever seen. it's no wonder you're seeing stars brighter. congrats on the excellent ep!

[asaint]

Great choice in a 30mm eyepiece. The 30mm Ultima is my favorite in that focal length. I've tried a bunch and the Ultima has never left.

allister

[EdZ]

Those are four real nice eyepieces. I own all but the 18 Ultima. I have and now only ocassionally use the Meade 18mm SWA. I use the UO 18 ortho more often.

the 30mm Ultima is also one of my favorites. I recently bought a second one to use them as a pair in my BT100 binocular telescope. Unfortunately, the second 30 has a fraction of a mm wider barrel and it will not fit in my BT100. I need to sell this one and try buying another one.

edz

[LivingNDixie]

EdZ,

WHy doesn't it fit? Is it an older or newer one, has Celestron changed the barrels slightly over different production runs? Thats really weird to me Ed that your eyepiece won't fit your focuser...

[Tom L]

So change the barrel...

[SAL]

Yes, I have a generic Plossl that I received with a scope purchase. It's actually a nice little Plossl compared to other generics I’ve used, but the barrel on it is slightly out of round. I still use it fairly regularly, but can't quite screw filters into it due to the shape error... (Scott)

[square_peg]

Those are four real nice eyepieces. I own all but the 18 Ultima. I have and now only ocassionally use the Meade 18mm SWA. I use the UO 18 ortho more often.

the 30mm Ultima is also one of my favorites. I recently bought a second one to use them as a pair in my BT100 binocular telescope. Unfortunately, the second 30 has a fraction of a mm wider barrel and it will not fit in my BT100. I need to sell this one and try buying another one.

edz

That's a first. Someone selling a 30mm Ultima. You don't see many people ever parting with one of these. Now I know why.

[EdZ]

To answer the question a few posts up.

More than one thread over the last few years discusses the problem some people have had with the inconsistency of the 30mm Ultima barrel. It's generally described by some people as a tight fit. I have about 6 different diagonals. It's extremely tight in one of them and fits all the others, some snugly. So tight in that one diagonal that the diagonal needs to be taken out of the focuser and tightly gripped in one hand to forcefully remove the 30mm from the diagonal.

The BT100 must be just a fraction of a mm smaller that it won't allow that one 30mm barrel to fit in. You couldn't bang it in with a hammer. BTW, my other original 30mm fits just fine.

There is no changing the sleeve on the 30mm Ultima. You would need to buy another sleeve that is proprietary to the 30mm Ultima model. The sleeve top where it screws onto the rest of the lens barrel is just like part of the lens barrel, black and the same diameter as the rest of the eyepiece barrel.

edz

[Syzygy]

square peg,
Good to hear that you like that Ultima. I bought a pair of 18 Ultimas earlier this year and I love them. I going to expand my Ultima collection in the near future.

[lighttrap]

The BT100 must be just a fraction of a mm smaller that it won't allow that one 30mm barrel to fit in. You couldn't bang it in with a hammer. BTW, my other original 30mm fits just fine.

There is no changing the sleeve on the 30mm Ultima. ...EdZ

That's a real shame. So I guess there's ZERO chance that it would work in a Vixen BT80, which has notoriously tight and finicky focusers. Still, with both Allister and EdZ singing the praises of this 30mm Ultima, I've got to say that I'm majorly curious.

Is there anyway that the barrel sleeve could be lathed down just a few thousandths? If it detaches, that would seem pretty trivial for a machine shop.

Mike Swaim

[erik]

if you're near an orion or celestron dealer that stocks the ultrascopics or ultimas, you could just bring your diagonal into the store and try out different ep's to see which fit. i've never had any problems with my ultrascopics fitting into my focusers or diagonals, but synta focusers are notorious for have loose tolerances, so i wouldn't be surprised if your vixen is tighter. most syntas i've seen are too loose, so even the ultrascopics have a bit of room in the focuser which isn't always a good thing, especially when you're trying to accurately collimate the scope...

[EdZ]

Mike,

I'm going to take my chances and pick up another 30. As I said, my original 30 fits just fine.

In the BT100 the 30mm Ultima will give 21x with a 2.5° Tfov and a 4.8mm exit pupil.

edz

[matt]

The barrel of MY 30mm Ultima works just fine, but some filters won't fit the thread!

congrats on the acquisition of a very pleasant eyepiece to use.

However, I would say that in fast scopes (like my f/5 dob) it does show some ("some" being more or less bother"some" from observer to observer) off-axis astigmatism (the eyepiece is to blame, not the telescope, as I have a 27mm Panoptic which has a wider field but does not show the same off-axis blobs).

[Dave Mitsky]

IMO, the 30mm Ultima is one of the best buys in eyepieces. The 35mm Ultima will produce a bit more TFOV but the eye relief at 25mm is a bit on the long side.

Dave Mitsky

[square_peg]

I was at an elevated dark site last night (more on that later) and really came to appreciate the 30mm. I had done a quick two-star alignment just so the scope would track, then started looking for DSO's the old fashioned way. With just the star charts from 'Nightwatch', my stock red dot finder and the 30mm I was able to locate:
M13
NGC457
M10
M28
M22
M8

The Lagoon Nebula (M8) was particularly pleasing. It really is much more rewarding when you find these things without using goto. The 30mm makes astronomy fun in small scopes.