Ags

Oh, I have tried! The Nirvana 16 has been in an ST80, Skymax 102, C6 at F10 and C6 at F6.3 (with flat field). It behaves consistently in all of them. ...And then on some nights it gives phenomenal views of the moon. Can eyepieces be subject to tidal forces?

I am very short sighted and I have presbyopia too.

I know I am in the minority. It's either my eyes or my eyepiece. I should have sent the Nirvana 16 back at the time, but I really wanted to like it.

@John I am thinking of our contrary feelings about the Nirvana 16mm. You say it is comparable to the equivalent Nagler, while I find it unacceptable. I suspect the reason may be my eyes are unable to compensate for the field curvature.

I do find eyepiece reviews so difficult. We can't see through other people's eyes. I also think the 4mm shootout I linked to above is limited by the high magnifications being used. I don't know what the seeing was like, but the reviewer does acknowledge that 4mm was pushing it on the night.

Here is a direct and recent shootout between a another TMB Planetary clone and an SLV at F4.9: Looks like a draw or near draw (considering only on-axis performance) according to the OP and some replies in the thread. Gives me pause for thought.

On the subject of TS HRs, here's a glowing review from back in the day. Do you still have the HRs, @John? I certainly don't regret my HRs but I did feel the 9mm was a bit behind a Hyperion 17 + fine tuning rings.

Just to clarify my above statement - Lanthanum is a rare earth element, so to say the eyepiece has a lanthanum element is the same as saying it uses rare earths.

@Louis D Vixen state SLV use lanthanum glass. https://www.vixenoptics.com/Vixen-SLV-2-5mm-Eyepiece-p/37202.htm

@michael.h.f.wilkinson I will PM you about EP peregrinations! Back on the topic of the SLVs, how do you find the 5mm specifically as that is the one I will get first? I am also thinking of getting the 4 and 6 and 9... and maybe the 15... and then the 25 too to have a complete range... This is to complement ES 68 degree EPs (16, 20, 24) for widefield and ES 82 degrees (6.7 and 11) for the midfield.

I used to live in Lelystad, and travelled up to Sneek and Leeuwaarden a few times, never quite to Groningen. I don't have a car any more or I would be happy to make the trip 😀

That's a kind offer, but I live in the warm glow of Schiphol! Groningen is practically another country 😀 But you've sold me on the SLVs already.

Ten years ago when I bought a couple of TS Planetary HRs (6mm and 9mm) the general buzz was they were almost as good as a Radian. I certainly liked mine and the effect they gave of looking into a magic pool of light (caused I think by the smallish FOV, the twist-up eyecup, and comfortable eye relief). Fast forward to 2020 and the same TS Planetary HRs are now generally considered worse than BSTs... Really? I am looking at getting a few oculars around the 5mm mark for planetary, lunar and double star viewing - and the two types I have my eye on are the TS Planetary HRs and Vixen SLVs. I know the SLVs would be better on axis than the HRs, but by how much? Certainly for lunar viewing 58 degrees would be better than the 45 degrees of the SLVs (the shorter SLVs only have 45 degree fields, not 50). Also weight is a consideration for me - the HRs will be significantly lighter. Can't recall why I sold my HRs... was it because I switched from an F13 to an F5 scope? Is this a factor now I have F6 scopes? But I see that the styling of the HRs has changed since I bought them. Has quality declined?

I have exactly the same problem with my C6 SCT! You would think scope manufacturers would get a basic thing like this right... 😡

In comparison to plossls they are heavy and long.

Seems pretty good! Overall happy. It has been awesome for DSOs and Lunar. Adding a 0.63 reducer improved it - giving both wider fields and better high magnification views. It needs regular collimation though. It's worked out fine on the AZ GTi - I only got the Fi tube not the mount. The weight is 3.3 kilograms. Only weak spot has been double stars - not the best star shapes and not very clean separation between tight pairs.

I got a 20cm M12 bolt (longer ones are available) and the Explore Scientific Dob Counterweight set (with this set you get 2 1kg counterweights for the price of one): By the way, I know this doesn't look very balanced, but my counterbalancing is primarily to reduce strain on the ALT gear not the AZ gear.

Ethos 17mm 100°. Nearly a degree field of view but still about 120 magnification.

My setup (C6 with reducer) doesn't really support 2 inch eyepieces, so the 24/68 is as wide as I will go. Just had another session, still couldn't tease any structure out of the Cat's Eye. Had a look at the Dragonfly cluster (C13) which is very nice with some colored stars and the Double Cluster, again seeing lots of color in its stars tonight with the ES 24/68. Finished off with a quick peek at Albireo, which was so lovely I thought why not have a quick look at the Double Double. Went on to look at Zeta Lyrae, 61 Cygni (a personal favorite, I really like equal strongly colored pairs), Eta Cass and finally Sigma Cass.

@Solar B Aesthetics is a religion not a science, so we'll have to respect our diversity of opinion 🙂 ... I do like the top of the Morphii with their dinner-plate eye lenses. @Stardaze I think it's a 6.7 not 6.8? But it is a special eyepiece - looking through the ES last night I kept thinking "I want more of these" and when I looked through the Nirvana I couldn't help thinking "I want less of these". I'm thinking of adding the ES 82°4.7, 8.8 and 11, and the ES 68° 16 and 20 (I have the 24/68 and it is superb)... How do you find the 11?

I find dew is a problem in warmer weather usually - humidity is higher in the summer, and then the temperature plummets on a clear night...

I also struggle at opticians. Just thinking about going for a check-up makes my eyes water.

I hope bifocals will work for me. I am short-sighted but for the past few years can't see close up with my glasses on. I think my lenses just aren't flexible any more - which might also be why I don't get on with the Nirvana 16mm. I am forever putting my glasses on or taking them off... Seriously considering the Morpheus 17.5 mm now. And thinking the Morpheus 12.5 might be a nice companion for it. Last night's outing was very expensive in more ways than one! The Morphii are a bit pricey for me but seem to justify the cost based on every single review I've read. Aside from price concerns, the other two things that give me pause are (1) the Morpheus line are just about the ugliest quality eyepieces out there and (2) they are pretty heavy. The alternative would be to get the ES 68 degrees 16 mm and 20mm, if these are anything like the 24 mm I know I would be happy with them. The only thing I don't like about the 24mm is the weight (same as Morphii).

Really please I found it too, the sky was uncommonly bright last night and "normal" is Bortle 8 for me. C6 seemed almost too bright to be a nebula, and the pale green color was quite apparent. Will definitely revisit this one on the next clear night, and would love to image it. Good it is quite northerly so it will stay in my skies for longer. Would love to see it under a dark sky, but travel is out of the question for now...

Thanks, I guess I was due a new prescription anyway as I think I need bifocals now. That Nirvana 16 mm is bugging me. The off axis blur can't be field curvature from the telescope as the .63 reducer is a flattener. Despite liking it on some nights I think it has to go, it just doesn't work with my eyes. Maybe the Morpheus 17.5 is what I need. Or for less weight and money the ES 20/68...