Eyepiece upgrade - advice needed

[Jonny_H]

Hi all,

As per the subject - I have been getting urges as of late to 'upgrade' the few eyepieces that I started off using. These being the BST range and more specifically the 8mm, 12mm and 18mm.

Whilst my scopes and setups are mainly around AP, I do enjoy a visual session also.

My current scopes are a SW Esprit 100ed and Stellalyra 8" CC and have been using the 8" CC more recently for lunar visual but  I plan to use both scopes for visual and AP.

Anyhow.....I have enjoyed my BST's but a part of me is wondering whether I am missing out on better image quality/colour quality etc... by having 'better quality' eyepieces? 

I have read very good reviews on eyepieces from the likes of TV, Pentax & Baader, but by upgrading your eyepieces to more premium brands - do you see noticeable differences over say the BST's?

Ideally I would like to try out several pieces to see which best suits my eyes but I wanted to get views/thoughts from the forum as a starting point.

 

Thanks,

Jonny

[Zermelo]

Others will know much more, but here's a thought from someone in a similar position, having a similar conversation with myself, but not previously having gotten around to writing it down (and If this doesn't add anything to the discussion, I'll wait with you for an answer from elsewhere 😀)

I have an inexpensive 150mm F/5 Newtonian, and I've been wondering where in the optical chain the current "weakest link" lies, i.e. the one(?) that's limiting the overall performance.  I realize that the answer might vary according to which aspect of "performance" is under consideration, for example the presence of coma may be determined more by the primary mirror, whereas the extent of CA would depend rather on eyepiece or barlow.

Like you, I've already made the no-brainer upgrade from stock EPs (to BSTs in my case too) and seen a considerable improvement in image quality. I suspected that the primary and secondary might still not be performing to their limit, so I dipped a toe in again and bought a second hand ES 82 degree 6.7mm. I've had a few sessions since then to compare the ES with the BST 5mm and 8mm. So far, I would say that the ES does give tighter star images, with the central disc smaller and a sharper diffraction ring, and I've split some doubles with the ES that I couldn't with the BST 5mm. However, I've also noticed that images in the ES seem slightly dimmer, which gives the BSTs the edge on some other types of fainter object.

So I've noticed a small, but definite improvement - in at least some aspects - with the more expensive EP (and of course, the FOV is also larger). I also have a Mak 127, and have seen similar results with that. Though at F/11.8, the EP upgrade question is slightly different; assuming that the OTA optics are again not fully exploited with a Starguider, there are some EP upgrades that would be unsuitable for use at F/5, but unproblematic in the slower scope.

Another aspect to the question is whether or not you're considering an upgrade to an EP of simliar characteristics. The BSTs seem to me to be quite general purpose, middle-field-of-view eyepieces. You could upgrade to, say, a high-quality orthoscopic that might deliver better on-axis performance, but with reduced FOV. Or perhaps to a design that is well-corrected across a much wider FOV, even in a fast scope, but might perform much the same as the BST within the central 60 degrees. You need to decide which aspects you're going to compare.

Your Esprit is, I think, a fast ED triplet, of similar speed to my reflector. The classical cassegrain is more like the Mak; but I'm assuming that both OTAs are intrinsically superior in quality to mine, and therefore likely to be capable of performance beyond what the BSTs can deliver. Whether that improvement is worth the expenditure is moot. I'm happy I tried the ES; I'm still undecided whether my ageing eyes would notice any improvement in the Skywatcher OTAs from ratcheting the EP up to around the £200 mark. But then, even if not, I could still use them on my next scope ...

[Don Pensack]

What are you looking for?

1. more eye relief?  Given your choice of eyepieces, probably not this one.
2. a wider apparent field?  This is a good reason to upgrade.  You have a LOT of choices.
3. Sharper star images?  If you are talking about the center of the field, given your scopes, this may not be a reason to upgrade at all.  Possible, but not guaranteed.
4. Better contrast in the eyepiece?  Possible, but the dryness and transparency of the air matters more, given what you already own.
5. less chromatic aberration of star images in the outer field?  Again, possible, but not guaranteed.
6. a flatter field?  This might be accomplished, but if you see no curvature of field (edge and center focus at different points) in what you have, not a good reason to change.
7. a higher light transmission to see fainter stars and more details in other DSOs?  Today's eyepieces all transmit within a few %.  Sharp differences here are extremely unlikely.
8. less field distortion when panning?  Possible, but not guaranteed with other eyepieces.
9. less edge of field brightening?  Have you noticed any?  If not, be sure to read reviews before buying, or ask on the forum.
10. an easier-to-obtain-and-hold exit pupil?  Possible, but not guaranteed.
11. Better color fidelity?  Cooler in tone?  Warmer in tone?    Warmer tone helps on planets and Moon and seeing carbon stars, while a cooler tone may seem more natural.  Most discussions of this are "tempests in a teapot".
12. Less internal light scatter?  HIGH likelihood of improvement here.  But read the reviews.  Many higher end eyepieces yield a lot of internal light scatter.

So it helps to identify what you want to change before you upgrade.  The one place you are sure to see a major difference is if you go to eyepieces with a wider apparent field.

[Jonny_H]

Thank you for your responses. I think this highlights the complexities of selecting/choosing eyepieces which seem to be equal to or not far behind choosing a telescope.

My query was really very much generic at this stage albeit a wider apparent field would be one of my criteria. I guess it was more the 'quality' I was wondering about but it seems like this in itself is a minefield!

 

Regards,

Jonny

[bingevader]

I think the biggest question to ask is, what's your budget!?

I've been very gradually moving to 82º EPs and I'm very happy with those that I have purchased for my 8" dob (so not terribly demanding!).

However, this has been going on for some years, at Christmas times and birthday times, as my budget wouldn't stretch to anything else, or over a shorter time period!

[Jonny_H]

1 hour ago, bingevader said:

I think the biggest question to ask is, what's your budget!?

I've been very gradually moving to 82º EPs and I'm very happy with those that I have purchased for my 8" dob (so not terribly demanding!).

However, this has been going on for some years, at Christmas times and birthday times, as my budget wouldn't stretch to anything else, or over a shorter time period!

Yes budget certainly plays a role! 

In answer to that - I don't really have a budget as such. I have no objections in paying a high premium and build a quality eyepiece collection over a longer period of time.

Having said that....some pieces are eye-watering expensive and i certainly can't justify spending £800+ on a 21mm TV Ethos for example. That would get you a rather nice scope!!

I would probably say £200 - £250 ish is the maximum before I would start to think otherwise.

I don't think i would have any issues with my 8" CC but my Esprit 100ED would certainly be more demanding I think. Whilst I would probably use the CC more for visual work I don't want to, if it can be helped, solely base eyepieces for it. I would like to keep the option of the 100ed open also.

Edited July 26, 2021 by Jonny_H

[Louis D]

In that price range, I would probably go down the Morpheus route.  I have the 9mm and 14mm, and both compare favorably to Pentax XW/XL and TV Delos offerings.  The 14mm is regarded as the weakest of the line, and yet it is quite nice in my experience.  I would probably skip the 14mm if starting fresh and get a 12.5mm and/or 17.5mm instead.  The 14mm and below are actually 78 degree AFOV eyepieces while the 17.5mm is actually 74 degrees, IIRC.

[Jonny_H]

Thank you for the info.  I have been looking at the Morpheus range recently too. As you say they certainly seem to hold their own against the heavy hitters.

Lots to think about....let the research and reading continue 🙄