Louis D

In two first floor coat closets at the back in a climate controlled house. I would never keep anything nice in the shed. All the bikes stored in there have rusted chains, seized cables, and white mold growing over the paint. It's drier here in Texas on average than in the UK, so I would think sheds there would be even more toxic to equipment.

Just bigger in field, weight, and overall bulk. Sharpness and clarity across the field appear the same at f/6 for me. I can't speak to f/4.7 usage, though.

I have the 12mm Nagler T4 and 10mm Delos. The Delos is sharp and flat to the edge. It is also a bit sharper in the center than the Nagler. The Nagler has a bit of exit pupil finickiness, probably due to some SAEP (Spherical Aberration of the Exit Pupil). The Delos has a super stable exit pupil. Both have adjustable eye guards, though the newer Delos version stays in place once locked down with the twist ring. The Nagler's 20 year old "Instajust" version is not well liked in the astro community for multiple reasons. The Delos is super easy to use with eyeglasses while the Nagler requires mashing your glasses into your eye socket to get close enough to take in the entire field. If you don't wear eyeglasses, it's considered to have very comfortable eye relief. There's also the 12.5mm Morpheus which isn't quite as sharp to the edge as the Delos, but is noticeably wider and also free of SAEP. Instead of the Nagler, I'd probably try the new 12.5mm APM 84 degree which has been getting positive reports. Below are my 9mm/10mm eyepieces and 12mm eyepieces for reference. You can see that the Nagler wanted to kidney-bean due to SAEP with the wider and slower camera lens for the full view image. The 12mm ES-92 is like a Delos on steroids. Sharp center to edge, no SAEP, and enough eye relief for eyeglass users. However, it lacks an adjustable eye guard which made it a no-go for @John recently since he doesn't wear eyeglasses when observing. It's also huge and heavy.

Understood, but I got the impression the OP wanted an eyepiece in the immediate future, and I wanted to avoid disappointment on his part if he decided on a discontinued eyepiece and only then found out it has no immediate availability. While you might have implied it is only available second hand in your original posting, you never explicitly made that clear. I always try to recommend currently available eyepieces to relative newcomers to astronomy since waiting 6 months to a year or more for an eyepiece to become available on the used market isn't really viable for them. What are they supposed to use in the meantime? Of course, they could put out a wanted ad and perhaps get lucky immediately. I've heard people wanting the 22mm Vixen LVW have had success with this approach, and perhaps it would work with the 20mm NT5. I waited 5 years for a 22mm Nagler T4 to come up used for what I consider to be a reasonable price due to a minor cosmetic defect in the outer finish. Until then, I continued to use my 22mm AstroTech AF70 quite happily.

Which is only available used since it was discontinued by TV in 2016 and has been sold out for some time.

Does anyone have any additional knowledge of Sunny's continued use of the Meade brand going forward? I see no hint of Sunny discontinuing usage of the Meade brand in the marketplace so far.

I generally recommend putting the most money into the eyepiece likely to get used the most often, thus my recommendation. I would avoid spending a bunch of money in the 20mm range as you're likely to skip past it in the future for higher powers. In that range, I would recommend the 22mm Omegon Redline SW, TS Optics Expanse WA, AstroTech AF70. It served me very well for years before upgrading to a 22mm Nagler T4, but I still find it easier to use eyeglasses than the NT4. You see that it holds its own pretty well against the vastly more expensive NT4 below at f/6 at least. Perhaps a bit less so at f/4.7.

I tend to use powers between 75x and 100x the most often, so I would recommend getting a 12mm to 16mm premium eyepiece. As such, there's the 13mm APM HDC XWA, 12mm ES-92, 13mm Nagler T6, 16mm T5, 12mm and 14mm Delos, etc. I would avoid the 14mm Morpheus as it is the weakest of the line with some field curvature and edge astigmatism. I would also avoid the 14mm Pentax XW due to field curvature. Your choice will depend on the amount of eye relief you like to have, the size of the apparent field of view you like to see, the weight and bulk you and your scope will tolerate, and the price your wallet will bear.

I would check the scope/eyepiece combination in the daytime on a neutral surface like an off-white wall (even if out of focus) to see if the color cast persists. I would also hold the eyepiece above a white sheet of paper and see if the view through it imparts a color cast or darkens the view significantly. If the two views differ, then the scope is involved as well as possibly the eyepiece. If they're similar, its the eyepiece. I'd also check the field lens side of the eyepiece for an attached filter as others have suggested. A third check would be to look through the scope at the wall without an eyepiece and looking strictly for color cast and dimming.

I like the 17mm better of the two. Perhaps a bit more stable exit pupil, a bit sharper at the edge, a wider true field of view, and it's closer to parfocal with my other eyepieces that focus at the shoulder. My A-team case is pretty hefty as well with the two ES-92s, decloaked 30mm ES-82 (orignal style) and 40mm Meade 5000 SWA, 22mm Nagler T4, 30mm APM UFF, 10mm Delos, 9mm and 14mm Morpheus, 7mm and 3.5mm Pentax XW, 5.2mm Pentax XL, 9mm Vixen LV, and three 1.25" medium and long barlows, and half a dozen filters. There's still space for a 20-something ES-92 if they ever make one (or it just displaces the NT4) and possible one or two other giants. I really like my 35mm Baader Scopos, but I can't justify the enormous space it would take up to add it to this case, so it lives in a large secondary case of eyepieces. It's physically bigger around than either ES-92 and slots between them in weight.

As an example of this, consider that right now, only Samsung and TSMC are at or close to the cutting edge for digital chip lithography. Intel is falling behind despite being the market leader for years. Pretty much everyone else (IBM, Motorola, Global Foundries, UMC, etc.) has dropped out due to the extreme cost of jumping to the next node ($7 billion at last count) and are sticking with legacy capacity. If we get down to only one vendor in another decade, which seems likely, then the world will be at their mercy if they want a chip fabbed in the latest and greatest process node. That winner will be in the position to pick market winners and losers based on who they choose to partner with and who they snub. Competitors without extremely deep pockets (think 10s of billions of dollars) won't be able to jump into the market as suggested above for astro gear. At that point, I would foresee China investing billions in a captive company to enter the market for domestic supply and possibly external sales.

With eyeglasses. I can see how they might be finicky to view through without glasses to keep your eye spaced at the correct distance. Conversely, I find most short eye relief ultrawide field eyepieces exceeding frustrating with eyeglasses because I can't mash my eye in tight enough with glasses to see the whole field, so what's the point? Without glasses, the field is an astigmatic mess negating any benefit of a premium eyepiece. Dioptrx get expensive if you have to buy one for every eyepiece or irritating if you have to move it from eyepiece to eyepiece during an observing session. Sorry to hear you didn't get on with the 12mm ES-92. How about the 17mm version?

To get the most out of your soon to arrive Hyperions, you may want to spend a bit more to get the Revelation/GSO coma corrector (which is on sale at a great price!). It needs a 25mm spacer tube (can use the Hyperion spacer rings) added between the optics element and eyepiece holder, but after that, it's pretty good to go for most eyepieces that focus within 5mm of their shoulder. It will not only correct well over 95% of the coma at f/5.9, it will also substantially flatten the field. I've noticed marginal eyepieces benefit the most from using a coma corrector because now all you have to deal with is the eyepiece's inherent astigmatism. It does require about 12mm of additional in-focus (back-focus) which is substantially less than the Paracorr or ES CC. It only magnifies by 1.1x as well. 10% can be lived with quite easily, I've found.

Another up-vote for the 10mm Delos. However, if you can handle a bit more power, the 9mm Morpheus is just about its equal. Magnification-wise, it's not all that different as you can see in my test photos below.

Avoid the 22mm 70 degree versions with the Celestron Ultima LX or Olivon 70 twist up eye guard. Even all the way down, each version eats up eye relief and is non-removable for Dioptrx usage. Stick with the AF70, Omegon Redline SW, or TS-Optics Expanse WA versions with the screw-off eyecup.

And I've got 3 of those 4 as posted above. 😃

Weirdly enough, I find the 3.5mm XW perfectly corrected right to the edge like the older 5.2mm XL, unlike the 7mm XW which mostly suffers from chromatic aberration and a bit of astigmatism. I am extremely picky about edge astigmatism, so I don't know how to explain my experience with this wonderful eyepiece relative to Pentax diagrams.

Whether or not the secondary becomes an issue depends on the ratio of the secondary diameter to the primary diameter, the operating exit pupil, and the size of the eye's entrance pupil. Let's consider a worst case where an observer's eye is closed down to about 2mm due to solar observing. Now, suppose the telescope has a 35% obstruction by diameter and is operating with a 6mm exit pupil. That obstruction will occupy 0.35*6mm=2.1mm of the exit pupil's dead center. That means the observer will have to dodge their eye around the central obstruction to see anything at all. This may have been similar to what you experienced with the 130pds. There's nothing subtle about seeing the central obstruction. You know it when experience it. I don't obsess over light loss or obstruction issues when mixing and matching eyepieces to telescopes. I've got a variety of faster and slower scopes and longer and shorter eyepieces. There's no reason not to use a combination if you like the resultant view even if a few photons smack into your iris instead of your retina. This is certainly more likely if you're not fully dark adapted. This hobby is about enjoying views of the skies after all.

Try keeping a porch or yard light on nearby so your eyes don't dark adapt. At full moon, it's as bright as asphalt at noon, which is to say pretty dark as seen below in comparison to the truly bright Earth. It's just that your eyes are more than likely adjusted to darkness.

Which TV eyepieces would these be? The discontinued 15mm Panoptic and 17mm NT4? Did the original TV Wide Angle line come in 15mm and 17mm focal lengths? Regardless, probably not great for eyeglass wearers or for those on budget.

It really depends on the focal length. I find the 9mm and below Meade HD-60 and Starguiders to be very good. The 12mm are decent, and the 15mm/18mm ones are just so-so. The 25mm versions are a mixed bag. The Meade is better corrected, but the Starguider isn't bad. The HD-60s in general have better eye relief than the Starguiders due to their eye cup design. I don't know what to recommend at 13mm to 20mm with long eye relief and good correction with a 60 to 70 degree field of view at a bargain price. I've used Astro-Tech AF70, Morpheus, Delos, Pentax XL, Nagler T4, and Explore Scientific 92 eyepieces in this range. The ES-92 rule, but are heavy, large, and expensive. At 22mm, I would recommend the various 70 degree 2" versions sold under Astro-Tech AF70, Olivon 70, Omegon Redline SW, Celestron Ultima LX, etc. It shows more true field than any 1.25" eyepiece. However, I would not recommend the shorter focal lengths as more and more edge aberrations creep in the shorter you go, kind of the opposite of the HD-60 and Starguider lines. The 17mm is still passable, but not great. Perhaps if bought used for $70, it could be recommended. At 30mm, I would recommend the APM Ultra Flat Field or its equivalent from other brands. It is worth the money. The 24mm APM UFF is decent, but not worth the price. The 22mm AF70 type is far superior to it in side by side comparisons. Avoid the 35mm Aero ED since it does not have enough eye relief for eyeglass users. If the eye lens hadn't been so recessed, it might be a gem for eyeglass wearers. The 40mm Maxvision SWA was a great deal, but they seem to be sold out now.

Then there are the astronomy niche companies like Astro-Physics who are run by technical types and underprice their products relative to market demand and have never allowed quality to slip. Somehow, they continue to operate. Perhaps not as profitably as they could, but they soldier onward.

I'm wondering how the 30mm XW compares to the 30mm APM UFF at almost twice the price. As well, how the 40mm XW compares to the 40mm Meade 5000 SWA (Maxvision) at almost 4x the price I paid for the Meade.

I use the 23mm 62 degree aspheric in my binoviewers with the eyecup pulled off for widest field views, and they work great for that purpose. Of course, I'm generally operating at f/18 with a 2x barlow nosepiece achieving 3x ahead of the binoviewer so I can reach focus. Below are images taken of and through this eyepiece and others close to it in focal length in my f/6 AT72ED refractor. I have the same issue with strong astigmatism and inability to wear contacts, so the vast majority of my eyepieces have long eye relief. These are from a thread I started showing the views of and through all of my eyepieces. I've never tried the 66 degree Svbony eyepieces at 6mm and 9mm because of reports of strong SAEP (kidney-beaning) which drives me nuts. The 15mm and 20mm versions are just modified Erfles/Konigs, so have poor edge correction. I would start out with the BST Starguiders (i.e., AT Paradigms). I compared them to the Meade 5000 HD-60 line, and the only major difference is they lack a bit in eye relief thanks to the eyecup design.