Don Pensack

I strongly disagree. When I reviewed a scope several years ago that used a William Optics Binoviewer as standard equipment, adding this Barlow to the binoviewers increased chromatic aberration horribly, added horrible spherical aberration, and added astigmatism and vignetting. It was a trainwreck. Adding a simple GSO Barlow was much better.

Yes, the genealogy of the Celestron Axiom is: Axiom--Japan Axiom LX--China (JOC) Luminos--China (company is ?) And the Ultima name: Ultima--Japan (probably Ohi Optics) Ultima LX--China (Barsta) Ultima Edge--China (UO)

The Nirvanas are made by United Optics and available under many labels, including Meade and Stellarvue. They are made in 4mm, 7-8mm (some companies say 7mm, others say 8mm), 15-16mm (same as the 7-8mm), and 28mm (2")

Something in-between: 12.5mm Baader Morpheus. It has a (measured) 78° field and plenty of eye relief for glasses. It is noticeably wider than the XW and the Delos and has excellent sharpness and contrast.

LOL. It makes my eyelashes look longer! Seriously, though, I used to work in a store that sold binoculars and I had to clean all kinds of stuff off the eye lenses on the binos ever couple days so people would see clean images. Mascara is as bad as rubbing crayon or wax on a lens. It's tough to remove! Alcohol basically didn't work. But ROR took it off on the first go around. Amazing stuff.

Be careful. Human vision can see well beyond 100° with peripheral vision. You can see the whole field at a glance in a 120° eyepiece with peripheral vision, but NOT direct vision. Foveal vision--the center of the retina we use to look directly at something--cannot be redirected to the side of a field larger than about 68-70° without rolling the head over and looking through the eyepiece at an angle (as you would do with a porthole to see farther at the edge). Much of the time, whether you are even aware of doing so is simply related to your experience with the field size. I have used 100° eyepieces since 2007, so I found the 92s easy to use and about the same as the Ethos eyepieces I was familiar with. But if you want to look directly at the edge (and in practice you really don't), you have to roll your head over. If you try to simply avert your eye to look at the edge, you would move your pupil away from the exit pupil of the eyepiece. To look with direct vision at the edge means you are looking through the eyepiece at a 46° angle. Try doing that without rolling your head over and you'll see your pupil moves several millimeters to the side to do so. And that doesn't work with eyepieces. So the people who maintain you can take in the whole field at a glance with direct vision are blowing smoke. It's anatomically impossible. Peripheral vision is easy.

I compared ROR to Windex and a lens cleaner that was a mix of isopropyl alcohol and water. ROR was vastly superior to the other two. I also compared it to a Nikon lens cleaning fluid you don't mention. The Nikon fluid was very close, but ROR was still better at removing oils and mascara stains.

Is that a bad thing if other states raise pigs in a cruel and inhumane manner? As for Prop.65, more information for the consumer is not a bad thing. A label that identifies the potential problems with one product allows me to decide whether or not it is important to me. Lead in eyepieces glass is not important to me, while lead in glassware I drink from is. Since there are not thousands of knowledgeable inspectors checking each and every product, nor is the state willing to pay for that, the only alternative is to put the label on every product containing lead-containing glass. Lots of studies of areas with concentrations of particular cancers point to environmental factors being a root cause, and rarely is it a single thing. We are all lab rats for industry, who basically only responds to a problem AFTER it has caused a problem. Far better to require they prove safety for humans BEFORE the product comes to market.

Well, at least you have corrected the coma. However, where eyepieces are concerned: Inexpensive, well-corrected to the edge, widefield--choose any two. A fast scope unfortunately requires eyepieces designed for the fast f/ratios, and that does not describe most lower priced eyepieces. The APM Ultra Flat Fields are a notable exception, though they were designed to yield excellent star images at f/5. They may not fare as well at f/4, though I know the 30mm does fine. It would just seem a shame to correct the coma to get better star images and then use eyepieces that have substantial astigmatism in the outer field at that f/ratio. The APM Ultra Flat Field series is also available under the Meade UHD label, Celestron Ultima Edge, TecnoSky Ultra Flat, Altair Astro Ultra Flat, and Orion Ultra Flat names, and few focal lengths from China under the Svbony label. That might not be a bad place to start. Add a good 2X Barlow to cover all the necessary magnifications.

The assumption that paying more money means the eyepieces will work at a faster f/ratio is a false one. Eyepieces have to be designed to not yield astigmatism in the outer field at f/4, and very few eyepieces are. This is one of TeleVue's claims to fame. I would also add Pentax, Nikon, Leica, and Zeiss to that list. So far, very few Chinese eyepieces make that list. The APM XWAs do well at f/4 (and the other brand names for the same eyepieces). The APM 30mm Ultra Flat field is also a good performer at f/4. Every eyepiece design has a "critical f/ratio" below which edge of field astigmatism increases. Explore Scientific has not really aimed their designs at the f/3-f/5 market except the 92° series, which does work quite well in faster f/ratios. The Orion LHDs also work fine at faster f/ratios. I've explored many lower-priced eyepieces in scopes of f/3.45-f/5.18 (all coma corrected). Baader does not make anything appropriate, though they work OK at f/5.1 (f/4.4with Paracorr). All the older designs: Ramsden, Huygens, Kellner, Plössl, König, Erfle, Abbe Orthoscopic, Monocentric, should be avoided if you are looking for correction to the edge.

As we get older and glasses earing becomes more important, we look for longer eye reliefs in eyepieces. Were it not for that fact, I would still be using Ethos eyepieces at each focal length instead of just below 9mm. We do have more choices, today, in LER eyepieces, just very few of 80° and larger.

I have used the new 8.5mm, 6.5mm, and 4.5mm. They are not good, with the most internal light scatter I've ever seen in eyepieces. Additionally, the 4.5mm has serious chromatic aberration. The older 8.8mm, 6.7mm, and 4.7mm were better eyepieces. ES does not make "planetary" focal lengths with long eye reliefs. The post by vlaiv points out a few that might work.

17.5mm Morpheus--21.75mm field stop 22mm LVW--24.9mm field stop 22mm Barsta 2"--26.8mm field stop. 24mm Panoptic--27.0mm field stop Not really a fair comparison, since one is not usable in a binoviewer. I would caution that many people cannot use the Morpheus eyepieces in binoviewers either because they are 54mm in diameter.

If you have 2" capability, the 70° Super Wide Angle eyepieces from Barsta are just as good and have more modern coatings, so a little bit brighter. Available as: Arcturus Ebony Omegon Redline Astromania SWA Skywatcher SWA Tecnosky SWA Telescope Service Expanse ED

OK, I'll bite. I range from 61x (5.2mm exit pupil) to 493x (0.6mm exit pupil): My 3 most-used: 14mm (130x), 11mm (166x) and 9mm (203x), all medium powers. Honorable mentions (used very often): 17.5mm (104x) a low power, and 7mm (261x) a high power in the 12.5". Less frequently used but do get some focuser time: 22mm (83x), 8mm (228x) and 6mm (304x). The 6mm is my most used planet eyepiece, but I don't look at planets much (those little balls of light pollution). Least used except under special circumstances: 30mm (61x), 12.5mm (146x), 4.7mm (388x), 3.7mm (493x) Some of the eyepieces I consider redundant, but how do you part with an eyepiece you really like, even if it isn't used that much?

CO2 snow would not be used to clean eyepieces, though.

I may be a contrarian here, but I don't regard that as an "upgrade". A true upgrade to the Starguiders would be the TeleVue Delites. They are optically better in nearly every way. But don't expect miracles. We're talking maybe 5% better.

I heard they were also discontinued by Vixen.

I'll be a year older before it sees first light, LOL.

True words. Though I have found some eyepieces that are bargains in that department. At f/5.75, my current coma-corrected dob scope is not exceptionally hard on eyepieces. I have seen eyepieces that function better in that scope than in my f/7 apo refractor. So if an eyepiece performs well in the dob, that doesn't mean it will perform well in all scopes, especially refractors, with their much more strongly curved focal planes. I discovered, for instance, that the Baader Morpheus line works exceptionally well in the dob, and in a friend's f/5.18 (f/4.5, coma corrected) dob, and in another friend's f/4.8 (f/4.2 coma corrected) dob. They performed quite poorly in a friend's f/3.45 dob (f/3 coma corrected). The point is that the scope will make a lot of difference in the performance of a lot of different eyepieces. The good news is that if an eyepiece works well at f/4, it will work well in longer f/ratios. The bad news is that if an eyepiece works well at f/6, it might not work well at faster f/ratios. And if you are bothered by field curvature, it's best to keep the radius of curvature longer than 1000mm. That's easy in a reflector, but hard in a refractor, where, unless the scope has a built-in field flattener, the radius of curvature is only about 1/3 the focal length on average. There aren't too many refractors out there with 3000mm focal lengths or longer. The FC issue is one of the reason I keep the apparent fields to 60-63° in my short FL apo. And one of the reasons I really regret selling my TeleVue NP101.

Q-Tips and any decent cleaning fluid will do it. Here is what TeleVue says: https://www.televue.com/engine/TV3b_page.asp?id=103

In my experience, the exit pupil is better controlled, with less spherical aberration (SAEP) in the SLV line than it was in the LV line. I think the LV line was also sold by Orion under another name. With SLVs, you want to either buy new or have the right to return it if used. Early versions of the SLV had a bright shiny spacer under the eye lens that resulted in massive internal reflection in the eyepiece. Later versions fixed this problem, apparently. If you buy used, you may not know which version it is. Of course, that doesn't matter if taking an eyepiece apart and blackening interior pieces is not intimidating.

But you are probably not using another GPC/OCA with the binoviewers, in which case the Barlow is serving that function. It will work, sure, but the Barlow probably isn't anywhere near its rated power when doing so.

lens nearest the eye: eye lens lens nearest the scope: field lens tube the lenses are in: Upper barrel and lower barrel. Lower barrel also called the insertion barrel

The field lens in that eyepiece is desperately in need of edge blackening. Coatings look good.