Louis D

Don't forget, the ES is also heavier than the APM by 290g (43% heavier). The ES also has a bit less usable eye relief by having its eye lens more recessed. I've never had an issue with non-waterproofed eyepieces relative to my waterproofed ones.

Do these work as well as Tele Vue Plossls in faster (sub f/5) scopes?

I hate to tell you, but you'll need a "booster refractor" sooner than you realize as this "cure" wanes in effectiveness over time. 😉

It would probably perform even worse than my 29mm 90° AFOV Rini Modified Plossl (possibly a 3 doublet (6 elements) Erfle variant in reality). It's the one second from the left below and second one down in the FOV images. It measures out to have a legitimate 90° AFOV photographically. Projection yields a wider and more inaccurate AFOV measurement because the lower barrel forms the field stop, and the projected circle gets quite fuzzy and indistinct near the edges, so I won't list it here. Usable eye relief is 10mm, but it feels much less in use. The edge is a blurry mess of astigmatism and other aberrations, so it is of limited utility. I didn't pay much for it from Paul himself back in the day, so I keep it as a rather unique, hand crafted eyepiece against which to compare other UWA/HWA eyepieces. It's ironic that it performs about as well or better than the 30mm Kasai Super WideView 90° (which is really only 83° AFOV) and cost over $400 20 years ago. It was a bad 30mm Leitz 88° copy, was priced at a fraction of it, and was still a terrible deal. One plus for the Rini is that it somehow has no chromatic aberration across the field while the Kasai has loads starting just off axis. Check out the neat rainbow effect in the edge view of the Kasai. I don't know of another eyepiece with that much chromatic aberration.

Hold off buying these second hand. The AAS should have Willmann-Bell's existing new inventory available online in the near future once they've completed relocating it to an ecommerce fulfillment center. Hopefully, the prices will be closer to the old new prices rather than the current used prices.

What material did you use? I'd probably use ~1/4" closed cell foam sheeting. There's even heat moldable versions that would retain their shape after cooling and not droop into the light path.

There, I added one for the Starmaster 7" Oak Classic from an Astromart ad. It must have been a later version because it has a Zambuto mirror. The earlier ones were equipped with Raycraft mirrors.

Welcome to SGL! WOW, what a picturesque town. I'm envious.

If you're in the US, the 10mm Pentax XW goes for $269 right now while the 12mm ES-92 goes for $799, a huge $530 difference. In fact, you could almost buy three 1.25" XWs for the price of one ES-92 (you'd need $8 extra). Another possibility would be the APM Hi-FW 12.5mm. You would still have great sharpness while remaining in a 1.25" barrel. The price is $375 in the US and €247.90 in Europe, both excluding taxes. This puts it in the XW price range.

Another possible "classic" would be Rick Singmaster's Starmaster 7" Oak Classic which was practically a classic from day one as its name boasted. I rarely see them come up for sale publicly. They generally never get sold until the original owner passes away or are privately sold among club members at many times their original price. It has been imitated but never duplicated over the years.

The media has dubbed this event "Snowasis". 😏

Maybe someone got this one with their order up at the Tan Hill Inn.

I picked up a Chinese made copy of this scope, except it is 70mm/300mm, for about $25 brand new just as lock down started. Interestingly, there's a ~35mm metal aperture stop just behind the objective lens and another 50% stop midway down the focuser tube. I assume both were to improve the image quality by doubling the f-ratio. I removed the objective stop by simply pushing it out after removing the lens cell and focuser. I then made a 2" focuser from PVC plumbing parts. Now, I've got a 70mm super finder when used with a 2" 40mm eyepiece like my Pentax XW or Meade 5000 SWA yielding 7.5x at 9.3 degrees TFOV. Field curvature is high, so I use a spare TSFLAT2 ahead of the diagonal to good effect. I find it ironic I'm putting about $700 of optical parts behind a $25 70mm objective. But hey, I had them laying around for other purposes, so no biggie.

The problem I've had with some lower cost 90+ degree eyepieces is that the eye relief is so short and my eyes are so deep set in my sockets that I simply cannot push in close enough to see the entire field at once because the top of the eyepiece is typically too broad to fit within my eye socket. I've even seen this with vintage ~80 degree AFOV binoculars that had rigid eye cups which were about as deep as the usable eye relief. Even with my eyeglasses off I couldn't take in the entire AFOV. Other UWA eyepieces have too much SAEP to be able to take in the entire AFOV at once, such as the Meade MWA 26mm, and to a lesser extent, the 12mm and 17mm Nagler T4s. I have to pull back a bit to get a usable exit pupil with these eyepieces, losing a bit of AFOV in the process. I haven't had either issue with the 12mm ES-92 thanks to its fairly well controlled SAEP (not perfect, but not terrible) and long usable eye relief.

I think in some cases, it helps for the scope to have been at the top of the heap in terms of quality at the time it was made. Quite a few AP refractors from the 80s and 90s are referred to as classics in the classifieds with the caveat that they aren't quite at the top of the APO heap anymore, but are still excellent performers.

Not really, it's just that some CC/Barlow combinations simply won't come to focus in some telescopes due to limited in or out focus.

The DFW/San Antonio/Houston Texas Triangle would cover England with ease (60,000 mi² vs 50,000 mi²).

I've got a #8 pale yellow filter labelled as minus violet similar to the Meade #8 below, and it doesn't do nearly enough on an ST80 to improve contrast that's lost to stray violet light, so I've got a GSO #12 on order for $15 to see if it improves the view. I'm sure a Baader 495 Long Pass would be superior, but I'm not willing to spend $53 on an experiment involving what appears to be a non-interference coating filter. I'll also try stacking it with a generic M&SG filter I've got to see what effect that has as well. This graph indicates yellow color filters to be a bit of gamble as to what you'll actually get, so I'm going to try going more saturated this time: If the #12 yellow doesn't cut it, I could always try a #15 dark yellow.

When cleaning completely disassembled eyepieces during refurbishment, I've found hand washing with dish detergent and my finger tips over a folded towel (as a safety catch) to be the best way to completely remove really stuck on oil and organic goop. I then finish with the solvent based cleaners and microfiber cloth to get things squeaky clean and streak/spot free.

I've found that having a large aperture in light polluted skies allows globular clusters to nicely resolve at powers above 200x. Small apertures simply don't have the resolution or limiting magnitude to do this. At higher powers on smaller targets, light pollution is much less of a problem than on large objects at lower powers. Many planetary nebula also respond well to aperture in light polluted skies. Planets also respond well to increased aperture if they are high enough above your local horizon and the seeing is steady.

Most likely dust motes on the field lens of the eyepiece because it is closest to the focal plane and thus are most nearly in focus. Take the eyepiece out of the focuser, flip it around, and look at the bottom lens. It should be fairly simple to clean them off once you identify them.

Basically, since California requires this label, it's cheaper and easier to stick it on every box regardless of where it's being sold. If CA was a small market, it would probably be ignored and/or boycotted by manufacturers. California's latest effort to bend the world to its will is P12 which effectively bans the sale of out of state pork in their state.

Apple, pear, and grape juices often contain trace amounts of arsenic, and I've yet to see a P65 warning on them.

I "wonder" if anyone has done a lens cleaning solution comparison between Baader Optical Wonder Fluid, Residual Oil Remover (ROR), Zeiss Lens Cleaning Wipes, and Windex. To reiterate and expand on an earlier post of mine, here are their ingredients: ROR MSDS: Ammonia 26° - 0.775% Sodium Chloride - 0.830% Isopropyl Alcohol - 4.266% Liquid Soap - 9.011% Distilled Water - 85.118% Baader Optical Wonder Fluid MSDS: Ethanol - 25% Propan-1-ol (n-Propanol or n-Propyl Alcolhol) - 35% Zeiss Lens Cleaning Wipes MSDS: AQUA = Water Propan-2-ol = Propanol Ethanol = Ethanol 5-CHLORO-2-METHYL-2H-ISOTHIAZOL-3-ON = Methylchoroisothiazolinon 2-METHYL-2H-ISOTHIAZOL-3-ON = Methylthiazolinon Windex Glass Cleaner MSDS: 2-Butoxyethanol - 0.5-1.5% Ethylene glycol hexyl ether - 0.5-1.5% Isopropyl Alcohol - 1-5% Water - 60-100% Windex Glass Cleaner Website Ingredients: 2-Hexoxyethanol Isopropanolamine Ammonium Hydroxide Lauryl Dimethyl Amine Oxide Sodium Dodecylbenzene Sulfonate Water

If they're similar to the older LVs, then they are warmer and view a bit darker.