Louis D

But can you see anything at night (moon, a street light, etc)? If so, "night vision". 😉

There are several advantages to using longer focal length eyepieces with a Barlow/GPC/OCA/OCS: 1. The light cone is slowed down allowing lower cost eyepieces to perform well. 2. The eye relief is better in longer focal length eyepieces which makes viewing more comfortable. 3. Longer focal length eyepieces are less likely to magnify collimation imperfections in the binoviewer.

Makes me glad I'm a bit of an eyepiece hoarder. I can just go to my collection to try something different. My grown daughter can also borrow from it like a library.

Anytime they're having a backyard get together, pop over the fence top and say "Hi!". I did that with a neighbor who got so mad he threatened to beat me if I did it again. I asked him to repeat his threat while I recorded it with my phone. He backed down realizing that was assault, plain and simple, under US laws. As long as I'm on my side of the fence, there's nothing he can do to stop me from interrupting his get-togethers with a friendly "Howdy neighbor!".

I got my neighbor to back down on his lights by going out nightly with a Cree LED tactical flashlight and shining it in his family room windows, zig-zagging it all over the place. When he came out in a huff, I pointed out I was trying to astro observe, and was trying to figure out why his security lights came on every time I came out my backdoor or moved around my own back yard as if it was a criminal act to do so. I told him I was trying to figure out if they were light or motion sensitive sensors. He rearranged them and turned down the intensity and motion sensitivity. They didn't seem to like having the tables turned on them with regards to nuisance lighting.

You can ask a moderator to delete the extra posts. I've had it happen when my internet connection was flaky, and I hit return multiple times before it actually posted thinking the first time didn't work. They all got queued up until my connection returned.

You compromise relative to the best corrected eyepieces out there, but not relative to these crappy MA eyepieces supplied with the scope. Most 8-24mm zooms have 7 elements and tend to work pretty well by most accounts. The 7.2-21.5mm ones are also well thought of. In fact, you can see how two zooms compare in an f/6 ED refractor at 12mm in the comparison image I posted just above. Both are clearly better than that 12mm Meade MA which is comparable to your stock 10mm eyepiece.

Thanks. It's too bad they're so crappy. Below you can see the 9mm and 12.5mm generic Kellners I got with my ST80 20 years ago relative to much more expensive eyepieces. They're not bad except for eye relief and vignetting: Edit: I just noticed I do have an MA, the 12mm Meade Astrometric MA that I picked up for cheap used. I remember using it and thinking, this is bad. Especially so since it is sold for astrometric usage. Now I'm wondering how an MA differs from a properly executed Kellner. I found this CN post by Martin Pond which indicates the field lens is acrylic in a 25mm Meade MA with a slightly curved instead of flat outward facing first surface. Using Acrylic instead of glass for one element could certainly account for the poor image quality.

What exactly is this stock 10mm eyepiece that everyone pans? Is it a Ramsden or Huygens? Kellners are generally not as bad as the descriptions of this 10mm.

Are you using the same coma corrector in both? I have certain eyepieces that exhibit a fuzzy field stop without a CC, and a sharp one with one. I've never noticed SAEP becoming more or less pronounced with or without a CC. Is this the only scope that causes the Nikons to kidney bean? It is very odd indeed. I've not heard of this issue before. Do any other eyepieces in your collection kidney bean under the same conditions? Do the Nikons kidney bean with or without the EiCs installed?

I use a Meade 140 nose piece screwed onto the front of my binoviewers, and I get right about 3x with the combination. The 140 Barlow is 2.4x by itself. I think being a medium length Barlow helps limit the power growth when used with the longer binoviewer path.

However, it's far less of an increase than using a 2x Barlow nose piece to reach focus.

You'll probably want to remove the focuser from the tube as you suggest. Next, see if there is a way to remove the plate holding the pinion against the rack. Once the pinion is removed, the focuser tube should slide out. Do all this over a cookie sheet or other lipped pan to catch loose parts. Once the focuser tube is out, you can inspect everything for damage. Hopefully, nothing is permanently damaged.

Just ask the retailer if the eyepiece is marked as Taiwan or China.

Large objects, yes, but not globular clusters, planetary nebula, planets, double stars, compact open clusters, galaxies, etc. 300x to 700x is quite usable in the desert Southwest and on Florida's Gulf coast. This is similar to the Canary Islands by my understanding. However, it's quite difficult to drive a giant Dob to the Canaries. Perhaps there are other areas in Europe with dark skies and stable seeing conditions?

Possibly because few Europeans have large enough trucks or vans to haul them to a dark site compared to the average American? It's like hot air ballooning. You need a large vehicle to haul a large, heavy object to where ever it is you're going to use it. Same goes for towing a boat to a lake or the coast for some weekend fun on the water.

Putting the ES-92 into a tele-extender would work, but it creates a very long lever arm. However, it won't matter to the Dob because it can't twist on it's axis. The Morpheus 6.5mm should be fine between 5mm and 8mm. Luna does fine at high power even with unsteady skies due to the large features and high contrast. Maybe some tiny, low contrast details won't show. The planets really do need steady skies for high powers. Planetary nebula less so. Globular clusters will mostly resolve at high powers in unsteady skies, but the individual stars will blink in and out quite a bit. However, you still need steady skies to resolve their cores well. The moon will naturally dim to acceptable levels at high powers. Brightness is dependent on exit pupil which is a function of f-ratio (scope focal length/aperture) and eyepiece focal length (EFL/FR). So, you are partially correct, increasing aperture while keeping all other variables constant does indeed increase brightness (EFL*A/SFL). If you increase aperture while also increasing focal length of the scope at the same rate, brightness will remain the same, but magnification will increase along with resolution. You'll probably want to get a coma corrector to allow your ES-92 to shine to the edge. If your budget is tight, the Revelation/GSO CC works well with the addition of a 25mm spacer ring between the optics section and the eyepiece holder. I find it corrects well over 95% of the coma at f/6. For the price of an eyepiece, it is well worthwhile. I just recommend removing it for high power work because it adds a bit of spherical aberration. That, and replace the pot metal screws with M4 cap head steel or brass screws from the hardware store. I had one of the original screws shear off completely. Somewhere down the road, you should spring for a set of entry-level binoviewers and a pair of 60 degree eyepieces around 16mm along with a good quality 2x Barlow to reach focus to view the moon and planets. Brightness becomes a non-issue because both eyes see the same level of illumination (half that of mono-viewing), and two eyes allow your brain to work as intended to pick out fine detail and subtract out eye fluid floaters. Mars was showing loads of detail at closest approach in my binoviewers while mono-viewing was a bit disappointing due to the brightness and lack of apparent detail. I can even view the face of the full moon with binoviewers and see loads of details that are completely blown out mono-viewing. There's no rush to buy everything at once. Metering out your purchases over time can help keep your interest in astronomy alive after the initial thrill fades in a year or two. For example, you'll probably want to add a small ED scope for wide field, low power views. However, it will need a mount, so that's best left as a purchase far down the road once your wallet has recovered.

Correct. Despite them all having the same AFOV and eye lens diameter, the 22mm version is fairly easy to take in the view while the 12mm and 17mm are more difficult. I think it comes down to undiagnosed SAEP: I think this is also why the 12mm ES_92 is slightly more difficult to use than the 17mm version. I find it interesting that SAEP grows within many eyepiece lines as the focal length shrinks (NT4, ES-92, AT AF70). It seems to have something to do with the increasing power of the negative lens section of each eyepiece line.

I liked the 17mm ES-92 so much that I bought the 12mm a year later. A 23mm to 26mm version would be welcomed to give my 26mm Meade MWA the boot for good. As far as eye positioning, try dealing with the 12mm and 17mm Nagler T4s. Both are incredibly tiring to use due to their super finicky exit pupils. The ES-92s are a dream to use by comparison. Even with my eyeglasses off (exposing my raging astigmatism), I find I have to push in pretty far to see the entire field with the Ethos I've tried at star parties. They seem more like the T2/T6 Naglers as far as eye relief in that you can't really hover back from them and take in the entire view. I like that I can rest my glasses on the turned down eye cup of each ES-92 and easily take in the view without having to push in. It makes for a more relaxing view.

Or, if you have a filter threaded extension tube and enough in-focus, thread one filter on the bottom of the extension tube and the other on the bottom of the eyepiece. Rotating the eyepiece with respect to the extension tube will vary the darkening.

You might also check in with Denis (the binoviewer guru) about microscope eyepieces that work well. I regularly use a set of 15x Bausch & Lomb widefields meant for binocular heads on microscopes. They were designed for just such a usage and are super comfy and reasonably sharp. Leica and Zeiss have more modern versions that are well regarded. You do need to use them at f/12 or slower because they were designed for slow microscope f-ratios.

A bit off topic, but is the top of that handle a picatinny rail?

The 80mm Equinox should be providing crisp and contrasty views if allowed to properly acclimate. My 90mm triplet APO takes 30 minutes to an hour to acclimate. It's kind of a mess before that. Try downsizing the secondary in the Orion 6" f/5 Newt to 30mm in diameter or so to get to a 20% by diameter obstruction. The level of contrast at that point rivals APOs with zero false color. You're just left with spider diffraction spikes, but curved vanes can spread out the spikes to make them less noticeable if they bother you.

The OP could start with an f/5 Newtonian and replace the secondary with an undersized one if contrast is more important than full illumination. I can't find any 6" f/8 Newt OTAs under 14 pounds. Is it just the extra tube length adding 4 pounds?

Just found the Meade LX85 6" Modified SCT at 9 pounds. There's also the 6" f/5 Newtonians at 10 pounds.