Louis D

Given that cordless electric drill chucks have a really reliable, centering action that releases every time, why can't that same mechanical action be scaled up for eyepiece holders?

According to @Tiago Ferreira, the Baader Click-Lock does not center the eyepiece/camera/etc. See video below queued up to about 3:00 where he demonstrates it pushes in from only one side. Basically, it sounds like an eccentric cam was used to achieve the clamping effect rather than using a true collet action.

Those old eyepieces are pretty easy to disassemble with a lens wrench/spanner. Once apart, you could try soaking the fungal coated elements in bleach or mildew remover to see if you can kill the fungus and then start cleaning the elements. If it's between lens element in the cement, it would require a lot more work to loosen the lens cement to separate the lens elements to get at the fungus. Of course, any lens coatings are probably etched beyond hope by the fungus. I'm just tossing out ideas to make lemonade out of lemons.

Santa brought several filter wallets for my ever growing filter collection, and 1.25" and 2" 650nm shortpass (light cyan) filters to experiment with to cut unfocused red light in my achromats. Sorry, no photos yet.

Just a heads up, I had to swap in a higher amperage (same voltage) power supply for a similar seat heater several years ago. The one it came with was just too anemic to do much heating.

Wrong way round for that adapter. That one is for using 1.25" eyepieces in an 0.965" focuser. This is the adapter needed for these eyepieces.

Wide True FOV or TFOV is generally associated with longer FL eyepieces. Apparent FOV or AFOV is eyepiece design dependent.

I would forget about galaxies except for M31 and its satellite galaxies. Under those skies, you're just seeing the cores of the very brightest ones, and then only dimly. Star clusters should still look good IF you can find them in the murk and pump up the power to decrease the background sky brightness. Planets, lunar, and solar observing are not really affected by sky brightness, so they're really good targets for urban astronomers. Nebula can be seen with a narrowband OIII filter. The slightly wider passbands of UHC filters might show some details. The Orion Nebula, being the brightest nebula in the sky, is good even from urban skies if you pump up the power. Planetary nebula, at least the brightest and most compact ones, are visible from urban skies if you pump up the power. The largest and brightest globular clusters don't quite resolve in a 6" scope. It's close, and the outer fringes start to resolve. They're still worth trying to observe from an urban site IF you can find them in the murk and pump up the power. I highly recommend getting familiar with planetarium software like Stellarium to learn where things are in the night sky at different times of the year at different times of the night. Also, some planetarium apps like SkEye will allow you to turn your scope into push-to to get you into the general vicinity of objects when no guide stars are visible. You just need to work out a way to mount it to your scope, but not so close to the metal tube as to throw off the compass. Having lived near NYC for 6 years, your greatest nemesis can be smog that can obscure even the sun on a clear day. If a front or storm clears out the sky of pollutants, your Bortle number can suddenly drop a notch or two for one or two nights because nothing but clean air is scattering light pollution leading to less sky glow. You'll learn to plan for those conditions.

Then you just squeaked in with that purchase. Don's retiring for a second time at the end of the month/year and will close his store. From what I've read, he plans to continue astro observing and participating on the various astro forums.

Certainly not the best if you need to transport them any significant distance, especially if walking or biking. In that case, a suitcase/travel Dob would be more appropriate, but you have to build them yourself as Reiner Vogel has done many times over. I don't understand why no manufacturer has stepped up to make these commercially. They would make recommending Dobs even easier.

I wasn't a fan of the Radians' SAEP on bright objects (lunar and solar), so I went with Pentax XLs back in the late 90s. The XLs also seemed to have more eye relief than their LVW counterparts, which was important to me as an astigmatic eyeglasses wearer.

That is nice and dark by suburban standards. I'm in Bortle 7 or worse in most directions. I would think either a 30mm or 40mm would work well under your skies. I actually use both regularly, so it's not an either/or situation. The 40mm (Lacerta ED, Pentax XW, ES-68) is best for really big objects or groups of objects and for centering smaller, but brighter ones before swapping to a higher power. The 30mm UFF is nice for framing slightly smaller objects or groups of objects at a higher contrast level, higher power, and rendering them more sharply while using a smaller, lighter eyepiece that typically balances better when swapping with higher powered eyepieces.

If you want a widest field view without breaking the bank, or dealing with a lot of weight, the 40mm Lacerta ED is very good. I've found it to be just a bit less sharp at the edges than my 40mm Pentax XW. The Lacerta appears to still be available from this dealer where I bought mine. Here's my review of it: Keep in mind, if you live in light polluted skies, the sky background will be very washed out at that power/exit pupil. However, the Pleiades and other large star clusters will look very nice in it.

Since many early rockets used RP-1 (a highly refined kerosene) just as SpaceX's Merlin and Kestrel engines, I don't see how it's all that much worse now than then. Also, consider all of the burned kerosene in the form of jet fuel, also highly refined, in airliners every day. SpaceX is migrating over to methane fueled engines for their future rockets. I have no idea how it compares to RP-1 as a pollutant, though.

I've really been enjoying my GSO 5" f/5 Newtonian with Linear Bearing 2" focuser for quick outings. It's low cost, relatively light, holds collimation very well, has no cool down issues, has sharp optics, puts the eyepiece up nice and high so I can keep the tripod low for stability, goes from wide field to high power views with merely an eyepiece change, and has a usable two speed focuser. You might need a pier extension for your mount to use one without hitting a tripod leg at high elevations. If you're picky about edge to edge sharpness at low to mid powers, you might want to pickup a GSO coma corrector for it. If you concentrate mainly on high power viewing, you'd want to remove it anyway because it introduces spherical aberration at high powers.

Maybe by sheer luck, it's that weird thread size on Arcturus (and other entry level) binoviewers' nosepiece upper end. It's somewhere around 26mm from what I've read and been able to figure out.

Seriously Steampunk looking. I love it! I'm picturing the astronomers of the day like this:

I recommend using a cell phone holder to attach mobile phones to eyepieces if you want to do afocal photography. DSLRs don't work well in this application.

I couldn't figure out from the translated description if the black optics section is removable and 1.25" filter threaded. If so, it might work well with binoviewers to reach focus. Right now, I use the optics section of a Meade 140 APO Barlow for this purpose.

Artemis is also not a long term, viable option. Congress mandated they use the leftover, reusable Space Shuttle main engines that were sitting on the shelf since the end of that program. However, they're being thrown away with each flight. There are enough engines for 4 or 5 flights. After that, they'll either have to restart production of a very expensive engine, find an alternative engine and flight certify it, or redesign Artemis as a whole. Yet one more way that legacy defense contractors have one hand tied behind their backs when trying to design something "new".

Legacy space operators are under the gun to have flawless flights. This necessitates really long review processes and long inter-launch periods as more reviews are conducted. SpaceX by comparison, being a commercial space operator, can pretty much make their own rules, at least until the money runs out. I've worked in both realms, and generally, commercial operators get things done faster, but with more failures along the way.

Where did I say they don't? I simply said that if you're going to compare triplets based on price (which is what the OP seemed to do), make sure they are both using the same grade of glass. After that, price difference comes down to quality of the lens figuring/polish/coatings/etc., tube mechanicals (focuser, lens cell, baffling, etc.), labor costs, factory profit margins, middleman markups, dealer markups, differing import tariffs, etc.

You're comparing apples to oranges with the Esprit triplet comparison. It uses FPL-53 equivalent instead of FPL-51 equivalent glass as in the Askar. The former is considerably more expensive than the latter. That, and I find the Esprit line priced on the high side for a Chinese made product. Synta (SW) makes a good product, but so do JOC (ES/Bresser), Sharpstar (Askar and many house brands) and Taiwan's Long Perng (many house brands). Do your homework and choose the accordingly.

How so? I'd say the best way to break a 2" filter would be to screw it onto the bottom of a 2" to 1.25" eyepiece adapter and then insert a long barreled 1.25" eyepiece into the adapter.

Okay, but supposing you did want to directly use 2" filters with it, you could use this 1.25" to 2" Step Up Ring attached to the 1.25" filter thread.