Louis D

Valid question. I do, and I sometimes pick up reflections off of my eyeglasses on bright objects. I'll shift my head angle slightly to move the reflection to be less annoying. Also, off-axis light rays in wide angle views will suffer from chromatic aberrations, so I have to roll my entire head to look at the edge so the edge rays are entering my eyeglasses perpendicular to them. This causes me to lose the opposite side of the view. Contacts cure most of these ills, but I can't stand wearing them.

I've been using my Arcturus BV with the nosepiece from a Meade 140 2x Barlow screwed into the nose of the BV to reach focus in my Dob, and to boost focal length by 3x. My Dob has has only 25mm of design in-focus, and I've tried this kit in various other scopes I own with only marginal focus shift from using an eyepiece alone, so I know it will reach focus in pretty much anything. For eyepieces, I prefer smaller, lighter eyepieces such as the 20mm Svbony 68 degree red lines or adapted 15x B&L microscope eyepieces. Big, heavy, wide eyepieces can be difficult to get your nose between and to achieve balance on smaller scopes. The Barlow is vintage as are the microscope eyepieces, although I had a machinist make the adapters for me. However, all up, I spent less than $400 on everything over the past decade, so I don't feel too bad using them so infrequently. I've seen amazing details on Mars at opposition with this kit, so I know it's all working well together in the Dob. Basic, entry level BVs can work fantastically well. Just make sure to get a version that uses collets instead of thumbscrews to hold the eyepieces. You may still need to fill undercuts with tape if the barrels aren't smooth to avoid tipping during tightening.

The original bins appear to be 10x50 and very similar to these ebay and amazon listings. Apparently, the factory would print whatever you wanted on them for the right price.

I had my doubts about the 35 meaning 35mm objectives as well. I figured it was either an 8x21 or 10x25. So, basically, they got absolutely nothing right with their numbers on those bins, either.

I asked about the metal fittings because I've seen too many of the plastic leg clamps on the the rectangular legged aluminum tripods fail. Once they crack in two, you can never extend that leg again until you replace or repair that fitting. That's not to say that all metal is perfect. I've also seen the top casting holding the three legs crack on some premium photographic tripods after being overloaded with the legs spread wide. Ideally, CNC machined fittings from high quality billets of metal alloy would be ideal, but expensive.

Of course, but what about the increased contrast due to the darker sky background? That, and Uncle Al's whole "Majesty Factor". 😏

Here's a Tasco 60x35 on Mercari. What's the 60 supposed to mean? Is the 8° the apparent or true field of view? At 60x, an 8° TFOV would be impossible. An 8° AFOV would be miserable to use. If I'm doing my trig correctly, a 76 meter field at 3000 meters amounts to a 1.45° TFOV, not 8° TFOV. Assuming a 50° AFOV, that would amount to 34x, not 60x.

Sounds like a 13mm Ethos might be the only eyepiece you'd need in a 127 Mak most nights if you could deal with the eye relief. It would almost combine the 24mm and 13mm eyepiece functions into one.

Too bad for Pentax. I've been fishing around for a Father's Day gift to myself, and the 23mm was one possibility. I'll continue to give it a hard pass since Don and I seem to have similar eye socket depth. C'est la vie.

It seems odd to make a knockoff of a Tasco binocular rather than a knockoff of a premium brand. For reference, what sort of counterfeiter would make knockoffs of purses costing under $100? The whole point of counterfeiting is to make huge profit margins, and that isn't going to happen making knockoffs of low-end products like Tasco. My guess is that the same factory that makes Tasco had blems or extra product produced after they finished a run of official Tasco or similar binoculars and sold them as a lot to a jobber to recoup some of their losses. The jobber may have had the printing added after receiving the lot. That would explain why the collimation was off, assuming it wasn't due to mishandling by the original purchaser.

Too bad they weren't made to work with focusers and adapters in general. I could see this attitude working if they were a huge telescope marketer with eyepieces as a side business, but the opposite is true.

If we assume that it's 20mm design ER from the center, and we machine off the top of the barrel to be flush with the eye lens's edge (ignoring for now that it will fall out if tipped too far), that saves 4.5mm of usable ER at most. So 20 - 4.5 = 15.5mm maximum usable eye relief for eyeglass wearers if the eye lens could somehow be flush mounted to the very top of the barrel. That's quite tight for most eyeglass wearers with deep set eyes like Don and me. Subtract a mm or so to secure the eye lens, and now you've got 14.5mm of usable eye relief. Perhaps a monocle is in order for these eyepieces even if redesigned? 😄

I like my Redline (AT AF70, etc.) eyepieces' take on 2"/1.25" barrels. For the 17mm on down (in terms of focal length), they have a screw-on/off 2" skirt that is parfocal with the 1.25" barrel. You can leave it on all the time (as I do) or off all the time (for 1.25"-only scopes), or swap it in and out if that's your thing. I'd like to see more eyepiece adopt this very useful feature. I haven't found any particular advantage to the Tele Vue style non-removeable skirt on my 12mm Nagler T4 or 14mm Meade 4000 UWA smoothie. There's generally not enough 1.25" barrel sticking out to safely lock it into a 1.25" focuser, not to mention it vastly increases the in-focus requirement in this mode. Also, you can't use 2" filters with the skirt unless you screw on a 20mm 2" extension first. It seems like a solution in search of a problem.

I thought it was sold in bbl or barrels on the open market.

I can't quite remember if I need to be resting my glasses on the eye guard or hovering just above it. I'll have to check sometime. On my 40mm Lacerta ED, I know have to have my glass resting on the retracted eye cup to see the entire view. I might even need to push in a bit. The 35mm Aero ED requires me to mash my glasses into the eye cup to see the entire field. At the other extreme, my decloaked 40mm Meade 5000 SWA allows me to hover well above the eyepiece in relaxed comfort with 24mm of usable eye relief. It also has better edge to edge correction and field flatness as compared to the Pentax XW-R 40mm, but it is more massive.

You could do like me and start playing with them indoors taking pictures of standardized targets through them. 😁

Thanks so much. Yes, I was measuring at the edge. That might explain the 20mm/12mm eye relief difference for the XW-85s if the 20mm refers to the design eye relief which will be ~8mm more than the usable eye relief (12mm).

I have no idea how that would work with folks who charge at home using solar panel generated electricity. The chargers themselves would have to have internet connectivity to report home charging for purposes of taxation. This then has the issue of folks living off-grid who don't have internet connectivity.

Has anyone posted a 3/4 image of the top of the 23mm Pentax XW to any thread anywhere? I can't find one. I'm just curious how much the eye lens is recessed from the top of the metal barrel. I've measured my 40mm Pentax XW-R to have at least 7mm of eye lens recession from the lip of the exposed metal barrel once the eye cup is screwed off. Have you measured the eye lens recession with the toothpick method on the 23mm XW? It would be a shame if Pentax did the same with it and wasted 7mm of usable eye relief for no particular reason.

Agreed. Down here in Texas, they're trying to vastly increase yearly electric vehicle registration fees to cover some of the lost fuel tax revenue as a stop-gap measure. As far as the original topic, that 1/4"-20 UNC tripod thread is likely to live on for a very long time due to the sheer number of cameras, tripod heads, and other accessories that use it. It has the inertia of heavily loaded freight train behind it. The changeover from steam to diesel-electric locomotives went quicker than getting rid of this tripod thread for its SI equivalent, whatever it may be.

Unless your Dob tube is a Sonotube or aluminum, then not that useful unless you put a curved steel plate on the inside of the tube.

Just think how high your electrical costs will be when they apply road use taxes to it when EVs become dominant.

My colleague at work rapidly switched from imaging with a ~5" Newtonian and DSLR to imaging with a ~80mm ED refractor and dedicated astro camera and filter wheel. The difference in quality of results is like night and day, with the refractor winning big time. I'm not saying to go the same route. I'm just providing a recent anecdote of someone starting out in astrophotography like yourself.

Just to keep derailing this thread, do Brits go around discussing engine power in kW instead of horsepower? If they do, they kudos for being consistent in using SI units.

Here's a great photo from a CN post showing the difference a UV/IR filter can made for DSO imaging: And here is another image showing how Mars can benefit from an IR-pass filter: