Louis D

I've got a CF tube with some scratches I plan to fill with clearcoat and polish out. What polishes did the manufacturer recommend? There are dedicated CF polish kits out there, but they're not cheap. I've got metal polishing compounds for jewelry, but I'd hesitate to use them on clearcoat paint.

I read that initially as they've been destroyed. Whoops.

You might want to inquire over on Cloudy Nights as well. Being US based, you might have better luck there. There are certainly quite a few Porta-Ball users over here who could help you out. Unfortunately for you, I'm not one of them. As I recall from star parties, it's actually a fairly simple scope to assemble and collimate, so don't be too concerned about the complexity of this undertaking. One odd thing about them is that the primary mirror collimation knobs come up alongside the mirror because the backside of the mirror cell is inaccessible due to the ball construction. BTW, don't be tempted by low ball offers to sell that scope. They are worth many thousands of dollars and are still in demand on the secondary market.

You are correct. I was thinking about that when I wrote that. However, I still found it effective to confirm comet ZTF using that off-spec Zhumell OIII filter. It was the only part of the sky that didn't dim. When attached to the eyepiece, it wasn't as effective because the blinking response wasn't activated in my brain. I could sort of detect it by sweeping past its position in that case. It's similar to how I can't see a camouflaged animal until it moves, then it's obvious.

If you have a long eye relief, low power eyepiece, try the blinking technique with the filter between your eye and the eyepiece. This is how I've been comparing filters for false color reduction on achromats. It's easier to see subtle differences between filters when you rapidly move them in and out of the exit pupil. You can even try stacking filters this way to see if one is more dominant than another. For instance, an HB or OIII should look the same with a UHC stacked ahead of it since the UHC should typically be passing both HB and OIII.

See inline comments.

Doesn't it seem like the 9mm circle should be 50% larger in diameter than the 27mm circle in this ad photo?

Many folks with 127 Maks are trying to get to wider true fields of view rather than higher powers by using Barlows. I switched to a 2" visual back and put a 2" diagonal on mine to massively increase the true field of view by using widest field of view 2" eyepieces. Sure, there is some light falloff beyond the field fully illuminated through the 27mm rear port, but the human eye has difficulty noticing it.

Are these threads under the eyecup? Most of these threads tend to be either M37 or M43, depending on the width of the eyecup. The 30mm UFF is different from most others because it has such a large eye lens. I think it has an M45 thread. Measure the width of the threads with a ruler, and see if it is closer to 37mm or 43mm to figure out which it is.

It's definitely hard to make back your R&D costs on such small production runs. The only reason smartphones are reasonably priced for what they do is because their R&D costs can be amortized over tens of millions to hundreds of millions of units. Imagine what astronomy tech would be like if practically everyone around the world owned astronomy equipment.

You could pick up a ZWO Seestar 50 and have an integrated solution. They are not yet generally available, though.

No one said I can't dream about what I'd like to see for future eyepieces. The OP did ask "what even are we lacking?". Clearly we are lacking an affordable and compact line of light intensification eyepieces.

It also depends on how bright your skies are already. If you're under Bortle 7 and up skies with lots of humidity as I am, about the best you can hope for is to be able to identify the coma amongst the murk by using a comet filter to suppress some of the background sky glow.

I'd like to see an integrated light intensification line of eyepieces at a reasonable price. I know there's EEVA and nightvision stuff, but it's so hodge-podge right now. Some sort of elegant, compact system. I mean, if they can offer that ZWO Seestar 50 for $500, you'd think someone could offer an eyepiece sized light intensification/collection unit for $500 to $1000.

My Zhumell OIII filter is actually right shifted enough that it picks up the Swan bands better than the OIII bands. I used it to help pick out C/2022 E3 (ZTF) in Bortle 7 skies. It was all but impossible to pick out without it. Of course, not every comet is as green as ZTF, so it may have been a special case. You can see below how right shifted the Zhumell is relative to old and new Lumicon OIII filters. If they are all this way (no guarantee), a used one might make for a good poor-man's comet filter.

Eyepieces, binoviewer, Barlows, various correctors, diagonals and any other small, expensive optics go in pick-n-pluck foam cases of various sizes and quality. These blow molded plastic storage cases are tough enough that can be stacked feet deep in the back of a coat closet. Filters go in photography filter wallets for easy access. Finder scopes, both optical and unit power, go bubble wrapped in relatively shallow cardboard boxes. Nothing gets piled on them in the closet, so I don't have to dig for them, and so they don't get crushed. Scopes stay in cases if they came with one. Bigger ones (6" and up) rest vertically in the backs of coat closets. Some with nice finishes are bubble wrapped inside duffle bags. Filter wallets (see above), collimation tools, Allen wrenches, red flashlight, cleaning cloths, laser sights, laser pointers, multi-finder stalks, adapters, spare parts, distance-only observing eyeglasses, compact sky map, and various small random bits and pieces I might need for observing or snapping quick pics go in a large plastic toolbox with a lift out top tray for the smaller, most often used things. Things I rarely need or have retired but not sold or given away are stored in cardboard boxes on a high shelf in my bedroom closet.

You mean like this? 😄 I used massive oversharpening and pumping up the color saturation along with pulling in the highlights side of the histogram. Your rendering is much more reminiscent of how Jupiter looks visually, which is refreshing and pleasing to this visual observer. I think I made it look a bit like an old school webcam video frame capture from the 2000s. Keep up the good work! I look forward to seeing more of your images.

Looks great to me. Nice job!

What have I started with my ruler photos?!?!?

My photographic OCD side kicked in when I saw that picture and decided to see what I could do to clean it up a bit. Here's the result:

So, wouldn't insulating the metal tube outside and inside (with flocking) slow down dewing?

I have a sonotube OTA on my Dob, and I've never had dewing issues like those shown in @Mike Q's image. Does painted "cardboard" dew more slowly than metal?

I'll leave your last question to the imaging experts on here. I only dabble in afocal projection imaging on solar system objects.

The Barlow lens is inserted in the focuser and then the bare camera (no taking lens) is inserted in the Barlow. The magnifying effect is dependent on the focal length of the Barlow and the separation distance between it and the imaging plane. Since Barlows never list their focal length, just know that a 2x Barlow is roughly 2x in magnification if the focal plane is at the top of the Barlow's eyepiece holder. Since the imaging chip will be somewhat to a lot farther back from that plane, the magnification will be higher than 2x. As others are alluding to here, increasing magnification demands increased tracking performance. On bright solar objects like the moon and Jupiter, you can get away with poorer tracking by letting stacking software handle the details of stacking thousands of short exposure images.

You left out telenegative projection which adds a Barlow lens to regular prime focus photography for greater magnification and eyepiece projection where the eyepiece directly projects its image onto the imaging chip (or film for old schoolers). Neither of these use a taking lens on the camera/imager. Afocal projection is what most beginners do first when they hold their phone's camera up to the eyepiece. It is the only technique requiring a taking lens on the camera/imager to form the final image.