Louis D

How do you avoid bursting pipes? Here in Texas during Snowmageddon 2021, without power to run furnaces, many houses ended up with burst pipes in the walls, ceilings, and floors. Do you folks rarely go below freezing in the winter despite being at 53°N?

Being that Artemis is in the US, and having been bombarded by the following TV commercials a few years back, I'd recommend Flex Seal or Flex Tape for the job: 😁

Just keep an eye on the wood through which the metal rod passes. It can split, dumping you on the ground:

Those feet will also be great to keep it from sinking into soft soil.

Here is Ernest in Russia's testing/review of the entire line as the Levenhuk Ra.

Absolutely with the 5 1/4" ones. There were square hole punches that worked very well for this purpose.

Just saying, when I take a statistical cross section of an observing field of dozens of scopes of all types, and the SCTs are putting up the least pleasing images regardless of aperture, I'm going to blame the design. After attending multiple public star parties in the 90s, it was clear enough to me that I took a hard pass on buying an SCT and instead bought a Dob (Newtonian). A Dob simply wasn't what I thought of as a desirable telescope as a newbie (big, dumpy, awkward, undriven, yard cannon, etc.), but multiple comparisons over several years lead me to that decision. I'm still using that scope 24 years later on a regular basis. I've since added an achromat, an ED, an APO, a big Dob, and a Mak, but I still love that midsized Dob all these years later. Other than an EdgeHD, I haven't seriously considered getting an SCT of any size in those 20+ years.

Stars don't focus to pinpoints. They're a bit bloated at best focus compared to the view through a refractor or Newt under the same conditions. Planets don't manifest much distinct detail as compared to other designs. This SCT mushiness becomes painfully obvious at star parties if you take the time to walk around the observing field and check out the views through a multitude of scopes all dealing with the same conditions. There's simply no way every SCT is out of collimation when so many advanced observers are about. Only the Edge HD design has shown sharp images rivaling Newts and refractors in my experience. As such, I'm going to chalk the mushiness up to uncorrected spherical and other aberrations in a standard SCT.

Well, you are working with a 1.3mm exit pupil, which is fairly small, but certainly not very small. Try looking at the aerial image without an eyepiece as you did before and see how dim the telephone pole looks. I just had a funny thought. The upcoming generation of kids will one day ask why they're called telephone poles when they mostly carry electricity or perhaps broadband lines. It's funny to see them try to dial a rotary phone in a period school play. My daughter was doing just that 10 years back in a high school play. She dialed the number and then picked up the receiver! Us oldies in the audience stifled our chortles as best as we could.

Same here in our part of Texas. Locally quarried white limestone from an ancient inland seabed is a very popular as an exterior cladding:

Shorty Barlows don't have to be bad. The 1990s Japanese made Celestron Ultima, Orion Shorty Plus, Parks Gold Series 2x Barlow is a very good shorty Barlow. It uses 3 elements and seems to work about as well as my TV 2x and Meade 140 2x. On the other hand, I have a generic shorty Barlow from the early/mid 2000s that is so bad (adds fuzziness to image), a guy I permanently loaned it to insisted on giving it back to me after 6 months of use. 🤣

That US flag on the USD side above looks more like the Chilean flag which is often confused with the Texas flag: Chile: Texas:

At 60mm and f/15, it should be basically apochromatic:

I wonder if there was an equally long and skinny extension tube that originally came with it? You can locate the focus point by lining it up on the moon as you did before and then hold a thin, white sheet of paper behind the focuser, noting the distance where the image is sharpest on the paper.

Since they're all made by KUO, they should all be optically identical. There's an extensive thread on the Astro-Tech version of the 28mm on CN.

I've always assumed most of these commercial Dobs glue their secondaries onto the holder since there isn't a proper lipped holder as with the Astrosystems secondary holder: I seriously doubt these commercial builders drill a threaded hole in the back of the mirror for a bolt to thread into. That's the only other way I could conceive of attaching the secondary mirror without a lip or clips.

I hadn't thought about it, but I do use the arm rests on my plastic patio chair to steady myself while observing. I would sorely miss it with a perch style chair.

I would lean toward either the GSO made StellaLyra 8" f/6 Dobsonian for features or the JOC made Bresser Messier 8" Dobsonian for its mechanics. The latter's focuser can be upgraded later to dual speed if desired. These two and the Synta made Sky-Watcher Classic 200P Dobsonian are all going to be similar optically.

Yes, the old R&P focusers slopped all over the place. You can wedge plastic milk jug shims into them sometimes to reduce the slop by making them a bit more Crayford like.

Looks ready for a night launch. 😉

The problem as I understand it with the Synta focuser is that it is not natively 2" without either tall adapter, so you can't use a stock, low profile 2" to 1.25" adapter. It's a bit larger: Does anyone make low profile versions of these Synta adapters? The Lumicon Low Profile 2 Inch Prime Focus Adapter almost looks correct if you need a male T2 thread:

OMG, yes. Those Synta eyepiece adapters are atrocious. The whole point of having the focus point so far outside the tube is to facilitate astrophotography, but you can't take advantage of it with their focuser setup. If they went with a low profile focuser from the factory and moved the focus position in closer to the tube to exclude AP, they could shrink the secondary size and improve visual contrast. As it is, they've got the worst of both worlds with the current focuser. Poorer visual contrast and lack of AP backfocus.

CATs vs cats. Nothing against the former (I've got a 127 Mak), and nothing against the latter as long as it's not living in my house or yard. 😉

I've got eyepieces that require over 20mm more infocus than I have even with a low profile Newt focuser. My solution is to screw the optics section of my GSO coma corrector directly onto the end of the eyepiece and send it deep into the focuser that way. The CC grabs the incoming light cone sort of like a relay lens and sends it up to the eyepiece where it can then reach focus. The CC correction isn't perfect, but neither is the eyepiece I'm using it with. Maybe you could do something similar with a GPC/Barlow element screwed directly to the bottom of the ADC?

OMG, rental photo equipment is often battered beyond belief by professional photographers. I only buy used photo equipment from novices who have barely used their equipment and need quick cash.