Louis D

If you can see the rings of Jupiter from Earth with any telescope, you'll be miles ahead of pretty much any ground based scopes. They weren't even discovered until 1979 when the Voyager 1 spacecraft passed by Jupiter.

Sure, buy a bigger scope and observe from more stable skies if you want to get more magnification and thus more detail. A short f-ratio 102mm achromat is never going to show you Jupiter in lots of detail. Even a with a 102mm APO, it takes time to pick out subtle details in the bands. With a suitable eyepiece though, you should be able to see at least one band on Jupiter with that scope. I've done it with both one of those 76mm f/4 Newtonians with a spherical primary mirror and a Plossl eyepiece (though I don't recall the focal length of it) and with a short tube 80mm achromat with a Plossl eyepiece, so your 102mm achromat should be able to manage it. I suspect your 10mm eyepiece is the weakest link and needs upgraded. A quick fix your scope's chromatic aberration would be to get a 1.25" Yellow #8 filter to cut out the violet-blue fringing. If that doesn't help, try a 1.25" light green #56 filter to cut out both the blue and red ends of the spectrum.

The TS-Optics version of the AT72EDII, the TS-Optics Doublet SD Apo 72 mm f/6 - FPL53, recommends the TSFLAT72.

Toric lenses work for some folks, but not others, for astronomy observing. They are weighted at the bottom by making them thicker so they will rotate to the correct position for astigmatism correction when looking horizontally. The problem arises when looking mostly downward into an eyepiece. The contact lens will then start to rotate out of best correction position for some people because gravity is acting on the lens as a whole to pull it off of the eye. I haven't tried contacts at all, myself. I get pinkeye infections far too easily without them whenever I get a head cold.

I generally don't insert Barlows all the way into the focuser to avoid racking the focuser out so much. Of course, this assumes the Barlow is long enough to allow this to work. Focal extenders are just the opposite. They need lots of in-focus to work. As such, many focusers can't be racked in far enough to reach focus with them.

I know 25585 (Richard?) really likes his as well. He's only active over on CN now.

I finally compared my new 2.5mm TMB Planetary clone to my 3.5mm Pentax XW and 2x Barlowed 5.2mm Pentax XL on the moon last weekend. I used my sharpest Barlow, a 1990s 1.25" Orion Deluxe 2x from Japan in my 6" f/5 Newtonian. It's about 6 inches long, so it very gently diverges the light cone limiting aberrations. That, and it has at least one baffle to limit stray light. Sorry, I forgot to mention I was using a new to me GSO 6" f/5 Newtonian with their dual speed focuser. It was mounted on my DSV-2B. I kept the coma corrector out of the optical train to limit introduced spherical aberration on axis. The views were probably best with the 5.2mm XL by itself, followed by the 3.5mm XW just due to the ever tinier exit pupils involved. However, at about 2.5mm, the Barlowed Pentax XL was a bit sharper and contrastier, but not by much. The bigger difference was the 5.2mm XL's wider AFOV and much longer eye relief that made using it even without eyeglasses much more enjoyable and relaxing than using the TMB clone. Of course, the Barlowed XL was way fatter, longer, heavier, and more expensive than the TMB clone. For the money, the 2.5mm TMB is a really good deal for a rarely used focal length. I seriously doubt I'll use it much going forward, but it made for an interesting learning experience. It reinforced my view that 1mm is about the smallest exit pupil I can comfortably use for any significant length of time.

Tried it out this weekend splayed out almost to the max so I could sit in a stackable patio chair while viewing through the eyepiece of my GSO 6" f/5 Newtonian on my DSV-2B mount. It worked great. I did have to put vibration suppression pads under each foot; but once I did, it was rock solid with no vibrations at all. If you look for used Bogen 3051/3251 or 3033/3036 tripods, you can save a bundle. I picked up a used 3033 for my daughter's camping kit off of ebay for $75 in absolutely new condition 3 years ago. It had been used to shoot a corporate video years ago, and then was stored and forgotten for over a couple of decades.

Same thing with the AT72ED. I mounted an 8" dovetail bar to the mounting foot. To reach balance with 2" eyepieces requires clamping the bar just about even with the focuser knobs.

Not so much in the US. Without sales tax, the SW 72ED ranges in price from $400 to $540 while the Astro-Tech AT72EDII FPL-53 is $489. For comparison, the Astro-Tech AT70ED is $329. It is the closest successor to my AT72ED. The TS-Optics 70 mm F6 ED is identical and priced at €318.49 excluding VAT. Both brandings have an R&P focuser.

I have the 127 Mak as well, and the 72ED is way more of a G&G scope thanks to its wide field of view, lighter weight, and more compact size. I'm not sure the 127 Mak would be much of an improvement over the 102ED that the OP wants to replace, other than being shorter. The 90 or 102 Maks might work for the OP based on weight and size, though.

It need not be any thicker than the eyepiece barrel thickness which is at most 1mm. Kept at that width/thickness, it would not contribute to vignetting. The SW/WO diagonals go with at least a 3mm lip, which is completely unnecessary. I have a 1.25" WO diagonal with just as thick a lip, and the vignetting in a 32mm Plossl is quite noticeable.

Good report. A little disappointed to hear that even with a Dioptrx you can't see the entire FOV. BTW, did KUO ever send your test Dioptrx back to you? I'm surprised you needed only 8mm of additional in-focus in 1.25" mode. Looking at the diagram below, I figured it to be much more than that. The diagram showed it would be closer to 32mm inward from the 1.25" shoulder, or 24mm inward of the 2" focus position. Did the housing get significantly changed or did the focus point end up somewhere between the 1.25" and 2" shoulders instead of 8mm above the 2" shoulder?

I've had an Astro-Tech 72ED for quite a few years now. It's a great grab and go scope. Even though it will accept 2" eyepieces, I've had trouble with heavier ones causing the focuser tube to slip as you approach zenith. I've tried increasing the loading tension, but it still slips. I'd recommend an R&P focuser if possible. I've read that the SW 72ED focuser has rather limited travel and can cause problems when using a 2" diagonal. The AT 72ED (from Long-Perng, I believe) doesn't have this issue with its long travel focuser. Visually, it doesn't show false color except above 100x. Even then, it's a mild violet that could be filtered with a weak yellow filter if it bothers you. Both it and the SW have FPL-51 equivalent glass. Overall, it's a fun scope for low to mid power viewing. It can also be used up to about 125x without too many false color issues. If you can stretch your budget, I'd probably get the TS-Optics Photoline 72mm Doublet APO or Astro-Tech AT72EDII FPL-53 if starting from scratch. These would have better color correction, better R&P focuser, and better rail attachment.

Check to see if your SW diagonal has a restrictor ring at the bottom of the eyepiece holder tube. If it does, I'd make sure any replacement does not have one. I know the GSO made 2" dielectrics do not have this issue.

It's a Celestron Regal Zoom 8-24mm that has had the original eye cup screwed off and replaced with some aftermarket bits and pieces. It was sold with Celestron Regal spotting scopes. I've measured the actual focal lengths to be 8.2mm to 21.2mm. It's step up from the standard Celestron 8-24mm zoom, but not quite as good as the Baader Hyperion Zoom. The biggest issue for astro usage is that there are no filter threads. The lower lens group goes right to the end of the barrel at one end of the zoom range. Here's some photos of mine. The upper two are from a 65mm spotting scope. The bottom one was the version sold à la carte with markings for all three spotting scope sizes. Yours must have been sold with a 100mm spotting scope.

Same with the 30mm 80 degree WideScan III clones. It has horrible field curvature leaving the outer 50% blurry. However, the central 50% is pin sharp. It's noticeably sharper than the 30mm ES-82 in that area. By over-correcting refractor field curvature, I discovered it actually has fairly low astigmatism in the outer 50%. If it was sold with a field flattening group ahead of the field stop, it would be a real contender.

Zero. Covered under the $800 personal de minimis exemption. I can't help it if other countries don't reciprocate.

That makes it $110 cheaper than buying it in the US. Add in the fact FLO doesn't charge state sales tax, and you save even more.

Blue/violet color fringing is classic achromat chromatic aberration. Observing at higher powers will reveal it more clearly. As for why the MA looks worse at night, stars are the absolute acid test of optics. Any aberration anywhere in the field will be seen with stars. Even aberrations in your observing eye will be seen. Extended objects seen in the daytime are much more forgiving than stars because your brain is forgiving of blurred objects, but not of aberrated stars.

The venerable 60mm slow achromat was THE go-to Christmas gift telescope for decades. Back in the day, the mounts supplied with them were a bit better than today's mounts (vintage scopes came with a cast iron head and hardwood legs). The scope isn't the issue with a 60mm f/11 achro, it's the mount they come with nowadays. They typically can't handle the long moment arm. The fact that little kids have great difficulty hovering over an eyepiece and keeping their hands off the scope and mount when observing tends to doom these scopes today. They go off target at the slightest touch and/or shake incessantly long when touched. Focusing and nudge tracking become aggravating in a hurry.

Make sure to consider size, weight, and transportability for both camping and backyard use.

Wow, someone is asking £70 for one which almost the new price when VAT is removed (£74). Unless that person is collecting VAT, that is ridiculous. In the US, we always price used equipment against the new, without tax, price.

Mostly for resolving globular clusters like M22 and M13 at 200x and above. Much below that, and they just look like a fuzzy spot.

I haven't found a grill cover that lasts more than a season or two under our hot Texas sun, hail, high winds, deluging rain, ice storms, etc. I just bought a 100% heavy gauge stainless steel grill so I don't need to worry about covering it. As such, I would never leave any astro equipment outdoors here under any soft cover all season long. Perhaps at a star party during the day, but that's it.