Louis D

You may need to put silicone bumper feet on your finder base's corners to keep it from rocking on the small diameter focuser. I had to do this with my QuikFinder base.

I forgot to add this thought of mine on uniformed individuals like my kids: It should scare us informed voters that many, if not most, voters are completely uninformed or worse, misinformed, on most topics, and yet they choose our representatives via their votes.

My grown kids don't watch TV except to stream Netflix and such. They don't watch the news because it makes them upset. Better to be uninformed and happy than informed and unhappy is their mantra I guess.

I only use long eye relief eyepieces and always wear eyeglasses, so I only clean my eye lenses once every decade or so. I just went through a thorough cleaning of them last summer. I just use the edge of a microfiber cloth to lightly flick away any loose particles. I find Windex on a clean cotton cloth works best to remove stuck on tree sap dots, my main problem. I then use a dry microfiber cloth to buff out any remaining streaks. I sometimes turn the eyepiece upside down and huff moisture upward onto the eye lens to facilitate wiping away the last streaks. I've used this same technique for 40+ years of cleaning camera lenses as well without any issues.

I totally get the spikes as well until it acclimates. I was a bit shocked at first, but I gave it some time, and they settled down. If you were still seeing them hours in, then yes, you had a bad sample. Visually, I haven't seen any CA in focus. It's kind of blue-green on one side of best focus and sort of red on the other. That too, was a shock to someone who had always used reflectors where there's no color on either side of best focus.

If you know of a better APO consistently coming out of China, I'd like to know so I can recommend them. I will admit I forgot to mention Long-Perng's APOs which are also pretty decent. If your budget stretches to $5000 or more, TEC and AP make excellent APOs. I'm sure Europe has some fine locally made APOs as well, for a price.

I have no doubt those ebay laser sights are way over 5mW. They tend to be brighter than pen lasers. That, and they burn through large lithium ion batteries. It does make them easier to follow into the sky, though. All that and the unfiltered IR is why I won't use them at outreach events. They're just too dangerous for casual use.

The Luminos are not well known for outer field sharpness. They are also known for edge of field brightening (EOFB) where the outer field looks slightly brighter than the axial part. I would recommend the BST Starguider (Paradigm, etc) 5mm for a starter. At 60 degrees AFOV and 12mm of usable eye relief, it will feel like a massive improvement over the 6mm Plossl for not a lot more money. It's also only 6.8 ounces, so pretty light and compact. I also find it to be quite sharp across the field with no blackout issues.

I get spiky stars with my triplet for the first 30 minutes or so at high powers, then it settles down. Despite it claiming to have a temperature compensated lens cell, I have my doubts.

I would err toward an FPL-53 doublet over an FPL-51 triplet. The correction is about the same, but the former is lighter and acclimates more quickly. I spent $900 used a couple of years ago on a TS-Optics Photoline 90mm f/6.6 FPL-53 APO triplet. It takes 30 minutes to acclimate, so that part is a bit annoying. Otherwise, the images and mechanics are superb. It's made by Sharpstar in China which has been churning out just about the best APOs lately from there. The KUOs are about the same quality level, and both are well ahead of Synta mechanically. My point is, educate yourself on what you want to buy as you are doing here and then watch the classifieds and jump on one when it comes up used.

Don't mess with the three grub screws around the perimeter of the focuser. Those control focuser rotation tension as vlaiv says above. It is the larger holes you want to use as vlaiv says above. One for fixed orientation, one for rotation with the focuser. I have no idea why you would want to put a finder scope on it. Get a 2" diagonal and a 35mm to 40mm widest field 2" eyepiece, and you've got an 11x to 12x, 6+ degree finder scope built in. I do use one of the two holes to attach a Rigel QuikFinder foot to it. That does make sense. I have the Astro-Tech AT72ED version of that scope. I've attached the manual for it below. Astro-Tech 72ED.pdf

Multiple vendors in the US report them as being discontinued. Last price was $169. I think the Chinese made 8-24mm knockoffs pushed them out of the market.

Try removing the four screws holding the rack against the pinion. That should allow you to remove the pinion and then slide the focuser tube out. You may want to remove the focuser from the tube for the next step as well via the three screws attaching it. Clean out all the gunk out with carburetor degreaser spray or similar on both the focuser body and focuser tube. Relube it with white lithium grease. Reassemble everything in reverse order and adjust the four pinion screws to achieve the focuser tension you like. You may also need to verify that your focuser is aligned with the optical axis. A laser collimator in the focuser tube is pretty effective for this. You just need to ensure the laser beam exits the dead center of the objective. There are other methods, obviously, but I'm not familiar with them. You just loosen the three screws slightly and gently adjust the focuser's aim. Tighten them when you're satisfied you're realigned.

Has the wife ever noticed it in there? I know I can obscure new items in my garage pretty easily because it's rather cluttered.

Then post images of what you've got and we can all take a swing at trying to figure it out. Often times, the barrel and retaining rings dictate the order. Double convex lenses can be troublesome when they're almost, but not quite, symmetric and can fit in either direction. Sometimes, the negative field lens can be flipped as well as everything still fits.

More than likely by the looks of it. At least Orion didn't double the price like they usually do with their rebrandings.

Get a used Tectron Dob that collapses into a single, closed cube shape and can be used as an end table.

I bought another branding of that scope for $24 shipped last March off of ebay. I've converted it into a 70mm superfinder with a 2" visual back for widest field views (9 degrees with a 40mm Pentax XW at 7.5x). It uses 0.965" eyepieces, not 1.25" eyepieces. Check the insertion barrel diameter of the supplied eyepieces on yours. I has a ~35mm aperture stop just behind the 70mm objective, probably to improve image quality on such a fast objective. I removed both the focuser and objective cell (three screws hold each in place) and used a small block of wood to push the stop out of the front of the tube. It's just held in place by friction. I then reblackened the interior because it got all scratched up by the plate being pushed out. The focuser tube itself has another 50% by diameter aperture baffle that can't be easily removed, so buying wider field eyepieces may be of little use because they'll just vignette. All that said, it makes a decent, low power spotting scope as delivered. As I've redesigned it, it makes for an astoundingly good wide field finder. It came with a pretty decently corrected 70mm f/4.3 achromatic doublet and metal tube that was worth the $24 alone.

The WO 1.25" diagonals have a constriction in the eyepiece receiver that causes vignetting for widest field 1.25" eyepieces. I have one I use with my binoviewer (22mm clear aperture, so doesn't impact me), so I can confirm this constriction. I use GSO/Revelation 2" diagonals with my refractors and even my 127 Mak with a 2" visual back. They allow me to use my extensive collection of 2" eyepieces in them.

I suppose you could use ultra narrowband filters to block most light pollution. They would allow you to do fairly decent nebula photography. They don't come cheap, though. Astrodon - 1.25'' Mounted OIII 3nm Narrowband Filter Astrodon - 1.25" Mounted Narrowband H-Alpha 3 nm Filter Astrodon - 1.25" Mounted Narrowband NII 3 nm Filter Astrodon - 1.25" Mounted Narrowband SII 3 nm Filter

Check the following diagram to see if the shapes match your lenses:

I can't resolve the smaller/farther away GCs either in an 8" Dob.

I also do that with pick&pluck foam to prop up shorter eyepieces. I just shove some plucked pieces into the bottom of the hole.

I use a GSO/TPO/Revelation coma corrector with a 25mm spacer ring between the eyepiece holder and the optics section. As long as your eyepieces focus within 5mm of their shoulder in that configuration, at least 90% of the coma will be corrected along with flattening the field slightly. It appears to be currently unavailable in the UK in any branding.

Back in 1998 when I bought my 8" Dob, it came with no eyepieces. I bought a 2" 38mm Rini MPL from the seller as a "finder" eyepiece, a 14mm Pentax XL for mid-range power, a 9mm Vixen LV for a bit more power, and a 5.2mm Pentax XL for highest power. With my strong astigmatism, I had to buy long eye relief eyepieces, and the only options back then were the XL, LV, and LVW lines. The XLs were $240 back in '98, which is about $390 apiece today.