Louis D

I captured some images with the field flattened AT72ED while using the following eyepieces: Meade 5000 Plossl 40mm: 61° AFOV, 27mm of usable eye relief, and a 43mm diameter eye lens Agena UWA 80° 30mm: 81° AFOV, 18mm of usable eye relief, and a 38mm diameter eye lens Meade Silvertop Plossl 9mm: 48° AFOV, 5mm of usable eye relief, and an 8mm diameter eye lens I chose them because the first two have long eye relief and large eye lenses while the last has short eye relief and a small eye lens, and they present a range of AFOVs from 48° to 81°. I took the images with my trusty Samsung Galaxy S7 and with a Canon Rebel T3i (600D) mounting Olympus Zuiko 21mm f3.5, Olympus Zuiko 50mm f1.4, Sigma 50mm f1.4 EX DG HSM, Vivitar Series 1 90mm Macro f2.5 (otherwise known as the Bokina lens), and Canon 18-135mm at 18mm/f3.5 lenses. I chose them because the phone represents the baseline I've taken most of my eyepiece AFOV images with, the 21mm is fairly fast while being quite compact, the Zuiko 50mm is fast and compact but a bit poorly corrected, the Sigma 50mm is fast, bulky, and very sharp, the Vivitar is considered one of the finest macro lenses ever produced (though there is a bit of purple abberation at f2.5), and the Canon zoom because it's my everyday lens on the DSLR. Below are the images grouped by eyepiece. The Vivitar produced too much image scale with the 9mm Plossl, so I substituted the zoom at the very end. I was a bit too tired at that point to go back and use it with the other two eyepieces for reference. If you select them and view at full resolution, you are getting the exact resolution I was getting for each image. There was no resampling. Capturing edge images was a royal pain. After capturing all these images, I wasn't quite sure what I was supposed to be looking for, so I @vlaiv will look at them tell me if they reveal anything. I know I much prefer capturing the entire image in one go with the camera's phone. It's quick, easy, and very repeatable.

Well, if you weren't paying rental fees on the unit all those years, consider the losses as payment toward unpaid rental fees. It might have been the owner pilfering the cream of the crop on you. If you were paying rental fees, the owner had no right to change the lock, and you've probably got a legal case against them.

Welcome to SGL. I remember when I was about 6 years old that I first wanted to be an astronomer and then a paleontologist as well. I guess it comes with that particular age. Now that I've taken up astronomy in my later years, I guess it's about time for me to take up paleontology next. 😉

Search for "wheeley bars" and "scope buggy" for off the shelf solutions.

You could build a wheeled dolly out of wood and caster wheels, and then put cups for each tripod foot on it spaced appropriately. Next, tighten cargo straps or heavy duty bungee cords down from the center of the tripod to hold the tripod firmly to the platform. If the whole thing still seems top heavy and tipsy, put a 40 pound bag of sand or steel plates around the center of the platform to move the center of gravity lower. You can even add corner jacks to avoid lifting the tripod off the dolly.

With its M43 eye cup thread, you could probably add a Morpheus eye cup extender and M43 threaded eye cup if that became an issue.

I bought one of these off of ebay to allow for a 9x50 RACI, RDF/QuikFinder, and GLP to all be mounted simultaneously in the single finder foot. They're quite sturdy and allow the RACI to almost be mounted in line with the altitude axis which is best for balancing purposes.

Vendor thread on CN about APM zoom eyepiece 7.7mm-15.4mm , 75° Constant FOV. CN discussion thread about it in eyepieces forum. Basically, it's still in development by Markus Ludes and his Chinese counterparts. They're trying to finalize the ergonomics of the design it seems. The optical design seems pretty stable.

For fun to change things up. I love the enormous eye lenses and long eye relief of my giant 2" eyepieces when wearing eyeglasses. It's very relaxing to use them because I don't have to touch the top of the eyepiece with my eyeglasses to take in the entire FOV. It's nice to use them at a larger image scale once in a while with a telecentric Barlow/magnifier. Don't use a non-telecentric 2" Barlow with widest field 2" eyepieces. They'll hard vignette ruining the whole experience.

It is if you're an American. It's basically voluntary to pay sales tax on imported items (except through ebay and other onine marketplaces). We never pay VAT on imported items, and the sellers don't have to collect American sales tax, so the sales are basically tax free unless we voluntarily remit sales tax to our governing authority. I guess Americans buy so little via direct imports that the taxing authorities can't justify creating a bureaucracy to collect it. That, and any items under $800 are duty free. As such, it's often cheaper for me to buy items from the UK/Europe/Australia/Japan and ship them here than it is to buy them locally. Returns are a pain, though, if anything goes wrong. I've noticed that UK/Euro prices are competitive with US pre-tax prices even with the ~20% hidden VAT included. That's what makes them so cheap when cross-importing because VAT goes away and nothing else gets added.

Get a 50mm RACI finder. The field of view of 127 Maks is insanely narrow. The finder will help you get your bearings after putting the scope on target using a RDF or Telrad/QuikFinder.

No, I don't own one. I did try my green Optica b/c line filter without any additional ND or polarizing filtration because the line filter cuts out so much light. I didn't spend a whole lot of time with them, but I didn't notice any "Aha!" moments with any of them. I did buy a SVBONY ND3 filter to put on the eyepiece. It almost makes the image too dark. I guess an ND2 filter would be about right if I could find such a thing. I'll go back to using the included variable polarizing filter for now. If I set it to about ND2 and then rotate the eyepiece, I can get additional polarization due to the polarization effect of the wedge itself on the incoming light. I put a UV/IR cut filter on the front of the wedge and didn't notice any particular heating of it when I removed the wedge. It reflects rejected wavelengths rather than absorbing them, so I think that helps prevent heating. Optica b/c line filters from their 1978 catalog. The band-passes are labelled violet, blue, green, yellow, orange, and red (from left to right in the diagram below) on the filters themselves.

Nice work @vlaiv. Your next experiment is to confirm if eyepiece aberrations are reduced when using the phone camera versus the DSLR lens. I theorize there is no difference because the eyepiece sees only the telescope and the camera lens can't undue aberrations once introduced into the image train regardless of combined working f-ratio. I will admit that the enormous depth of field of wide angle phone cameras will compensate for image field curvature. In particular, the 30mm WideScan clone eyepiece has tremendous field curvature to my presbyopic eyes, but it looks really nice in a phone camera image. It's the Agena UWA 80° 30mm below. Notice how readable the rulers remain so close to the field stop. When viewing with my eyes, those edge images were a blurry mess until I refocused for the edge. As such, you cannot judge field curvature of eyepieces using these phone camera images. Your f/1.4 image would probably reveal how it really should look to the human presbyopic eye. Notice how the strong astigmatism in the Rini MPL 29mm and chromatic aberration in the Kasai Super WideVue 90° remain even in the phone camera images? No improvement. That's pretty much what my eye saw through each eyepiece.

Another option would have been to try and locate a used 18mm Meade 5000 UWA in 1.25" barrel to get the widest field possible at about the same exit pupil as the 16mm ES-68.

Same for registered individuals/businesses who collect sales tax on new items as well as used items. However, ebay and other online peer to peer marketplaces are now collecting sales tax on all sales, foreign and domestic, by registered and unregistered sellers. Is this happening with VAT as well in the UK?

You asked.

Hidden VAT is not an issue in the US. Prices are always listed before sales tax is added. Keep that in mind when comparing US to UK astro prices. That might explain why some folks in the UK price their used gear significantly higher than Americans even when exchange rates are accounted for. Are UK individuals (sellers or buyers) required to collect/remit VAT on used gear sales? Technically, individual American buyers are supposed to remit the appropriate sales tax on items bought from other individuals or from overseas sellers, but literally no one does this, and there is no enforcement effort anywhere except for private used car sales. Sales tax in that situation is paid when and where the vehicle is registered. Gasoline, cigarette, and liquor excise taxes are hidden, though. I find it interesting that most other countries hide their consumption tax.

Perhaps not the highest power, but often thought of as among the nicest large binoculars, the Fujinon LB150 Series – 25×150 MT-SX Binoculars: APM in Germany sells all sorts of giant binoculars including several variants of this Fujinon if that sort of thing interests you. If you like looking at pictures of giant binos of the past and present, here's a page full of them at Oberwerk.

And pull out your cellphone/smartphone (UK mobile?) camera for comparison shots with each eyepiece.

If I see something expensive I want, but can wait on buying, I'll let it sit on CN classifieds for 2 or 3 weeks and make an offer for about 80% of their asking price. We generally move toward 90% of asking price, but I insist they eat the PP and S&H fees at that price. I end up saving hundreds of dollars in those cases.

Check out my first look of the SVBONY 68° Ultra Wide Angle 20mm eyepiece:

Based on a recent comment by another SGL user that the SVBONY 68° Ultra Wide Angle 20mm eyepiece was sharp and gives very clear images in an f/6 Dob, I thought I'd get one to try out in my field flattened f/6 AT72ED refractor to see if somehow this repackaged $30 eyepiece is working some kind of miracle at that price point. I measured it to have a 67° AFOV, a 68° effective AFOV (eAFOV) due to slight edge distortion, a 23.7mm field stop, 14mm of usable eye relief, a 24mm diameter eye lens, and 3.1 ounces (88g) in weight. As such, it lives up to the ad for the most part. Since it has been raining almost constantly here for the past 4 weeks, I haven't been able to get out and observe at all. I think the night skies cleared up by early morning once during that time. As a result, I'm constrained to indoor testing for now. It's a bit shy on eye relief for me when wearing eye glasses. I need about 2mm to 3mm more eye relief to see the entire field comfortably. However, I would estimate I can see about 80% of the field while wearing eyeglasses. It's easy enough to tip my head slightly to take in the edges. The eye cup snaps up and down with relative ease, and yet it stays up when used without eyeglasses. It's very similar to many budget Plossl eye cups. The center appears to be sharp, but the edge sharpness falls off noticeably in the last 25% of the field. Refocusing did not improve things, so it appears to have a flat field insofar as I can tell in an f/6 field flattened scope. I'm guessing astigmatism is the primary cause of edge unsharpness since I didn't see any appreciable chromatic smearing. It is not sharp edge to edge at f/6, but it is pretty sharp over the central 67% (45°) of the AFOV. As such, it performs as well as a 20mm Plossl while providing more context. Here's a couple of group beauty shots of the SVBONY alongside its more expensive competitors. It certainly is a handsome looking eyepiece in gloss black, textured grip ring, engraved white lettering, and snazzy red anodized beauty rings. It's much nicer looking than the earlier incarnations of this line of eyepieces such as the Orion Expanse and other 66° UWA variants. It looks much more expensive than it's price tag would suggest. It's also very compact for what it does. It's fairly dense, though. I was surprised by its heft in my hand. Here's the updated 18mm to 22mm comparison image taken through the eyepiece of my standardized rulers target. I've included the original eyepiece group shot for context. I didn't feel like digging out all the other eyepieces to reshoot it. Just imagine the new SVBONY slotted between the generic reversed Kellner and the Orion Centering SWA eyepieces. As can be seen above, the SVBONY holds its sharpness farther off axis than the 20mm Orion Centering SWA, but it is not as wide in AFOV or TFOV. It also has 3mm more usable eye relief which is quite noticeable. I did not notice any SAEP kidney beaning in daytime usage. The view is quite easy to acquire and hold. It is head and shoulders better than the 20mm generic reversed Kellner in all respects except for physical size. The SS zoom is incredibly sharp at 21.5mm, but also incredibly narrow in AFOV and short on eye relief (11mm). Since the SVBONY can't zoom, it's not a relevant comparison. It performs slightly better off axis than the 19mm GR Konig, but it is only marginally wider in AFOV. I think the SVBONY is likely an improved Konig variant based on tear downs of the 20mm Expanse I've seen on CN. There's a slight chance this version has been redesigned, but I'm not disassembling mine to find out. Both the 18mm Meade HD-60 and AT Paradigm (BST Starguider) hold their sharpness better to the edge, but both have noticeably narrower AFOVs. The HD-60 also wins out on usable eye relief at 19mm versus only 12mm for the Paradigm. The 22mm AT AF70 holds its sharpness much farther off axis and is slightly wider in AFOV. It also has more usable eye relief (16mm that feels more like 18mm in use). It isn't much of a surprise it's better given how much bigger and more expensive it is. And of course the 22mm Nagler T4 rules them all for sharpness and AFOV width, but at a significant size, weight, and price premium. It's also a bit tight on usable eye relief at 14mm, although it feels like 16mm in use. Once I get some time under the stars with it, I'll report back. If I like it enough, I may get another for binoviewer usage.

It is optically the same as the 24mm ES-68. However, it has better eye relief due to the eye lens being less recessed.

Actually, they're quickly cut down by crews of unregistered immigrants working for cash. Grind the stump, and there's little evidence of what happened.

A nearby city has an ordinance protecting trees with trunks greater than 19 inches in diameter at 4.5 feet off the ground from being cut down without council approval even if dead. Generally, they require them to be moved if they impede construction. This can cost $125,000 to $250,000 per tree and take weeks of preparation.