Louis D

Are you observing sitting down? I can't observe standing up at all. I weave and bob about too much.

Try a #56 green. I preferred the lighter green image of it over the darker #58 for solar viewing.

It could have been spherical aberration and poor glass quality/polish in the 120 killing detail and contrast. Well figured, high quality achromats of 120mm can be quite expensive just for the objective and cell.

Nope, that's a poorer quality Chinese made Barlow. FLO's is a GSO Barlow made in Taiwan.

A fellow stargazer had a couple of these scopes setup on a table near his main scopes at an outreach program. He was letting anyone use them as they pleased since he picked them up used for $20 or less each. The hardest part was aiming them since they were low on a table and the table got in the way of getting in the right spot to aim them with the RDF. I came over and aimed them at Jupiter by shooting from the hip, so to speak. Once I got them on Jupiter, it was obvious that an f/4 spherical mirror is pretty abysmal beyond the inner 50% of a mid-power eyepiece. Right in the center, I could make out Jupiter's moons and maybe a belt. The general public enjoyed the views through them once I got them on target. However, I understood why these show up so often on Craigslist, FB Marketplace, and in thrift shops for cheap.

I had been intrigued by the TMB Paragon 40mm for quite some time now based on many favorable reports both on here and on CN by experienced observers. However, every unauthorized rebranding of it had been sold out for quite a few years, until this June. When I saw @badhex's post below, I realized a new batch had been ordered from the factory by Lacerta and could be bought new from European retailers: I did my research and ordered one from Europe within a week. It arrived 5 days later, so not bad for crossing the Atlantic. Being VAT and sales tax free (as well as tariff free being from Europe and under $800) helped pay for the stiff shipping fees. First Impressions It arrived in a plain black box so many eyepieces are being shipped in recently, except that it didn't have any white end label identifying what's inside. The foam appeared a bit old. I'm wondering if they did a huge production run of these a decade or more ago, and put them on a shelf just waiting to be marked with a brand name when a new order comes in. The actual rubber parts of the eyepiece don't seem old, though. However, the rubber band holding the inner eyepiece bag shut was getting a bit gooey and brittle and broke immediately as I removed it, adding to my suspicions. Having the OVL Aero ED 35mm already, I was a bit taken aback by the larger size of the 40mm version. It's noticeable wider and taller than the 35mm. It seems just as solidly made. Overall, it is a very handsome eyepiece without being overly bulky or heavy. Observation Impressions Being in the middle of a drought, I was able to go outside with it the same night it arrived. I used my TS-Optics 90mm f/6.6 FPL-53 triplet APO with TSFLAT2 field flattener for comparison. Being that my view of the sky is obstructed by trees and houses, I was only able to test it on a bright star versus several other 40mm and 35mm eyepieces. Contrary to Badhex's report of it being worse corrected than the 35mm, I found it to be better corrected, but not by a wide margin at ~f/6. I'll stick by my long held view that the 35mm is good out to 75% to the edge from the center. The 40mm pushes this out to about 85%, a nice gain in usable field of view. The 40mm Pentax XW-R performs slightly better. It shows more chromatic aberration and field curvature, but less astigmatism near the edge. There's astigmatism out there in the last 15%, but it is significantly less pronounced once refocused for the edge. The 40mm Meade 5000 SWA performs nearly perfectly to the edge, showing just a bit of astigmatism in the last 5% or 10%. However, it has lots of pincushion distortion, inflating the size of everything at the edge. The 40mm has a sharp field stop while the 35mm seems to have a fuzzy field stop. If I push in and tilt my head, I can see under the fuzziness that there is a sharp field stop in the 35mm ED. This is similar to the Meade 26mm MWA's field stop behavior; however, I'd say you only gain a degree or so at the edge instead of 2 degrees or more for the Meade. On a later night, I was able to observe the moon just past first quarter in my 8" Dob with GSO coma corrector. It really showed how much chromatism the 40mm Pentax XW-R has, and by comparison, how little the two ED eyepieces have. The 40mm Meade falls somewhere between the two extremes. The 40mm Meade distorts the moon the most while the others barely distort it at all toward the edge. I added the 35mm Baader Scopos Extreme and 26mm Meade MWA to the mix for near widest field comparison purposes. The Scopos is basically sharp to the edge while the MWA is nearly so. However, the extreme SAEP of the MWA made it all but impossible to see the edge. The Scopos yields the best contrast of all of them by far. Crater rays and shading in the maria were very pronounced and lively, seemingly jumping out at me. The others barely showed these features once I had noticed them in the Scopos. This aligns with my experience viewing rich star fields in the Scopos. Stars are tighter and more pronounced relative to other widest field eyepieces in my collection. One other thing that stood out was how hard the Lacerta 40mm was to insert into and remove from the GSO CC. I mean, really hard. I was afraid I'd get it stuck in there. None of the other eyepieces had this issue, although the 35mm ED was exhibiting a bit of stickiness. I didn't notice this in the GSO dielectric diagonal on the 90mm APO, nor was it a problem when using the eyepiece natively in the Dob's focuser. I measured the insertion barrel diameter of all of them with a micrometer, and all seemed to be right at 2" within a few thousandths; so I'm chalking it up to the black finish on the Lacerta's barrel somehow causing the issue on a really humid night. I then tried all without the CC, and none were happy with the inherent field curvature or coma from the primary. The Scopos probably handled it best having an integral telenegative element (Smyth lens) decreasing the speed of the incoming light cone for the positive, image forming elements. However, it had an indistinct field stop without the CC for some reason. The rest maintained field stop appearances similar to their non-CC versions. Next, I tried them all in a GSO ED 2x 2" Barlow with a Tele Vue Panoptic Barlow Interface without the GSO CC since I don't have enough in-focus for both at the same time. Surprisingly, the 40mm Lacerta didn't improve very much at the edge. The 35mm ED improved a bit more, but was not perfect. The 40mm Pentax didn't play well at all with it. The outer field wasn't sharp anymore. The 40mm Meade SWA worked exceptionally well with the Barlow, showing a sharp edge and flat field. The 35mm Scopos and 26mm MWA both worked well Barlowed, but there was a bit of exit pupil instability with the former and no change in SAEP with the latter. The 40mm Lacerta was a bit tight in the TV PBI, but not as bad as in the GSO CC. I also tried them all with the Dob on the sun with a Baader solar filter. It pretty much reinforced my lunar impressions. Stray light control seemed best in the Scopos for both the sun and the moon. It had the least "fogging" around both and the highest contrast. I could begin to make out subtle surface patterns near the edge of the sun in the Scopos that were nonexistent in the others. The 40mm Lacerta was no better or worse than the rest on axis as far as fogging. In all cases, the 40mm Meade SWA has the most eye relief by far (almost too much) for eyeglass wearers, followed by the 40mm Pentax XW-R (just enough), then the 40mm Lacerta ED (able to just take in the entire field by pushing in), and dead last the 35mm Aero ED (impossible to take in the entire field at once with eyeglasses). Blackouts of any type were not an issue in any eyepiece on the moon or sun. The wide, flat top of the Meade made it the most uncomfortable to view through (head tipping is required). The rest viewed with a similar level of comfort. The rubber grip rings of all the non-Meades were equally nice for handling. The bare metal of the Meade makes if feel kind of anti-establishment or industrial, which is fine. Testing Over the last few weeks, I've been doing some indoor "optical bench" testing, so to speak. Overall, they reinforce my observation impressions that the 40mm Meade 5000 SWA is the best corrected, the 40mm Pentax XW-R is the next best (but with noticeable chromatic aberrations), closely followed by the 40mm Lacerta ED and then the 35mm OVL Aero ED. Here is a side by side image of the four comparison eyepieces showing the decloaked 40mm Meade 5000 SWA on the left and the Aero ED 35mm on the right. I chose these four because all have at least a 44mm field stop diameter and reasonably good field correction. Notice how tall the 40mm Lacerta is relative to the others. It's definitely not compact. Here is a table of measured values I obtained by taking images through my AT72ED f/6 refractor and then taking measurements and making calculations to get the focal length, FOV and FS values. I also did the flashlight test as a second AFOV measurement technique and to measure the eye relief. Notice that the Lacerta ED has the least additional edge magnification of the three 40mm eyepieces. As a result, it has the narrowest AFOV, yet has a field stop diameter second only to the Pentax. The Lacerta is also closest to being a true 40mm in the center. The measure eye relief of the 40mm Lacerta is a bit misleading since it feels like 16mm in use, needing to push in just a bit to see the entire FOV. The 35mm Aero feels like 14mm of eye relief, needing to smash my eyeglasses into it to see the entire field, so also a bit misleading. I've experienced this discrepancy between measured and feels like eye relief values with other eyepieces as well, so it's not unique to these ED eyepieces. Here is my standard 32mm to 42mm eyepiece AFOV image taken through the AT72ED, but with the Lacerta 40mm added near the bottom. Please excuse the different lighting due to different sky conditions outside the nearby window. Notice how well the Lacerta hangs with the Pentax left to right. Also notice how much smaller the Lacerta AFOV appears than the Meade above and the Pentax below despite all having a similar TFOV. Since I was at the resolution limit of my Galaxy S7's camera, I decided to get out my 90mm APO for another round of images of just the four main contenders to have increased image scale. The scope was placed at roughly the same position as the AT72ED (which I slaving recreate for each of its photoshoots), but not exactly. I ordered the images this time by best to worst overall correction, top to bottom. Notice that the Lacerta again is not that far behind the Pentax, but both are well behind the Meade. However, the 35mm Aero is definitely a step behind the 40mm Lacerta. Next, I got out my 127 Synta Mak and took the same images on the same day from the same position. Notice that all get sharper, but the 35mm Aero is still not completely sharp at the edge. Last, I added the Lacerta to my SAEP/CAEP comparison image at bottom center. Like the 35mm Aero, it doesn't exhibit obvious blackouts. There is a bit of a shadow that dances around the field, but it is as unobtrusive as the ones in the APM UFF 30mm and TV Panoptic 27mm. Conclusions Overall, I really like the Lacerta ED 40mm as a light weight, lower cost alternative to the Pentax XW-R 40mm at f/6 or slower. If eye relief were a bit longer, it would be even better. The eye lens is recessed 7mm, so it could have really comfortable eye relief for eyeglass wearers if the top were redesigned. If anyone has been wanting to get a 40mm ED, but couldn't because they were sold out, now is the time to get one before this run is sold out as well.

Ah yes, 10° less orbital inclination than ISS (41.58° vs. 51.64°).

I'm curious if anyone has the patent number(s) because I'd like to read up on their claims section(s).

Have you tried imaging China's space station yet?

Does anybody know if Celestron has patented any part of their Starsense technology? It's not like plate solving is a novel concept, however applying it to DSCs may be novel enough to patent. I ask because what is to keep others from adding it to their own planetarium apps and turn them into DSCs?

At f/6, the WO SWAN is going to start showing astigmatism at around 60% out and be a complete blur in the last 15%. The APM UFF is going to be perfect edge to edge. I guess it depends on your tolerance for edge imperfections. If you nudge your Dob often enough, you could keep the object in the inner 50% of the WO where it will be sharp. The problem I found with these types of eyepieces is that they fail as finder eyepieces because stars look like nebula in the outer regions, so it makes it difficult to locate globular clusters and planetary nebula and center them for higher power viewing. Compare the lens design of the WO SWAN (5 elements in 4 groups) with the APM UFF (9 elements in 5 groups): The APM UFF is a technological tour de force. It employs a novel telecompressor stage before the field stop such that the field lens (40mm) is larger than the physical field stop (30.4mm), while the effective field stop is larger (36.4mm) than the physical field stop. This keeps the eyepiece very narrow for it's focal length and AFOV while allowing for near perfect correction. The 30mm APM UFF is so good, I swapped out my venerable 27mm Panoptic for it in my A-Team eyepiece case. Compare that to the 35mm Baader Scopos Extreme which is a giant beast with a typical telenegative stage ahead of the physical field stop, which is larger than both the field lens and the effective field stop diameter:

Since the 30mm APM UFF is so much better in the same price range, I don't know why anyone would look at the 31mm Hyperion.

Exactly, the image scale has to match to merge. However, it's really easy to judge because objects not only have different sizes between images, they are also displaced radially from the center by different amounts. It's actually super cool to see the merge happen and the brain locking the two images together suddenly with much greater fidelity than either image alone.

Not really. I just grab both zooms and twist them in sync until the power roughly frames what I want to view. I then slowly adjust the zoom at my nondominant eye back and forth a bit until the two images snap into merger. It's pretty quick and obvious when it happens, much more so than when best focus has been achieved. I originally had concerns it would be an issue merging non-click-stop zooms in a BV, but it hasn't been an issue at all. Besides, with click-stops, you're relying on tight manufacturing tolerances for the two eyepieces to be perfectly matched at every click-stop. If one eyepiece's click-stop magnification is slightly off from the other eyepiece's, it would be hard to move the zoom mechanism of one of them off by a small amount because the click mechanism would want to force you onto the nearby detent. Thus, you're having to force your brain to merge two images of slightly different magnifications in that situation. It's doable, but not comfortable long term. To avoid a headache or eyestrain during power changes since my brain is trying to merge unmergable images, I concentrate on the view through my dominant eye since I can't twist the two eyepieces at exactly the same rate. This would be an issue with click-stops as well unless you looked away entirely and just counted clicks.

They toss in a seal with each eyepiece? Cool!!!

Do Maks also get a bunch of SA when moving the mirror far away from the design point?

Does the R/C induce SA?

I compared the BST Starguiders (AT Paradigms for the set I picked up) to the Meade 5000 HD-60s in the following thread some years back: I preferred the HD-60s due to much better eyeglass friendliness and somewhat sharper views. The 12mm and lower focal lengths in both lines are the standouts. Unfortunately, the HD-60 line has been discontinued. The Celestron X-Cel LX line is the closest in performance to them from what I've read that are still being sold new. I compared the SVBONY 68° Ultra Wide Angle 20mm, which is optically the same as the TS-Optics UWA 20mm, to other eyepieces in the 20mm range in the following thread: You can look at the AFOV images to get an idea of how it performs at f/6. It's fine in slow scopes (f12 and up) in my experience, but I wouldn't recommend it for your scope (f/6.5). They're also terrific in binoviewers when used at f/18 in my experience.

Rini eyepieces are generally made from uncoated or single coated surplus lenses, and as such, have loads of internal and surface reflections. They also don't generally have defined field stops, so they have blurry field edges. They're fine for beginners on a budget starting out as I was 20+ years ago, but just about any commercial offering gives contrastier and sharper views. I wouldn't pay over $40 or $50 for one. I have the 1.25" 35mm MPL, 2" 38mm MPL, 2" 29mm MPL, and 2" 42mm Erfle. You can check out my images of each of these Rini's AFOVs in the following thread and compare them to commercial offerings in the same comparison images:

You could repeat the experiment at a narrower field of view with the eyepiece alone to see if the astigmatism was R/C induced. If it goes away or greatly reduces, it was the likely culprit. If there is no change, it's likely due to the eyepiece. That's all I was suggesting to help narrow down the source of the astigmatism you were seeing.

I got a sharp view of Venus last year through an ST80 using a green filter. I don't remember which one I was using (I have several), but it got rid of the red/blue smearing of both the achromatic lens and the atmosphere. Mainly its phase became obvious.

The mirror's backside probably got a bit of rough handling during manufacturing, that's all. I would shine a bright light through the glass from the side to look for deep imperfections like stress fractures. Surface scratches on the backside of the mirror are purely cosmetic. Thoroughly check the rest of the scope for real damage like bent spider vanes or tube crinkles. Those can't be fixed by the end consumer.

Online eyepiece specs have been known to be wrong by wide margins, so take those numbers with a grain of salt. I've read that the ES equivalents sold by Ali Express can be factory seconds based on user experiences. Returns via AE can be a pain in that case. I would hope that Opticstar sells first quality optics.

I usually just blow off dust and then huff some breath moisture onto the surface and lightly wipe the fingerprint off with a clean microfiber cloth. Don't scrub. Repeat huffing and gently wiping with clean sections of the cloth in various patterns until it comes off. I've been using the technique on camera lenses, eyepieces, and filters for decades without noticeable degradation of the coatings. The quicker you get the fingerprint off, the easier it is to remove in my experience. When I'm in the field in the dark, I wouldn't trust myself using cleaning liquids around optics other than breath moisture. I'm loath to put chemicals on optical surfaces unless it's to remove hardened/sticky gunk, which most fingerprints are not. The exception would be fingerprints at outreach events. But, I wouldn't have my nice optics available for touching in that situation.

You were both probably seeing diffraction spikes from the secondary mirror spider vanes if it was a cross shaped artifact. Try creating an off-axis aperture mask from cardboard or foamboard to leave only an unobstructed circle between spider vanes. That should get rid of the spike artifacts and decrease the dazzling effect of Venus in particular by masking down your aperture a bit. Adjust the measurements below for your 8"/14" scopes.