Don Pensack

The issue isn't the eyecup, it's the cap. Change the cap to one that fits better and the problem goes away. Measure the diameter of the rubber eyecup when folded down and look for a cap with an I.D. 0.5-1.0mm smaller so that when it's pressed on it is tough to remove. And it will stay on. This is not a problem with just that eyepiece, many TeleVue eyepieces have caps that slowly inch their ways off the eyepieces just sitting there. The 24mm Panoptic is notorious for that.

Maximum possible eye relief with a 30mm lens at 82° = 17.26mm from a horizontal line across the eye lens. If the eye lens is concave, add the concavity to the 17.26mm figure to get the "from the glass" eye relief figure.

As long as your scope is longer than f/8, you'll like it. At f/5, I could see almost 50% of the field out of focus with astigmatism, so the Masuyama (which has excellent contrast, BTW) is not an eyepiece for the shorter f/ratios.

And, the zoom is the equivalent of 11 eyepieces spaced a half mm apart, or 21 eyepieces space 0.25mm apart, etc. Can't beat the price. It has some issues (eye relief at the short end), a longer-than-average 1.25" barrel, etc., but so do other inexpensive eyepieces.

Meade is owned by Optronic Technologies, Inc, a US company, owner of Orion in the US. The scopes are imported, and 99.9% likely to have metric threads.

Look up a Baader Contrast Booster filter to see more details on Mars. "Fireflies dancing about" is an apt description for reflections from the cornea to the eyepiece and back again. Not all short focal length eyepieces are prone to this, but stay away from Kellners and Erfles as these are notorious for that. Fully multi-coated Plössls are often good, but eye relief gets really tight about the 8mm range. A suggestion I could make is to Barlow a longer focal length eyepiece you know doesn't have the problem. It often is sharper across more of the field, too, because the Barlow doubles or triples the f/ratio of the scope before the light enters the eyepiece, making the incoming rays more parallel, which reduces induced astigmatism in the eyepiece. That really cleans up inexpensive designs like Plössls, Königs, and inexpensive widefields.

Mars is still a decent size till about the end of the month.

The 30mm is in a different league. It's truly a high-end eyepiece. You won't be disappointed. It's a real 70°. And sharp down to f/4. KUO really has a superb eyepiece here, with the 30mm--contrast and sharpness are excellent.

Its presence is less noted the shorter the focal length. It was present in all of them, but the 14mm was the worst, the 10mm a bit better and the 7mm and shorter weren't bad enough to have much impact. But then, I didn't use them on the moon, and a smaller pupil diameter would have made them harder to use.

As counterpoint to the zoom argument: --zooms have narrow fields of view compared to fixed focal length eyepieces. Generally, wider is better--more engaging. --zooms provide too many in-between powers. If your scope yields 50x, you really don't need a 60x or 70x eyepiece. When you change the magnification, you want there to be a visible difference. With the zooms I've used, I pretty much always used them at 4-5 settings and skipped the in between settings. --no zoom I've tried, and that includes the Leica Aspheric, was the equal of separate eyepieces in edge of field correction, lack of spherical aberration, sharpness of star images, lack of edge of field brightening, or contrast. (well, the Nagler Zoom was, but I wanted more than a 50° field). Fixed focal length eyepieces can be better (though not all are, of course, which is why to read reviews) that zooms, and if you have those better fixed focal length eyepieces, returning to zooms is not a viable option. Which is why I have advocated for a starter set of 3 eyepieces to get your feet wet in astronomy: https://theskysearchers.com/viewtopic.php?t=18374

The StellaLyra makes the 9th label of the 30mm available. But it is quite cost-effective. Kudos to FLO.

Cameras can capture things invisible to the eye, but the view through the eyepiece can encompass a greater dynamic range. You can see the Trapezium in M42 at the same time you can see wisps of nebulosity in the Fish Mouth. You can see details in the Regio Centralis at the same time you can see the very faint nebulosity almost a degree away that closes the oval. Here is a sketch that captures what can be seen visually, which would be an impossible image: https://www.cloudynights.com/topic/399146-sketch-of-m42-m43-dobsonian-22/?p=5112451

If you were a visual observer, you'd appreciate that: There is a lowest power that works in the scope. There is a highest power that works in the scope. The range of usable magnifications is likely a 15:1 range or larger. Seeing conditions often limit the maximum to a lower power than the highest. You want the magnification changes to represent a noticeable difference when you move up in power. Objects in the night sky come in a huge variety of sizes, from, perhaps, an arc second up to over 14,000 seconds. needless to say, the magnification for one is not the right magnification for the other. So, to yield a reasonable range of magnifications, you will need around 6-8 eyepieces. And if planetary observing is a featured use, due to the seeing conditions, many like to have several high power eyepieces close together to accommodate the fact each night may have a different highest power usable. I think people build up much larger collections of eyepieces because they have multiple telescopes, or because they simply don't get rid of older, unused ones.

It looks like there is evidence the lower retaining ring was loosened and retightened with a tool that had blades wider than the slots in the retaining ring. And that caused the scuffing on the paint. However, I'm a bit concerned about the stuff on the lens right inside the retaining ring. Either the lens is filthy or, maybe, the same tool that chipped the paint scratched the lens as the ring was tightened. I hope not, and that it cleans right off with a cotton swab and some alcohol.

This process, called "blinking", doesn't work well in light polluted environments because the ambient light reflecting off the nebula filter is brighter than what can be seen through it. It works OK in really dark skies, but, as a technique, its true value is in planetary use, where you can quickly see what filter you want to use to yield the detail you want to concentrate on.

You don't focus on the nebula, you focus on the stars in the field (and there is always a star to focus on). And unless the filters are perfectly parfocal, which they realistically are not unless extremely expensive, like Astrodon filters, having the clear filter is a waste of time. Because you'll have to refocus on the next filter anyway. The H-ß filter will be the darkest of all, so having it follow another filter with a wider bandwidth might be a good idea.

The 30mm Ultima Edge focuses only 5.1mm above the focal plane of the scope. That says your scope's focal plane is very far out in the focuser travel if you had to use an extension tube. I wonder if it's possible to lower the primary mirror in your scope by a few mm so you don't have to use an extension tube.

I've discovered a lot of eyepieces have internal vignetting, which can make the field stop somewhat vague in the flashlight test. It's usually pretty easy to see where light goes to zero, though. The more difficult part is determining where the exit pupil is because if it's large and there is SAEP, its position becomes quite vague. Though, this doesn't make a large difference in the calculation of apparent field if the circle measured is at least a meter from the scope. I discovered that this measurement can be improved by stopping the scope down, making the f/ratio longer and the exit pupil much smaller. It is pretty easy to determine the exit pupil position when the exit pupil is small. Some day when I have time, I'll do this with a bunch of eyepieces to determine the accuracy of their eye relief figures. At this point, I don't have enough data to determine how accurate that figure is for most eyepieces. I propose an index card with mm markings on it that can be held up to the eyepiece to measure the effective eye relief, added to a measurement of the lens depth. The advantage would be a determination of both design and effective eye reliefs at the same time.

http://astro-talks.ru/forum/viewtopic.php?f=32&t=1483#p41976 Go down the page to the second chart, which has hyperlinks to each individual review. Personally, I use the flashlight test to measure apparent fields, but the best I can do is +/- 0.2°. Ernest is a designer, so likely has more sophisticated instruments to measure the apparent field, like: http://www.southastrodel.com/Page209.htm#:~:text=A dynameter is an astronomical,particular eyepiece through a telescope https://adsabs.harvard.edu/full/1970JBAA...81...24C https://trioptics.com/us/products/optitest-visual-measurement-instruments/ https://www.cloudynights.com/topic/574401-an-easy-way-to-measure-apparent-field-of-view/ S&T uses a pivoting magnifier similar to a theodolite that can measure apparent field to <0.1°

Many brands Astromania BST (Barsta) Lunt Omegon Orion OVL (First Light Optics) Skywatcher Telescope Service

Well, not quite dead on: XW: 40 68° 30 68° 20 70° 14 69.4° 10 68.4° 7 69.3° 5 69.3° 3.5 68.5° XL 40 63.3° 21 61° The point is that without some serious pincushion distortion (not Pentax' general rule), a 28mm is more likely to be ~52° in a 1.25" barrel.

That's true. Distortion can make a difference. But are you sure the XL28 was really 55°?

My field analysis: https://www.cloudynights.com/topic/849945-new-85°-pentax-eyepieces/?p=12369694 and the following post as well. If you just touch the eyecup with glasses on, but do not press, I think you will see maybe a 75° field? I didn't analyze that, but the field didn't get that much larger when pressing hard to see the field stop. It also seemed a little easier in the 16.5mm than in the 23mm.

Sorry to burst your bubble, but that 27mm focal length has a 53° apparent field in all 8 labels (maybe more) it's sold under. The whole line is also sold in colors if you look up "AngelEyes". https://www.aliexpress.us/item/2251832657095693.html?spm=a2g0o.productlist.main.3.74a32ed8hivC3Y&algo_pvid=9c214683-03aa-4896-a23e-04b5f0916fb0&algo_exp_id=9c214683-03aa-4896-a23e-04b5f0916fb0-1&pdp_ext_f={"sku_id"%3A"65093639638"}&pdp_npi=2%40dis!USD!69.9!48.93!!!!!%4021021d7b16716629313185371d0793!65093639638!sea&curPageLogUid=RhVSeCCVfg2F 8, 12, and 16 are 60°. The 19mm is 65°. And the 27mm is 53°. When dealing directly with China, beware false advertising. There's a lot of it. Likewise, a 36mm 1.25" Plössl would have at most a 47° field, and likely smaller.

Low price: BST Starguider ED or the Barsta 58° eyepieces that are very common. Both are available under many different labels. FLO has the Starguider EDs. A little more: Celestron X-Cel LX or Meade S5000 HD60. The Meades would only be available used. FLO has the Celestron X-Cel LX. High-end in the same apparent field: TeleVue Delite. Looks like FLO has those too.