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24mm 68-deg Eyepiece Shootout


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Four nights under the stars with Bill Paolini's 24mm Hyperion, my old Meade 5000 24mm SWA, and a good friend's 24mm Televue Panoptic



First night, January 12 2008, at Emma, an old cemetery, the only thing left of a town in the middle of a present-day cotton field …

http://www.rootsweb.ancestry.com/~txcrosby/emma/cemetery.htm

Since this location is 30-odd miles east of the city, the western skies are a bit washed out, but the tiny light domes above Post, Texas, 29 miles to the south, and the burg of Ralls 6 miles to the north provide no real problems, such that all directions except the west are quite clear, with the Andromeda Galaxy, the Double Cluster, the Beehive and the Milky Way all naked eye objects on this evening. On the other hand, Mars gave us nothing but an orange blob when we bothered with it. The 4 day old moon set early at 22:28 this Saturday night. Alright!

Telescopes used:

Don Fritz's 12.5" F/4.8 truss dob with Meade mirror in a homemade Coulter-to-truss tube

Your Humble Narrator's Astronomy Technologies 80mm ED F/6.875 refractor

Another friend's Celestron C-8 SCT

M1 in the 12.5" dob and the Hyperion was a knockout. That's one nice nebula for that eyepiece in a big dob. Yielding just over 1 degree in the eyepiece, the 6'x4' image was framed nicely in the center.

The Double Cluster through my AT80ED was pretty much a wash, performance-wise, amongst the Hyperion 24, 5000 SWA and Pan 24. This scope with these eyepieces projects just less than 3 degrees, easily framing the clusters in their entirety with room to spare.

At M81/82, we compared the Televue 32mm Plossl to the Hyperion 24mm in the C-8 SCT. Honestly, I preferred the higher powered, more encompassing image of the Hyperion over the very sharp, but small, TV Plossl. No doubt this is a personal preference thing, and perhaps other targets would result in differing favorites, but that's how this target was for me in the SCT.

The biggest challenge for edge of field correction came at M35/NGC 2158. I always enjoy framing these two clusters together, and in my AT80ED, that's no problem. However, I guess the actual size of the clusters is just a little bit more than 1 degree. Not much, but just over 1 degree. In the big F/4.8 dob, the Panoptic displayed M35's farther northern edge and NGC 2158's complete self -- flat and clean. The Meade 5000 did just about as well. The Meade had a small amount of extra edge distortion, but that was right up at the edge of the field and didn't distract from the overall framing of the paired clusters.

Then it was the Hyperion's turn and, wow, what a difference! It couldn't frame both clusters in an appealing manner. The Hyperion 24's edge turned funky WAY into the clusters. You could either look at NGC 2158 with a half-baked M35, or M35 with a half-baked 2158, but not both in an acceptable presentation.

At Andromeda, M31/32/110, I was surprised at the way the Panoptic 24 produced a more 3-D effect, with the dust lane actually visible in my AT80ED, detail not noticed in the Meade 5000 nor the Hyperion.

The second brightest star in the sky, Canopus, grazes the southern horizon at a line well below and between Sirius and Betelgeuse at 33.5º N on late January evenings and this night was no exception. Walking around my neighborhood park on the 10th of March, I caught bright Canopus setting low in the southwest along the horizon.

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The second night, 08 Feb 2008, was at the local University Observatory, the Gott, about 12 miles north of the city. The southeastern skies are quite washed out. Northern, western, and northeastern skies are very good. The Jet Stream forecast for the South Plains wasn't very good that evening. Concrete pads 20 meters south of the observatory provide excellent setup for scopes.

Telescopes used:

Same 12.5" F/4.8 truss dob & AT80ED F/6.875

With targets of the Double Cluster, Andromeda, and M42/43/Trapezium, we set about observing. We noticed the seeing coming and going, with the Jet Stream whipping the air like agitated water refracting light in a stream. This was most pronounced at higher power on the Trapezium.

The Hyperion 24mm provided excellent on-axis performance but showed greater edge astigmatism on M42. The Meade 24mm SWA was equally excellent on-axis, but better corrected at the edge, only astigmatic right at the edge. The Pan 24 had the flattest field and framed the huge nebulae of M42 & 43 best.

Just for grins, I threw in my Antares Elite Plossl 25mm, which did a VERY nice, sharp job on M42, albeit somewhat truncated compared to the 68 degree Apparent Field of View oculars. Although the AEP gave a very good view, M42 and environs benefit greatly from the extra True Field of View of the 68's.

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The third night, 10 Feb 2008, had us at a friend's house on the eastern edge of the City. The moon was a waxing crescent. The 12.5" dob, along with Don's (newly acquired off AstroMart) Orion 120ED refractor and my own AT80ED providing the horse power.

The targets were the usual suspects, the moon, M31/32/110 and the Double Cluster. Again, the Pan 24 produced the flattest field, followed by the Meade, then the H24, though all three produced nice views and framed things better than another friend's TV 32mm Plossl and my own AEP 25mm.

For something different after the moon was down a ways, we turned our attention to the lone winter globular M79 in Lupus, quite high here in West Texas later on this evening. It was best in the dob and framed best in the Pan 24, though all three were excellent on-axis.

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The fourth and final night of testing, 29 Feb 2008, found us back at the Gott. This was refractor night, with Don's Orion 120ED and my AT80ED.

On the Double Cluster and M35/NGC 2158, I initially found myself preferring the cooler tones of the Hyperion 24 and Meade 5000 24mm SWA to the warmer Pan 24 in my AT80ED. The Pan just seemed more subdued. This effect lessened, however, as one "˜takes in' the view and observes a while. At first glance the H24 and 5000 produce a brighter, cleaner effect, but with careful examination, one realizes the Pan is missing nothing in terms of apparent stars. They're all there.

In the F/6.875 AT80ED, all three produce flat, 2.967 degree fields without objectionable edge distortion. Ironically, when looking through the 120ED after the 80ED, the Meade/Hyperion cool-tone advantage over the Panoptic disappeared, given the extra brightness inherent in the larger objective. The relatively slow F/ratio of the refractors minimized edge of field correction advantages of the Meade and Pan so prominent in the fast dob.

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In the end, I prefer the TV Pan 24, more than anything else for the practical aspect of weight. An 80mm ED refractor is rather sensitive to great variations in weight on the diagonal. The 8.2 ounces of the Panoptic just fits better and more easily, with fewer problems if I move from my 4 ounce 20mm TV Plossl to the Pan or vice versa. But the 11.6 ounces of the Hyperion, and especially the 14 ounces of the Meade? Uh-oh. People who regularly use Meade UWA, larger Naglers, other Hyperions, or other heavy wide angles would probably be nonplussed by my predilections, and rightly so. But a man's gotta balance what a man's gotta balance "“ and still find time for the stars!

The Pan 24's better image of Andromeda on the 1st night out was the only time during the testing when the Pan 24 produced a noticeably better image than the others across the FOV. I'm not entirely sure why this happened. Once, when comparing the BO/TMB 6mm to a WO 6mm SPL, a friend and I changed scopes for the "˜opposite' view. He was convinced the BO/TMB was better while I thought maybe his SPL was. I honestly think we both just caught a moment of clarity in the atmosphere and both got the "˜best' view of the night during our momentary clearing at the opposite scope. Which was really better? I'm honestly not sure to this day. My friend sold his SPL and bought a BO/TMB. They were both excellent "“ and obviously quite close in quality.

Location, location, location: I live on the Plains of West Texas. I go to other places to observe, Central Texas, South Texas, and the mountains of New Mexico, too. But on these four nights and generally, I am subject to the air here on the South Plains. We're pretty high up, altitude-wise, at almost a kilometer above sea level, but having no natural barriers to the winds, the Jet Stream is often unsettled and bothersome here. This is more of a problem for high powered viewing. For example, almost all of the Cloudy Nights community is convinced the Pentax 8.5mm XF performs better on-axis than the 8mm BO/TMB, but for the life of me, I've yet to see any differences. I'm not saying the Pentax isn't better, only that I haven't seen it with my own eyes, but again, I live in a place that rarely allows subtle differences to appear. I feel that my "œAndromeda" phenomenon noted above is one such instance. Bill Paolini himself has posted that, on nights of average seeing, he preferred the BO/TMB 8mm to the Pentax XF, and only on those nights of best seeing did he find the XF to outperform the BO/TMB. I'm afraid on the plains of West Texas, that theoretical distinction is blurred to obscurity for me "“ at least so far. BTW, I own the 12mm XF and have a lot of respect and admiration for these Pentax eyepieces.

I ended up buying the Pan 24 from my good West Texas friend and selling my Meade 5000. I doubt I would have bothered, however, if the Meade weren't so darned heavy. I have a predilection for light-weight, high performance optics, and eyepieces are no exception. However, if I were low on cash and wanted to get a feel for the 68 degree AFOV world, I wouldn't hesitate to recommend the Hyperion. In fact, in F/7 and above scopes, it performs quite nicely and weighs a bit less than the rest of the Hyperion family. The Meade and TV Panoptic take care of the sub F/6 world handily. The Meade 5000's screw-up eyecup is ingenious and innovative, and its eye relief is better. This doesn't affect me much since I'm not an eyeglass wearer and found the eye relief comfortable in all three models -- and I'm not a fan of 11mm TV Plossl ER.

Recommendations? Well, if you can afford the high price of the Pan 24, it's performance is hard to beat. At $310 SRP, it's kind of hard to justify, but they can be found used for about $100 less, which helps, of course. The Meade 5000 come in at $249 SRP, and used they can be had for around $170 or less. If you have a lot of heavier eyepieces in your stable and its 14 ounces won't affect things much, by all means, this one will save you a little money at only a small decrease in edge of field correction compared to the Pan 24, all the way down to F/4.8 But if you own a scope at F/6.5 or above, the Hyperion 24 is one of the best deals going in the astronomy market today. Even faster scopes can still make use of its wide field, though some targets might get a bit muddy at the edges. Many can tolerate this given the high throughput in the center of the FOV.

Bottom line "“ get one of these eyepieces. Unless you've already by-passed the 68 degree AFOV world in favor of the 82 degree one (Naglers, Meade UWA's), you'll be glad you did. There's something much more appealing about the vista through one of these 24mm super wide angles than 25, 30 or 32mm 50 degree eyepieces can afford. I can't recommend buying any of the better 50 degree AFOV eyepieces in these sizes unless you have some specialist inclinations. Outside of public star party eyepieces, I'm not one to have specialized sets, and prefer to keep things simple. My 25mm AEP is now in my public star party set. If you're like me and have been myopically focused on Plossls and such, you're doing yourself a great disservice if you don't try out the 68 degree AFOV world. And the 24mm size is one fantastic place to start, since you maximize the field of the 1.25" eyepiece barrel. Partner, in this shootout, everyone wins a hold of one of these. Draw!

Collin Smith
Lubbock, Texas

Special thanks to Don Fritz and Bill Paolini for making this review possible.



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