Sunday, June 29, 2014

 

Return of the Denkmeier


This is just what I was afraid was going to happen, muchachos. “What’s that, Unk?” The arrival of summer has brought mucho clouds with it—big surprise. With the Solstice came the afternoon thundershowers whose clouds linger well past sunset. Not that I didn't have hopes for this past Saturday evening. The cotton-picking Clear Sky Clock (I still can’t get myself to call it “Clear Sky Chart”) showed a few light blue squares, so Unk high-tailed it to the Possum Swamp Astronomical Society dark site. I had a mission, you see.

The genesis of that mission came one recent morning when I was puttering around the New Manse. I don’t teach at the university in the summer, and I was caught up on my writing for Sky and Telescope for the moment, so I was idly rearranging some of the astro-gear I’d stashed in the shop when we moved in. What should I run across in the course of that but the case containing my good, old Denkmeier binoviewer.

If you were a member of our avocation about ten years ago, you’ll recall binoviewers, devices that allow you to use two eyepieces with a telescope for binocular-style observing, enjoyed a tremendous vogue for a few years. They’d been around for a long while before that in the form of surplus microscope stereo viewer heads, but the fields of view those permitted were limited due to their small prisms, and their minimalist optical coatings meant you lost a lot of light. They were cool enough for viewing the Moon and planets, but that was it.

As the 21st century got underway, though, TeleVue and other companies began selling binoviewers specifically designed for astronomical use, including on the deep sky. Using two eyes at the scope seemed a natural, and before long, in addition to TV, new outfits like Denkmeier, Siebert Optics, and Burgess Optical jumped into the two-eyed-viewing game with a wide range of binoviewers from inexpensive imported ones not much different from the old microscope heads to massive (and expensive) models capable of using 2-inch eyepieces.

For a couple of years, Unk was binoviewer crazy. I tried and reviewed not just the TeleVue and Denkmeier units, but models from Burgess, Celestron, and others.  New binoviewers, including, natch, el cheapo Chinese ones, were hitting the market every day and the binoviewing forum on Astromart was insanely active.

Yessir, binoviewing was all the rage for a while. It almost took on the tenor of a holy CRUSADE against what us cognoscenti called “Cyclops (one-eyed) observing.” Then, after a few years, it all just stopped. Well, not really. There’s still an active binoviewer forum on the pea-picking Cloudy Nights BBS, but the binoviewer brigade is unquestionably smaller than it was in its heyday. Why? I’m not sure. Hell, I’m not completely sure why I stopped binoviewing.

Suddenly, Unk, like a lot of other folks, went back to Cyclops-style. In my case, it wasn’t because I’d come to dislike binoviewing.  I’d just moved on to other things—largely Stellacam and then Mallincam video cameras. When it came to visual observing, those dadgum Ethos eyepieces had me in their grip. Stingy ol’ Unk wasn’t about to spend for pairs of ‘em and a 2-inch binoviewer that could handle the long focal length 100-degree jobs just to keep going with two eyes. So, the Denks stayed in their case for dern near eight years.

Which brings us back around to Unk idly peering at the Denks’ case one bright suburban morning.  Almost against my will, I picked up said case, dusted it off, and carried it inside the house. There, I had a look at the Denkmeier Standard binoviewer. Still in perfect shape. There was the StarSweeper f/6 focal reducer I’d used with it on so many nights. And the pairs of Hands On Optics GTO Plössl eyepieces I’d accumulated for the Denk—I’d meant to upgrade to “better” (wider AFOV) oculars, but never quite got around to it before I stopped binoviewing.

Anyhoo, looking at the Denk, I began to recall how much fun I’d had with it, and soon went from reminiscing to becoming determined to take the thing out to the PSAS dark site Saturday night and see how it would work with my Edge 800 C8, Mrs. Emma Peel.

That was the plan, anyhow, and Saturday dawned reasonably clear. Then came those dadgum early evening showers, which left plenty of clouds behind when they finally moved out. Should I throw in the towel? When I’ve done that, I’ve often missed a great night, so I stuck to my mantra:  “If It Ain't Raining, Head to the Dark Site.” Unk loaded up the 4Runner, Miss Lucille Van Pelt, and lit out about 7:15 in the p.m.

This time of year, there’s always a chance the clouds you are seeing over your head are a local phenomenon, and that a few miles away you’ll find blue sky. That was the theory, but when I arrived at our much-loved observing site, an airfield that is closed at night, the clouds were, if anything, thicker than they had been at home. What was that off to the west?  A lightning bolt in a particularly thick patch that appeared to be headed my way, dagnabbit.

I hung out on the field for another half hour to see if the sky would improve or if I’d be joined by any of my Possum Swamp A.S. compadres. “Nope” to both. I visited with the big yellow tomcat who makes his home in a hangar, killed a few more minutes walking around, and finally did throw in that accursed towel at about 8:30. With thunder booming and lightning growing ever  closer, Unk quitted the field with no little alacrity. I hadn’t unpacked a thing, so it wasn’t long before I was back at the New Manse, ensconced in the den and watching Svengoolie, who was showing a goodie, Curse of the Werewolf.

I’d seen that urpic of a horror film just a few months back, though, so I didn't give it my full attention. Instead, between draughts of Yell I was ruminating on the question of what the next blog should be about. Since my plan to do dark site binoviewing was now in ruins, I thought I’d give the Mallincam Micro EX a good workout in the backyard. It had impressed me at the Deep South Regional Star Gaze Spring Scrimmage in April, even though I’d had to shoot through sucker holes.

Alas, the weather gods ruled against the Mallincam, too. I hope to get the Micro out of mothballs soon, but I wasn’t able to last week, which was even cloudier than the previous one had been. Thanks to Mr. Jack Huerkamp, I have a new video cable and am ready to go whenever the weather changes for even the slightly better.

What about this week? There’s always the vaunted “My Favorite Fuzzies” and “My Favorite Star Parties” to fill in the holes, but then I had an idea (Unk still gets 'em occasionally). It occurred to me some of y’all missed the binoviewer explosion of a decade ago and might be interested in reading my review of the Denkmeier Standard from back then. This piece has appeared in several places over the years, including Cloudy Nights, and I was happy enough with it, but one look showed it could use some serious tweaking. Which is what I did. Next week, you should get “Revenge of the Return of the Denkmeier,” but this morning, from 2004, here is “Return of the Denkmeier”

As some of y’all may have read, I had the opportunity to test the Denkmeier II Binoviewer a couple of months back. I was suitably impressed, but due to the weather we were experiencing down here on the Gulf Coast at the time, my opportunity to use the “Denk” on a variety of objects was limited.

Saturn looked great, the Moon looked great, but clouds and haze prevented me from using the binoviewer on any but the most prominent deep sky wonders. M42 was superb and so were a couple more bright Messiers, but conditions didn't allow going deeper. What I wanted to know was “How does a binoviewer, a modern top-of-the-line binoviewer, do on a wide variety of deep sky objects?” Especially dimmer ones. Sadly, the Denkmeier II had to go back to its maker, so I was left wondering.

Unk was not to remain in the dark long. The good folk at Denkmeier Optical soon asked if I'd like to borrow their newest baby, the Standard binoviewer, for further testing. Since my experience with the Denk II, the company’s 2-inch binoviewer (the barrel that goes in the star diagonal only; the eyepiece holders are 1.25-inch), had been positive enough to make me something of a binoviewing convert, I couldn't help but say "yes."

By way of background, before I tested the Denkmeier II, I was not much of a fan of binoviewers. I had never had much success using them. I couldn't easily merge their images, resulting in eyestrain and headaches. Even when I could get the two pictures together, objects, including the Moon and planets, seemed dim, and longer focal length wide field eyepieces were “vignetted”—their fields were cut off. I was pretty sure binoviewing was Not for Me.

You can read the story of my experience with the Denkmeier II in my review, “How I Learned to Stop Worrying and Love Binoviewers,” but to boil things down for y’all, I found it easy to merge images with it. Observing with the Denk II was far more comfortable and rewarding than I’d imagined.

In fact, the only criticism I had of the Denkmeier was its friction-fit eyepiece holders. None of my eyepieces ever dropped to the ground, and they would stay put when I slid them in and out for diopter adjustment, but they weren't as secure as they could have been. According to Denkmeier, that one problem had been corrected. They said both the premium Denkmeier II and the Standard Denkmeier (1.25-inch barrel) now had twist-lock self-centering eyepiece holders. I figgered that would be a far better arrangement and was anxious to see how well it worked.

When the box containing the new Denk arrived at Chaos Manor South, you can bet your old Uncle immediately ripped into that sucka. Within was a black plastic case of obvious sporting goods store heritage—a pistol case like they sell at Academy—that nevertheless provided adequate protection for the binoviewer and its accessories.

Inside that minimalist case was Denkmeier’s Standard SCT Package. In addition to a 1.25-inch barrel binoviewer, there was a 2" StarSweeper (focal reducer), a 2x "multiplier" lens (Barlow), and requisite adapters. The binoviewer itself? I could tell at first blush that the eyepiece holders on the Standard were a major improvement. Smoothly threaded, they held eyepieces securely when the lock rings were screwed down and seemed easy to use as well as attractive.

Naturally, the arrival of the new binoviewer brought considerable cloudiness with it. Apparently, the dreaded new scope curse doesn't just apply to telescopes. Nevertheless, I was able to get the Denk out to the Possum Swamp Astronomical Society’s in-town observing site for a shakedown one night. Using it there showed how much nicer the new eyepiece setup was, but the light pollution didn't allow me to assess what the Denkmeier could do with the deep deep sky. 

For that, I needed dark skies. Well, the legendary Chiefland (Astronomy Village) Star Party was right around the corner. For those of y’all who've never attended that event, you dang sure should; the skies are D-A-R-K and the temperatures are almost always balmy into the late fall. The trip to the CAV is a reasonably easy one for me; it’s about 6 hours from the Swamp to Chiefland, which is roughly 65 miles north of Gainesville in the Florida interior.

Anyhoo, I packed up the Denk, a box of eyepieces, and my faithful NexStar 11 GPS, Big Bertha, one amazingly cloud-free November Friday morning, and my old friend Pat Rochford and I made tracks for the Chiefland. In due course, we were Checking into our usual “campsite,” the Chiefland Holiday Inn Express, and proceeding on to the CAV. There, as it always is for the two big bi-annual star parties, the observing field was jam-packed with telescopes and amateur astronomers, and it took us quite a spell to find a spot to set up our scopes.

For once, it looked like Pat and I had hit Chiefland just right. It appeared we'd be favored with two excellent nights, and we were. I spent the first one working my observing list (I am determined to finally finish the dadgum Herschel 400) in single eyepiece mode with the aid of the StarSweeper focal reducer. As I reported in my earlier review of the Denkmeier, I'm impressed with that gadget with or without a binoviewer. It provides a decent-looking field edge with most eyepieces, and I really didn't miss the Celestron f/6.3 reducer - corrector I normally use with the NexStar 11. One thing’s sure:  the StarSweeper is mucho better than the f/5 reducers we used in the bad old days.

I did break out the Denk for Saturn on the first night, and with the planet riding high as 3 a.m. approached, the view in a pair of 8mm Plössls was freaking amazing. I was just blown away, campers. The color variations across the ring system, from the dusky red of the Crepe Ring to the dirty yellows and snowy whites of the A and B rings, was amazing. The disk itself was highly detailed, with the banding beginning to look more like Jupiter's belts than the faint pastel smudges you usually see on Saturn.

Yes, as I don't think many folks will dispute, you can see more detail on the planets with a binoviewer than with a single eyepiece, no matter how good that single eyepiece. But that’s the Solar System, which has always been the beat of binoviewers. Would the Denkmeier Deepsky Binoviewer live up to its name? That was a question for the next night. Just as I finished admiring the ringed wonder, the sky began to degrade noticeably and Mr. Pat and I retired to the Holiday Inn for cable TV and, in Unk’s case, a large portion of the Rebel Yell.

Saturday dawned clear and reasonably crisp (it’s hard to escape humidity down Chiefland Way, even in November), and it was obvious it was going to stay that way. Pat and I hit the Chiefland Wal-Mart for some necessities—beef jerky (for the field) and Kolorado Kool-aid (for after)—and proceeded to the CAV to prepare for what would obviously be a long evening of deep sky voyaging.

Enough with the Cyclops-style deep sky observing. As the Sun sank, I declared my NexStar 11 a "single-eyepiece-free zone" and got the binoviewer ready to go on the telescope’s rear port. Using the 1.25" barrel version of the Denk was not a huge hassle. Yes, the Denkmeier II has some advantages beyond a 2" barrel, including superior coatings and tighter optical tolerances. The Standard doesn't give up much of anything optically that I could see, however, and I found its smaller barrel not to be a problem.

A good 1.25 – 2-inch adapter, my compression-ring-equipped Intes, in a 2-inch star diagonal provided a secure mounting for the binoviewer and I didn't miss the larger barrel of the more expensive Denk. The Denkmeier Standard is, like any binoviewer, heavy, especially with two eyepieces onboard, and you definitely want to use it with a hefty 2-inch diagonal and adapter. The StarSweeper reducer, which is a 2-inch accessory, can either be attached to the the nose of the Denk via an included adapter or screwed onto any 2-inch – 1.25-inch eyepiece adapter that is threaded for filters—which is what I did.

I suppose the most memorable view I had on Saturday night was NOT M42, though I did take a good long look at it once it cleared the horizon, natcherly. No, the hit was M33. With a pair of 25mm Plössls in the Denk and the StarSweeper screwed-on, it was perfectly framed. Big enough to show plenty of detail, but enough dark sky around it to provide good contrast.

The first thing I noticed when Bertha’s slew stopped at the Triangulum Galaxy was how easy it was to see spiral structure. The Pinwheel shape was prominent. This was a good night, however, a very good night, so to make sure conditions weren't giving the Denk a big leg up, I removed the binoviewer and switched to a single eyepiece, a 22mm TeleVue Panoptic. The spiral structure was considerably less evident. Back in went the Denk in a right quick hurry. The galaxy's huge HII regions, its equivalents of our Orion and Tarantula Nebulae, were picked off one after another, but the real treat was the tiny burning nucleus of M33 winking in and out.

Of course, there's always the question of brightness when using a binoviewer on the deep sky. There is no question that a binoviewer decreases the amount of light reaching each eyepiece. There’s a beam-splitter dividing the light between two oculars, after all. How obvious and serious is this? With the Denkmeier Standard, it was evident but not a handicap. Yes, when I went back to Cyclops-mode observing, I could detect an increase in image brightness, but not as much as I expected. Anyway, the increase in detail I noted with the binoviewer was well worth a small brightness penalty.

Did this decrease in brightness make any objects normally visible in the C11 disappear when I used the Denkmeier? No. I found any galaxy visible with a single eyepiece was also visible in the binoviewer. I took particular care to check this, and looked at a variety of smaller galaxies in the magnitude 12 – 13 range. Any that were visible in a single eyepiece showed up in the Denks as well. As with M33, brighter galaxies that had details to give up gave up those details more easily to the binoviewer than to a Cyclops-mode eyepiece.

Sumpin’ else kinda cool about the Denk? You sure can "wow" people with it. Being a recent convert to the binoviewing religion, I naturally wanted to do a little proselytizing, but I didn't really have to. The word spread that I had a Denkmeier, the only one on the field, and that ensured I had a steady stream of visitors wanting to check it out. One look at M42 peppered with "3D stars" and I had plenty of converts.

3D? Yep. Obviously, the tiny baseline formed by the distance between your eyes ain’t close to large enough to show any sky object in true 3D. However, your brain doesn't know that. You are looking with two eyes, so you MUST be seeing in three-dimensions. The faux 3D effect produced by a binoviewer is both beautiful and downright startling.

There were, by the way, several other brands of binoviewers on the field and I had the opportunity to compare their performance to that of the Standard Denkmeier, if not in side-by-side fashion. My opinion? For me, the Denkmeier worked better and was more comfortable to use. I do understand "comfort" when using binoviewers is a subjective thing, and that what suits one person might not suit another, but I can only report what I experienced, y’all.

Did I say M33 was my fave? Actually, my most memorable observation at Chiefland was not M33. Oh, that was great, but the greatest sight came in the last hour of the star party, just before it was time to head back to the motel in preparation for the drive home in the morning. Done showing off M42 to yet more visitors, I moved the scope to the nearby and normally subdued Running Man Nebula just north of M42 in Orion’s Sword.

In the past, I'd often admired the star cluster there, NGC 1977, but I’d never been completely sure I'd seen the nebula around the bright stars, the Running Man. It's like the Merope reflection nebula in the Pleiades; it's easy to mistake scattered light in the scope/eyepiece for nebulosity. Nevertheless, the Denk pulled-out the real deal. Not just haze around bright stars, but a big thing fanning off into space and showing surprising detail—including a dark central region in the shape, of, yep, a little running man.
What a night! Wish you'd been there.

And so it went Down Chiefland Way back in 2004, muchachos. What Unk wonders nearly a decade later is whether he'll still like the Denk as much in 2014 as he did in 2004.  I have hopes. And reservations—my eyes are certainly not what they were ten years ago, and I have never had a particularly easy time merging images, not even in low power binoculars. We shall see. Stay tuned.

Next Time: Revenge of the Return of the Denkmeier.

Comments:
Rod - After reading the Ioptron Zeq25 thread at CN, and of course the VX thread, what in your opinion the better of the two mounts. I will be using a C8. I've been real happy with my LXD75 but its time for a new "value" priced mount I think.

I do 30 sec images and stack them, so I guess I main criteria is round stars at 30 seconds.
 
Well, the thing is...I haven't used the ZEQ-25 or even seen one in the flesh. All I can say is I am very happy with the VX and do not believe the iOptron will equal it in goto accuracy, at least. ;)
 
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