Ok, I’ll eat my words.
When was it? Last week, perhaps, or the week before? That I tried binoviewing once more and swore that would be my last trip down that road?
See, I have ventured into binoviewing a total of five times now over several years. My most successful experience was with an early Denkmeir and they worked best for me on the 8-inch SCT I had at the time. That was about six or seven years ago. I’m not sure why I stopped using them. Perhaps just too much of a bother to change powers – and they were rather big and awkward and subject to getting knocked about.
Since then I’ve tried the closely related Earthwins and had to return them because – as with the Denks – found them too large, and awkward, and complicated to use – especially for the kind of public outreach I was doing then. You can’t have people line up for a view and then spend half the time adjusting the binoviewers for each person. Too bad, because the view can be absolutely stupendous as I found last night when I approached a new, inexpensive pair with an entirely different attitude.
Yes, your approach and expectations matter. In this case I made up my mind that I would treat the binoviewers as if they were a pair of binoculars with fixed eyepieces and that’s all I would use for that observing session. That’s much different than the mind-set you have when viewing in cyclops mode and frequently popping in one eyepiece or another with little to do but make a slight focus adjustment. That approach can’t be taken with binoviewers where they can:
- radically change the scope balance on a mount
- the interpupillary distance may need to be changed
- the focus will change considerably – I mean considerably – from a single eyepiece to a binoviewer
- the changing focus can mean with a SCT enough image shift to actually lose sight of your target, or at least require recentering
- the individual eyepieces may need to be adjusted so they show they both are in focus
- and, depending on design, you may have to pull the binoviewer out of the diagonal and screw on a barlow lens just to get them to come to focus in a refractor – hey, in my case I also had to change from a 2-inch diagonal to a 1.25-inch one
Bottom line, that’s a lot of screwing around. Denk, Earthwin – and perhaps others – get around some of these issues by adding lenses that slide in and out in a patented mechanism, thus giving you two or three different powers with minimum hassle – but also adding bulk and weight to the whole set up.
So, my solution? First, i changed my mind set and expectations and it turned out to be a real lesson in how expectations relate to perceived outcomes. As i say, i decided to treat the binoviewer/scope combination as if it were a fixed-power binocular – with the bonus that with some hassle I really could change powers, but it would be more involved than with a single eyepiece and I shouldn’t do it casually. This mindset actually complements my observing philosophy where I think too often that I tend to flit around too much and not stay on target long enough.
Second, I bought – new for $179 – a pair of the Chinese imports from Orion – simple, light weight binoviewers, and as it turns out, quite effective in terms of my lower expectations. In these I settled on a pair of 20mm TV Plossls and I decided to use them primarily in the observatory with an 8-inch Meade SCT – a typical alt-az “go to” set up where most of the time I ignore the “go to” part, but take advantage of the tracking. Tracking also encourages time on target and makes using the binoviewer less stressful.
And I loved my initial experience despite really crappy conditions – a nearly full Moon, way too much dew, and high clouds frequently interfering, not to mention abysmal seeing.
The detail on Jupiter was terrific even through a dew-covered corrector plate. The Great Red Spot just jumped out at me – despite the moon being right next door. And I know it’s just our mind playing tricks on us, but damn, Jupiter looked like a sphere rather than a disc! And the Moon? Hey, it was like taking a helicopter ride over a landscape that was fascinating even though mostly flatly lit. Almach, a favorite double, was pretty darned good as well – and I was transfigured by my view of what I regard as a Klingon Warship – the brighter stars of the open cluster M34. That cluster has a fascinating set of pairs as well and even though the Moon was washing it out and the binoviewers stealing some of the light the 8-inch mirror was gulping down, I was transfixed. I even liked the view of M31/32, but by this time I was struggling with clouds and quickly gave up trying to spot M110 in the moonlight and mist – and yes, I did put the 2X nosepiece on and it did give a nice view of Jupiter and the Moon, but I need more time with it.
So I came in, jotted some notes, then decided there were enough sucker holes to give this thing a try on the TV85 – at least find out if it would come to focus. So I put the LXD75 on the deck, didn’t bother with a battery – just slapped the TV85 on and pointed it manually at the Moon – big blob. Uh huh. Put on the 2X Barlow – and Orion does warn you that you may need this to reach focus in a refractor. Nope – didn’t do the trick. So I took out the 2-inch diagonal, put in a 1.25-inch diagonal and tried again. This time I could reach focus as long as I used the 2X Barlow. Eh – not bad, but I would have to have real good reason to change things around that much. Binoviewing is nice, but for now I think I;’ll consider that the TV 85 is a clyclops scope – and I really don’t want to try the binoviewer on anything smaller both because of light loss and weight.
The Orion isn’t the weight of the Denk, but it’s not light. The Denk in the old Big Easy package I had most recently used – no special switches or anything – weights 20 ounces. The Orion is an ounce or two lighter. But add the switching mechanism to the Denk and it really bulks up and the price is much more. I guess price was a major factor here. I could accept the idea of the binoviewer/scope as a fixed-power binocular at the $170 price of the Orion – not at the $500 price of the Denk Big Easy.
Truth is, the Orion binoviewer, even with an extra Plossl eyepiece counted in is roughly the equivalent of one my Naglers on the used market – so this is a binoviewer I can treat as another eyepiece. Again – frame of mind – it means a lot. 
Anyway, somewhere I had read – I think it was in the Denk literature – that you shouldn’t use the binoviewer with a focal reducer on the SCT. Hmmm. I wanted to give the C6 SCT a turn with the binoviewer through the next sucker hole and there was a focal reducer on it. Certainly would give me a wider field and make finding things easier. Hell – I left it on. And guess what – no obvious problems. I need to investigate this more, but my first impression was” “I love it.” There was the Moon again, looking like a 3D globe with some space around it – 47X in a six inch by my calculations. Now that’s a nice step up from my 20X60 binoculars. Yeah! Lot’s of possibilities there.
I went back in, put up a “wanted” ad for a pair of 15mm TV Plossls and quickly ended up with an offer for some 13mm of the old Circle “NJ” type. I like those, so I bought them. I also think the 13mm a better choice in terms of powers with the C6 or the eight inch than the 15mm. SO given the focal reducer, this is what the two sets of eyepieces – 20 and 13mm Plossls, plus 2X Barlow – wo;; offer me.
In the 8-inch I will then have 100X, 154X, 200X and a mostly unusable 308X – on the C6 with focal reducer the range will be more reasonable:
47X, 73X, 94X, and 146X
Take out the focal reducer and the C6 goes from 75X, 115X, 150X, and 230X – not too shabby.
But, of course, I need to return to my mindset of fixed binocular. Switching this stuff around won’t be that easy. In fact, the only relatively east switch will be to just change to the Barlow. See, changing the eyepieces means refocusing each eyepiece individually. Something that goes smoothly enough, but. . .. well, I need experience with the system with both sets of eyepieces and I won’t have that second set for about a week. It’s on its way now from Canada. Then , given the price, maybe I should get another Orion and put the 13mm eyepieces in it, then treat the two binoviewer as if they were individual eyepieces, putting one or the other in the diagonal. Don’t laugh. If the convenience factor is important enough and I continue to really enjoy binoviewing – and I do like using both eyes – afterall, it’s what most people are born with, so . . . stay tuned.
Oh, and about those new binoculars . .. .
Yeah, there was more going on than binoviewing this evening. I was also putting Ed Zarenski’s advice to the test and finding out that I probably do have some astigmatism and this is what has frustrated me with low power binocular use – especially when trying to split doubles.
The binoviewers arrived yesterday just a few hours after UPS delivered a new pair of Pentax 20X60 binoculars. I put them on the P-mount and in darkening twilight – and a whole lot of moonlight – was able to see all four moons of Jupiter with ease. With the 1030IS I could see three moons – two were close enough together to blend as one. OK – that’s inconclusive. I was also able to split Albireo. That was more encouraging, though it was hard to judge because seeing was so poor.
But later the trees moved enough to give me a quick shot in yet another sucker hole at Mintaka. With the 10X30s I could detect the secondary – with the 20X60 mounted I could see it just as plain as could be. That’s encouraging. But the important note here is that I have tried repeatedly to see Mintaka with the 15X70s mounted and can’t. Now that might relate to objective quality, but I suspect what it relates to is exit pupil and an undiagnosed problem I think I have with astigmatism. The 15X70s have an exit pupil o f 4.6mm. The larger the exit pupil, as Ed pointed out, the more problem you will have if astigmatism is an issue. The exit pupil with the 10X30s and 20X60s is the same – 3mm. And with both those binos the primary settles down enough to allow me to see the secondary. The extra power and light grasp of the 20X60s just makes it easier than with the 10X30IS.
Don’t get me wrong. I still love IS and I still want the Canon 18X50IS at some point. The exit pupil would be even smaller – BUT, their cost is prohibitive right now. Maybe after I sell a few more things
