JMI Reverse Binoculars

Here are my inexpert comments and experiences of the JMI 6" Reverse Binoculars, which I used on 05Sept2010 at New Mexico Skies, Mayhill, NM.

This instrument ... or these binoculars... (singular or plural?)... make for an interesting night of observing! The odd thing is they are aimed over your shoulders, so you look down into the eyepieces. This doesn't really take long to get used to, though. Also, you "steer" the rig with handle bars, which is kind of fun.

The instrument was mounted for me but not aligned. The alignment process is not difficult but is best performed with two people. Since the instrument is a basically pair of Newtonian reflectors, they sometimes need to be collimated (aligning all the mirrors). This was the case this night, but unlike my experiences of trying to collimate my own Newts, this was relatively painless and aided greatly by being done by pushing a couple buttons. Focusing is also relatively easy and need only be done once for the night -- assuming there is only one observer, that is. At any rate, focusing is also done by push-button, and so is changing the distance between the eyepieces. Push buttons make it fun. Yeah, I'm easily amused.

I was expecting a pretty strong 3-D effect, but that didn't really play out. There was a sense of it a few times, like with the Lagoon Nebula and some other larger targets, but generally the views were not unlike a regular telescope.

The quality of the views optically was probably not equal to the CPC 11 from the previous night, but good nevertheless -- generally bright and clear. Objects started going out of focus or getting streaky toward the edges. This wasn't really a problem, but more finicky viewers might take offense. I'm not sure if that is a function of the instrument or the eyepieces or the combination of the two, to be honest. There is only one set of eyepieces (20 mm), which meant not having to refocus all the time, which would be a pain. I would have liked to have had more magnification for some targets, but the 20 mms  provided a good experience with generally enough magnification and enough field of view for most objects.

The two great benefits of the binoculars that I found were that eye fatigue was greatly reduced and that images were better than a single 6" scope could provide. Since you don't have to close one eye or split your vision between two different views, my eyes didn't get tired at all, and I had none of those episodes when I just have to look away at something else for a while that usually set upon me. Also, after looking at a few objects with one eye, then the other, then both, I was amazed how very much better the binocular image was! The brain does a wonderful job using both sets of data to improve the single image. This made using the binoculars well worth the experience.

The computer with the digital setting circles took a bit of getting used to, but proved to be very useful ultimately. It's a Sky Commander. The mount is alt-az (that is altitude and azimuth, which is sort of like aiming a cannon -- swing it around, tilt it up or down), and there is no motor drive, so it's like a Dobsonian with two tubes. The computer has a wide variety of catalogs, most of which I've never heard of. I used the Messier mostly with occasional NGC entries. The NDS catalog took me a while to figure out -- Named Deep Sky! Ah! Then it was very useful.

The mount was quite solid, and wind gusts didn't upset things much or for long. The handle bars were kind of loose at first, which introduced too much play in locating objects, but once I figured out how to tighten them it was much better. There was still some play, though, and the azimuth movement was not particularly smooth. Without a tracking drive, that made constantly recentering the object (which must be done without a tracking drive) a bit more annoying than it needed to be. This might be a matter of some fine adjustment that one would do on a permanently mounted instrument, whereas this one gets put away when not in use.

Despite the difficulties, I had a good and satisfying night out, enjoying many objects (see "A List, Part 2, or Another List"). I don't know that I'm sold out on big binocs yet, but there are definitely some advantages:

• Better views per inch of aperture
• No eye fatigue
• Although there is still some awkward standing for middle-low objects if you don't have an observing stool, there is much less neck-craining.

 So if someone offered me my choice of a CPC 11 or the 6" reverse binocs, I'd probably take the 11, although I'd have to think about it for a little bit. If someone offered me the 6" binocs straight up, I wouldn't hesitate to take them. ... er, it. Whatever.

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