Small telescope quest reloaded: the PICO-6 60mm MaksutovJune 26, 2016
This came a couple of weeks ago. I got it from Kasai Trading in Japan – here’s the link. They market both a 60mm Maksutov-Cassegrain, which is the PICO-6 shown here, and an 80mm Mak-Cass called the PICO-8. These appear to be the same scopes as those sold in Europe as the Omegon MightyMaks, which are available through Astroshop.edu (here) and Amazon.co.uk (here).
It’s been a while since I posted about small scopes, and after getting the little SV50 refractor nearly six years ago, I declared my small telescope quest complete. But the SV50 turns out to be a more satisfying finder than stand-alone scope, even for air travel. For deep-sky work when I’m traveling, I’m usually happy with binoculars (most recently on the Channel Islands), but sometimes it’s nice to check on the planets, too, and the SV50 just doesn’t have the reach.
I thought this little Mak might be just the ticket. As you can see, it is tiny. It weighs just a bit over 1 pound. Here it is with a regular-sized beverage bottle and my largest eyepiece, the 2-inch 32mm Astro-Tech Titan.
And here it is next to the SV50. The SV50 has a focal length of 210mm and a focal ratio of f/4.2. The PICO-6 has a focal length of 700mm and a focal ratio of f/11.7, which makes it roughly equivalent to the 60mm refractors sold by any number of astro vendors. I actually tested the PICO-6 side-by-side with London’s 60mm f/11.7 Meade refractor. The refractor threw up a brighter image – no shock there, since it’s unobstructed and has no mirrors to reduce light-throughput. But much to my surprise, the PICO-6 was a hair sharper: it could resolve fine details and split close doubles beyond the reach of the refractor. The differences weren’t dramatic, but they were there.
The PICO-6 comes with a dovetail bar and a brass compression ring in the visual back. Both required a bit of work. You can also see two of the three collimation screws in this photo.
I could not get a diagonal to seat in the visual back. After some investigation, I found that the brass compression ring could not fit neatly down into its groove. It had been poorly made, and had an extra flange of metal in two places that made it wider than the groove. It was the work of 5 minutes to grind down the extra width with my Dremel, but it’s still pretty disappointing. I don’t know how these things are made, but it seems unlikely to me that anyone could have seen this and not known that it was a problem.
Also, on the Kasai Trading “Dear Customers” page (here), under the heading “Quality Inspection” it says (courtesy of Google Translate):
Astronomical telescope of our handling is through the “Jisshi inspection” all by Kasai will be shipped to the customer. This is a test carried out by actually seen the night of stars, most practical-world, but the one that is adopted for performance is a test, it takes time and effort, also takes place on the night of good clear weather of seeing because it can not be accurate inspection unless, depending on the weather will give sometimes can not keep our promise of delivery date. Excuse me, please understand that effect.
That makes it sound like all of the scopes are star-tested before they go out to customers, but that clearly is not the case, because the scope I received was unusable until I fixed the visual back.
UPDATE: I was mistaken. According to Mr. Kasai in an email to a Cloudy Nights user, all of the scopes are tested before they ship out, but when they test them they unscrew the visual back. Here’s the key quote, and the “somebody” he’s referring to is me:
Also I dare to emphasize the fact that we do perform visual test on each unit with artificial stars – to check the residual aberration, collimation and mirror shift. Somebody who bought PICO-6 suspected us of this fact, as the brass ring in the eyepiece adapter was bent and it couldn’t accept an eyepiece easily. I feel sorry we forgot to check this defect on this case, but still this has nothing to do with our visual test.
Full message here.
So, I guess they do test them all. I still think it’s dumb to test all the scopes optically but not mechanically – sending out a scope that is unusable until one of the parts has been further machined is arguably worse quality control than sending out a scope has some spherical aberration. But at least they are optically tested, and I retract my claim that they aren’t.
The dovetail bar is also a bit wonky. It’s a couple of millimeters narrower than the Vixen/Orion/Celestron standard, so it will fit into a standard dovetail slot, but you really have to trust the thumbscrew because it will be the only thing holding the scope into the mount. I solved this by putting the scope on a dovetail shoe for the pistol-grip ball head shown here – by design or coincidence, that shoe is a good fit for standard Vixen dovetails. With the help of that shoe, I was able to use the scope with my Universal Astronomics DwarfStar alt-az head. More on that soon.
Now, it may sound like I am down on this scope. I’m not. I wish the quality control was a little higher, but the problems were not unfixable. At least for me, with almost nine years of experience tinkering with telescopes – I can’t recommend this scope for anyone who isn’t prepared to do some work on it. And optically it’s okay. It arrived out of collimation, but with a little help from Polaris I was able to get it tuned up enough to catch Saturn’s Cassini Division and split Epsilon Lyrae cleanly into all four components at 117x. After the mechanical difficulties with the scope, that was a welcome surprise.
Then I flew with it, but that’s a story for the next post.