REVIEW OF SUMERIAN OPTICS ALKAID 16” TRAVEL SCOPE
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Starmaster 28 cm. ELT Shorty Dobsonian
- the aperture was large enough for resolving fine lunar and planetary detail, and for finding and observing detail in a large number of deep sky objects
- the focal length was short enough for comfortable "sit down" observing anywhere in the sky
- the scope's major components were light enough in weight not to damage my back, and could be set up in less than a minute
- the tube fit comfortably across the back of my Corolla wagon
The down sides were poor mechanical design, which I was able to fix to some extent, but not fully, and optics which, while decent, were not as good as those in my smaller scopes. The death knell for the Meade came when we bought a Passat wagon: while larger in most respects than the Toyota, the cargo space was slightly narrower, so that the Meade tube would only fit in diagonally, eating up way too much cargo space.
Two years ago I bought an Orion Argonaut 15 cm. Maksutov-Newtonian (actually made in Russia by Intes and sold as their MN61). The optics of this scope were better than anything I'd ever used in my life, and made me long for a larger scope with comparably fine optics, but with all the convenient features of my Meade Dobsonian.
My dream scope appeared last summer when Rick Singmaster announced a new model of his popular Starmaster ELT (Easy, Lightweight and Transportable) series: an 11" (28 cm.) f/4.3 truss-tube Dobsonian reflector. Starmaster Telescopes in Arcadia, Kansas, has in a few short years developed an enviable reputation for high quality Dobsonian telescopes, and all but their largest scopes use mirrors made by Carl Zambuto in Rainier, Washington, probably the finest mirror maker in the world today. His mirrors deliver resolution and contrast comparable to those of the finest apochromatic refractors available, but with much larger apertures at a much more reasonable cost. Starmaster had produced an 11" f/5.4 version for some time, but Rick decided he wanted a shorter version for his personal use since he, like me, prefers to do his observing sitting down. As soon as people saw or heard about this f/4.3 version, the orders started to flow in, and mine was among the first!
Starmaster 11" ELT Shorty, with Rick Singmaster at the eyepiece.
Many months later, in March of this year, my telescope arrived via UPS carefully packed in four large boxes. It took a couple of hours to get all the pieces together. What was immediately obvious was the beautiful craftsmanship of the scope: 3/4" oak plywood finished like quality furniture. The design is a bit different from the usual truss-tube Dobsonian. Rick uses industrial Velcro on the altitude bearings and there are only four trusses rather than the usual eight. I was dubious about this until I saw that the trusses are held under tension using captive hardware so that the resulting structure is extremely rigid. Provided I put the four trusses in the same four positions, the scope holds its collimation quite well when transported between viewing sessions. At home, I leave it assembled and move it from my garage to various locations in my yard using a hand cart from Home Depot.
The scope comes with a JMI DX2 focuser and Rigel QuikFinder as standard equipment. I prefer an optical finder, so I replaced the QuikFinder with a Celestron 7x50 illuminated finder. This upsets the balance a little but I fixed it by adding a 1 pound weight behind the mirror box. Knowing how common dew is around here, I ordered a built-in heater for the secondary; this is powered by a 9 volt battery.
One area where Rick differs from most other big Dob makers is in his method of mounting the primary mirror. Instead of using a sling, the mirror is supported by two solid pegs, each 45° away from the bottom of the mirror. Rick's thinking is that this is the way most mirrors are mounted for testing in manufacture, so it seems like a good idea to come as close as possible to this when the mirror is actually being used in the scope. Two more posts are located equally spaced around the top of the mirror, and all four posts have little toggles which extend over the edge of the mirror to hold it safely in place. There is about a millimeter of space left between these and the upper supports and the mirror itself, so the only points of support for the mirror in use are the three pads behind the mirror and the two posts at the bottom. It's a little bit unnerving when you point the scope towards the horizon to hear the mirror tip forward with a clank against the top restraints!
There are numerous small touches that tell you this is a quality product. There is an oak plywood cover held by Velcro over the primary mirror. The secondary comes with a fitted cloth bag to protect it, complete with drawstring. There is a roll-up carrying bag with compartments for the four truss tubes. A shroud made of elasticized cloth, so that it doesn't sag into the optical path, is also standard equipment. There's even a little oak dowel with a pad at one end which fits into the mount to keep the tube horizontal while cooling down or if you want to store the scope outdoors.
Because of its extremely short focal ratio, f/4.3, Rick recommends a Tele Vue Paracorr coma corrector be used routinely, and the mount is balanced for its presence. The Paracorr is dispensed with when using a Barlow lens or a binoviewer because of the longer effective focal ratio.
So far the Starmaster has proven to be absolutely superb optically and mechanically, well worth its premium price. It arrived rather late in Jupiter's apparition, so I only had one session under superior seeing, in which I saw a level of detail I've never experienced visually in decades of studying Jupiter. Features on Saturn and the Moon, such as the crepe ring and the Catena Davy, which are generally challenging to see, are dead easy with this scope. On the few nights I've had it at a dark sky site, I've been amazed at the wealth of subtle detail visible in bright objects, such as the spiral arms of M51, and the ease of spotting really faint objects. Good optics are just as valuable for deep sky as for lunar and planetary observing.
Since I knew I would be using this scope a lot for the Moon and planets, I ordered an Equatorial Platform from Tom Osypowski in California. This is a motor-driven platform upon which the Starmaster sits. This gives 1 1/4 hours of equatorial motion before the platform needs to be reset, which only takes a few seconds. This arrived a couple of months after the scope itself, and has proven to be a great enhancement. Besides the tracking of solar system objects, it gives the deep sky observer the best of both worlds: a scope with all the ease of movement of a fine Dobsonian, but which tracks automatically as soon as it's let go. It becomes easy to locate a star field, and then let the Platform hold it in view while consulting the star chart as to the next part of the star hop. The tracking is sufficiently accurate to allow lunar and planetary photography and piggyback star field photography.
Although I'm extremely satisfied with this scope myself, I quickly noticed
that it had a strange effect on the people who saw it at public star parties
this spring. Despite the fact that this is the most expensive and finest quality
scope I have ever owned, the most frequent question I get from the public is
"Did you make it yourself?" It seems that the Dobsonian design itself
is so different from the popular conception of what a telescope should look
like, that people have a hard time coming to grips with it. The other problem
is that its most obvious construction material is wood, again not something
the public associates with precision instrument making. My only answer to this
attitude is to invite people to take a look through The Munchkin (so named because
it's short, and it's not in Kansas any more)...the proof of the pudding is in