Saturday, August 30, 2008

set up a Dob

Yesterday Ian W told me he had brought up his home-made 12½" Dobsonian telescope. He planned to set it up for visual astronomy (while he had his refractor taking CCD images).

I asked if I could do the set up. Get some experience with a large truss-tube Dob. He said, "Sure!"

So, after reviewing the weather data from his trailer, Ian suggested we do it now. OK! We said hi to recent-arrivals Lora, Phil, Skeena, and Callebaut and got to work.

We unpacked the gear from his pick up truck. The base and upper assembly were stacked together which required the two of us to hoist. The tubes were in a separate canvas bag with a handy (and clever) shoulder strap.

I removed the bungee cords from the assembly and lifted the top piece (with focuser, secondary mirror, spider) clear. It was surprisingly light.

We inserted the hinged tubes into the base but did not tighten them down. I lowered the upper assembled onto the hinge points of the truss. Cam locks secured the upper assembly. Then we tightened down the tubes in the base.

Ian W is a distributor for Dobsonian truss covers. So we fit the Spandex cover over the tubes. And with that we were basically done. At least the main things.

We affixed the Telrad and its heater. We attached the 9x50 finder scope and its heater. We ran the power conduit from the upper to the lower assembly. We attached the digital setting circles hardware and associated cabling. Ian had done some clever things. By integrating junctions for the dew heating equipment in the upper and lower assemblies, it kept the neat and tidy. Finally, we inserted a flocking paper-clad semi-circle plate behind the focuser.

Overall, the whole process was not long. You could probably do it all in 5 minutes or less, once familiar with the steps.

It is a beautiful telescope. Stunning workmanship.

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