Starhopper Overhaul

Being very short on time lately while still wanting to mount and use my new 8" f/6 Bob Royce refigured mirror, I purchased a Starhopper listed for local pickup here in Salt Lake City so I could use the mount. (I put my “Tent Snap Telescope” project on hold so I could finish the Starhopper project this weekend).

Swapping mirrors, I got the immediate gratification I desired (and found my Royce mirror to be excellent), but quickly discovered all of the Starhopper's shortcomings. So I went to work overhauling the Starhopper into a real telescope, with excellent results:

1) Stiffened the rocker box with aluminum C-channel

2) Moved the azimuth bearing pads from an inadequately tiny radius on the ground board to the corners of the rocker box and applied Ebony Star to the top of the ground board

3) Replaced the pitiful nylon altitude bearing tape with Teflon. Soon found this made altitude movement too smooth with the small Starhopper trunnions, so I added Velcro (loop side) to one trunnion--now I can switch eyepieces without having to rebalance and the alt movement feels just right

4) Better feet from nylon rod turned on my lathe--there were originally six short rubber "feet" that hardly kept the ground board off the ground

5) Made new azimuth pivot assembly

6) Rounded over rocker box corners and applied rubber T-molding to prevent abrasion that happens during transport

7) Swapped tubes for one I had stored away—new tube is covered with countertop laminate on the outside and black velvet on the inside (I had stored it because it was an early attempt at gluing velvet and it had some areas that didn’t stick well—oh well, perfect for this).

8) 2-inch focuser

9) Secondary holder assembly: nylon turned on lathe, steel banding strap for the vanes

11) Three comfortable handles—one for the tube and two for the rocker box to aid in repositioning as necessary during observing

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12) Cell assembly modifications…

The original Starhopper cell was designed for a conical mirror. I sold the mirror and the heavy upper half of the cell it was glued to. I quickly found that I really needed all that weight on the back end to keep the center of gravity low so the tube didn't bottom out in the rocker box. To remedy this, I bought two cast iron plumbing caps--ground one down to fit inside the other and welded them together, then painted the outer one and screwed it onto a rubber stopper I used to replace the original weak and insufficient collimation spring. Convenient: two birds with one stone/stopper.

Well, my tube had the focuser hole drilled already and was a little too short for my eyepieces to come to focus conveniently with this mirror, so I opted to move the rear assembly almost an inch out of the tube rather than drill an ugly new focuser hole. This meant making extension mounting blocks and a rear fan solution that is also completely outside the tube. Three fans should cool the mirror very quickly.

Finally, I took that compressed rubber stopper idea from my “tent snap telescope” and used it to wedge the battery in the rocker box. Battery slides out without much effort, but I made an RCA plug for my charger so I don’t have to—I just unplug the RCA cable that goes from the on-switch on the rocker box to a jack on the tube (for the fans) and plug charger into the rocker jack—makes life easy.

Woodwork is usually most of my telescope-making time, so this actually went faster than building something from scratch, even though I changed almost everything.

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