Ad Astra Observatory

With the new “rake” and “splay” angles calculated, I cut out a 30°rotation jig, and was able to bang out another prototype when I got home. I should have spent a couple more minutes on it, getting the hole spacing right, because I think this new block is a winner.

I was so confident that I had the block nailed that I went over to a friend’s house to have the upper truss poles cut to length. They end up being a hair shy of 36″, but it won’t make a difference to the angles, and they are all the same length, which is most excellent.

I also picked up the rest of the thumbscrew knobs; of course the hardware store only had 11 of the 12 I needed; one knob will be mismatched until I can get my hands on another one.

I bought some 1/4-20×4″ bolts, too. I like the pan head ones best in initial testing. I need 12 of those, too.

I tried to minimize the spacing between the poles. That didn’t work out. So I went back to the 3/4″ spacing that I’m running right now.

Once I got the hang of the rotation jig, things went pretty smoothly. I was able to end the night with 2 identical clamps, which allowed me to put 4 of the truss poles into a configuration that stands on its own. Neato!

I need to go get some more 2x4s from the scrap pile (although I’m nearly ready to decide whether I might want to just bite the bullet and buy some hardwood to do this) so I can start cutting out the 6 blocks for the upper truss. If I have enough 2×4 on hand, I should be able to cut the remaining 4 (or all 6, if I change wood) Saturday morning. Installing them will take some serious time. Then I have to work on the middle ring, and once that’s done, I can start testing focal length to determine the length for the lower truss poles.

One step at a time.

Next post, I hope to have the upper truss clamps complete.

A very productive night.