Ad Astra Observatory

Trixie’s new OTA is complete.

I woke up this morning with a significant to-do list. I had to complete the LTA clamps, cut the LTA tubes to length, and construct the LTA.

I cut the clamps first thing, but then had to sit around a bit until my buddy with the metal-cutting saw got home. I finally decided to cut them myself, and went over to Dale Hardware (a most excellent hardware store if you live in the area) and picked up a bucket for my new Dust Deputy and a metal blade for the chop saw. John called, so I decided to take the tubes over there instead.

The tubes took a lot of cleanup, so I was about ready to build out the truss around 3pm or so. I put it all together, and…

my decision to change the cut angle was in error. The truss wasn’t sitting properly on the rings.

I hemmed and hawed and finally decided to cut out a new set of LTA clamps, with the original bevel angle. I’m getting pretty quick at cutting out clamps, but I have to admit I’m getting a little sick of it. I’ve probably carved enough to make 3 telescopes by now.

The new clamps worked perfectly.

I attached the clamps to the middle ring first (through-screwed into the ring and a little into the UTA clamp), then to the bottom ring.

One last trip to the hardware store for some extra screws, and suddenly, Trixie is reborn!

The OTA is still pretty light; 35.5# without mounting plates. That’s about a 10# difference from the original build with the straight trusses, but feels significantly lighter than the final layout, with strings, turnbuckles, etc.

The scope is a real pretty beast right now. All those truss triangles look really awesome. It’s like a testament to the power of trigonometry.

If you see the scope form certain angles, it plays optical illusions, making it look like it’s all skewed:

One last shot:

Tonight I’ll collimate. Then I can watch stuff go by zenith until I get a mount settled.

The hard part is done, but there’s still a couple of things to do.
– attach the mounting plates
– figure out where to put a finder
– sand and varnish all the new parts
– replace the two temporary clamp knobs (hardware store only had 11 in stock, and it turns out one of those was a 5/16, not 1/4)

The varnishing is tedious work, but other than that, everything left is pretty straightforward. I can probably figure out the mounting plates in an hour or so.
I’ve also been thinking that I want to build out a Dob mount for Trixie, so that I could, theoretically, use it for visual while the NJP is doing something else. I have a 10″ dob mount lying around, but I think I’ll probably have to build something from scratch. The idea is to attach side bearings to the mounting plates (maybe with DAs?) so they can be removed and the scope converted back to an astrograph easily.

I’m excited to try Trixie out again! I hope that this time, the flexure problem will be gone, and I can finally give Trixie the photography workout she deserves.

It feels good to have the tough part behind me.