Ad Astra Observatory

Armed with the final measurements, I started prototyping the lower tube clamps. The angle is really extreme on the lowers. I wonder if I had gone to 4 rings if maybe I would have either gone from corner to center on the ring pairs, or whether I would have ended up doing straight trusses, because those angles would have started getting really crazy.

The first prototype looked good, but the spacing between the struts was way too high, like 22″ or something.

So I scratched my head for a long time, then more or less arbitrarily chose a new bevel angle for the second prototype. That one came out pretty close (at least I think it’s pretty close — it was starting to get late), so I decided to drill the rest of the pole clamps.

I have to say that I’m not as confident in the lower assembly as I was in the upper. I’d done a few more prototypes on the UTA, and with fixed pole lengths, there were fewer variables to deal with. But, I decided that, even if I’ve messed up all 6 LTA clamps, the worst case scenario is that I have to re-cut the tubes and re-drill the clamps, which is a bit of a waste of time, but isn’t all that expensive of an error. Besides, I may decide that straight trusses work for the bottom half of the scope. 🙂

Anyway, I drilled all 6 clamps. I just need to cut them apart in the morning, and assemble them, and I’m ready to cut the tubes and have a fully-assembled OTA!

Next steps:
– cut the clamps
– assemble the clamps
– cut the tubes
– attach the clamps to the 2 LTA rings (note: the center ring is going to be problematic, nothing for it, just work it out — maybe those 4″ bolts or threaded rod might come into play…)

Once that’s done, the OTA is all together. Then the only thing I have left is to figure out how to reattach the mounting plates. I extended the LTA a bit, so I have to create some kind of bracket. Crossing that bridge when I come to it.

Since it’s going to be tough having a new OTA around with no mount, I might spend tomorrow afternoon knocking together a Dob mount for Trixie. We love multitaskers.

It’s late. G’nite.