Disappointing update to the EQ platform

Struggled with the EQ platform (see below) and only briefly observed M51. Used SharpCap Pro for the first time but without reliable tracking did not do any live stack.

About the EQ platform

Original setup

Before tracking, my sub frames were usually 0.2s or 0.5s.

Once I got the EQ platform, I was able to get 1s or 2s sub frames (and a few rare 5s).

Originally, the EQ platform used a hex bolt that was filed to be faceted. It was not great for EAA because the edge would cause jumps in the image. Also, after a while, the platform started skidding on the bolt. 

Mod #1 Anti-slip tape

I reached out to the maker of the platform. He suggested adding weights. Instead I decided to use anti-slip tape on both the platform and the bolt. Slippage stopped and the movement became smoother (except for some jerkiness when the tape was brand new). I was able to get 2s or 5s sub frames (and a few rare 10s). 

Unfortunately, the tape quickly wore off and tracking degraded (back to 2s max).

Mod #2 Gear and gear rack

Last few days, I worked on installing gears and a gear rack for smoother movements.

Initially I used a single gear. 

What I did not realize is that the board does not rest on the same part of the bolt as it rotates. It follows an arc not a straight line causing it to derail half way through.

So I bought a second gear, some low-friction sleeve bearings (I'm using a slightly thinner shaft so the bearings help it sit better through the holes of the red casing). When I ran a test, I noticed the board was moving faster which makes sense since the  diameter of the gear is around twice the one of the bolt. Because the motor drive speed can be changed, I did not foresee any issue from that. I also noticed the wood creaking and vibrating but only a real life test would tell me if that would negatively impact imaging.

Real life test of new setup

Taking advantage of the clear sky, I got to try my new setup. 

I found multiple issues:

- the gear can come loose from the bolt (if the set screw is not tight enough or come loose).

- similarly, the motor's set screw can come loose, in which case it no longer spins the bolt.

- the two gears don't stay in perfect alignment (maybe because it starts skidding a bit or it is tilted slightly when under load), so the teeth of one become an obstacle to the gear rack. The observed effect is the stars drift for a short while then jump back to their initial position (more or less) every few seconds. This constant motion means we are back to square one where exposure times can only be very short.