[Paul Haese]

Final update - Problem solved

Firstly, I want to thank everyone who contributed to the thread. I would like it to be instructive of how to sort problems on an expensive mount if it is second hand and how to get things sorted on the software side.

My recommendations-

Don't use any other programs other than MaximDL, Pinpoint, Tpoint, Tpoint mapper and TS. This combination gives me 100% pointing plates solves except when an obstruction is in the way (ie cloud or roof or trees). Its plate solving has resulted in the model below.

Check your mount thoroughly. In my case I had an incorrectly installed worm gear (grub screws were lose) and the dec axis has a worn spring in the spring plunger assembly (soon to be fixed too but still operates at present).

Read the manuals several times and call mates to help in understanding and nutting out a fairly vague set of instructions (Rally I will have agree to disagree about how things are read). Use this thread as an instructive base for where to start. Each persons gear is different but some common aspects are present.

Check all the connections to camera and gear regularly, sometimes things slip or just work lose (this did not happen in my case but I just checked anyway).

Now for the piece de resitance, the model below is 181 points. Pointing without terms was 62 arc seconds across the sky. I got clouded out and could not finish a 250 point run but the model was reducing in arc seconds on each hit after 150.

The PA information on the first part of the model at 50 points showed no need to move the mount and so i continued on to do a larger run. It now shows that ME is nearing the refracted pole for my observatory and and the MA is just a touch out. Some mild refining could be done later but for now it is not necessary.

The fit information shows that the terms used were as per recommendations (that sigma should be around or less than half of the value applied). I used 6 extra terms to result in a 10.3 arc second pointing of the mount.

The scatter plot confirms that the run does not have the North South divide it had in previous runs, and this would indicate that the mechanical errors have been eradicated from the system. The remaining errors are mostly going to be lost in the noise.

Now onto imaging again. I did a test pointing at the lagoon through high cloud and the mount put the center of the image in the exact center of the lagoons cluster. Very happy with this results and relieved this matter is finally sorted.

Thanks once again for the help.

PS Brett I am thinking 15 seconds in MA is fine and something around your refracted pole is fine. In reality anything under a minute on each is pretty good. Just my opinion though.