If you are new to this post thread it might be a good idea to check back on a few posts to see where this project started and how it has evolved:
I managed to drag myself out last night to test the new tracking mount under a clear (suburban light poluted) sky. It felt like there was a million different settings to get right for this to work. I used the PDH (http://www.stark-labs.com/phdguiding.html) software (version 1) to interpret the image from my webcam to decide how to adjust the tracking system in right ascention (RA). I do not have any way to adjust declination (Dec) and therefore that part is ignored.
After I set the tracker up on the Meade tripod and made a very mediocre attempt at polar alignment I started up the tracking/guiding system and got nowhere. I could not figure out why the guidestar was drifting west no matter what I do. Agter a while I discovered that my Arduino sotware still had the step directions in the same way as my previous mount used and that it was driving the wrong way! After a quick edit to correct this I tried again and at first thought that something was not working because it looked like my webcam was not sending updates to the PHD software. I opened the tracking graph on PHD and saw that the tracker was actually tracking very well for a system that was not optimised at all. I got a correction graph that was ±3 pixels accurate. The guiding was very jumpy and this is probably due to my asymmetrical Arduino software stepping rates for the +RA and -RA ST-4 interfaces. Should be easy to fix this for the next try. I will try to smooth out the tracking to control the sudden RA events. Here is an image of the RA tracking graph from PHD. The grid is spaced at 1-pixel increments on the y-axis.
I downloaded the log file and used Excel to create a graph of the RA data:
These two graphs are not from the same tracking period but shows the typical results I achieved last night.
The proof of the pudding lies in the results. I took a five minute (302 seconds) with a Canon 600D, Canon EF-S 60mm lens at ISO200 and f/2.8. The image shows a sudden jump in the mount and this might have been me or one of the overcorrections that I have to smooth out in the guiding settings. (Please ignore the rest of the image as I was only interested in the tracking performance.) Click the image for a larger version.
I was surprised to see that I captured a small galaxy in the image! It turns out that the galaxy is the Sculptor Galaxy or NGC253.