|
Thanks for all your suggestions. I am pleased to report that I was able to guide in both RA and Dec on the weekend - a first for me.
From what I can tell, PHD tries to calibrate in both RA and Dec - if for some reason it can't calibrate in Dec, it turns off the Dec guiding which explains why my guided photos looked lousy over about 120 seconds.
Steps I took to sort it included:
1. I adjusted the balance on my OTA
2. I dumped version 5.1 ASCOM and re-installed version 4.1. I then replaced the Meade driver with the modified driver on Craig Stark's site. This enables pulse guiding
3. I removed the backlash adjustment from my Autostar - it was set at 10% so I took it down to zero.
4. I manually took up the backlash in 1 direction (north I believe) before calibrating.
Still no joy
Then the clincher - I increased the pulse setting for calibration from 250ms (the default I think) to 1000ms. Hey presto, it calibrates in Dec and I'm off.
Of course the clouds then came in but I had time to shoot off a 5 minute shot of Orion at ISO 100. This is quite a breakthrough for me and I'm pleased as punch - to do this and finally get a handle on drift alignment in the space of a month leaves me feeling quite chuffed.
Here's the Orion shot. It suffers from coma as the OTA is a Schmidt Newtonian (MPCC is on back order), the colimation is a bit out and the camera doesn'sit quite square on the focal plane as I need to have the Tring sitting a bit out from the extension tube to bring it to focus - hopefully the MPCC will deal with this too.
Having said all that, I think this a good shot at more than twice the exposure I have been able to achieve before.
Pete
|