[JohnH]

Finally a clear night and I am able to use the qguider again.

I now have the Qguider configured correctly to work with PHD and find it to be a very light, sensitive and accurate guidecam. In fact it is far superior in this use to the Orion Starshoot I used before. Whereas I was limited to +/- 1 pixel with the color camera I am getting +/- 0.2 with the Qguider, this means I do not have to use a barlow (less weight/flexure and bigger fov). It really is a pleasure to see the guide field sprinkled with usable stars at 1s without having to use TEC.

Last night I did a series of 5 min shots of M8 as a test - I did no polar alignment - just placed the tripod in the normal spot set DEC corrections to go in one direction only (S) and let PHD 1.5 take the strain.

The result is attached...this is my best autoguided result to date but I still have a couple of questions so can I ask for some comments on the guiding please? To assist I have attached plots of the RA and DEC erorrs and associated corrections applied.

Guidecam exposure was set to 3 seconds to minimise seeing effects but I see fairly frequent and large spikes in RA, these all seem to be about the same magnitude and so I assumed these spikes are seeing related, however on reflection, if they were, I would have expected to see a similar frequency and size of spike in in DEC but that is not the case? The scale is 2.8" per pixel on the dx/dy plot and ms on the corrections plot. I have RA corrections applied at 0.7x.

If these spikes are not seeing related what is the most likely cause? Currently PHD "sees" these errors as real and attempts correction, the hysterisis setting and slow RA guide speed seem to have prevented this from causing wild oscillation but I would like to understand what is going on. Can seeing excursions really persist for > 3 secs at this sort of rate?

I plan to re-do this test using Guidemaster 2 for comparison.