One of my mounts is a Tak NJP and has quite low PE to start with.
I have always gotten best results with 1 second autoguiding exposures.
Others have said that is too fast and its better to have longer guide times. That is not the case with my mount. The argument against it is the mount could chase the seeing. But if everything is turned down and not too sensitive I find I get the best results.I did find once or twice that 2 seconds was a bit better when the seeing was poor (in summer) I find 4 secs the PE has built up too much.
Where I image the seeing is usually fairly good and that helps too.
I also have the aggressiveness turned right down and use the lowest correction rate. So its gently gently so its not correcting the last overcorrection all the time.
I also find with guide stars that some give better guiding than others. don't pick a double or don't pick a guide star with another similarly bright star nearby.
I take a 1 sec image at full frame, then I click on subframe (CCDsoft) and drag a rectangle around my guide star of choice. Now the frame is only a partial frame of the full frame (I don't want a brighter star coming into the frame and confusing the software).
I get X Y errors routinely under .1 pixel with the occasional .25 but usually in the range of .05 to .20 pixel errors. This will give me round stars.
Also check no cable drag and your scope is well balanced. Sometimes you get bad errors and its confusing and its because a cable is dragging on the scope.
The first thing to check with bad guiding errors is balance and then polar alignment. An accurate polar alignment makes everything easier including your go-tos.
Greg.
Quote:
Originally Posted by Paul Haese
That is an interesting point Greg. I had thought that this camera was more sensitive than a DSLR. And; like you say I should not be treating the camera as a DSLR. So 10 miute subs it is. I just have to get my off axis guider co-operating so that guiding is better. Not sure what is going on there as I thought I had guiding nearly sorted with the guide scope. I have some bad egg stars. Perhaps another look at polar alignment and guide parrameters.
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