Question M 1 + APT + MGEN2 or MGEN3: spontaneous drift during guide: "stall"

Hello,

I encounter sudden guiding "bars" (not only short spikes but for several seconds) which seem to happen randomly.
MGEN2 or MGEN3 is connected via ASCOM (actually no other workaround in APT). The dithering after each image runs regularily.



personally my impression is this happens more likely when pointing to the zenith.

@Stefano:
is this possibly something similar to this topic (ST5 / keypad)?
www.avalon-instruments.com/forum/install...o-mgen-ii-guider#882


update:
my impression is it seems to be a kind of backlash problem - with a backlash-free mount?
How can it be?

like here:
www.avalon-instruments.com/forum/welcome...uiding-assistant#904

any help really appreciated, thanks!

cs Peter

Peter, I am also seeing significant DEC backlash and can only dither RA. When I look at a DEC dither on the PHD2 logs it can still be settling 30 -90 seconds later depending on how big the dither is. I noticed that PHD2 will issue a settled command back to the imaging software and sometimes the DEC axis is still moving. So those streaks you see might be the movement at the start of the image capture while the DEC axis is still moving.

If the dither command sends the DEC axis in the same direction it was previously moving then there is no backlash to remove and it will settle before the image capture.

The attached picture shows a dither in which it took a long time for the DEC to finish. You can see PHD2 gave a settle failed before it was finished. I did have some small tails on stars for that capture.

Try to dither in RA only and see if that helps.

Rick

Rick, I could solve this particular problem by making APT a longer pause after dithering; the exposure began when settling after dithering was not yet completed.
2nd: APT finally has native support for MGEN3 guider; earlier connection was "only" via ASCOM which in my case caused problems.
3rd: I keep the keypad always connected; taking it off led to problems in my case
cs Peter