Guiding spikes

GaryQ

I have attached 3 logs about my guiding. Is it possible you can look a them and tell me why the spikes are so large, especially in the Dec?

I can go from .3/.4 total to 10. in a very short period of time, then recover just as quick, but I loose data. Last night, 071723, I lost 25 minutes of data. On log 070923, i think the issue there was switching guide stars. But the next two nights were not.
Thanks for any help.

phd2-guidelog-2023-07-09-204438.txt

742kB

phd2-guidelog-2023-07-13-213111.txt

484kB

phd2-guidelog-2023-07-17-205215.txt

835kB

GaryQ

HELLO!!!!

johnpd

It would be useful if you gave us the equipment you were using: mount, primary scope and camera, guide scope and camera. The log does indicate the mount is the ZWO AM5 and the guide camera is the ZWO ASI290MM Mini. Also how long were your subs.
I am not an expert on this but in looking at the last log (7/17), it seems that almost all the Dec spikes are related to points where dithering has been executed. Log#2 (about 1hr 39m long) looks pretty good except for those points. Dithering appears to occur about every 6 min. Log#4 appears a little rougher with some RA spikes. There is one large Dec spike (@23:22) prior to one dithering occurring, but all the rest occur at the point of dithering. Imaging should be turned off during dithering so those spikes at dithering should not affect your images.

EDIT:
In Log#3 (21m) there was one point towards the end where you lost the guide star.

JohnD

johnpd

A few notes from the first guiding log (start at 23:53:44). There are about 6 Dec spikes unrelated to a dithering adjustment plus the last one (near the end of your first guide session) is huge and has a RA spike associated with it. Not sure what might have happened with that one.
#1: 21:10:38 -19
#2: 21:36:46 -10
#3: 21:46:22 -4
#4: 22:00:33 -6
#5: 22:14:56 -3
#6: 22:26:20 -100
[+RA spike] -55