HEQ5 guided worse than unguided

[symmetal]

During the last three days of good weather I can't get a decent image with my ASI071 and ZS61 on an HEQ5 without having oval or sausage stars. Up until then I had no problems. Running out of ideas I tried 5 min unguided just to see what happens and the image was much better.

Here's two subs in SGP and the PHD2 trace. Just noticed I put ZS71 by mistake in the label bottom right. For the unguided section I just ran the guiding assistant. This is one of the better guided subs. Often they're much worse. RA is horiz and Dec is vertical and the camera and guide scope are pointing at the same area. PA was within 30" using Sharpcap. The Dec drift unguided is around 1.5" in 5 mins which is not bad. Everything's bolted down tight with no flexure. No wind either.

The PHD2 movement indicated particularly in RA unguided is greater than guided. The elongated stars are generally on a diagonal not always the same one.

My Atik1/FLT98 on AZ-EQ6 imaging at 1.9"/pixel with guide scope at 6.19"/pixel often has similar shape guiding graphs to the HEQ5 and sometimes worse when at low altitudes but I have no problem with misshapen stars and they're still tighter stars than on the ASI071.

Anybody have any ideas on what the problem is? I'm a bit stumped. 

Alan

[bottletopburly]

Have you checked pulse settings haven’t reset themselves to default 0.1 I have had Eqmod do that before my Eq6 are about 0.8 

[symmetal]

6 hours ago, bottletopburly said:

Have you checked pulse settings haven’t reset themselves to default 0.1 I have had Eqmod do that before my Eq6 are about 0.8 

Thanks, I did check the guide settings and they were still at 0.5 as they were before. I also recalibrated and the calibration was fine. There is quite a bit of Dec backlash but it didn't enter the backlash zone while guiding. I also tried different balance settings but it made no difference. Previously I hadn't worried about even about getting good balance as with the relatively large image scale, fairly light setup and guiding it wouldn't be taxed very hard. The images always had small round stars. But not any more. 

Alan

[newbie alert]

Balance  and good pa is really important for guiding

[symmetal]

1 hour ago, newbie alert said:

Balance  and good pa is really important for guiding

I tried all the balance options and the Dec only drifted 3" in 10 mins unguided so the PA was good. 

The elongated star images on some guided subs showed movement of over 20" while the guiding trace showed 2" p-p movement with occasional spike being 3"

Alan

[symmetal]

I've just remembered that PHD2 installed the latest 2.6.7dev1 just before this problem started. It also installed on my other rig and that has had no problems but it might be worth trying the previous 2.6.7 version. Can't see PHD2 deliberately driving the guide star off and not actually showing it on its display or graphs but I'm willing to try anything. 😁

CO is reporting clear up to midnight though it's rather windy at the moment.

Alan

Edited April 16, 2020 by symmetal

[symmetal]

Clear for the moment and no wind. Older version of PHD2 installed and even changed power supply in desperation but just the same. 

The 5 mins unguided just shows the 10" RA periodic error having an effect on the star shape. Imaging at 2.74"/pixel that's 3.6 pixels movement which looks about right.

The 5 mins guided shows about 8 pixel movement errors in RA and Dec which is 22" drift in both axis. 

The Dec trace hasn't changed in guided vs guided. What's going on! This is so frustrating!

Alan