EQ6R startrails after meridian flip

[danny1976]

The last few days I can't image right after a meridian flip. My guiding numbers before and after meridian flip are just about perfect, around 0.3" 0.4" RMS error. So 2 hours before meridian flip my 10min exposures are perfect, nice round stars. Then after meridian flip and my stars are trailed severely but the guiding is perfect. I don't see any strange jumps, it is as flat as a pancake and yet the stars are trailed.

I tried checking "Reverse Dec output" in PHD2 but that made things worse and Dec guiding was kicked out completely.

upload image

The target is the Flying Bat nebula which is close to Polaris. My mount EQ6R and PHD2. I checked DEC and RA balance. Any help is appreciated.

[Yoddha]

Hi Danny,

If the guiding is perfect, but there is elongation it could be flexure in the system, mirror flopping or other mechanical issue it the system.

Also, it is good to have slight de-balance in both axis, this helps to guide out backlashes...

[danny1976]

Also, it is good to have slight de-balance in both axis, this helps to guide out backlashes...

I tried that but doesn't help.

If the guiding is perfect, but there is elongation it could be flexure in the system, mirror flopping or other mechanical issue it the system.

Everything looks very tight. I use a refractor, 2600MC and 30mm guidescope. A while ago I messed with the RA tensioning and now I have huge backlash which only goes away after 30s of tracking. The problem is nobody wants to take in the mount and adjust the RA tensioning for me. They said go back to the dealer but he is the one who first started messing with the RA axis. And now I don't know what to do. I can't get it right. If I tension it too hard the RA axis is blocked. If I release the tension a little then it has a lot of backlash.

But before meridian it works perfect. Only right after meridian this happens.

[Yoddha]

Is it possible to be a cables tension?

[danny1976]

I'm taking care of cable management and I have a SVbony powerbox. 2hours before meridian flip no problem, I'm getting 0.5" guiding and perfect round stars. I do the flip and all hell brakes loose. Guiding still great but stars elongated severely.

I think my mount can't keep up because the object is close to polaris.

[Yoddha]

Could you give it a try with another target?

[danny1976]

My mount is at Dark frames ltd in England for fixing RA backlash. When I get it back I will try another target.

[chris_g]

Hi Danny,

I've seen what you just described but haven't had a clear night since then to see what night be causing it.

Happening with my NYX-101 mount Ivo. Guiding looks good with flat star trails after flip. I've got an AZ -EQ5 and an EQ6-R that I hope to test next time out.

Had nothing to do with the flip process since I slewed manually but if I recall, it was near the polar region, not sure though.

Clear Skies,
Chris

I hope