Poor tracking with EQ3-2 and Synscan

[CoolJWB]

For quite a while I've had an issue where the images I take have trails that show up when going higher then about 20 seconds exposure time. I do a rough polar alignment where you can still see the polaris in the scope as I live in the north of Sweden and the EQ3-2 mount doesn't allow for accurate adjustment above 64 degrees.

I'm 100% sure that the locatation, time zone and time is correct, I've also parked the scope to the position with the scope facing polaris and the weights downwards. I did a 3 star alignment and after a 1 min exposure with my Olympus 420 the result was as the first image I attached. For 20 second exposures I get the second image attached but once in a while without having touched the scope (yes I am 100% sure of this, I stood perfectly still a good distance away from the scope and triggered the shutter with a remote control) I get results such as the third image.

My guess is that the cogwheels are slipping somehow but I'm gonna ask here to be sure.

 

Edited March 29, 2020 by CoolJWB

[Davey-T]

Have you tried lowering tripod legs to get better PA ?

Dave

[CoolJWB]

26 minutes ago, Davey-T said:

Have you tried lowering tripod legs to get better PA ?

Dave

Yes, I tried and it got better, but that's the results you're looking at... The polaris wasn't fully centered and I will try to get it more accurate next time but could it be another issue or is the polar alignment the key issue here? 

Edited March 28, 2020 by CoolJWB

[Davey-T]

Polaris shouldn't be centred as such although depending on your image scale it shouldn't have to great an effect.

xxxx

[michael8554]

For unguided imaging you will need excellent PA.

I can't open your ORF files, but I would imagine you have Periodic Error in RA with this mount.

2 hours ago, CoolJWB said:

I'm 100% sure that the locatation, time zone and time is correct,

These settings affect the accuracy of goto, they have no bearing on good tracking for imaging.

Michael

[CoolJWB]

21 hours ago, michael8554 said:

I can't open your ORF files, but I would imagine you have Periodic Error in RA with this mount.

Michael

They're now in .png format and I think you're right. I'll try to investigate further into periodic error correction, all guidance is appreciated!

[jambouk]

The location, time/date, altitude, three star alignment etc has nothing to do with your tracking accuracy. The tracking accuracy is mostly an index of how good your poor alignment is and how good your kit has been engineered. There isn’t much you can do about the latter, but you can take steps to work out how to improve your poor alignment. You have a synscan, so if your handset / firmware allow, there is a handset poor alignment routine you could undertake, I’ll post a link to it. What is the focal length of your telescope and imaging system? If more than 1000mm or so, then you may find even with perfect poor alignment you still get trailing stars at 20-30 seconds. 
 

James

[jambouk]

Handset polar alignment routine:

https://stargazerslounge.com/applications/core/interface/file/attachment.php?id=395030
 

Edited March 30, 2020 by jambouk