Star tails?

[Muzz]

Hello everyone,

Just a small query I am trying to identify the root cause of the problem with my star trails as attached.

I am new to this and still trying to learn but I have seen this before in my shots so it would be nice to ID & fix what I am doing wrong.

I have only ever done 5 nights with this hobby. Using an AZEQ6 & 9.25" 

I am wondering if it's my polar alignment as struggling with that.

Sorry to be a pain but appreciate any help.

Clear Skies,

Murray

 

[Kropster]

How long were the exposures?

[knobby]

Hi Murray, how are you taking images ?

Looks like slight movement when shutter fires ... Only the brighter stars are 'trailing'.

 

[Muzz]

Hi Kropster & knobby,

I'm using Backyard EOS & my 5D II. I wonder if it's then mirror lock related? 

Maximum was 70 seconds.

I did 20 frames at 45 seconds then 20 frames at 70 seconds all at ISO 800.

Then stacked using deepsky stacker.

[michael8554]

Hi Murray

The trailing seems to be roughly in the RA direction, based on M51's orientation.

So could be several things causing this - Periodic Error, or poor guiding, but I guess you're not guiding.

Is the trailing on all of your subs?

If it is PE then find an image with no trailing, then images either side of that will get worse, then better as they approach the next good one, based on the usual sinusoidal PE shape.

Otherwise, dunno  :->

Michael

[LukeSkywatcher]

Same issue came up a few days ago. The word backlash was mentioned. Its as if something is "stuttering" after taking the exposure. Shutter methinks.

[newbie alert]

Imaging with long focal lengths is tough...everything has to be spot on Inc PA.. how are you polar aligning at the moment?. Once you have sorted the issue then that be a fantastic image