Trailing stars - whats going on?

[Maho]

Hi everyone,

I'm new to astronomy and my recently purchased equipment include: SW 130PDS and Ioptron CEM25P GoTo. I used my Olympus EM10 M2 camera.

On the first night I was out I just slewed my mount to take pictures of random stars in the sky to test various camera settings. I pointed the scope to Vega and took a number of images at 4 second exposures at 1600 ISO. Even with that short exposure, I still seem to have elongated stars, any longer that 4 seconds it would elongate even more.  Can anyone advise what I'm doing wrong? 

edit - I've uploaded images in JPEG

 

 

Edited September 25, 2020 by Maho

[MarsG76]

You need to give us more information about your setup.. how are you guiding?? ... although first thing I would do in your situation is check and triple check your polar alignment... and get it as close to perfect as possible.. 

[Maho]

No guiding on this. I manually used the hand controller to point to Vega.

Regarding my star alignment, I tried a two star alignment and the target was off by some distance and used the hand controller function to slew to the target star and pressed enter. I was using the supplied 6x30 finderscope that came with the mount.

(I think I may have answered my own question)

 

[MarsG76]

2 minutes ago, Maho said:

No guiding on this. I manually used the hand controller to point to Vega.

Regarding my star alignment, I tried a two star alignment and the target was off by some distance and used the hand controller function to slew to the target star and pressed enter. I was using the supplied 6x30 finderscope that came with the mount.

(I think I may have answered my own question)

 

What about your polar alignment accuracy?

[Maho]

Because of the small garden with the high walls I was in, I couldn't see polaris. What I did was use a spirit level to balance and a compass to point the mount to north.

[MarsG76]

5 minutes ago, Maho said:

Because of the small garden with the high walls I was in, I couldn't see polaris. What I did was use a spirit level to balance and a compass to point the mount to north.

In that case your trailing problem is definitely due to poor polar alignment... you need to have a very accurate polar alignment to get drift free long exposures, (not to mention guiding, especially at high focal lengths and depending on exactly how long you want to expose your subs)... just using a compass will not even be close to what you need, and with your stars trailing at 4 seconds, tell me that your polar alignment is way off... this is what you need to get right first to progress in your astro imaging.

Edited September 25, 2020 by MarsG76

[Maho]

Thank you. Because of limited sky available in the garden, thought I'd test camera settings. Good to know that camera settings arent the main issue.

Through an eye piece, the stars look sharp.

[MarsG76]

Just now, Maho said:

Thank you. Because of limited sky available in the garden, thought I'd test camera settings. Good to know that camera settings arent the main issue.

Through an eye piece, the stars look sharp.

They will look sharp because your eye is not picking up the drift like your camera... if you cant see polaris that you need to drift align after the rough polar alignment, to have a chance of getting your scope ready for longer sub exposures.