ASI294mc to Rokinon 14mm setup problems

dustcloud

I am having focus problems "long star trails in the corners" with this setup. Focus in the center is perfect.

It is a ASI294mc connected to a 2" Filter holder to a Rokinon 14mm lens.

Using the L-eNhance 2" filter for narrowband imaging in the city.

I think the backfocus is off. Maybe the ASI294mc needs to be closer to the Rokinon lens.

Is there a solution to this - - how to connect a ASI294mc to a Rokinon 14mm and use a L-eNhance filter ???

Are their field flatner that could be used?

Do I need a narrow filter holder? or is additinal spacers required to the ASI294mc?

All help appreciated !!

IMG_1121.JPG

wvreeven

If the stars are lines pointing away from the center, you’re not close enough. If the stars are little arcs, you’re too far away. Not sure how to do that in your case though, sorry.

rosswalker

If the stars are lines pointing away from the center, you’re not close enough

No, if your stars point into (or away from) the center, you are too close. You need to add spacing.

If you stars circle around the centre, you are too far away. You need to remove spacing.

wvreeven

Sorry, I got that first part wrong. Thanks for the correction!

Support@ZWO

I recommend you figure out how much the back focus distance this lens requires and arrange the adapters.