Weird Star Shape from Camera Lens
Posted 06 October 2013 - 03:18 AM
Sorry for the newbie question.
I am using Vivitar 200mm F3.5 lens with my non-mod Canon t3i.
I also use astronomik CLS filter.
For this setup, I use iOptron SkyTracker to take wide field.
I just acquired this 200mm lens from ebay and tried on several nights.
What happen was the (bright) stars' shape look funny -- not round but kind of like half-round. I roughly tried different focus, f-ratio, and ISO but the bright stars always look like "half circle".
Please see the image (one sub) below. This is at ISO1600, 2min sub and target on North America Nebula).
Is this looks like a problem on the lens or tracking ?
Posted 06 October 2013 - 01:14 PM
Posted 06 October 2013 - 03:27 PM