This might be a stupid question, but what effect does aperture have on seeing (if any)?
The reason I ask is because I find that seeing here is rarely good enough that my 6 mm EP in my 10" dob (200x) doesn't look wobbly - though when it doesn't it's great!
If I had a 12" at 200x (I realise that is a different FL EP), would the image be equally wobbly (assuming we're looking through both scopes together!), or can you push a 12" to greater a mag than a 10" given the same seeing conditions? I realise there would be a difference in brightness of image....
Everard, I used to have a 10" LX200 SCT, with a focal length of 2500mm. My current scope has a 20" mirror, but has an identical focal length of 2500mm.
I find the seeing limitations are not dissimilar. Perhaps I push the Mary Rose a bit harder with higher mag because the image is brighter, and so it can withstand a bit more power for DSOs, but star images are just as degraded at the same power due to seeing conditions.
I have seen mention of smaller scopes being less effected than larger ones due to the size of individual "seeing cells", which are supposedly cells of calmer air. The idea being that smaller scope can view inside a smaller column of air and not be 'straddling cells'.
Sounds like a load of hogwash to me.
What does affect larger scopes more is thermal mass of the optics causing a temperature difference between the optics and ambient air temp. If your mirror is > 1 degree away from ambient, the seeing will always look poor regardless of how good sky conditions really are. Fan forced cooling and ventilation can help here.
