Bad seeing on Mars in 10" dob

[Aston]

I was out observing through my new 10" dob in a Bortle class 4 area with almost no clowds and a temperatur of -10c. I collimated the scope and watched Orion nebula, Andromeda galaxy and even the M110 galaxy next to Andromeda, all looking good to me(stars well focused). When i got to mars(at approx 40 degrees inclination) the image was horrible, i tried both 9 and 4,5mm eyepieces, checked the collimation with an unfocused star and with my laser collimator, but everything was ok. Mars was smearing, unfocusable and the image had a lot of mirage. I could tell it was something big and round, but it had no other signs of being a planet. 

Is this simply a bad seeing? Or could the collimation requirements be so high that im not able to use my "out of focus star"-test and laser collimator to get it right?

 

[John]

That sounds like simple poor seeing to me. Mars is now a small target (under 9 arc seconds in apparent diameter) and the seeing has been variable to say the least over the past few weeks.