Does my scope collimating?

[Hypernova]

I'm unsure if it does or not. The thing is when I try and focus on a bright star like Albireo, it doesn't completely focus and appears much like a a many pointed disc no matter how fine the adjustments. It does look a little bit like the atmospheric turbulence image on astro baby's collimating page so I think it could be that???

My scope is a Skywatcher 200p Dobsonian.

[LukeSkywatcher]

I was gonna say yest it needs collimating but i see you have already read AstroBaby's thread. The atmosphere is very turbulant just after sunset as the air is starting to cool down after the day. It improves as the night goes on and really the best time to observe to get little turbulance is an hour or two before sunrise.

[Doc]

When you defocus on a star do you see wave like movements over the star. If you do these are thermal currents rising within your scope and are a sign of insufficient cool down.

[Hypernova]

When you defocus on a star so you see wave like movements over the star. If you do these are thermal currents rising within your scope and are a sign of insufficient cool down.

I haven't noticed any, but I will take a look shortly as the skies are relatively clear here at the moment.

[Hypernova]

Thanks a lot to you both, I have just had a peek at Capella after about 10 mins of cool down which I know is insufficient and I have noticed a rippling effect across the out of focus star.

[Doc]

An 8" dob will need at least 45 minutes to cool down maybe more.