When i looked at a star in the sky, its colour flickered as did its intensity. why does this happen?

Distortions in the atmosphere make it seem like they flicker.

yeap, this is the main problem with surface telescopes (as well as absorption) and the reason people are developing laser guide stars and adaptive optics. have a google for them, they are quite interesting. THe asme adaptive optics technique can be used for advanced retinal imaging

Yea, I've seen one of those telescopes on discovery that has a computer constantly bending and contorting the mirror to help correct for this. (i think the mirror is actually made up of many smaller mirrors). Nonetheless, its quite amazing.

Distortions in the atmosphere? Is that the only reason? I was hoping for something more interesting but if thats the only reason then fair enough.

Originally posted by greg1917

Distortions in the atmosphere? Is that the only reason? I was hoping for something more interesting but if thats the only reason then fair enough.

 

 

Nope, just a bunch of different density layers of air and good old refraction. And throw in suspended particulate matter (dust, vapors)

Originally posted by blike

Yea, I've seen one of those telescopes on discovery that has a computer constantly bending and contorting the mirror to help correct for this. (i think the mirror is actually made up of many smaller mirrors). Nonetheless, its quite amazing.

 

It is one very thin flexible mirror with a bunch of actuators behind it - at least the ones I have seen. they may have multiple mirrors for bigger devices though.