Q: Apple TV display second desktop only??

Not for Dual screen. Just for airplay if your mac can do it

No, but you can try airparrot.

http://airparrot.com

I just downloaded airparrot and after adjusting some settings I was able to set my television up as a dual screen through Apple TV.  I use Propresenter as a Youth Minister at my church and this setup allows me to do that.  Thank for the info.

I could use some help getting this setup! I am trying to accomplish the same thing with airparrot 2 but haven't been succesful. When I connect to airparrot and choose "extend desktop" , I am able to connect to my second monitor. It seems as though propresenter doesn't recognize it that way, and will not display the program on my second monitor?

Any ideas, if I use airplay without airparrot it works fine?

Thanks

Its called extended desktop...

Use AirPlay to display video from your Mac on an HDTV - Apple Support