http://www.nikonchat.com/p90-nikon-accessories/
Is it possible to connect a Nikon Coolpix P90 to a telescope?
If so where can I find the adapter or accessories? Thank you!
It is possible, but the camera itself is a poor choice for astrophotography. According to the comments I read, the camera sensor is noisy settings low ISO and color quality becomes poor at high ISO settings. If you have not purchased the camera, go with a standard digital SLR. Canon XTi or XSi choice would be better, as there are applications that can replace the cameras native limit of 30 seconds (something that Nikon is not easy to support.