M13 (Hercules globular cluster) through a 40 inch reflector.
Here's a Hubble shot. http://en.wikipedia.org/wiki/File:Messier_13_Hubble_WikiSky.jpg
The Pleiades in my own back yard using my 4" deep sky binocs is also a stunner.
http://en.wikipedia.org/wiki/File:Pleiades_Lanoue.png
M13 (Hercules globular cluster) through a 40 inch reflector.
M13 must have been awesome through a 40-inch. It's beautiful enough through my 8-inch at home with tons of light pollution, so I can only imagine. I did see the Omega Centauri cluster with my naked eye ... very visible ... but I didn't have a telescope !
What is the most impressive astronomical object you've seen with your own eye through a telescope?
For myself: I've seen Saturn through the old 36-incher refractor at Lick Observatory (it was a special night for the club I used to belong to) and you could clearly see the Cassini Division; and I've observed the Whirlpool Nebula through a 20-inch f/5.6 Newtonian where I could make out the connecting material between the two bright parts of the galaxy.
But I think the most impressive was seeing the Ring Nebula through a Celestron 14 on Fremont Peak in California where I could actually see the central star.
Amy