That is nice sensitivity with the big Cassegrain. 

Never have seen a satellite look like that. 

Another great target for the big 17" Cass would be Andromeda's Parachute - gravitationally lensed quasar. Not the right time of year just yet. In June in your area will be up late ~ 2am. I've goofed around attempting to image it with my idk10 silly, not enough focal length or mirror.

RA: 1 : 47 : 9.53 
DEC: 46 : 30 : 35