The current setup in the observatory. The Canon EF 70-200mm f/2.8 L IS USM II is piggybacking on the TS-115, taking wide field images at 135mm f/4. Yes, that's right! I'm using a telesphoto lens as a wide-field imaging scope. Who knew?
If you're going to do this don't forget to turn off image stabilization. It matters, a lot.