Way back in the days of the Virtual Star Party, you were taking Astrophotographs with a DSLR and a Dob on an EQ platform. Question, did you have issues getting focus? Did you use a Barlow to move the focus point?
Funny you should ask!
Yes, I had issues finding focus because DOBs aren’t generally set up for prime focus AP, and often require the sensor to be closer than the focuser allows (not enough “in-focus” distance).
I figured out that using a coma corrector for newts, (like this), the problem is solved with only 0.1x mag. It gave me about 10mm or a little more “out-focus” distance that was perfect for my old Zhumell 10″ Dob.
For planetary use, I used that same Dob and EQ platform, but only with either 1 or 2 Barlows, excluding the coma corrector. There was plenty of focus distance with that setup.