T-Mount? & Sony A390

[LesCM19]

I have a Vivitar 500mm mirror lens that I put an M42 adapter on to use it on Praktica MTL3 & MTL5 bodies many years ago when I used to dev & print. At the back of the lens body is a ring/lip with a bevelled channel around the circumference which 3 grubscrews of the adapter fit into.
What I want to know is, is this a T-Mount or T2 etc and can I get this lens onto my Sony A390?

thanks

Les

 

[lexie]

if you still have the m42 adaptor to fit onto it what about an m42 to sony/minolta, i don't know how it would work with focusing though.

2 adaptors might be a step to far

 

[LesCM19]

The plot thickens...
The ring containing the bevelled channel unscrews and the thread there seems like it might be an M42x0.75 (T-Mount, I think, then) because the Praktica M42 lens cap doesn't quite fit.