Information on the Altair 80mm maxiguider

[Stuart1971]

Hello all,

I am looking for some information on the Altair Astro 80mm maxiguider, I have acquired one of these and want to start using, but first I would like to know a couple of things, like the backfocus length, and also what this thread is that’s use on the back, as I have a good quality helical focuser that I want to use, but his has M42 thread on, 

so if anyone can help, it would be much appreciated... 👍