|
I think he used the 2" Powermates he had to hand.
The total magnification would be 2 x 4 = x8
Depending on the camera and the connection used...the back focus would be slightly different. TV provide direct T thread attachment adaptors for the Powermates.
The "best" Powermates will depend on your scope and the focal ratio.
Think about f25-f30 as being the "sweet" spot for imaging....so if you have a f10 SCT, a x2.5 would be good, but if you have a f5 system then an x5 may be better....
HTH
|