Black box query.

[Merlin]

To save having to take the side plate off the PST black box and keeping dust out,

, does anyone know the distance from the front of the internal Barlow to the front face of the box?

I can then measure out the 200mm distance that the Barlow face has to be inside the focal cone of a f.10 donor 'scope.

[Peter Drew]

According to the PST mod write-up by Merlin66, the front edge of the PST tuning ring should be 200mm inside the focal point of the donor refractor. Works well on my mods.

[Merlin]

Thanks Peter for that crucial bit of information. The rest of the Stage 1 procedure looks straightforward enough.