Baader Mk111 MPC back focus measurement

[libraryman]

Hi all, is anyone using a Baader Mk111 coma corrector with the QSI 583?

i'm trying to use it on an Orion Optics f.4.5 newt, the back focus is said to be 55mm but where is it measured from?

Note the small spacer i have made fitted to extend the back focus to 5mm!

Ray

[Altais]

I don't have the Baader MPCC Mk III, but from what I understand from this site, you need a distance of 55 mm between the T2 thread on the coma corrector and the camera sensor. Hope that helps.

[libraryman]

Hi Lars, thanks for the reply, I emailed Baader and received a reply today, the measurement is indeed taken from the bottom of the T2 thread, however.... There are two...48mm & 42mm.

It is taken from the base of the 42mm thread and therefore my picture is incorrect!

I now need a 5 mm spacer, hopefully 1st light optics have some!

Ray

[Altais]

Hope it works out. 

Clear skies!