I ordered one from Hutech
He matched up the parts I needed and it also takes a 52 or 48mm filter with step down ring.
Just tell Ted what distance you need from chip and the lens type and he will sort it out.
Is this one here at the bottom of this page
http://www.hutech.com/astro/deepskycam/index.htm
Detals on site are very sketchy but just email them.