I recently purchased an EdgeHD 800. I'm mounting it on a NexStar SE 6/8. I want to minimize the light path behind the rear opening when using a 2" diagonal, not only to allow the diagonal to clear the mount when looking at zenith, but also to optimize the clear aperture. I already have a Baader T2 1.25" Prism Diagonal and 10mm SCT-T2 adapter for 1.25" eyepieces and binoviewing. At this time I'm not interested in binoviewing with 2" eyepieces or binoviewing deep sky at all. But I would like to minimize the light path when utilizing a 2" diagonal and 2" eyepieces.

So far I've been able to clear the NexStar mount when the OTA is pointed at zenith, but the diagonal misses the mount by a mere 3mm! Too close for my comfort at a dark site. This is with the OTA pushed up as far as possible in the NexStar saddle. To do this, I removed the 2" nosepiece from an Orion 2" Dielectric mirror diagonal and attached the diagonal to a 10mm Baader SCT-T2 adapter via a T2-2" adapter ring.

I'd like to have a 2" diagonal setup that would give me more clearance between the EdgeHD 800 OTA and the NexStar mount. I'm thinking about this Baader T-2 Maxbright 2" Mirror Diagonal. http://www.optcorp.c...onal-2inch.html I would attach it to the rear opening of the EdgeHD with my Baader 10mm SCT-T2 adapter.

On the other hand, the Baader T-2 Prism Diagonal that I already own has a 34mm clear aperture. The Baader T2- Maxbright 2" Mirror Diagonal has a 35mm mirror surface, only 1mm larger. Couldn't I use the Prism Diagonal for 2" eyepieces? Why would I need the T2 Maxbright or any other diagonal besides the Baader T2- Prism Diagonal I already have?

It doesn't seem, though, that the T2 Prism Diagonal is recommended for 2" eyepieces The product description includes this:

A Note from Baader: "We do not recommend this housing for 2" eyepieces. The clear aperture is 34 mm. Only at the telescope side you can choose either a 2" (#16) or 1.25" (#14) nosepiece. At the eyepiece side we only recommend 1.25" eyepiece holders.

And yet another product description for the same Baader T2 Maxbright Diagonal says that it is a 1.25" diagonal, not a 2". http://www.highpoint...-diagonal-max-1 What's going on here? I don't want to buy a diagonal that might vignette some of my wider field 2" eyepieces.

Mike

**Edited by Sarkikos, 21 August 2014 - 10:58 PM.**