[chrissara]

I hope not to start a flame war here, but I have just purchased a 12" Dob from Sirius Optics in Brissie. It is the Southern Cross one.

Whilst I am aware there are cheaper Dobs out there e.g. Bintel, Andrews Com etc, I understand these use BAK7 mirroras opposed to Pyrex mirror on the Southern Cross. (I understand the Southern Cross is a clone of the Orion models or made by the same people in Taiwan and that it has a 1/12 Wave Parabolic Pyrex Mirror)

Anyway, is it true Pyrex is a better type of mirror than the BAK7? Similar and no difference? What I understand is true is that this type of Dob does not need a fan due to its better temperaure control.

Just really wanted to get some thoughts. I have already purchased the unit and am sticking with it, and am just seeing what pro's/cons there are over the Andrews/Bintel type ones that go for $899-$1000.