[Argonavis (William)]

I visited a local telescope vendor on Friday and inspected his rebadged GSO dobsonians. The price of these are amazing - for the 12 inch model about $1395. The altitude and azimuth movements were very smooth, which makes it very usable at higher powers. The bearing are friction adjustable. The focuser movement was also very smooth and impressive. Overall I am very impressed with the quality offered for the price. The only thing I don't like is the rocker box made from cheap melamite materials rather than something more durable like plywood.

The owner assured me that the mirrors are pyrex (unlike other GSO dobs, which are BK7 glass) and that the figure is 1/12 wave. Presumably this means that it is 1/12th wave Peak to Valley, which translates as 1/6 wave deviation from the ideal parabolodial. This squeeks inside the 1/4 wave Rayleigh criterion, so they are correct in calling them diffraction limited. He told me that this is very good for a machine produced optic. I would tend to agree, although machine produced optics tend to suffer micro-ripple surfaces. This would not be detectable using a raw wavefront error rating. Maybe these are very smooth, as he assured me (continuing his sales spiel) that one of his sales agents reports extensive details on Jupiter using the 8inch model (How many bands? really?).

I was wondering what experience people had had with these Guan Sheng Skywatcher/BT/Southern Cross telescopes? I would love to test one against my 12inch f7 of known very high quality, but I don't have a spare $1.5k just to satisy my curiosity.