BF30

I concluded, after a fair amount of Googling, prompted by Phil, that we have SolarMax BF30 at the CAO. This is the 2" straight-thru blocking filter from Coronado. It is 30mm and yields an image size of 27.2mm. It came with a 1¼" zero-length reducer. It is for telescopes with a 3000mm or shorter focal length.

The information on the net is crap!