Astro-Physics 15" Ribbed Mounting Plate for 900 Mount for all Astro-Physics refractors, except Traveler and 130EDFS.
Our CNC machining center started with thick aluminum plate and carved out the excess material leaving a strong rib support structure. The finished plate is 0.75" thick, 15" long and 6.5" at its widest point. The width of the plate tapers to 4.75". A pair of keyhole slots that measure 3.2" between centers are provided at each end. The distance between these pairs of holes is 13.75". Due to the ribbed structure, you may not be able to drill additional holes to suit your mounting rings.