And, I took some test data with 20476 = bare shutter today, only 1x sig,drk,bac @ 0.1 sec via Oriel incandescent + gray plaque ...it was hard to get a dim enough light to be on scale... then 6x more bac scans @ 1, 10, 30, 60, 90, 120 sec exposure, all at -60 deg C TEC. There are 1.5x log sheet(s) + 4x photos.