Oval formation forming a remarkable couple with Messier A. Seems
to result from a low-angled impact.
Few steep slopes supporting Messier A to the West.
Pretty high walls.
Flat and little extensive floor and oval.
Dimension: 12x12Km / 7x5Mi
Height/Wide ratio: Unknown height. Impossible calculation.
Interest : Exceptional formation
Observation period: 4 days after New Moon or 3 days after Full Moon
Minimal Instrument: 100 mm refractor