Decay of X-ray source A 0535+26

The All-Sky Monitor aboard Ariel V is described, and observations with it are reported for the transient X-ray source A 0535+26. It is noted that the observations were conducted in such a way that the decay phase of this source could be studied. The source's overall light curve between 3 and 6 keV is presented, and some decay features are described. The decay effects are compared with those observed in other transient sources, including Cen X-4, 2U 1543-47, and A 1524-62.