The cycle length of the U Geminorum star HT Cassiopeiae

The mean cycle length of the catalysmic binary HT Cas, which is remarkable because of the shortness of its orbital period, has been determined as 400^d±50^d. The hitherto assuixed value of 30^d proved unfounded. Some aspects arising when classifying long-cycle objects and SU Ursae Majoris variables are pointed out, a s well as the relation between large cycle length and small accretion rate.