Ratriman

It indicates length of the night, i.e. the period from sunset to sunrise. It is also measured in hours, minutes and seconds (ghatis, palas, vipalas).

Dinman + Ratriman = 24 hours = 60 ghatis
= 24 x 60 minutes = 60 x 60 palas

Everyday there is change in Dinman and Ratriman.