Comments are so common, and so useful, that a 32-byte COMMENT column should be considered part of the basic data, even though it may be blank for the majority of the data. This field may be used to append comments to a particular observation, such as DOME IN THE WAY?, MOON ON MIRROR, or CONTRAIL.
General comments, such as Cirrus low in NW, or LUNCH BREAK, should be stored as data with the OBJECT field set to COMMENT. Comments longer than 32 characters can be split into 32-byte pieces with the same time value. The time field MJD_OBS should always be filled in, but the rest can remain undefined.