Selection of stars which are earlier than a given type

Rather than matching a single spectral type, it may be necessary to find the stars earlier or later than a given type. The first selection is described here and the next item will described the other one.

The combination of the command mk and the standard option -lt allows to select the stars earlier than the spectral type given on the command line

mk -lt "spectral type"

However, only the spectral type is taken into account, and not the luminosity class.

Example:

mk ts -lt B3 lists the stars earlier than B3