PlanetsCentral

 +0     WORD    Version Code (?)
 +2  22 BYTEs   unused
+24 500 WORDs   Visibility Information. For each planet:
                 bit 0  unused
                 bit 1  player 1 saw it
                 bit 2  player 2 saw it
                 ...

Until version 2.2, this file is stored in host byte order, i.e. little-endian on (for example) Intel machines and big-endian on Suns. Since version 2.3, it uses little-endian order, like all other VGAP file formats.