There are three common coordinate systems which can be used when analyzing the Yohkoh data. This is the full resolution IDL pixel address when using SXT images. The coordinates are rectangular. A is a rectangular coordinate system relative to sun center as viewed from the earth in units of arcseconds.
H signifies the heliocentric coordinates.
The solar B-angle is taken into consideration when calculating this value. These coordinates are spherical. HXT signifies the HXT pixel address in 126 arcsec units. The first three of these conventions have a two element array for each point described.