If you previously purchased the Galactic Trilogy CD, you can, at any time, purchase a refresh of the disk. This allows you to have all the latest updates to the interpretive text The Soul of the Sky and the ephemerides of the centaurs and Trans-Neptunian Objects all in one place. And you'll get the latest updates to The Galactic Ephemeris
Of course, you'll continue to receive updates of the latest data at no cost sent via e-mail only even if you do not refresh your disk.
To order your update CD: