This was made using a custom FreeBASIC program I wrote to directly generate a 1388 x 1683 TIF file chart from a text file list of the galaxies' coordinates and magnitudes. The text and labelling were added manually because the code isn't that sophisticated; it just properly plots the galaxies, with a darker dot the brighter the galaxy, and outputs a text file with the x,y coordinates so later the right galaxy number can go with the right dot. You can perhaps do this sort of thing yourself (or learn to), starting with this tutorial on making both BMP and TIF graphic files.