Orthographic graticules

 

 

 

 

These graticules were prepared by Ben Burrell – a past Assistant Director of the Mars Section. After being printed (with 50-mm disks) on a transparent sheet they can be used as overlays to determine the coordinates of markings on drawings or images, as described in the Director’s paper in J. Brit. Astron. Assoc., 106, 332–334 (1996).