Some of you might find this useful. A free open source PC>camera control software for Nikon and Canon. It uses Wifi or USB and the list of supported cameras is here:
http://digicamcontrol.com/cameras
It also has an Astro module:
Astronomy module
A simple module to help long exposure photography with scripting support to automatize repeating tasks. For precise focusing it is used a special live view window where it is displayed the focused star size and controls to set live view brightness and magnification
http://digicamcontrol.com/
Trevor
