Not sure where to post this - as it cover both equipment (on/off axis guiders) software and processes - how to maintain optimal focus over a long duration imaging run.
The article / process / software works with MaximDL and other software and comes ForeSight Innovation (the very clever folks that pioneer On Axis Guiding).
http://www.innovationsforesight.com/SharpLock.htm
Rather than leverage expensive temperature compensating focusers Sharplock works by tracking the guidestars shape and pattern to work if focus needs adjustment and by how much and in which direction.
Clever stuff - has anyone tried this?
I note ONAG and Sharplock are written up in the latest issue of Astronomy Technology Today -
https://www.astronomytechnologytoday...e.asp&id=Mar14
Will have to see if I can find this somewhere (or subscribe online)!