Celestron users might know about one wonderful device - StarSense AutoAlign. It allows to perform completely automatic star alignment. Basically it does astrometry for achieving this. And here rises a question for users which doesn't own StarSense - what if I want to use for astrometry not the main telescope, which is doing the photography, but the guider? We run into a problem - optical axes of the main telescope and the guider can't get completely parallel even we try very hard. How this is solved with StarSense? Correction procedure! We need to tell StarSense what is the misalignment between optical axes. For this we align main telescope to a star and tell StarSense to calculate the difference.
This is the algorithm for getting the same functionality in Ekos:
1) User points main telescope to a star and position it to the center as precise as possible;
2) User replace eyepiece with camera. Focus and after that center it with the help of a cross-hair;
3) Tell Ekos to guide the star - it must remain in the center;
4) Sync to the centered star in the KStars;
5) Run astrometry on the camera attached to the guider;
6) After pressing a conventional button Ekos calculates the misalignment between optical axes of the main telescope and the guider. It will be used for further pointing of the objects (and alignment procedures in Ekos also).
Something like this... Very useful functionality for users with main telescope which have big focal length and cameras with small sensors (but even with big sensors it is indeed a problem, especially with poor polar alignment)!
This is the algorithm for getting the same functionality in Ekos:
1) User points main telescope to a star and position it to the center as precise as possible;
2) User replace eyepiece with camera. Focus and after that center it with the help of a cross-hair;
3) Tell Ekos to guide the star - it must remain in the center;
4) Sync to the centered star in the KStars;
5) Run astrometry on the camera attached to the guider;
6) After pressing a conventional button Ekos calculates the misalignment between optical axes of the main telescope and the guider. It will be used for further pointing of the objects (and alignment procedures in Ekos also).
Something like this... Very useful functionality for users with main telescope which have big focal length and cameras with small sensors (but even with big sensors it is indeed a problem, especially with poor polar alignment)!