Thanks all for your responses. All the guider has to do is guide well enough to keep a star in a 80 arc second circle. I do not plan to use it to guide for AP work. The time it take to start guiding was what I did not know. I down loaded the PDF file for the guider , but it did not give a definitive answer as to how long before guiding took place. I would be guiding for 10 sec each interval times 3 intervals ( 30 sec) in four color bands, B,V,R,I then move to the next star. When I move to the next star will it take the same amount of time to calibrate or will the previous calibration be used ? Thanks Ken Sikes -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.