[Startrek (Martin)]

ZWO have used ( or copied ) a similar algorithm to PHD2 for their guiding feature in ASIair.
A Dark Library is created and used for your specific camera and exposure times to distinguish between a hot pixel and real pixels , thus reduce the risk of guiding on a hot pixel instead of a true guide star.

This is needed as our guide cameras are not cooled and depending on the type of camera and exposure time a hot or warm pixel can be an annoying anomaly. A Dark Library doesn’t improve your guiding it just ensures you guide on a guide star which is the most important thing.

PHD2 also has an additional feature called a Bad Pixel Map which is another way of mitigating / distinguishing hot or cold pixels in the frame and thus eliminating the risk of guiding on a hot / warm pixels.

So it’s important to create your Dark Library !!

Hope that answers the query

Martin