Tom C wrote: > It's when you combine virtually identical multiple exposures, "stacking" > them to reach a final image that has a total exposure time equal to the sum > of the individual exposures. > > It's useful in astrophotography for a number of reaons. The main one is > that a bunch of short, say 6 individual 30 second exposures, can be combined > The result is the accumulated photons of a 3 minute exposure. The neat > thing is that tracking error (irregularities in the motor drive or polar > alignment) can be virtually eliminated, because software automatically > aligns/registers the individual images so they overlay each other perfectly. > > The additional benefit we're talking about here is that the sensor can be > run at both a lower ISO and for a shorter exposure duration, both of which > reduce noise. > > Tom C.
Aha. Never thought of it that way! Thanks! Yeah, who asked me, right? <bg> keith -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
