thanks Dennis, Ken and Gary.
Gary - Bernhard Hubl works with st2000 for a long time. perhaps he has some interesing tips for you...?
http://hubble.heim.at/
Ken, the reason why the color chiop does a great job is cos the s/n ratio is so wonderful! h16 has a nice kodak chip - but the signal kind of drowns in the nnoise - it needs more data to stand out.