I am looking into buying a DBK to go with my 9.25" SCT. The question I am pondering is which model, I have already decided that colour is the way I wish to go at this time and there are two models I have to choose from. I am wanting to do some planterary imaging and deep space NGC etc. So I am torn between a DBK31AU03.AS and and DBK21AU618.AS. I need some help on which would be best if any would be, I know the ccd's are 1/4" and 1/3" and the resolution greater and all the basics I am looking at in a practical sense what should I expect to have in results from each. I am new so any help or light that some one can shed on this would be greatly appreciated.