Ahhh, I think I finally understand the missing piece that is bugging me.
It isn't so much that the DBK 41 has more pixels than the 21, it is more that the sensor is physically larger on the 41 than on the 21?
So the planet doesn't take up enough space on the sensor so you need more magnification to fill 'er up, and that means less light.
So would that mean that the larger the scope the larger sensor/higher resolution you could use as you have more light?
I imagine turbulence is less of an issue in the scope if you have been outside for a lot of hours and everything has stabilised. It seems that way when I am viewing, but I'm not sure if it is just because seeing always seems better at 2am when I should be in bed
