[g__day (Matthew)]

Hi all,

Just idly pondering and wondered what happens if you take a large aperture achromatic refractor and do narrowband shots through filters into a sensitive mono camera?

We all know achromatics won't focus all primary colours simultaneously, but I wondered if you use filters one at a time that only let red, blue or green light pass - and focus for each colour - does it matter that the other two colours aren't focused if you are simply filtering them out anyway?

Would happen if you took a say 150mm achro and mated it to a sensitive mono camera with good filters on a good mount and then integrated each shot?

How much better will an apo be then an achro if you are focusing one colour at a time through it?

Many thanks,

Matthew