|
I have only now got my head around this as I last studied optics in the early seventies. Below are four pictures.
The first is an image of a star and is what you see if you telescope is diffraction limited.
The second is a 3d representation of the Airy Disk
The third is airy disks resolved and fourth are airy disks unresolved
If you imagine the peaks a lot smaller then even in the unresolved case they would be resolved. This is also the reason bright stars are bigger than dim ones, as for really bright stars the dim rings (or Bessel function maxima) become quite evident and seem to merge.
Hope this makes it clearer.
I had forgotten I knew this. Everything is much clearer now.
Bert
|