Airy disk - Wikipedia
hexagonal crystals create a halo around the moon. in optics it is called an airy disk and size due to diffraction of light. I was able to observe this about a week ago from my home town. beautiful
Do Sensors Out Resolve Lenses? - Luminous Landscape
Lens Diffraction and Photography from Cambridge in Colour.
Understanding Diffraction - Diffraction Limited Photography: Pixel Size, Aperture and Airy Disks
Airy disks not resolved
Calculation of diffraction limit for various cameras (highest f-stop before diffraction degrades image)
Diffraction Limited Photography: Pixel Size, Aperture and Airy Disks
Lens aperture and diffraction. Nikon D5100 due pixel size 4.8 µm above f11 starts to show difraction, while Nikon D4 with pixel 7.3 µm shows difraction above f16.
Cambridgeincolour.com Lens Diffraction and other popular tutorials, using camera equipment, photo techniques, etc. Airy disks resolved