I learned in October 2022’s Breakthrough that the spikes of stars in high-power photos are called diffraction spikes. Why do they appear as two crosses at 45 degrees to each other?

The analytical modelling of the diffraction pattern produced by a laser pulse passing through a circular aperture, as shown in Fig. 1, was performed using Hertz vector diffraction theory (HVDT).

This pattern is a result of light waves spreading out and overlapping after passing through a small aperture, illustrating the wave-like behavior of light. Such patterns are central to understanding ...

A new publication from Opto-Electronic Advances, 10.29026/oea.2023.230039 discusses diffraction-limited visible imaging for large aperture telescopes.