removing background pattern from old photo

These threads and others like them may help:
Cleaning of scanned photo overlaid with pattern
[Feature Request] FFT denoise.

Briefly, we decompose the image via the fast Fourier transformation (FFT) and mitigate the repeating pattern using the magnitude component. For this image, it looks like this:

The star, lines and haze propagating from the middle are good. Attempt to remove the other ones; for example, with the clone or heal tools in GIMP. Be careful though, this method can introduce new unwanted patterns.