Amateur telescope making is one of the most quietly astonishing hobbies going: by rubbing two discs of glass together with abrasive, you can grind a mirror accurate to a fraction of the wavelength of light — and then see Saturn through glass you figured by hand.

It's a patient, almost meditative craft with a deep tradition behind it.

The honest reality is that figuring a mirror is genuinely hard and slow, and testing it properly takes care, so it rewards persistence over instant gratification.