I'm looking at an ad for a used Canon 1200mm f/5.6L EF USM Autofocus Lens where they are asking $180,000. Yes, that's not a typo.
I don't get it.
I'm an amateur astronomer and I know I can buy a killer 1200m refractor for well less than $180k. What makes this so expensive? I know that a good refractor only has a triplet (or a doublet) as the objective and a small, but complex, eyepiece. The Canon lens has 13 elements, 2 of which are flourite.
This isn't about this particular lens, and this question may well be better for an astronomy forum
But why are camera lens so much more expensive than refractor telescopes?