That's like asking why a Ferrari costs so much, it's just a car. There's a big difference from a mass produced car with automated processes compared to a product that is pretty much one offs and are made by hand. Pretty much every industry has the equivalent mass produced vs hand made. Leica makes camera lenses for the masses, but they also have a very expensive line of lenses that they only start the hand made process when you're check clears. Clothing, homes, etc all have versions of it.

So unless you can tell me that you've hand ground a telescope mirror of any size to have direct knowledge of the experience, I'd suggest taking a look at the process while considering the size of the mirror discussed. Even the base and the trusses for the assembly will have required design time and iterating through changes. Not sure why this seems so strange compared to all of the other things in life with "accepted" price tags.

Spot on, for a concrete example check this one out - there's a slight chance these are mass produced

https://www.usa.canon.com/shop/p/rf1200mm-f8-l-is-usm-lens

but the f5.6 version... doesn't seem to be:

https://www.the-digital-picture.com/Reviews/Canon-EF-1200mm-...

>https://www.usa.canon.com/shop/p/rf1200mm-f8-l-is-usm-lens

"Minimum focus distance of Approx. 14.1 ft. / 4.3 m. "

Which is conveniently able to be measured by taking the distance from the camera mount to the end of the lens, then doubling it! However, at least this is "affordable" enough to have a price listed. The Leica lenses I was referring to has the "oh boy, this is going to be expensive" infamous Find a Dealer button. Also, it's a set of 11 lenses, and for nearly double the price, they add in a few more wide angles and a few more telephoto lenses to the kit.

https://www.leitz-cine.com/product/summicron-c

Your answer is basically "it's expensive because other high end things are expensive, too!". Thats not what the GP was asking. Also a Ferrari is a bizarre comparison. Telescope has about 10 or less moving parts. Ferrari has hundreds, maybe thousands.

A real answer to this would be to break it down by materials vs labor. Not shaming them for being curious and then saying it's high end.

If you think a telescope has 10 or less moving parts, you don’t know what your talking about.

It's a huge piece of very pure glass, that has a precise uniform shape down to the nanometers scale. Another thing that I learned is they are first ground to a spherical shape, then a parabolic. It's a very time consuming process, although I don't have exact data.

And it’s time consuming partly because so few are made.

I guess the unit price could come down by 90% or more if you were to order a million of them, and could convince a manufacturer that you’re good for the money.

(And you may get something that’s superior, for example because they figure out that, at a million copies, extra money spent improving the software for adaptive optics can be more than made up by making the hardware a bit less rigid)

We’re spoilt by the amazing efficiencies of mass manufacturing.