Small refactors?

[Earl]

Why are thes scopes like William Optics Megrez 90 APO so expensive?

Im assuming there the best things for wide angle photography?

[russ]

It's all about the glass used, plus a rather nice finish.

[brianb]

Quality costs.

Fluorite triplets are considerably more expensive than ED doublets, but the extra is worth it for imaging ... which is what small refractors excel at.

[John]

Not all good ED doublets are expensive eg: the Skywatcher ED80 / Celestron C80ED. OK their external finish is not as glossy as William Optics but optically they are certainly in the same league.

[LukeSkywatcher]

Basically mirrors (reflectors) are cheaper to produce and can be made bigger because of the lower costs. Refractors use glass lenses and its more expensive to grind glass lenses then to make mirrors and this means most refractors have smaller apetures then reflectors.

"Compare the meerkat.com.............compare the market.com"

SIMPLE.

[Capricorn]

Combination of several things.

2 lens = 4 surfaces that have to be ground.

Mirror is just one surface to be ground.

On a mirror to an extent the "quality" of the glass is less significant. Internal "waves" make no difference as the light never passes through.

For a lens this is critical, the glass has to be uniform and in effect blemish free. So it is simply more difficult to get a suitable chunk of glass. More wastage means a higher cost per good bit.

The glass for a lens has to have certain refractive properties, to get these, fpl-53 for example, costs money. Again pretty common cheap plate glass can be used to make a mirror.

Overall lens cost more at each stage.