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submitted 2 months ago by xkcdbot@lemmy.world to c/xkcd@lemmy.world

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Title text:

I'm trying to buy a gravitational lens for my camera, but I can't tell if the manufacturers are listing comoving focal length or proper focal length.

Transcript:

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[–] marcos@lemmy.world 39 points 2 months ago (5 children)

Do not drink the liquid mirror!

I repeat. Do. Not. Drink. The liquid mirror!

[–] tacosanonymous@mander.xyz 10 points 2 months ago

But I’m so thirsty meow.

[–] TheHotze@lemmy.world 5 points 2 months ago

But its shiny, and smells interesting.

[–] Hamartiogonic@sopuli.xyz 3 points 2 months ago

Forbidden juice…

[–] elvith@feddit.org 3 points 2 months ago

Instructions unclear, drinking straw stuck in telescope.

[–] ameancow@lemmy.world 1 points 2 months ago (1 children)

But bathing in the telescope is still fine, right?

[–] psoul@lemmy.world 2 points 2 months ago

You can only do it once