3182: Telescope Types

Telescope Types

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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.

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Explanation

This is one of 57 incomplete explanations: This page was created recently ACCORDING TO A TELESCOPE POINTING BACK IN TIME. Don't remove this notice too soon. If you can fix this issue, edit the page!

This comic shows diagrams of a number of different types of telescope, some real and others made up by Randall. It includes both refracting and reflecting designs; see 1791: Telescopes: Refractor vs Reflector for the important (according to Randall) differences between them.

Type	Real?	Refractor/Reflector	Description
Prime Focus	Yes	Reflector	A telescope design where the observer/receiver is situated at the focal point of a single mirror. Rare in optics, but a common design in radio telescopes.
Herschelian	Yes	Reflector
Newtonian	Yes	Reflector
Galilean	Yes	Refractor
Keplerian	Yes	Refractor
Gregorian	Yes	Reflector
Cassegrain	Yes	Reflector
Cardboard tube	Yes	Neither	Looking through a tube helps you focus by removing distractions, but doesn't magnify the object being viewed.
Kaleido	Yes	Reflector?	A kaleidoscope isn't really a telescope, because the non-viewing end is closed. You view many reflections of tiny objects at the end, rather than remote objects. The mirrors are also usually flat, so there's no magnification.
Liquid Mirror	Yes	Reflector	A telescope using a rotating pool of reflective liquid (most commonly mercury) as a mirror. The diagram adds a straw so that someone can drink the liquid. This would likely not end well for the drinker.
Narcissian	No	Reflector	This is like a prime focus telescope, but the focus is outside the end of the telescope where the viewer is located. So they can only see themselves, greatly magnified. This is inspired by the myth of Narcissus, who fell in love with his reflection in a pool of water.
Gravitational	Yes	Refracting	These can't be constructed on Earth[citation needed], they're formed naturally by large stars (particularly black holes) and galaxies.
Geological	No	Reflecting

Transcript

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Discussion

no vampire jokes 🥀 (1791) TheTrainsKid (talk) 00:08, 18 December 2025 (UTC)

Got down some preliminary descriptions of each telescope type used 185.132.133.218 01:44, 18 December 2025 (UTC)

insert that one mickey mouse meme with the caption "what a fucking narcissist" Yaokuan ITB (talk) 02:33, 18 December 2025 (UTC)

abnormally low joke-to-real ratio for this format of comic! 2601:241:8002:3E0:C0A2:9DA:ED39:D13F 03:21, 18 December 2025 (UTC)

I noticed that... I think this might've originally been 'look at all these cool telescope types', but then he realized he had to put some sort of joke somewhere. --DollarStoreBa'al^Converse 03:27, 18 December 2025 (UTC)

Can someone make a category for The Core (2003)? It's been mentioned often enough. 83.245.251.49 09:22, 18 December 2025 (UTC)

Can you list 4 more comics then I will make the category. I think that is about the limit for when to make a new category. I know there are a few more but is it only 2-3more? --Kynde (talk) 14:00, 18 December 2025 (UTC)

All I can think of is 673: The Sun. --DollarStoreBa'al^Converse 15:09, 18 December 2025 (UTC)

Also mentioned in the title text of 2858: Thanksgiving Arguments. --208.59.176.206 15:24, 18 December 2025 (UTC)

> This would not […] end well for the drinker.

Would it though? Drinking elemental mercury, while not great on nutritional value, should be mostly safe (and I'm using that word quite loosely). The most danger would be while drinking and expelling it, when there's a danger of inhaling mercury vapors, right? --Coconut Galaxy (talk) 10:29, 18 December 2025 (UTC)

It wouldn't take much work to make the "Real?" column all contain only "yes" 136.32.133.124 12:05, 18 December 2025 (UTC)

As all others are refractors or reflectors, can cardboard tube be considered a diffractor? As it is the only thing that it does.--Trimutius (talk) 15:43, 18 December 2025 (UTC)

> Children may sometimes use tubes [...]

It's not just children. I've seen "viewing tubes" in at least a couple of places, hard-mounted metal tubes that point at particular points of interest. I'm not finding any good references, but here's a photo showing some at the top of a nearby mountain: https://maps.app.goo.gl/wwnYJ1zEQEXzjyJS8 Jordan Brown (talk) 18:07, 18 December 2025 (UTC)
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