Should A Refractor Be Called A Reflector?

Discuss your refractor type scopes here.
Refractordude
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Should A Refractor Be Called A Reflector?

#1

Post by Refractordude »


With the use of a diagonal, I think so. The diagonal REFLECTS light into the eyepiece.
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Re: Should A Refractor Be Called A Reflector?

#2

Post by JayTee »


NOPE!

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Re: Should A Refractor Be Called A Reflector?

#3

Post by Voyageur »


Granted, when you use a mirror diagonal with a refractor, the image created by the refraction of light is reflected to the eyepiece, just as your diagrams show. Using similar "logic" you could also say that a reflector is a refractor because the image created by reflection is refracted by the eyepiece. :roll:

But why would you want to do either of those things? The terms refractor and reflector make a practical and useful distinction between the two types of scopes on the basis of their optical properties and construction. So I'd say let's leave our terminology as it is!
Last edited by Voyageur on Mon Nov 11, 2019 9:16 pm, edited 1 time in total.
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Re: Should A Refractor Be Called A Reflector?

#4

Post by AntennaGuy »


I agree with JT. Although the optical quality of a diagonal is important, its primary role is simply to re-direct the beam. The image forming mechanisms are either lenses or mirrors. Since eyepieces are normally made from lenses, that leaves the main objective (lens = refractor, or mirror = reflector) as the determinant of whether a telescope is a reflector or refractor (otherwise we'd have to call nearly all telescopes refractors). There are some potentially confusing mixtures (e.g., Schmidt-Cassegrain, Maksutov, etc.). But those are normally still considered to be reflectors, while their aperture-sized lens-type elements are considered to be "correctors."
* Meade 323 refractor on a manual equatorial mount.
* Celestron C6 SCT on a Twilight 1 Alt-Az mount
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Re: Should A Refractor Be Called A Reflector?

#5

Post by pakarinen »


Should rotini be called linguini? I think not, but I could be persuaded to call it "Bob".
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Re: Should A Refractor Be Called A Reflector?

#6

Post by JayTee »


I'm sorry, I can't resist, should a golf club really be called a hammer. They are both tools and they both hit things.

JT
∞ Primary Scopes: #1: Celestron CPC1100 #2: 8" f/7.5 Dob #3: CR150HD f/8 6" frac
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notFritzArgelander
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Re: Should A Refractor Be Called A Reflector?

#7

Post by notFritzArgelander »


AntennaGuy wrote: Mon Nov 11, 2019 9:04 pm I agree with JT. Although the optical quality of a diagonal is important, its primary role is simply to re-direct the beam. The image forming mechanisms are either lenses or mirrors. Since eyepieces are normally made from lenses, that leaves the main objective (lens = refractor, or mirror = reflector) as the determinant of whether a telescope is a reflector or refractor (otherwise we'd have to call nearly all telescopes refractors). There are some potentially confusing mixtures (e.g., Schmidt-Cassegrain, Maksutov, etc.). But those are normally still considered to be reflectors, while their aperture-sized lens-type elements are considered to be "correctors."
Refractors are dioptrics.
Newtonians, classical Cassegrains and all mirror systems are catoptrics.
Maksutovs, SCTs that mix lenses and mirrors are catadioptrics.

The use of a diagonal is a nonessential option.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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Re: Should A Refractor Be Called A Reflector?

#8

Post by Refractordude »


notFritzArgelander wrote: Mon Nov 11, 2019 9:41 pm
AntennaGuy wrote: Mon Nov 11, 2019 9:04 pm I agree with JT. Although the optical quality of a diagonal is important, its primary role is simply to re-direct the beam. The image forming mechanisms are either lenses or mirrors. Since eyepieces are normally made from lenses, that leaves the main objective (lens = refractor, or mirror = reflector) as the determinant of whether a telescope is a reflector or refractor (otherwise we'd have to call nearly all telescopes refractors). There are some potentially confusing mixtures (e.g., Schmidt-Cassegrain, Maksutov, etc.). But those are normally still considered to be reflectors, while their aperture-sized lens-type elements are considered to be "correctors."
Refractors are dioptrics.
Newtonians, classical Cassegrains and all mirror systems are catoptrics.
Maksutovs, SCTs that mix lenses and mirrors are catadioptrics.

The use of a diagonal is a nonessential option.
I am wrong and great answer nFA
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Re: Should A Refractor Be Called A Reflector?

#9

Post by Don Quixote »


Have not read any but the OP.
Dude ! WTF ?!
HELL NO ! 😊
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Re: Should A Refractor Be Called A Reflector?

#10

Post by Bigzmey »


When I saw the title, I thought it should be called reflector, because it helps us to reflect on wonders of the sky. :)
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Re: Should A Refractor Be Called A Reflector?

#11

Post by j.gardavsky »


Yours according to the pic is diagonal double-dioptrix,
because both the light gathering optics and the eyepiece are dioptrics, and there is a zenith diagonal in between.

The other one, listed by not_Fritz, would be catadioptric-diagonal-dioptrix, ...
Regarding the old German Schiefspiegler, I have nothing better than calling it Schiefspieglerteutonics.

The Fraunhofer tracking EQ mount might be Equatoreanum penduli moveatur Fraunhoferi, ...

ZEISS has decided to call their refracting spotting scope, Diascope.
Following ZEISS, Thomas Baader has renamed the astroplanar remake into Eudiascopic

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Re: Should A Refractor Be Called A Reflector?

#12

Post by John Baars »


:sprefac: Pffffffff.....I am glad my refractors are still refractors..... :sprefac:
Refractors in frequency of use : *SW Evostar 120ED F/7.5 (all round ), * Vixen 102ED F/9 (vintage), both on Vixen GPDX.
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Re: Should A Refractor Be Called A Reflector?

#13

Post by yobbo89 »


The topic reminds me of folded refractors which have 2 or more mirrors in them as well as a refracting front lense .

Here are some images from the web
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Re: Should A Refractor Be Called A Reflector?

#14

Post by KathyNS »


My Newtonian is a catadioptric, because it really doesn't work properly without a coma corrector.
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Re: Should A Refractor Be Called A Reflector?

#15

Post by Don Alvarez »


me-yelling-at-my-cat-to-not-eat-my-salad-58434960.png
Telescopes: 10" SkyLine Dobsonian, 6" Apertura F5 Newt, Celestron Nextar GT90, Meade Infinity 80
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Re: Should A Refractor Be Called A Reflector?

#16

Post by Marcelo F. »


Image
Telescope: Dobson N 76/300 FirstScope DOB w/ DIY tripod adapter, 5x24 Finderscope.
Eps: 4mm Ramsden, 6mm Huygenian, 12.5mm Huygenian, 20mm Huygenian, 4mm Plossl, 10mm Plossl, 20mm Plossl, Barlow 2x, Barlow 3x, Barlow 5x, Solomark LP Filter, Dark Green Moon Filter.
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Re: Should A Refractor Be Called A Reflector?

#17

Post by helicon »


I also am glad that my refractor is truly a refractor. Though I could call it "Fred".
-Michael
Refractors: ES AR152 f/6.5 Achromat on Twilight II, Celestron 102mm XLT f/9.8 on Celestron Heavy Duty Alt Az mount, KOWA 90mm spotting scope
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Re: Should A Refractor Be Called A Reflector?

#18

Post by j.gardavsky »


KathyNS wrote: Fri Nov 15, 2019 2:00 pm My Newtonian is a catadioptric, because it really doesn't work properly without a coma corrector.
Kathy,
and when it makes spikes around the stars,
then it is catadioptric asterix,

JG
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Re: Should A Refractor Be Called A Reflector?

#19

Post by russmax »


A refractor is called a refractor because that is its name. Likewise with a reflector.
Language is by usage, so if you overthink it, people might tease you for it, as shown in the posts above.
--Russmax
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Re: Should A Refractor Be Called A Reflector?

#20

Post by Mandrew »


It’s a telescope!
Devout bino lover and Lunaholic! Scopes - Celestron RASA 8, Orion 180mm Mak-Cass, 6"f8 dob, ST80. binos - Orion 7x50, Oberwerk 8x56 LW, Oberwerk 10x50 Deluxe, 15x70 Deluxe, Oberwerk 100mm ED Binocular telescope.
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