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Glossary of astronomical terms -visual

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A novice to astronomy must be extremely confused when reading some of the threads on here, so I thought this might help.

This is just an introduction to the kind of language people use here: short forms, acronyms and so on. It's NOT a comprehensive list of technical terms; these are easily looked up.


First and most important:

SGL - Stargazers Lounge: this site! 😉

(Auntie) FLO - First Light Optics. Sponsors of this site and excellent retailers.



AP - Astrophotography (strange deviant behaviour that costs ££££)

BAA - British Astronomical Society

CA - Chromatic aberration. False colours on an image

CN - Cloudy Nights: an American astro website in some ways similar to SGL 😉

DSO - Deep-sky object: galaxy, star cluster, nebula, etc. See also PN, Glob.

EEVA - Electronically Enhanced Visual Astronomy (another good way to spend excess money! 😉)

Glob - globular star cluster 

OTA - Optical tube assembly. The scope without mount or accessories

LP - Light pollution 

PN - Planetary nebula 


Telescopes and accessories 

BIns / binos - binoculars (also sometimes binoviewers)

EP - Eyepiece: the bit you look into

Frac - refractor. Type of scope using only lenses 

Newt / dob - Newtonian reflector/ Dobsonian. Types of scope using mirrors. A dob is a Newtonian scope mounted on an easy-to-use base

Cat / Mak / SC / RC - types of scope using  mirrors and lenses 

Alt/az - altitude and azimuth (= up and down, left and right). Often used for a type of telescope mount.

EQ - Equatorial. Also used for a type of mount.

GoTo / go-to - computerised mount that automatically finds targets for you

RDF - Red dot finder. A non- magnifying tube with a red dot for locating objects and pointing the scope 


ES - Explore Scientific 

SL - StellaLyra

SW - Skywatcher 

Tak - Takahashi

TV - Televue 

WO - Williams Optics 



I'm sure there are plenty more that I've missed. All we need now is an AP user to do the same (I'm not qualified!).

Edited by cajen2
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15 hours ago, cajen2 said:

AP - Astrophotography (strange deviant behaviour that costs ££££)

I object! ( But not about the £££ bit🤣)

However, if you work out £ per image you are probably right.....

Ok. I withdraw my injection.... You are right.

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On 29/12/2022 at 17:14, Mike Q said:

CN is more of a warzone. 

Very true.  Lots of old goats over there - "Nahh, nahhh, nahhh, nahhhhhh!"  

However, some gemstones can be found in the fog of oral flatulence if you have the patience to search a bit.

Edited by jjohnson3803
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