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List of Terms and Abbreviations

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It can be a very daunting challenge when you first get started with astronomy or astrophotography, there are so many terms and abbreviations that can often be confusing and make very little sense!

Listed below is a comprehensive list of every common abbreviation and it's meaning that you may come across when you get started with astronomy. It will also serve as a useful list for some of the abbreviations that will be used in this forum.


AGN - Active Galaxy Nucleus

APOD - Astronomy Picture of the Day

ALT - Altitude

AU - Astronomical Unit

AZ - Azimuth

CA - Chromatic Aberration

CCD - Charged-Coupled Device

CME - Coronal Mass Ejection

CMOS - Complementary Metal Oxide Silicon - a type of camera sensor.

DOB - Dobsonian Mount

DSO - Deep Space Object (galaxies, nebula, clusters)

EAA - Electronically Assisted Astronomy

ED - Extra-low Dispersion Glass (used in objective lenses)

ESO - European Southern Observatory

EP - Eyepiece

EQ - Equatorial Mount

FIR - Far Infra Red

FITS - Flexible Image Transport System (file type)

FOV - Field of View

FRAC - Refractor (telescope type)

FW - Filterwheel

FWHM - Full Width Half Maximum

GC - Globular Cluster

GEM - German Equatorial Mount

GEO - Geosynchronous Earth Orbit

GEOS - Geosynchronous Earth Orbit Satellite

GIF - Graphics Interchange Format (file type

GLOB - Globular Cluster

GMT - Greenwich Mean Time

GPS - Global Positioning Sysytem

GR - General Relativity

GRB - Gamma Ray Burst

GRS - Great Red Spot (on Jupiter)

Ha - Hydrogen Alpha emission line

Hb - Hydrogen Beta emission line

HDF - Hubble Deep Field

HST - Hubble Space Telescope

IAU - International Astronomical Union

IC - Index Catalogue (a list of objects like the NGC or Messier lists)

IR - Infra Red

ISS - International Space Station

KBO - Kuiper Belt Object

LEO - Low Earth Orbit

LMC - Large Magellanic Cloud

LMST - Local Mean Sidereal Time

LP - Light Pollution

LST - Local Sidereal Time

M - Messier object prefix

MAK- Maksutov (telescope type)

NCP - North Celestial Pole

NEO - Near Earth Object

NEWT - Newtonian reflector

NGC - New General Catalogue

OIII - Doubly Ionized Oxygen emission line

OAG - Off Axis Guider

OC - Open Cluster

OTA - Optical Tube Assembly

PHD - Push Here Dummy (guiding software)

PN - Planetary Nebula

PST - Personal Solar Telescope

RC - Ritchey Chretien (telescope type)

RDF - Red Dot Finder

RFT - Rich Field Telescope

RGO - Royal Greenwich Observatory

RN - Reflection Nebula

SII - Singly Ionized Sulfur emission line

SCT - Schmidt Cassegrain Telescope (telescope type)

SETI - Search for Extra Terrestial Intelligence (organisation)

SMC - Small Magellanic Clouds

SNR - Super Nova Remnant

TH - Telescope House

TLAO - Turn Left at Orion (book)

UHF - Ultra High Frequency

UT - Universal Time

UTC - Coordintated Universal Time

UV - Ultra Violet

VHF - Very High Frequency

VLT - Very Large Telescope


Thanks to Stargazerslounge user Ant for creating this definitive list!

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