JWST Acronyms and Abbreviations

A reference list of acronyms and abbreviations used in JWST user documentation is provided in this article.

Also, the University of Arizona NIRCam team have provided a more extensive project-wide listing of JWST acronyms that you may find useful. (This link goes outside the JWST documentation site.)

Updates to this listing will be republished periodically as new articles/acronyms are added.

2MASSTwo Micron All-Sky Survey
4QPM4-quadrant phase mask (also FQPM)
4QPMC4-quadrant phase mask coronagraph
AAAssociate Administrator
ACassociation candidate
ACS(Context sensitive)
Hubble Space Telescope Advanced Camera for Surveys, or
JWST attitude control subsystem
ADattempt duration
ADI/ADISangular differential imaging/ADI strategy
ADUanalog-to-digital units
AGBasymptotic giant branch
AGNactive galactic nuclei
ALMAAtacama Large Millimeter/Submillimeter Array
AMIaperture masking interferometry
AOadaptive optics
APAaperture position angle (also PA)
APIapplication program interface
APTAstronomer's Proposal Tool
AR anti-reflective
ASDFAdvanced Scientific Data Format
ASICApplication Specific Integrated Circuit
AUastronomical unit
APO anamorphic pre optics

BFblocking filter
BMGbackground model generator
BOTAbright object target acquisition
BOTSbright object time series

Ccontrast (used in high contrast imaging discussions)
C&DHCommand & Data Handling
CAAcalibration assembly (NIRSpec)
CANDELSCosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey
CANUCSCanadian NIRISS Unbiased Cluster Survey
CCDcharge coupled device
CDBSCalibration Database System
CDScorrelated double sampling
CFMcoarse focus mechanism
CHMconstrained heat map
COBECosmic Background Explorer
COLLcollimator optics
COMcoronagraphic optical mount
CSACanadian Space Agency
CSVcomma separated variable
CVTCoronagraphic Visibility Tool
CVZcontinuous viewing zone
CV3cryo-vacuum test #3

DBSdichroic beam splitter
DCLDetector Characterization Laboratory
DD-ERS director’s discretionary early release science (see also ERS)
DDTdirector's discretionary time
DHSdispersed Hartman sensing
DMS/DMSWGData Management System/Data Management System Working Group
DN digital number
DPDiscovery Portal
DPAdouble prism assembly
DRMDesign Reference Mission
DSFGdusty star forming galaxies
DSNDeep Space Network
DSSDigital Sky Survey

EEencircled energy
EGSextended Groth strip
ELGemission line galaxy
EOGextreme outer galaxy
EPPOEvery Page is Page One
ERSearly release science (see also DD-ERS)
ESAEuropean Space Agency
ETCExposure Time Calculator

FC failed closed (NIRSpec micro-shutters)
FDFFight Dynamics Facility
FGSFine Guidance Sensor
FFAfull frame astrometry
FITSFlexible Image Transport System
FO failed open
FORfield of regard
FOTFlight Operations Team
FOVfield of view
FPfailure probability
FPAfocal plane array
FPEfocal plane electronics
FQPM4-quadrant phase mask (also 4QPM)
FRCFinancial Review Committee
FRDfocal ratio degradation


fixed slit
FSWFGS flight software


fine steering mirror


filter wheel
FWAfilter wheel assembly
FWHM full width at half maximum


general observer
GOODSGreat Observatories Origins Deep Survey
GSguide star
GSCGuide Star Catalog
GSFCGoddard Space Flight Center
GSC2.3 Guide Star Catalog 2.3
GSMFgalaxy stellar mass function
GSSSGuide Star Selection System
GTOguaranteed time observer
GTVTGeneral Target Visibility Tool
GUIgraphical user interface
GWAgrating wheel assembly

H2RGHAWAII 2RG Astronomical Wide Area Infrared Imager
HCIhigh-contrast imaging
HDUHeader data unit
HFFHubble Frontier Field
HGAhigh gain antenna
HLAHubble Legacy Archive
HSCHubble Source Catalog
HSTHubble Space Telescope (a.k.a. Hubble)
HUDFHubble Ultra-Deep Field
HWHMhalf width at half maximum

IBCimpurity-band conduction
ICDHISIM Command and Data Handling
ICEinstrument control electronics
ICRSInternational Celestial Reference System
IDSinterdisciplinary scientist
IDTinstrument development team
IECISIM electronics compartment
IFSintegral field spectroscopy (or spectrograph)
IFUintegral field unit
IMFinitial mass function
IPACInfrared Processing and Analysis Center
IPCInter-pixel capacitance
IPRinternal phase retrieval
IPSintra-pixel sensitivity
IRACInfrared Array Camera (Spitzer)


Infrared Camera (AKARI satellite)
IRSInfrared Spectrograph (Spitzer)
IRS2improved reference sampling and subtraction
ISinstrument scientist
ISIMIntegrated Science Instrument Module
ISMInterstellar medium
IWAinner working angle

JADESJWST Advanced Extragalactic Survey
JBTJWST Background Tool
JDoxJWST User Documentation (shorthand)
JISTJWST Interactive Sensitivity Tool
JPLJet Propulsion Laboratory
JWSTJames Webb Space Telescope

KLIPKarhunen-Lo`eve image projection

L2Lagrange point #2, specifically Sun-Earth L2, about which JWST orbits
LAELyman alpha emitter
LAPlimited access parameters
LEDlight emitting diode
LOCIlocally optimized combination of images
LOSline of sight
LRPlong range plan
LRSlow resolution spectroscopy (or spectrograph)
LSFline spread function
LTlight traps
LWlong wavelength
LWClong wavelength channel
LyCLyot coronagraph

MASTMikulski Archive for Space Telescopes
MAZmicrometeoroid avoidance zone
MCAOmulti-conjugate adaptive optics
MCEmicro-shutter control electronics
MGAmedium gain antenna
MIMFmulti-instrument multi-field
MIPSMultiband Imaging Photometer for Spitzer
MIRIMid-Infrared Instrument
MOCDMission Operations Concept Document
MOSmulti-object spectroscopy (or spectrograph)
MOSVizMultiobject Spectrometer Visualization Tool
MPCMinor Planet Center
MPPTNIRSpec MOS pre-image planning tool
MPTNIRSpec MSA Planning Tool
MRDPminimum recommended data products
MREmono-propellant rocket engine
MRPminimum recommended products
MRSmedium resolution spectroscopy (or spectrograph)
MSAmicro-shutter assembly
MTVTMoving Target Visibility Tool
MUmomentum unload

NASANational Aeronautics and Space Administration
NAVONASA Astronomical Virtual Observatory
NCPnorth celestial pole
NDneutral density
NEAnoise equivalent angle or near Earth asteroid
NEATMnear Earth asteroid thermal model
NEDNASA/IPAC Extragalactic Database
NEOnear Earth object
NEPnorth ecliptic pole
NGSTNext Generation Space Telescope
Northrop Grumman Space Technologies
NIRCamNear Infrared Camera
NIRISSNear Infrared Imager and Slitless Spectrograph
NIRSpecNear Infrared Spectrograph
NLRnarrow line region
NOInotice of intent
NOVTNIRSpec Observation Visualization Tool
NRMnon-redundant mask
NSFNational Science Foundation

OPDoptical path difference
OPEobservation plan executive
OSFobservatory status file
OSSOnboard Script Subsystem
OTEOptical Telescope Element
OTISOptical Telescope Element/Integrated Science Instrument Module

PAposition angle (also APA)
PAPPApupil alignment pinhole projector assembly
PARpupil alignment reference
PCprogram coordinator
PCAprincipal component analysis
PCEphoton conversion efficiency
PCGProposal Constraint Generator
PCRProposal Change Request
PCSpointing control system
PDFportable document format
PIprincipal investigator
PILpupil imaging lens
PMSpre-main sequence
PNplanetary nebula
POMpick-off mirror
POSSPalomar Observatory Sky Survey
PPCpost pixel coupling
PPSProposal Planning Subsystem
PRDProject Reference Database
PSFpoint spread function
PTCphoton transfer curve
PWpupil wheel
PVpointing verification

QEquantum efficiency
QY quantum yield

RAright ascension
RALRutherford Appleton Laboratory
RDIreferenced differential imaging
RMArefocus mechanism assembly
RMSroot mean square
ROIregion of interest
RPSram pressure stripping
RQErelative quantum efficiency
RSSreference star strategy
RVSRaytheon Vision Systems

sapparent separation
SAMsmall angle maneuver
SCAsensor chip assembly
SCPsouth celestial pole
SCATSecondary Combustion Augmented Thruster
SCSsimple cone search
SDslew duration
SDPScience Data Processing subsystem
SDSSSloan Digital Sky Survey
SEDspectral energy distribution
SGDsmall grid dither (or dithering)
SGDSsmall grid dither strategy
Si:Ararsenic-doped silicon
SIAFScience Instrument Aperture File
SIAPSimple Image Access protocol

System for Image Digitization, Enhancement, Control, and Retrieval Application-Specific Integrated Circuit


Set of Identifications, Measurements and Bibliography for Astronomical Data

SMDNASA Science Mission Directorate
SMOspectrometer main optics
SNRsignal-to-noise ratio (also S/N)
SPOspectrometer pre-optics
SODRMScience Operations Design Reference Mission
SOSSsingle object slitless spectroscopy
SPOspectrometer pre-optics
SRspecial requirement
SSAPSimple Spectral Access Protocol
SSRSolid State Recorder
SSSsame scheduling set
STMstandard thermal model
STScISpace Telescope Science Institute
SWshort wavelength
SWCshort wavelength channel
SWGScience Working Group

TAtarget acquisition
TACtime allocation committee
TAPTable Access Protocol
TDFtime domain field
TFItunable filter imager
TMAthree mirror assembly
ToO/TOOtarget of opportunity
TPStarget pointing specification
TSOtime-series observation
TSVtab separated variable
TTRBTelescope Time Review Board
TVTtarget visibility tool(s)

UDFUktra Deep Field
UTuniversal time

V3PAposition angle of the JWST Observatory V3 reference axis
VASvariable aperture system
VOVirtual Observatory
VOT Virtual Observatory Table
VPvisit planner

WATAwide aperture target acquisition
WCSworld coordinate system
WFCwide field channel
WFC3Wide Field Camera 3 (HST)
WFEwavefront error
WFS&Cwavefront sensing & control (also WS&C)
WFSSwide field slitless spectroscopy 
WISEWide-field Infrared Survey Explorer mission
WLweak lens
WOPRWebb Operations Problem Report
WS&Cwavefront sensing & control (also WFS&C)

YSOyoung stellar object

Notable updates
    Updated for 2022 Cycle 2

    Updated Link to U Az acronyms site.

    Updated for 2020 Cycle 1.
Originally published