Glossary

The following terms and acronyms are used in this Handbook.

ADC: Analog to digital

ABMAG: –2.5 log (Fn) – 48.60 where Fn is the flux from the source in erg cm–2 sec-1 Hz-1

ABn: Correction to ABMAG to account for the fact that the source spectrum is not constant in Fn (ABMAG=V+ABn)

ACS: Advanced Camera for Surveys

APT: Astronomer’s Proposal Tool

aXe: Spectroscopic Data Extraction Software

BOP: Bright Object Protection

calacs: ACS calibration pipeline software

CCD: Charge Coupled Device. Solid-state, light detecting device

CMD: Color Magnitude Diagram

CP: Call for Proposals

CR: Cosmic ray

CR-SPLIT: Division of a CCD exposure into shorter exposures to be used for cosmic ray rejection

CTE: Charge transfer efficiency

CVZ: Continuous viewing zone

DN: Data number

ETC: Exposure Time Calculator. ETCs are Web-based tools which can be accessed through the ACS Web pages.

ERO: Early release observations

FGS: Fine Guidance Sensors

FOS: Faint Object Spectrograph

FOV: Field of view

FTP: File Transfer Protocol. Basic tool used to retrieve files from a remote system. Ask your system manager for information about using FTP.

FUV: Far ultraviolet (~912 to 2000 Å)

FWHM: Full width at half maximum

GALEX: Galaxy Evolution Explorer

GHRS: Goddard High-Resolution Spectrograph

GO: General Observer

GSC: Guide Star Catalog

GSCII: Guide Star Catalog II

GTO: Guaranteed Time Observer

Help Desk: Facility for getting help on HST related topics via email. help@stsci.edu.

HRC: High Resolution Channel

HST: Hubble Space Telescope

IDT: Investigation Definition Team

IR: Infrared

IRAF: Image Reduction and Analysis System. The environment in which STSDAS operates.

ISR: Instrument Science Report

IUE: International Ultraviolet Explorer Satellite

K: Degree Kelvin

L-flats: Low Frequency Variations Flats

LMC: Large Magellanic Cloud

MAMA: Multi-Anode Microchannel Array

MCP: Microchannel Plate

MPP: Multi Pinned Phased, a CCD mode that reduces dark current rate

NICMOS: Near-Infrared Camera and Multi-Object Spectrograph

NUV: Near ultraviolet (~2000 to 4000 Å)

OTA: Optical Telescope Assembly

PASP: Publications of the Astronomical Society of the Pacific

PC: Program Coordinator

Phase I proposal: A proposal for observing time on HST

Phase II program: An approved HST program; includes precise detail of how program is to be executed

PI: Principal investigator

P-flats: pixel-to-pixel high-frequency flats

PRF: Pixel Response Function

PSF: Point-spread function.

PyRAF: version of IRAF implemented in the Python language

QE: Quantum Efficiency

QEH: Quantum Efficiency Hysteresis

Quadrant: Section of detector that is read-out by an amplifier. For WFC, there are 4 amplifiers, two for each detector, so each amplifier reads one 2048 x 2048 pixel quadrant.

RA: Right Ascension

RAS: HST simulator used in ground tests to accurately simulate the full field OTA illumination, and is used to calibrate HST instruments. Also know as RAS/HOMS, the Refractive Aberrated Simulator/Hubble Opto-Mechanical Simulator.

reference file: data file containing ACS parameters or calibration information which is used by the calibration pipeline

rms: Root mean square

RQE: Responsive Quantum Efficiency

SAA: South Atlantic anomaly

SBC: Solar-Blind Channel

SDSS: Sloan Digital Sky Survey

SITe: Scientific Image Technologies; company that designed the ACS CCDs

SLIM: Slitless Spectroscopy Simulator

SMOV: Servicing Mission Observatory Verification

S/N: signal-to-noise ratio

SNAPSHOT: Short exposures taken during unused blocks of telescope time.

ST-ECF: Space Telescope European Coordinating Facility

STAN: Space Telescope Analysis Newsletter

STIS: Space Telescope Imaging Spectrograph

STScI: Space Telescope Science Institute

STSDAS: Space Telescope Science Data Analysis System. The complete suite of IRAF data analysis and calibration routines used to process HST data.

synphot: STSDAS synthetic photometry (IRAF) software package

TAC: Telescope Allocation Committee

TECs: Thermal Electric Coolers

Tiny Tim: PSF simulation software developed by John Krist &
Richard Hook

URL: Uniform resource locator. Address for WWW.

UV: Ultraviolet

WFC: Wide-Field Channel

WFPC2: Wide Field Planetary Camera-2. Replacement for WF/PC installed during first servicing mission of December 1993.

WWW: World Wide Web. Hypertext-oriented method for finding and retrieving information over the Internet.