Acronyms
2MASS
Two Micron All Sky Survey: An infrared astronomical survey
AAVSO
American Association of Variable Star Observers: A group of variable
star observers and also the catalogue they have created
ADC
Analogue-to-digital converter: A device to convert an analogue signal
such as voltage to a digital one such as count
ADS
Aitken double star catalogue
Alt
Altitude: the vertical position of a telescope
AO
Adaptive Optics: A process using movable optics to improve optical
resolution
APT
Aperture photometry tool: A freeware multiplatform photometry tool
AU
Astronomical unit: The mean distance between the Earth and the Sun,
most often used in solar system physics
Az
Azimuth: The horizontal position of a telescope
CCD
Charge-coupled device: The detector in a modern astronomical digital
camera
CDS
Centre de données astronomiques de Strasbourg: The French body that
hosts SIMBAD
CMB
Cosmic microwave background: The afterglow, at microwave wavelengths, of the light that escapes during the era of recombination
CMD
Colour-magnitude diagram: A plot of absolute magnitude against
colour. The Hertzsprung–Russell diagram is an example of a colour–
magnitude diagram
CMOS
Complementary metal oxide semiconductor: A photon detector similar
to the CCD
CTE
Charge transfer efficiency: The rate at which electrons are lost during
pixel-to-pixel transfer in a CCD
CTIO
Cerro Tololo Inter-American Observatory: An international observatory based in Chile
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