Glossary

The following is a list of terms and abbreviations found throughout the documentation with their meanings.

Term	Description
ADU	Analog Digital Unit. The lightness value of pixels.
ASCOM	Astronomy Common Object Model. A Windows-centric API for astronomy-related device drivers.
Bahtinov Mask	A mask which has a specific pattern of light-diffracting openings that may be used to aid in achieving precise focus. Invented by Pavel Bahtinov in 2005.
Dithering	Moving the guiding output by a few pixels thereby shifting how light falls on the sensor. This technique minimizes fixed noise patterns and missing data due to hot or cold pixels.
DSO	Deep Space Object. Anything that is not an individual star or a Sol system object.
DSLR	Digital Single Lens Reflex Camera. Typically a hand-held camera with interchangeable lenses and a mirror for the viewfinder.
GEM	German Equatorial Mount. A common mount design.
Guiding	Using a second camera to lock on to a specific star. The star then acts as a reference point for correcting any unwanted mount movement.
HFR	Half-Flux Radius. A measurement (in pixels) which determines how focussed the average star is. Lower values indicate sharper stars. Focus precision and seeing conditions both affect HFR values.
J2000 and JNOW	Epochs (temporal reference points) based on the position of stellar objects as they were at January 1, 2000 11:58:55.816 UTC (J2000) or at the current moment (JNOW). It is expected that the next epoch will be J2050.
LRGB	Luminance, Red, Green, Blue. A typical color filter combination for creating color images using a monochrome camera.
OSC	One-Shot-Color. An astronomy camera equipped with a color sensor.
Plate Solving	Determining exactly where a telescope is pointing in the sky by comparing an image's stellar field to a database.
SNR	Signal to noise ratio.