Imaging Techniques
How celestial images are captured — astrophotography and its planetary, deep-sky, and narrowband variants, and the autoguiding that keeps a telescope on target.
- AstrophotographyImaging technique
Capturing images of celestial objects with a camera, from wide starfields on a fixed tripod to long, tracked exposures through a telescope. Astrophotography trades the eye's real-time view for the camera's ability to accumulate light over minutes or hours, revealing colour and faint structure the eye can never see. It spans planetary, deep-sky, and narrowband techniques.
- AutoguidingImaging technique
Keeping a telescope locked precisely on target during a long exposure by continuously imaging a guide star and sending tiny correction commands to the mount to cancel tracking errors. Autoguiding is what makes hours-long deep-sky exposures possible without the stars trailing.
- Deep-Sky ImagingImaging technique
Long-exposure imaging of faint, extended objects — galaxies, nebulae, and clusters — that requires accurate tracking of the sky's motion, often over many hours of accumulated exposure. Deep-sky imaging leans on an equatorial mount, autoguiding, and careful calibration to draw out signal from targets far too faint to see by eye.
- Narrowband ImagingImaging technique
Imaging through filters that pass only the light of specific emission lines — hydrogen-alpha, oxygen-III, sulphur-II — to isolate the glow of ionised gas and cut through light pollution and moonlight. Narrowband imaging reveals the intricate structure of emission nebulae and is the basis of the popular false-colour 'Hubble palette'.
- Planetary ImagingImaging technique
High-resolution imaging of the Moon and planets by recording thousands of short-exposure frames and keeping only the sharpest, to beat the blurring of atmospheric turbulence. This 'lucky imaging' approach, usually with a fast CMOS camera, lets modest telescopes resolve cloud belts on Jupiter, the rings of Saturn, and craters on the Moon.