Steps To Obtain An Astronomical Image

STEPS TO OBTAIN AN ASTRONOMICAL IMAGE Roberto Bartali

LIGHT WAVES FROM THE OBJECT

CELESTIAL OBJECT

GATHERED BY THE TELESCOPE

CAPTURED BY THE SENSOR

CONVERTED TO A BINARY NUMBER MATRIX

PROCESSED BY A COMPUTER

RESULTING IMAGE OF THE OBJECT

SCIENCE = (RAW - DARK - BIAS) / (FLAT - DARK - BIAS)

RAW IMAGE, of galaxy M51, contains photons captured by the telescope and noise generated by the imaging system.

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= Corrected raw image Bias frame shows internal noise, due to electronics, and defective pixels. Exposure time = 0..

Dark frame shows thermally generated electrons. Exposure length equal to raw exposure.

Flat frame shows difference in pixel sensitivity, dust on optic surfaces, fringes and vignetting.

= Corrected flat frame

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CALIBRTION FRAMES

=

SCIENCE IMAGE, of galaxy M51, corrected for internal and external errors and noise, ready for further image processing.