Seeing stars: the art of astronomical imagery

Initial images of data obtained from a space telescope are a far cry from the colourful pictures in astronomy books and websites. So how much effort do scientists really put in to get such amazing pictures? Physicist Tatiana Statsenko sheds some light on the matter.

The North American Nebula

Images of the stars and sky presented by astronomy laboratories often look like artistic masterpieces, but anyone who’s ever peered through a telescope at night will have seen something very different, if equally spectacular.

The raw data goes through a number of processes before we begin to see anything like those final artworks. Firstly, the light collected by the telescope is received by a charge-coupled device (CCD), which then converts it into a digital value. Initially, the result will look significantly less impressive:

NGC 7000, The North American Nebula
[http://wisp11.physics.wisc.edu/~soto/]

The grid effect is caused a by a mosaic CCD, a system which employs multiple devices in the  name of cost efficiency. The system then makes further adjustments by normalising the intensity of the images, a process used to retrieve all the features of the matrix and bring it into a range that is more familiar to the senses.

To obtain colored images, the telescope records light in different ranges of the spectrum, and then combines them afterwards.  Some of that light, however, appears on parts of the spectrum not usually visible to the human eye, so the data is represented in ‘false’ (i.e. observable by human) colours, to provide an idea, or interpretation, of what the stars look like.

Distinguishing the beauty of the stars, nebula and galaxies from amid the noise and turbulence is a skill in itself, and one that requires both scientific and artistic ability. Technical limitations have long been a source of frustration for astronomers, but, as we enter the apex of the digital revolution, devices are improving increasingly quickly.

Larger and larger telescopes are built year on year, and with names such as Large Binocular Telescope, Very Large Telescope and even European Extremely Large Telescope, it seems that those working with them are more concerned with applying their creativity to the images themselves rather than naming the devices that produce them.

Humans have always admired the night sky, and with the help of astronomers, the universe can be much more picturesque than in ‘real life’. Yet no-one would claim that these images are fiction – they are just a representation of distant beauty that would otherwise remain invisible.

About the author

A musician with a passion for science, Tatiana Statsenko is a Russian physicist currently studying in Europe.