A Brief History
From the beginning of civilization, the study of the sky has been a constant theme. Some scientists even claim that the prehistoric paintings of the Lascaux Cave are in fact depictions of constellations. True or not, astronomy is definitely one of the oldest sciences, if not the oldest.
For centuries, maps of the sky and the universe were created, most of them with a religious idea in mind.
Aside from the spiritual aspect of astronomy in the Occident, stars are also used for sea navigation. The Arab civilisation is at the origin of many star names and precise measurements of star positions.
At the renaissance astronomy was progressively separated from astrology and religion (not without difficulties). The invention of the telescope was critical to some of the most important discoveries of the renaissance.
With the invention of the telescope, the sky became even more impressive, and with the development of science and technology telescopes are becoming larger and larger.
The most famous telescope is probably Hubble. We are all familiar with incredible pictures like the pillar of creation.
But do you know where the colours come from, and if they are the real colours of the sky ?
The Hubble Pallette
If you thought that the beautiful colours from Hubble pictures are real, I'm sorry to destroy your dreams, but they are in fact false colours. Astronomers use the light to analyse the composition of stars and nebulae, and extract specific light rays showing the presence of a particular elements. These pictures are called narrowband images. By affecting these narrowband images at specific RGB channels, they can create the colour they want.
Here is an example of a Hydrogen Oxygen Nitrogen false colour picture.
Red = Hydrogen Green = Oxygen Blue = Nitrogen
Resulting HON picture
Pictures via : Almaden Observatory www.almadenobservatory.net/
The choice of colour can be decided by a scientific use : the picture has a visual composition information, but it is also the result of a personal choice and picture beauty. Hubble astronomers are also artists in their job.
If you want to create your own images using this technique, a software is available as a plug-in for photoshop.
The Night Sky
No need to have the budget of NASA to make pictures of space. A simple camera can create very impressive pictures of our galaxy and an amateur telescope can show nebulae in their full glory.
Space Art - The Intersection
Space art is somewhere in between science and science fiction. It is often used to illustration science articles. Space art is at present time the only way we have to visit our universe.