Hubble has been unlocking the Universe’s secrets for 30 years, leading NASA to showcase the most iconic images captured during this time. Three decades have unbelievably passed since the Hubble Space Telescope first beamed back amazing imagery responsible for single-handedly transforming mankind’s understanding of the universe.
Since launching at Florida’s Kennedy Space Centre in April 1990 Hubble has made more than 1.3 million observations from its near-Earth orbit.
Hubble has revealed stars being born, dying and colliding as far away as 13.4 billion light years distant.
The space telescope has helped scientists calculate the birth of the Big Bang 13.8 billion years ago.
This makes the universe approximately three times the age of our planet. as well as estimating the speed of its rate of expansion.
Thanks to Hubble, astronomers now also know almost every major galaxy has a black hole at sitting its centre.
Some of its most spectacular images ever shot have included unimaginably enormous clouds of space dust called nebulae, where stars are created.
Arguably the most Hubble’s most iconic image is the 1995 pics of towering columns of cosmic debris in the Eagle Nebula dubbed the Pillars of Creation.
Closer to home, Hubble also captured a comet colliding with Jupiter.
How NASA colourises Hubble Space Telescope photos:
Every deep-space photograph captured by the Hubble space telescope, in fact, began as black-and-white.
Hubble’s primary function is to measure the brightness of light reflecting off of objects in space, not to capture colour images.
In order to produce a colour image, Hubble captures images using broadband filtering.
This captures a general range of red, green, and blue light in a black-and-white image.
Those are only later combined to create a true-colour image of deep space.
Scientists who colourise Hubble images often go beyond true colour, in order to reveal portions of the image otherwise invisible to human eyes.
A popular example is transforming certain gasses into visible colours.
Hubble does this using narrowband filtering, changing extremely narrow wavelengths of the visible light spectrum corresponding to individual elements such as oxygen and hydrogen.
The colour of each image is then shifted to correspond to red, green and blue.
This how the images such as the Pillars of Creation image was created.
In that image, sulphur is represented by the colour red, hydrogen by green, and oxygen by blue, which is not where they actually sit on the visible spectrum.
But when you shift each element over so they correspond to either red, green or blue, and put them all together, a colourised map is created, which is considered far more useful for analysis.