In October 1946, the US launched a suborbital rocket from the White Sands Missile Range in New Mexico. This V2 rocket was fitted with a DeVry 35mm black and white motion picture camera. After reaching an altitude of around 105km, capturing a frame every second and a half, the camera came hurtling down. Though it was ripped to pieces, the film, kept in a protective steel cassette, survived re-entry and gave us the first picture—grainy and hazy—of Earth taken from space.
Space imagery has come a long way since. Images once captured with the help of high-altitude balloons and other kinds of aerial photography methods made way for ground-based observatories. Ground-based images of stars, however, are often fuzzy, and even overlap sometimes, because of the smearing effect of Earth’s atmosphere.
In 1990, the Hubble’s first light image was roughly 50% sharper than the image of the same region of the sky captured by an observatory in Chile. Now we are witnessing some of the most detailed images ever captured through space telescopes like the Hubble (launched in 1990) and its technological successor, the James Webb Space Telescope (JWST), launched last year.
Processing methods have improved remarkably too. One example is the composite image of Jupiter, as seen by the Webb, that the US space agency Nasa released on 22 August.
Even today, though, most space images are captured in black and white or grayscale. In fact, most astronomical data reaches scientists in the form of ones and zeroes, which are then translated into formats, including images. Colours too are introduced. Images taken by telescopes that observe at the “invisible” wavelengths are sometimes called “false colour images” or “representative colour images”. That is because the colours used to make them are chosen to bring out important details. This is done through coloured filters and image analysis software.
The Hubble has captured countless images for space enthusiasts and astronomers to marvel at. One was the Hubble Deep Field image, released in 1995, which captured thousands of remote galaxies.
Earlier this year, the JWST went further. In a fraction of the time, and far more detail, it “surpassed” the deepest image of the universe ever taken, notes Greg Brown, a Royal Observatory Greenwich astronomer, on the Royal Museums Greenwich website. “Unlike Hubble’s field, this image was deliberately focused on a specific galaxy cluster, named SMACS 0723,” Brown writes. “Webb, with a much larger mirror and its focus on red and infrared light, is better suited to seeing these distant galaxies than the much smaller, blue-focused Hubble ever could.” Brown adds that while even the shortest Hubble deep field took over a week to produce, “Webb needed to stare (at a part of the sky) for only 12 hours to achieve an image that almost certainly contains the most distant galaxy seen in infrared light”.
So, the next time you see a colourful image of a faraway galaxy, remember that it’s a result of both science and art.