At this moment, the Juno spacecraft is hurtling towards Jupiter where it is set to take up orbit on July 4. To help map the planet for that rendezvous, the European Southern Observatory (ESO) has used an instrument on its Very Large Telescope (VLT) to create a stunning image of the solar system's largest planet. To bring the image to life, the space agency relied on a technique known as "lucky imaging."
The piece of equipment involved in the creation of the image is known as VISIR, which stands for VLT Imager and Spectrometer for mid-Infrared. It is attached to the VLT array in the Atacama desert of Chile and is designed to pick up infrared light from celestial objects, which allows it to, in effect, see through much of the clouds and dust in the galaxy – as well as through Earth's own shifting atmosphere – to image objects that might otherwise be obscured. To avoid putting out its own infrared light, the instrument is cooled to temperatures close to -250° C (-418° F).
For this project, the VISIR instrument took a series of thousands of snapshots of Jupiter in a process known as lucky imaging.
"Sequences of very short exposures were taken of Jupiter by VISIR, producing thousands of individual frames," explains the ESO. "The lucky frames, where the image is least affected by the atmosphere's turbulence, are selected and the rest discarded. Those selected frames are aligned and combined to produce remarkable final pictures like the ones shown here."
By visually mapping Jupiter this way, researchers hope to enhance the work Juno will do on its 20-month mission orbiting and studying the Jovian atmosphere.
"These maps will help set the scene for what Juno will witness in the coming months. Observations at different wavelengths across the infrared spectrum allow us to piece together a three-dimensional picture of how energy and material are transported upwards through the atmosphere," says Leigh Fletcher of the University of Leicester in the United Kingdom.
Fletcher and his team are presenting the Jupiter image, along with others, at the the UK's Royal Astronomical Society's National Astronomy Meeting, taking place in Nottingham, England, now.
"The bluer areas are cold and cloud-free, the orangey areas are warm and cloudy, more colorless bright regions are warm and cloud-free, and dark regions are cold and cloudy (such as the Great Red Spot and the prominent ovals)," says the ESO of this image, which was also part of the project to map Jupiter in preparation for Juno's arrival on July 4