New Horizons

New Horizons for SALT

 

NewHorizonsPlutoSurface

The excitement is palpable as New Horizons draws near to its destination.

An interplanetary probe aptly named New Horizons was launched on the 19th of January 2006, with the intention of a flyby of the (former) planet on the outskirts of our solar system; the icy and mysterious Pluto. After a close to nine year journey towards Pluto, the deadline for arrival is drawing near –  New Horizons is scheduled to fly past Pluto on the 14th of July 2015! Since it is the only planet in our solar system never visited by a spacecraft from earth, this is an unprecedented achievement; one which the Southern African Large Telescope has been actively involved in.

New Horizons will begin its work long before it reaches Pluto. Around April, New Horizons and its on-board camera, LORRI (the Long Range Reconnaissance Imager), will begin taking pictures of Pluto and the five moons surrounding it – although there may even be more moons than we’re aware of!  These will be the first ever close up images of Pluto, and will be even better than the mysterious mottled images snapped by the Hubble Space Telescope. Hubble produced interesting images of Pluto which proved to be quite invaluable for picking out the flight path for the New Horizons spacecraft. The Hubble Space Telescope is usually reserved for tasks which cannot be done from the ground, such as High Spatial Resolution Imaging. The work which the team working with New Horizons is doing; spectroscopy, makes SALT a great telescope to do observations from, since SALT specialises in spectroscopic imaging.

The New Horizons team intends to take spectra of Pluto as it rotates. What this means is that they need to use spectroscopy in order to measure the spectrum of electromagnetic radiation coming from Pluto and its various moons. Spectroscopy is used in order to derive the properties of distant stars and galaxies, such as the chemical composition, temperature, density, mass, distance, luminosity and relative motion, and is what SALT specifically does. In order to take spectra of Pluto, the team needs to observe Pluto for about 15 minutes every night for thirteen nights, which will allow them to see the planet at a slightly different rotational angle each time.

SALT fortunately runs on a ‘queue-scheduled’ basis. This means that the New Horizons team will put in their observation request, and a SALT astronomer will observe Pluto for the required 15 minutes, and will then go on to observe the other scheduled targets which they have for the rest of the night. At SALT, many different targets are observed for many different astronomers each evening, while on a traditional telescope, the astronomer gets the telescope for the whole night, whether they plan to use the whole evening for observations or not. This makes SALT much more efficient for the New Horizons mission as it only needs short chunks of time. Since SALT is able to change instruments very quickly, for example from spectroscopy to imaging, it also supplies multiple forms of data.

SALT has thus been part of an exciting journey which will bring us to the edge of our galaxy and produce images of a planet which has for many years intrigued astronomers and the world alike! The count-down begins!

PS Keep an eye on our student section to read why Pluto is no longer officially classed as a planet!