Stargazing Oxford 2013 Project : Comet ISON

6 February 2013 by Fraser Clarke

Comet ISON on 28th January 2013

Comet Incoming! Here is the first image of Comet ISON taken for our 2013 PWT Stargazer's project. ISON is still as far away as Jupiter, but already a small tail is starting to develop... For this project, we will be imaging the comet every 2 weeks this year with the Philip Wetton Telescope (PWT) telescope here in Oxford. Check back to see how the comet develops, and if it delivers on its promise to be the brightest comet in 40 years!

The 2013 PWT Stargazer's Project was picked by visitors to telescope control room at Stargazing Oxford. From a choice of 5 projects, 33% of people choose the project "Tracking the approach of Comet ISON". For this project, we will image comet ISON every 2 weeks or so (depending on weather!) to see how it brightens and evolves as it comes into the inner solar system. Current predictions, though notoriously unpredictable, estimate comet ISON could be as bright as the full moon by the time it rounds the Sun early in 2014.

What are we seeing here? The image here is a combination of ten images taken over a 20-minute period on the early morning of 28th January 2013. At this time, Comet ISON was about 5x further away from the Sun than Earth is -- about the same distance as Jupiter is from the Sun. The comet is the little "smudge" in the middle of the image -- remember that in a year's time, this little smudge might be brighter than the moon! You can see a little tail starting to form, pointing to the upper-right in this image. The other objects you can see trailed across the image are stars.

Why are the stars trailed? The comet is moving relative to the background stars as it orbits around the Sun. Even at its current distance, it moves significantly over the 20 minutes it took us to take the 10 images. When we processed the images, we aligned each of the images so that comet appeared in the same place. That in turn makes the background stars look like they are moving...

Is this useful? Yes. a) It's fun! b) Predicting the brightness of comets is notoriously hard. Monitoring comet ISON as it comes closer to Sun will help make the predictions of its ultimate brightness more accurate. c) We've never observed "moving objects" (comets and asteroids) with the PWT before!! To make this project happen, we've had to get a new bit of software working. Now that it is, we're able to do a whole load more projects with comets and asteroids, which we can use for undergraduate teaching and even research projects.

The next image should be taken automatically by the telescope in the 2nd week of February -- check back here soon after to see how ISON is changing!

Categories: stargazing | Comet ISON | 2013 | PWT