2014Aug28_PaulNirmal_C2013A1_C104On October 19, at about 2:30pm EDT, comet C/2013 A1 (Siding Spring) will pass within 87,000 miles of the planet Mars (that’s about 1/3 the distance between Earth and the Moon) – and all the world will be watching, including a worldwide network of amateur astronomers known as The PACA Project!

PACA, or Pro-Am Collaborative Astronomy, is the brainchild of planetary scientist Padma Yanamandra-Fisher, who was a member of NASA’s Comet ISON Observing Campaign team last year. In fact, several of PACA’s current members contributed to the ISON campaign, with images, sketches, visual observations, and spectroscopy. And they’ll be providing similar data this weekend, when Siding Spring slips past Mars, and even as the comet continues on to perihelion six days later and back out into the outer solar system soon after. So, not only will this group of amateurs help scientists to learn more about the comet’s planetary encounter as it occurs, they’ll offer an opportunity to research the continuing effects on the comet itself. They’ll also be among the first to offer “encounter” images to the public, as much of the professional data will not be available until the following day.

You, too, can contribute with your own observations – or you can simply follow along as the PACA network updates with its latest images and data. You’ll find the PACA Twitter account here, the PACA FB Community page here, and the PACA C/2013 A1 Flickr album here. If you’d like to try to see the comet/Mars encounter yourself, check-out these tips from Bob King at Universe Today. (BONUS: Bob’s article leads with a stunning image from PACA member, Rolando Ligustri!)

PACA’s pro-am collaboration doesn’t end with Siding Spring. The group is monitoring several other comet events, including the recent fragmentation of a more distant comet, C/2011 J2 Linear. Be sure to keep your eyes on the PACA network, as they share their latest observations and discoveries!