The “green” Comet Lulin is now visible to the naked eye in the souther part of Virgo. If you are in a brightly lit area, you should be able to see it with a pair of standard binoculars.
The special comet alert stuff in the 1.2.1 rev of DS doesn’t work quite right (blast those engineers!), so you will have to go to http://www.spaceweather.com for sighting and brightness info, along with a lot of cool photos. I fixed the bug last night and now await Apple’s thumb’s up which should happen in a couple of days.