Red sensitive? Blue sensitive? How perceptive are your eyes to the colors of astronomical objects? One way to find out is to observe newly discovered Comet C/2011 L4 (PANSTARRS) with friends under a dark sky this month. (For more about this comet, including a finder chart, see “Get ready for Comet PANSTARRS” on p. 60). All you need to do is sketch the comet head and its tail(s) and rate their intensity and their color. It’s an exercise that’s both informative and fun.Astronomy magazine subscribers can read the full column for free. Just make sure you're registered with the website.