Pointing at distant stars

LROC began performing its star calibrations this week!

One of the critical calibration tasks associated with space imaging systems is determining a) the amount of light passed through the optical system and measured by the detector, and b) determining where your instrument is pointing. As you can imagine, these are important parameters to verify! The pointing is incredibly critical, because if you can't predict where your camera is going to image, you won't be able to target regions of interest correctly. We can collect data to help analyze both of these parameters by pointing the three LROC instruments at bright stars whose position is known exactly and whose magnitude (brightness) is well constrained. This is a complicated maneuver involving yawing the spacecraft, then using the LRO's Reaction Control System to slowly scan across bright stars (such as Vega and Canopus). When a bright star shows up in the images collected by LROC, then we can use this information to validate both the pointing and our camera settings.