This morning we awoke to clear blue skies and sun and, most importantly, low surface winds. Probably the best weather since we arrived here some 8 weeks ago! We are now preparing for a (hopefully...) final hang test where we will complete tests of our so-called pointing system.
Aside from the X-ray telescope itself the pointing system is very important for the science which PoGOLite intends to do. The Crab pulsar moves across the sky during the day, just like the Sun, and we must follow it with our telescope during measurements. We need to point correctly to within about one tenth of a degree. The pointing system uses a variety of sensors such as GPS, gyroscopes and accelerometers to figure out where the telescope is pointing. The same type of sensors can be found in your iPhone or Wii game controller. We also have sensitive cameras which can use star constellations to verify where we are pointing on the sky. Signals from the sensors are used to control motors which can make the gondola rotate under the balloon and change the elevation of the telescope. We have worked with a small company in Linköping called DST Control in the development of the pointing system.
-Mark Pearce
Översta bilden: Esrange personnel attaching the solar cells
Bild: Excitement as test results start to arrive
