We had an interesting evening last night down at the observatory. Three classes came down to do a little binocular astronomy. In the middle of the first class, just shortly after 7:00pm local time, everything started to shake! It turns out that we just had an earthquake, something we are not all that acustomed to here in New England. They happen from time to time, but most people don’t even feel them. This was a good long shake, measuring in at magnitude 4.0…. the funny thing: most of the students were flat on their backs looking up at the starry sky with binoculars, so it was a perfect opportunity to feel the quake. More information here at the USGS site.
For the next couple of hours, we notes aftershocks, but not in a way that you’d expect. We couldn’t feel them, but we saw them! We were using the echelle spectrograph which uses a high sensitivity video camera to track on the stellar targets. When an aftershock hit, we could see the star’s image vibrating back and forth rapidly on our screen.