The Astro community are calling for images of Cassiopeia taken this October. There was an unusual brightening of a star which might have been a very rare gravitational lensing event. There are plenty of observations after it brightened but only a few before. These would help confirm the shape of the brightness change curve which must be symmetric for a lensing event.This is in reference to an earlier thread on the BB.
Also see this news item on the BAA's website.