First, 105 kilometer-sized asteroid (58) Concordia will dim down 10.4mag star TYC 0835-00181-1 to 14 mag for about 5.4 seconds. The occultation is expected to happen at 23:14 CEST (21:14 UTC). TYC 0835-00181-1 is located in the constellation Leo, which is high in the springtime sky at this hour. For finder charts and all essential information, check Steve Preston's occultation prediction page.
|Occultation path of (58) Concordia on May 23, 2015. Credits: Steve Preston|
Just 14 minutes later and 11 degrees west, 54 km-sized (656) Beagle is set to occult 9.6mag TYC 0839-00959-1 down to 15.2 mag for about 3.7 seconds. The event starts at 23:33 CEST (21:33 UTC). Again, all essential information is supplied by Steve Preston.
|Occultation path of (656) Beagle on May 23, 2015. Credits: Steve Preston|
Both events are visible in almost perfectly overlapping paths that stretch along Scotland, The Netherlands, Germany, Czech Republic, Austria, Hungary and Romania. To see them, you need a small to medium sized telescope, an equatorial mount (to track the star), the finder charts, and a clear sky.
To do useful timings that can be used to refine our knowledge of the asteroid's size and determine it's shape, some preparation is needed. You find all kinds of resources here, among them tutorials in English and German.
Those living just outside the marked occultation paths are encouraged to observe as well. Prediction are sometimes off several kilometers and in rare cases possible asteroidal moons can cause additional occultations.