Shadow Transit on Jupiter!

Lucky Timing

The evening of March 23rd was almost perfect for observing with my new Stellarvue 130 mm refractor. Clouds cleared and the temperature hovered in the low 60's. A gentle breeze and low humidity prevented dew formation on the telescope. By incredible, miraculous coincidence all my neighbors had turned off their outdoor lights!

The one flaw in an otherwise perfect night was intense light from the full Moon. Only bright stars were visible in the moonlit sky. This wasn't a night for observing faint galaxies, but I was very comfortable viewing some red carbon stars and a few double stars. Once again, the telescope and mount performed well as I slewed from object to object. Eventually, I took a look at Jupiter and discovered a shadow transit in progress! I hadn't seen one of these in many years. This presented a great opportunity for imaging, so I quickly installed my video camera to record the event. The following image was produced by stacking the best 100 frames from a 1,000-frame video.

Three Galilean moons are visible. From top to bottom they are: Io, Ganymede, and Europa. The fourth moon, Callisto, was far outside the field of view in the upper left. The moon Ganymede is casting its shadow on Jupiter. This image was captured at about 10:20 pm EDT. If I had begun imaging sooner at about 9:30 pm, I would have seen Ganymede itself transiting Jupiter.

Now I'm even more excited about getting a color camera for planetary imaging. The image above would be even better in color!