Holey Jupiter! A Look Back At Friday’s Triple Transit

The moons Io and Europa, paired off to the right, and Callisto (far right) cast shadows on Jupiter’s cloud belts Saturday morning seen from Athens, Greece. The photo was taken 10 minutes after sunrise. Notice the shape of Callisto’s shadow. Credit: John Rozakis

We had great clouds this weekend and completely missed the “three holes in one” triple transit on Jupiter and both occultations of stars by the moon. Since you may have experienced the same frustration, the least I can offer you is a look at the event through the eyes of astrophotographers who were more fortunate.

Photo taken from Haaltert, Belgium by astrophotographer Bart Declercq. “Belgium got lucky, said Declercq. “After a really significant rain front passed over us during the early hours of the night, the sky cleared up in time to watch the amazing spectacle of a triple shadow transit on Jupiter, with Callisto, Europa and Io being positioned just right. The fact that the GRS also made an appearance is just icing on the cake.

Notice how stretched out Callisto’s shadow is. That’s because Jupiter’s a three dimensional globe and the shadow lies close to its edge, which curves sharply away from the observer. The curvature distorts the shadow into an oval. You can also see a hint of distortion in Io’s shadow (far right in Rozakis’ image) but it’s not as obvious in part because Io’s shadow is smaller than Callisto’s.

Just because you may have missed the triple transit, don’t let that stop you from enjoying the many individual (and occasional double) shadow transits ahead. For viewers in the Americas an excellent double transit will take place starting at 5:30 a.m. CDT Oct. 17 when Ganymede casts its shadow on Jupiter. Ganymede will be joined by Io’s shadow at 6:57 a.m., and the two will cruise together across the planet’s face until 8:27 a.m.

Thanks Bart and John for sharing your photos!

4 Responses

  1. Ralph Aguirre

    Jupiter’s Triple Moon transit was spectacular. I had similar views with my C14, last night here in Sacramento. The colors were very vibrant. I also noticed the GRS rolling into view during the triple transit. I’ve been looking forward to this for months. Fortunately, the weather held out over here. It was an impressive global event bring astronomers together from all corners of the globe.

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