Transits of one of Saturn’s Moons or the Moon’s shadow across Saturn’s disk are very rare events. Due to the tilt of the ring plane, we are only able to observe these events once every 14-15 years, when the rings are “edge on” as seen from our location on Earth.
Right now, we are in the middle of a “ring plane crossing” and in 2009, there are 4 visible transits of Saturn’s largest Moon, Titan, across the face of the planet. The first one occurred on January 24th, and I was fortunately able to capture 3 images to create an animation.
There are 3 more upcoming transits of Titan across the face of Saturn:
- February 9th: Approx 1am Sydney AEDST (February 8th 1400 UT)
- February 24th: Approx 11:15pm Sydney AEDST (February 24th 1215 UT)
- March 12th: Approx 10:15pm Sydney AEDST (March 12th 1115 UT)
Continue reading to find out more, where to find Saturn, and to see a simulation of where you will see the Titan and its shadow on the face of Saturn.
Each transit lasts only a few hours, and is only visible from small parts of the Southern and Northern Hemisphere where we are in darkness when the transit is occurring – including Australia, New Zealand and most of Asia. For America, Europe, South Africa and other parts of the world, they are still in daylight at these UT’s, so the transits are not visible for them. Countries with timezones roughly GMT+6 through to GMT+12 should be able to view the transit.
Below you can find a simulation (generated using Starry Night Pro) of how Saturn will look and where Titan and its shadow will be positioned during each of these transits. The screenshots for the simulations are generally taken early or mid-transit. Titan will begin transit an hour or two before the times shown.
The simulation and local times are for Sydney, GMT+11 (AEDST). Universal Times (UT) are also shown. To see the transit, a moderately sized telescope is needed (6″ and above), and conditions will need to be quite stable. It may still be visible in small refractors, however the seeing will need to be very good.
February 9th ~ 1am Sydney AEDST (Febraury 8th ~ 1400 UT)
February 24th ~ 11:15pm Sydney AEDST (Febraury 24th ~ 1215 UT)
March 12th ~ 10:15pm Sydney AEDST (March 12th ~ 1115 UT)
To find Saturn, look in the North-East sky after midnight in early-mid February, and after 10pm in late Feb/early March. Saturn will be visible as a yellowish “star” that doesn’t twinkle like the other stars. It will be about 30-40° altitude for mid-southern latitudes (Syd/Melb).
I hope you get clear skies to observe (and photograph, if that’s your thing) these rare events!
Thanks for reading.