Saturn Titan Transit With Shadow- March 12, 2009

Peter Natscher

All I can say is WoW! Seeing Titan¹s tiny sub-arc second ink-black shadow traverse Saturn¹s northern polar cap in early this morning hours was phenomenal. Movement of Titan¹s shadow was noticed inside of 10 minutes of observing. Seeing wasn¹t good enough to distinguish Titan itself from Saturn¹s as it partially passed over the northern polar cap. I set up my 10 in. Mak-Cass the afternoon before the 2:30-4:40 am event. After 4:30 am, Saturn was too low and behind trees in the west for me to see anymore. Seeing was fairly steady with no wind, but there was a lot of dew on my scope setup and only 25% of the sky showing through the quickly passing coastal clouds. I had to use anti-dew heaters on the Mak¹s corrector and the eyepiece to keep the optics dry. In the openings between the passing clouds, I enjoyed many 10 minute views of Titan¹s shadow. Titan¹s shadow was tiny (< 1 arc-sec), moved quickly across the northern polar cap, and was ink black -- reminiscent of Europa¹s tiny shadow on Jupiter. I was using a 8mm ETHOS eyepiece yielding 470X.

This is the last time Titan itself transits Saturn until Saturn passes superior conjunction with the sun, and when the earth is lined up similarly again with Saturn. After that, Saturn will be showing its northern side of the rings to us. Titan will continue to throw its shadow on Saturn for the remainder of this year as it passes between Saturn and the sun every 16 days.

Peter Natscher
Monterey, California