Rare transit of Saturn by its moon Iapetus on Monday 18th July

[Gfamily]

At 1am on Monday morning (for viewers in UK), Saturn's moon Iapetus will start a rare transit of the planet. It'll take about 10 hours to complete.

Discovered by Cassini in 1671, Iapetus's surface has two distinct regions, one bright, and one much darker. As it is tidally locked in its orbit, this means that it is 2 magnitudes brighter when to the west of the planet than to the east.

I would be very surprised if this would be visible, but worth knowing about if you're up and observing 

Edited July 16, 2022 by Gfamily

[Paz]

I had a look on sky safari and it says Iapetus is magnitude 11.5 at the moment it goes into transit. Aperture permitting that would be ok if it was a star on its own but I wonder how easy it will be to see near to the brightness of Saturn. In transit I wonder if it would look like a bright dot or a dark dot or just be invisible in the glare. It may be one worth trying for - I assume the temperature will mean observing in shorts and t shirt at 1am will be ok?

[johnturley]

3 minutes ago, Paz said:

I had a look on sky safari and it says Iapetus is magnitude 11.5 at the moment it goes into transit. Aperture permitting that would be ok if it was a star on its own but I wonder how easy it will be to see near to the brightness of Saturn. In transit I wonder if it would look like a bright dot or a dark dot or just be invisible in the glare. It may be one worth trying for - I assume the temperature will mean observing in shorts and t shirt at 1am will be ok?

I would very much doubt that it would be visible through amateur sized telescopes, I think only transits of Titan can be seen through these, but we will have to wait until 2025 to see them. 

[Space Hopper]

Just the moon transiting or will its shadow be visible at some point as well ?

If the shadow is visible, i may be in with a chance of spotting it....

[JeremyS]

https://stargazerslounge.com/topic/397067-transit-of-iapetus-on-july-1718/#comment-4263020