It's great to read about our neighbouring planets.
The transit of Mercury would be great to witness. Venus' transit was a great opportunity to hold that planet's shadow in my hand a few years ago.
I have yet to witness the transit of Mercury as it wasn't visible from Australia last year. The next one is due November 11th 2019 and I don't think it will be visible from down here then either.
I'm not sure if it's possible to capture Mercury's shadow in the same way, but I'd love to give it a go.
Thank you for sharing.