I saw the transit of venus on Tuesday. I wasn't going to miss a once-in-a-lifetime astronomical event if I had any say in the matter.
So I brought a handheld telescope to work and used it to project the sun's image onto a sheet of paper on the floor. Watching that tiny bite gradually appear at the edge of the disk over the course of several minutes, knowing that it represents the movements of the heavenly bodies, was awe-inspiring. Later, over lunch, I took some colleagues to the roof of the building to show them the hole in the sun's disk.
It still amazes me that until the 17th century orbital calculations this phenomenon was entirely unknown, but I can observe it easily with a basic piece of optical equipment.
One question I couldn't answer, though: Should I say a bracha on observing the transit? If so, should it be Shehecheyanu? Or Oseh Ma'aseh Breishit?
On the one hand, extraordinary celestial phenomena typically deserve a bracha: seeing a meteorite fall, for example. But this is a phenomena not familiar to Chazal, and one which is not visible to the unaided eye (you need either a solar filter or a projecting lens).
Safek bracha l'chumra, and I didn't think to ask a shaila in advance (who would I ask?), but if I didn't utter any praise of God, I certainly thought it.