Every so often, Mercury gets between us and the sun. It happens about a dozen times per century, but because of its relatively petite size, it takes some seriously high-powered gear to be able to see it. Luckily for the unarmed, NASA will be covering the rare event on Monday, May 9th. Here’s a preview of its trajectory:
The full transit — when a celestial body crosses in front of another — will last for over seven hours. Specifically, Mercury will be visible as a little black dot from about 7:10 a.m. till 2:40 p.m. EST.
The last transit was a decade ago, and the next one won’t be until 2019. After that, there won’t be another until 2032, which won’t be visible to those living in North America. (For that, you’ll have to wait until 2049.) If you live in western Europe, South America, or eastern North America, you’ll be able to see the entire transit. Here is where it will be visible:
Mercury has the most highly elliptical orbit of all of our solar system’s planets. Its rotation is so painfully slow, a day on Mercury is actually twice as long as its year. But it’s swift, too: It hightails around the sun every 88 days. When NASA’s Messenger spacecraft flew by the planet, it revealed that not all of Mercury is sunlit, meaning its permanently shadowed areas, like its poles, may contain water ice.
If you’ll be viewing it from the comfort of your home or office, you can tune in to NASA TV here, or glimpse some images from the agency’s Solar Dynamics Observatory here. Some universities also host public observing events, so check your closest department for info. Folks in the United States and Europe can attend any of these gatherings, compiled by the European Space Agency, which will also host a livestream.
If you do decide to face the sun yourself, don’t do so directly, as looking at it with the naked eye can actually damage your eyes (or, even worse, cause blindness). A handmade pinhole camera is not recommended for this particular transit because Mercury is just too tiny.
Be sure to use eclipse glasses or a telescope fitted with a solar filter. You can also buy a kit, like this one or this one recommended by the British Astronomical Association (BAA). The BAA also has some other critical tips on hooking up your equipment and keeping your peepers safe.