That Pesky Moon
 | Author:
Jeff Ross
Contributor |
Don't get me wrong. Our Moon is absolutely my favorite celestial object.
It's by far our closest astronomical neighbor, on average roughly 250,000 miles or 2 light seconds away. Of all the known Moons in our solar system, ours is the 5th largest in size. In relation to the planet it orbits, it is massive. Our Earth-Moon system could actually be described as a double planet. Indeed, that's how it looks from Mars.
The size of the Moon and its distance from the Earth combined to provide us with one of the most amazing things I've ever seen. Once or twice a year, somewhere on Earth, the Moon in its orbit around the Earth completely covers or eclipses the Sun.
On August 21, 2017, Laura and I joined friends from the Helena Astronomical Society in northern Idaho right in the middle of the path of totality of just such a total eclipse of the Sun. As we got closer to the time of totality it got twilight looking as more and more of the Sun was covered. Strangely, it didn't look like normal twilight. Light from the Sun was hitting us from above and was not the usual low lateral light.
We were able to watch the eclipse progress using a special solar filter over my 8" telescope. In the last few seconds before totality, we got to see the Diamond Ring as sunlight streamed through the valleys around lunar mountain peaks on the very edge of the lunar disk.
And then totality. The solar corona popped into visibility with colors ranging from blue through pink with pencil-thin magnetic lines streaming through an irregular cloud of light blue. In totality, it was safe to remove the solar filter from the telescope so we got to actually see the edge of the solar disk, complete with at least two solar flares that were each large enough to swallow several Earths.
And then it was over. As the Moon in its orbit cleared the westernmost edge of the solar disk, the Diamond Ring popped back into view for another few seconds. The solar filter went back onto the telescope but the most amazing part had passed.
So I can't be too upset that a big, beautiful Full Moon combined with some high, thin clouds meant that this year's Perseids meteor shower was pretty much a bust. Next year the Moon will be a slight sliver three days from New Moon, at the peak of the Perseids. We'll hope to see many meteors on a much darker August night.
With clear skies, of course.
