Lunar eclipse should be starting pretty soon

[yorkiefan_]

1/2 way there! Rayleigh scattering is so cool!

[yorkiefan_]

More than 2/3 coverage now!

[alaskayorkie]

A sliver of light left

[yorkiefan_]

The orange color is obvious now. It's caused because the light from the Sun is pretty close to white, and white light is composed of all the colors. Our atmosphere is filled with tiny dust particles that scatter light in random directions when they're small enough; e.g., about 1/2 a micron. The probability of a photon being scattered in a random direction by such a particle is proportional to 1 over the fourth power of the wavelength. So since blue has a shorter wavelength, it gets scattered much more often, leaving long wavelength red light as what we see. So every beam of light from the Sun that hits the shadowed part of the moon passes through the Earth's entire atmosphere first, and all the violet, blue, and green light is scattered away in random directions,leaving only yellow, orange, and red to hit the moon and light it!

[yorkiefan_]

It's the exact same thing that causes red sunsets: when the Sun is low on the horizon the light from it has to pass through a lot more of our atmosphere, so the dust and air particles scatter away most of the violet, blue, and green, leaving yellow, orange, and red mostly.

[yorkiefan_]

Just a tiny bit of the moon still lit outside our shadow. Now is the time to get outside and see this!

[yorkiefan_]

That little sliver just keeps hanging on. But in one minute it will be gone.

[yorkiefan_]

100% coverage now!

[alaskayorkie]

Thanks for the explanation! Wish I had a longer lens, but this 250 telephoto is better than nothing!

[yorkiefan_]

What's crazy, the moon is huge in our sky, at about 1/2 degree angular diameter. But the Andromeda galaxy has 7 time larger diameter: 3.5 degrees. If only our eyes were good enough to see it all. All we can see of it naked eye is the center. Wish I could be here 4 billion years from now to see when it and our galaxy collide. But alas, our Sun will have ballooned into a red giant, boiled away all our water, fried every living thing, and maybe even have swallowed the Earth by then. If only I could go another 200 million years to see Betelgeuse's likely supernova. It's about 6 times closer than the Crab Nebula, so its supernova would be 36 times brighter. And when the crab nebula supernovaed ~1000 years ago it could be seen in the daytime for weeks!

[yorkiefan_]

Definitely redder now than 15 minutes ago!

[alaskayorkie]

How long's it supposed to stay dark?

[yorkiefan_]

Originally Posted by alaskayorkie

How long's it supposed to stay dark?

I'd say we'll start seeing direct light on the moon in about 56 minutes or so. 16 minutes until it gets its darkest.

[yorkiefan_]

Nice view of Mars 10 degrees or so West too (and maybe 1.5-2 degrees higher).

[yorkiefan_]

I'm going to get to sleep now. What a spectacular sight to see this has been. Hopefully I'll have clear skies in 6 months when it happens again!