Lunar eclipse
It was a nice exercise to take a series of photos of the total lunar eclipse 28 August. I ended up clicking over 250 photos! Well, all of them were exposure bracketed so the actual number of frames are a little less :-)
The sky was clear, the weather was nice and the eclipse started at a more civilized time here in Australia than in some other parts of the world so it was an opportunity not to be missed. The photos in the montage below were taken between 7.00pm - 11.00pm AEST in Canberra, ACT, Australia.
Eclipse montage, originally uploaded by NavindaK.
The start of the series is from the bottom of the right hand side arc going up, which then continues up from the bottom of the left hand side arc.
It was only when I was arranging the photos in this montage did I notice the angle of entry and exit of the shadow. You would notice that the shadow 'enters' the moon almost directly from below and leaves it at an angle leaning left. It is as if the shadow traveled over the moon in a left bound arc. Incidentally, this is the same direction/path in which the moon rose up in the night sky. I have tried to approximately reconstruct the moon travel arc on the photo above.
I had a discussion with a friend of mine about the reason for this and he came up with an explanation which has to do with the plane on which the Moon orbits the Earth. Anybody else have any theories/suggestions as to why this is so?
posted by Navinda at 8:01 PM
8 Comments:
For those like me who missed the event, here is are some cool animations based on real pictures.
rz
sorry forgot the link http://www.shadowandsubstance.com/
Hi,
Here is my explanation for the phenomenon. first of all, imagine you are on a ball(earth). For the time being lets say that the earth is not tilted. Imagine the sun is behind you, casting a shadow in front of you. This shadow moves in earth-sun plane since earth is orbiting the sun. But we can ignore this movement of shadow for the duration of eclipse.
Now imagine the moon ball is floating in to this shadow region. The moon's orbit is also in the same plane as earth-sun orbit. Now if you were on earth's equator then you would see shadow across moon going in a straight line. If you were at a low latitude still you'll see the same thing. But if the earth is tilted, and is rotating, you are changing your angle of perception on an arc. Thus you see shadow is moving in a arc too. Btw this rotation of earth is exactly the reason why we see moon going across the sky. Along the same arc :)
rz
Thanks for the link and the explanation rz! The animations on that site are really nice.
I also believe it's the relative motion. If someone from Sri Lanka took pictures I guess you'd see a different path.
Thanks for the link Reza.
NB: my physics knowledge is very outdated. :-)
Btw Navinda, the Flickr photo does not appear anymore on your blog entry.
Thanks Nadee. It seems the photo appears in the main blog page but not when you click 'Show original post'. Not sure about whats going on.
This is My Favorite one out of all. Nice work Aiya.
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