No, that was not a spelling mistake. It is actually part of the partial-shadow of the Earth.
During a lunar eclipse, the Moon travels through the shadow of the Earth. If we manage to catch the entire movement of the Moon along with the shadow Earth casts on it, we can get something quite amazing, the actual shape of the Earth.
It is not that difficult to do this. But you need to basically sit through the entire eclipse and take photos periodically and stitch them together.
The photo above is a stitch of 9 photos taken roughly 15 mins apart. So how did I actually put it all together?
The movement of the Moon over a small period such as 2 hours, is a straight line if you track it over the Equatorial Grid. The only calculation you need to look for is to figure out how much of a overlap is there between the photos.
The Moon has an average width of about 0.5 degrees when viewed from Earth. I say 'average' because the distance from Earth to Moon varies due to its elliptical orbit around the Earth. The Moon also moves roughly 0.5 degree per hour across the sky. Basically, in an hour the Moon will move almost exactly its diameter across the sky.
During the eclipse, I timed my photos 15 mins apart. This meant that if you offset each shot by roughly quarter the diameter of the Moon, then you should get a complete collage of photos that are true to the reality. The photos were then blended using the Linear Light blending mode on Photoshop to create the above image.
The result is the shadow that Earth cast in to the Space, but fallen on the Moon that has now become a canvas.
So why is it called the partial partial-shadow? The second partial-shadow part comes from the fact that it is actually the penumbra or the partial shadow of the Earth that fell on Moon. So what about the first 'partial'? That is because in reality, the penumbra covered almost 89% of the surface of the Moon. However due to the glare, you cannot see that shadow properly. Only the darkest part of the penumbra is seen.
During a lunar eclipse, the Moon travels through the shadow of the Earth. If we manage to catch the entire movement of the Moon along with the shadow Earth casts on it, we can get something quite amazing, the actual shape of the Earth.
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| Part of the shadow of Earth, as seen during the lunar eclipse on 10th Jan 2020 |
It is not that difficult to do this. But you need to basically sit through the entire eclipse and take photos periodically and stitch them together.
The photo above is a stitch of 9 photos taken roughly 15 mins apart. So how did I actually put it all together?
The movement of the Moon over a small period such as 2 hours, is a straight line if you track it over the Equatorial Grid. The only calculation you need to look for is to figure out how much of a overlap is there between the photos.
The Moon has an average width of about 0.5 degrees when viewed from Earth. I say 'average' because the distance from Earth to Moon varies due to its elliptical orbit around the Earth. The Moon also moves roughly 0.5 degree per hour across the sky. Basically, in an hour the Moon will move almost exactly its diameter across the sky.
During the eclipse, I timed my photos 15 mins apart. This meant that if you offset each shot by roughly quarter the diameter of the Moon, then you should get a complete collage of photos that are true to the reality. The photos were then blended using the Linear Light blending mode on Photoshop to create the above image.
The result is the shadow that Earth cast in to the Space, but fallen on the Moon that has now become a canvas.
So why is it called the partial partial-shadow? The second partial-shadow part comes from the fact that it is actually the penumbra or the partial shadow of the Earth that fell on Moon. So what about the first 'partial'? That is because in reality, the penumbra covered almost 89% of the surface of the Moon. However due to the glare, you cannot see that shadow properly. Only the darkest part of the penumbra is seen.
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