APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Comments and questions about the APOD on the main view screen.
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APOD Robot
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APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Post by APOD Robot » Thu Mar 02, 2017 5:16 am

Image Annular Eclipse After Sunrise

Explanation: From northern Patagonia, morning skies were clear and blue on Sunday, February 26. This sweeping composite scene, overlooking Hermoso Valle, Facundo, Chubut, Argentina, follows the Sun after sunrise, capturing an annular solar eclipse. Created from a series of exposures at three minute intervals, it shows the year's first solar eclipse beginning well above the distant eastern horizon. An exposure close to mid-eclipse recorded the expected ring of fire, the silhouette of the New Moon only slightly too small to cover the bright Sun. At that location on planet Earth, the annular phase of the eclipse lasted a brief 45 seconds.

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Holger Nielsen
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Re: APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Post by Holger Nielsen » Thu Mar 02, 2017 9:02 am

This is one of the best composites of its kind. Well planned, beautifully put together. And luck with a clear sky. :clap:
Holger Nielsen

E Fish

Re: APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Post by E Fish » Thu Mar 02, 2017 2:48 pm

I had a moment where I was trying to figure out why the Sun was moving backwards through the sky, until I realized that I was looking at a composite from the Southern Hemisphere. There's another reason to take a vacation south of the equator! :mrgreen:

Guest

Re: APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Post by Guest » Thu Mar 02, 2017 5:19 pm

Shouldn't the sun be moving up and to the right, towards the south and eventually the west. or do things work "backwards" in the Southern hemisphere?

ta152h0
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Re: APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Post by ta152h0 » Thu Mar 02, 2017 6:18 pm

looks like an LED operating in a AC current, half wace rectified.
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neufer
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Re: APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Post by neufer » Thu Mar 02, 2017 7:38 pm

Guest wrote:
Shouldn't the sun be moving up and to the right, towards the south and eventually the west. or do things work "backwards" in the Southern hemisphere?
The Southern hemisphere is very "backwards" from what I understand
(although the sun does eventually [to] the west.
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MarkBour
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Re: APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Post by MarkBour » Thu Mar 02, 2017 8:55 pm

Nice sequence. If you draw a line along the apparent path of the Sun and call that "horizontal", then I can see that the Moon first cut into the Sun at the upper left (say about 10:30, if the Sun were a clock face) and then exited to the lower right (at about 4:30). The apparent motion of the Sun through the sky is all a matter of the Earth's rotation. The Moon's apparent motion would be a combination of the Earth's rotation and the Moon's orbit. I suppose one could calculate some things about the Moon's orbit from these facts. So far, I've decided that I think it proves (1) that the Moon's orbit at the time passed right above the same point on Earth that was having a straight-up Solar noon at the time, (2) that it must have had an apparent motion that moved southward faster than the Sun was moving southward (understanding that either of those values could be negative), and I think that with timing info one could determine (3) the comparative speed with which the Moon was moving more southward than the Sun.
... Edit: (4) Since the Moon did have an apparent left-to-right component as it progressed across the face of the Sun, that means it is moving right-to-left across the sky more slowly than the Sun, which proves that its orbit is in the same direction as Earth's rotation, slowing down its apparent motion across the sky.

Surely some of you will just read this post and sigh ... because I am just working through some ancient textbook astronomy here. But it is fun for me!
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Danilo Rosa

Re: APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Post by Danilo Rosa » Fri Mar 03, 2017 12:17 am

I am puzzled by the appearance of those clouds over the horizon: Shouldn't they be "smeared" over such a long series of exposures?

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Chris Peterson
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Re: APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Post by Chris Peterson » Fri Mar 03, 2017 12:25 am

Danilo Rosa wrote:I am puzzled by the appearance of those clouds over the horizon: Shouldn't they be "smeared" over such a long series of exposures?
The images were made through a very dark neutral density filter- so dark that essentially none of the landscape was imaged at all. That is, each frame would look like a black sky with a white solar disc against it. At some point (right before sunrise, from all appearances) an unfiltered image was made which captured the landscape, and became the background for the individual solar images.
Chris

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Danilo Rosa

Re: APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Post by Danilo Rosa » Fri Mar 03, 2017 12:29 am

Thank you Chris! Excellent answer.

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Re: APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Post by Cousin Ricky » Fri Mar 03, 2017 2:05 pm

Guest wrote:Shouldn't the sun be moving up and to the right, towards the south and eventually the west. or do things work "backwards" in the Southern hemisphere?
Travel to the southern hemisphere (as I have), and it’s amazing how fast you’ll notice that the Sun rises in the “wrong” direction. I’m sure that when Patagonian eclipse chasers travel to Oregon, the Sun’s movement will appear just as “backward” to them.

What’s more, if you’re observant, you’ll notice that the sunrise angle is different at every latitude. Where I live in the Caribbean, the Sun rises almost straight up, although still somewhat to the right. In Bolivia, it rose at a similar angle, but to the left. But when I traveled to southern Chile in late spring, it was downright disturbing how the Sun rose in the southeast, swung wide at a shallow angle to the north at midday, and then around to the southwest at sunset.

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Re: APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Post by DavidLeodis » Fri Mar 03, 2017 2:36 pm

There is a nice montage of 11 images in Vincent's section in AstroBin that were taken during the eclipse. This is the link:- http://www.astrobin.com/285836/

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Vincent Bchm
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Re: APOD: Annular Eclipse After Sunrise (2017 Mar 02)

Post by Vincent Bchm » Tue Apr 04, 2017 1:31 pm

Holger Nielsen wrote:This is one of the best composites of its kind. Well planned, beautifully put together. And luck with a clear sky. :clap:
Holger Nielsen
What a compliment! Thank you very much!

E Fish wrote:I had a moment where I was trying to figure out why the Sun was moving backwards through the sky, until I realized that I was looking at a composite from the Southern Hemisphere. There's another reason to take a vacation south of the equator! :mrgreen:
Exactly, there are some things here that are reversed! Can be disturbing at the beginning :)

Guest wrote:Shouldn't the sun be moving up and to the right, towards the south and eventually the west. or do things work "backwards" in the Southern hemisphere?
Nop, that's the way it goes when you are in the Southern Hemisphere. Keep in mind you're upside down!

Danilo Rosa wrote:I am puzzled by the appearance of those clouds over the horizon: Shouldn't they be "smeared" over such a long series of exposures?
Nop, I took the picture of the landscape (panorama) around 10min before sunrise, and then took the sun sequence with a filter. Then all the "suns" just had to be added on the "landscape"

DavidLeodis wrote:There is a nice montage of 11 images in Vincent's section in AstroBin that were taken during the eclipse. This is the link:- http://www.astrobin.com/285836/
Thanks for having noticed it and sharing it!