APOD: The Windmill and the Star Trails (2020 Apr 17)

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APOD: The Windmill and the Star Trails (2020 Apr 17)

Post by APOD Robot » Fri Apr 17, 2020 4:05 am

Image The Windmill and the Star Trails

Explanation: Stars can't turn these old wooden arms, but it does look like they might in this scene from a rotating planet. The well-composed night skyscape was recorded from Garafia, a municipality on the island of La Palma, Canary Islands, planet Earth. The center of the once working windmill, retired since 1953, is lined-up with the north celestial pole, the planet's rotation axis projected on to the northern sky. From a camera fixed to a tripod, the star trails are a reflection of the planet's rotation traced in a digital composite of 39 sequential exposures each 25 seconds long. Brought out by highlighting the final exposure in the sequence, the stars themselves appear at the ends of their short concentric arcs. A faint band of winter's Milky Way and even a diffuse glow from our neighboring Andromeda Galaxy also shine in the night.

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Ann
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Re: APOD: The Windmill and the Star Trails (2020 Apr 17)

Post by Ann » Fri Apr 17, 2020 6:26 am

The Windmill and the Star Trails Antonio Gonzalez.png
Today's APOD is a very nice picture where you can actually identify some of the deep-sky objects! :D

Just above the orange cloud bank you can see a cluster, and I was about to ask the same question as I asked last time, when the APOD was Star Trails Over Ragusa, "What cluster is that?". Joe Stieber helped me out by identifying it as the Alpha Persei Moving Cluster, seen here in a photo by Naoyuki Kurita.

Move to the upper left from the Alpha Persei Moving Cluster, and you'll come to two blurry but bright and obvious white splotches, which are very close together. They are, of course, the Double Cluster in Perseus, NGC 869 and NGC 884.



To the left of the Double Cluster in the APOD are two extended pink nebulas. They are the Heart and Soul Nebulas. I like Dimitrios Tsortanidis' picture so much that I want to show you his picture and not just a link to it. The Heart Nebula is the larger nebula and the Soul Nebula is the smaller one. You can also see how close the Double Cluster is (at least in the sky) to the Heart and Soul Nebulas.

The next extended pink splotch, visible if you move upwards and just a little bit to the left, is NGC 7822, seen here in a picture by Davide De Martin and ESA/ESO/NASA.






In the picture by Bob King at left, you can see the "W" of Cassiopeia (which is really hard to spot in the APOD), the Double Cluster and the Andromeda Galaxy. Note in Bob King's picture an orange-tinted star just barely peeking out behind the line of trees, below Andromeda. That star is Beta Andromedae, and it stands out quite well in the APOD, where it looks bright and orange.


IC 1396 by Mario Richter.png
IC 1396 with red supergiant Mu Cephei at the edge,
Photo: Mario Richter.






The pink splotch at top in the APOD is IC 1396, easily recognized by the fact that bright orange supergiant star Mu Cephei is located at the edge of this nebula.

Ann
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Re: APOD: The Windmill and the Star Trails (2020 Apr 17)

Post by Guest » Fri Apr 17, 2020 10:36 am

Stars can't turn these old wooden arms
But arms are already turning once a day, and the camera is turning with them! This is what causes the star images to form trails. :)

Lovely idea for a star trail image.

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Re: APOD: The Windmill and the Star Trails (2020 Apr 17)

Post by orin stepanek » Fri Apr 17, 2020 12:06 pm

I think this picture is special; windmill kind of reminds me of "Old Rugged Cross!" 8-)
Orin

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Re: APOD: The Windmill and the Star Trails (2020 Apr 17)

Post by neufer » Fri Apr 17, 2020 1:31 pm

Guest wrote:
Fri Apr 17, 2020 10:36 am
Stars can't turn these old wooden arms
But arms are already turning once a day, and the camera is turning with them! This is what causes the star images to form trails. :)
If the axis of windmill rotation was pointed directly at the North Star: it would be turning once a day.

However...just as with a Foucault pendulum one must take into account the cosine
of the angle between the Earth's axis and the axis of symmetry of the object in question.
Art Neuendorffer

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Re: APOD: The Windmill and the Star Trails (2020 Apr 17)

Post by MarkBour » Fri Apr 17, 2020 9:43 pm

Click to play embedded YouTube video.
... and the world is like an apple whirling silently in space,
like the circles that you find in the windmills of your mind.
Mark Goldfain

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Re: APOD: The Windmill and the Star Trails (2020 Apr 17)

Post by Cousin Ricky » Sat Apr 18, 2020 12:02 am

MarkBour wrote:
Fri Apr 17, 2020 9:43 pm
Click to play embedded YouTube video.
... and the world is like an apple whirling silently in space,
like the circles that you find in the windmills of your mind.
My KJ couldn’t find a karaoke version of Noel Harrison’s version, but he did have the Sting cover.
Click to play embedded YouTube video.
Click to play embedded YouTube video.
...Le voyage autour du monde d’un tournesol dans sa fleur
Tu fais tourner de ton nom tous les moulins de mon coeur

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Re: APOD: The Windmill and the Star Trails (2020 Apr 17)

Post by neufer » Sat Apr 18, 2020 1:45 am

https://www.imdb.com/title/tt0042367/quotes?ref_=tt_ql_trv_4 wrote:

Cyrano de Bergerac (1950)

Antoine Comte de Guiche: As for you sir, have you read "Don Quixote"?

Cyrano de Bergerac: I have, and found myself the hero.

Antoine Comte de Guiche: Be so good as to read once more the chapter of the windmills...

Cyrano de Bergerac: Chapter thirteen!

Antoine Comte de Guiche: Windmills, remember, if you fight with them... may swing round their huge arms and cast you down into the mire!

Cyrano de Bergerac: Or up, among the stars!
Click to play embedded YouTube video.
Art Neuendorffer

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Re: APOD: The Windmill and the Star Trails (2020 Apr 17)

Post by cheersforann » Tue Apr 21, 2020 6:42 pm

Thank goodness for Ann who makes sense of so many APODS which would otherwise be puzzles and worded mysteries.

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Ann
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Re: APOD: The Windmill and the Star Trails (2020 Apr 17)

Post by Ann » Tue Apr 21, 2020 7:45 pm

cheersforann wrote:
Tue Apr 21, 2020 6:42 pm
Thank goodness for Ann who makes sense of so many APODS which would otherwise be puzzles and worded mysteries.
Wow, that's amazing. I'm humbled. Thank you.

Ann
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