APOD: The Longer Days (2019 Jun 27)

Comments and questions about the APOD on the main view screen.
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APOD: The Longer Days (2019 Jun 27)

Post by APOD Robot » Thu Jun 27, 2019 4:05 am

Image The Longer Days

Explanation: This persistent six month long exposure compresses the time from solstice to solstice (December 21, 2018 to June 16, 2019) into a single point of view. Dubbed a solargraph, the unconventional picture was recorded with a tall, tube-shaped pinhole camera using a piece of photographic paper. Fixed to a single spot at Casarano, Italy for the entire exposure, the simple camera continuously records the Sun's daily path as a glowing trail burned into the photosensitive paper. Breaks and gaps in the trails are caused by cloud cover. At the end of the exposure, the paper was scanned to create the digital image. Of course, starting in December the Sun trails peak lower in the sky, near the northern hemisphere's winter solstice. The trails trails climb higher as the days grow longer and the June 21st summer solstice approaches.

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Newer

Re: APOD: The Longer Days (2019 Jun 27)

Post by Newer » Thu Jun 27, 2019 6:25 am

Just wondering why for about a week there the sun turned green.

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Re: APOD: The Longer Days (2019 Jun 27)

Post by Boomer12k » Thu Jun 27, 2019 6:58 am

Newer wrote:
Thu Jun 27, 2019 6:25 am
Just wondering why for about a week there the sun turned green.
I wondered that too... maybe mild clouds, but not dense? Or maybe air pollution, or something in the air... like pollen? Just my guesses...probably wrong...

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orin stepanek
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Re: APOD: The Longer Days (2019 Jun 27)

Post by orin stepanek » Thu Jun 27, 2019 11:54 am

These solstice to solstice pictures are always interesting! 8-)
Orin

Smile today; tomorrow's another day!

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Re: APOD: The Longer Days (2019 Jun 27)

Post by neufer » Thu Jun 27, 2019 12:29 pm

Click to play embedded YouTube video.
Boomer12k wrote:
Thu Jun 27, 2019 6:58 am
Newer wrote:
Thu Jun 27, 2019 6:25 am

Just wondering why for about a week there the sun turned green.
I wondered that too... maybe mild clouds, but not dense?
Or maybe air pollution, or something in the air... like pollen?
I just want to say two words to you: Olive Oil
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https://en.wikipedia.org/wiki/Casarano

<<Casarano is a town & sixth most populous comune in the Italian province of Lecce, in the Apulia region of South-East Italy. The town's economy is mostly agriculture-based, with olive oil being the main product.>>
----------------------------------------------------------
Art Neuendorffer

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Chris Peterson
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Re: APOD: The Longer Days (2019 Jun 27)

Post by Chris Peterson » Thu Jun 27, 2019 12:55 pm

Newer wrote:
Thu Jun 27, 2019 6:25 am
Just wondering why for about a week there the sun turned green.
Keep in mind that these images are made using black-and-white photo paper, and they are digitally inverted (because the solar tracks on the film are nearly black). The colors are the result of various physical and chemical changes that occur with brightness and exposure to the elements.
Chris

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Re: APOD: The Longer Days (2019 Jun 27)

Post by TheZuke! » Thu Jun 27, 2019 2:21 pm

Newer wrote:
Thu Jun 27, 2019 6:25 am
Just wondering why for about a week there the sun turned green.
"It's made of people!"

https://m.media-amazon.com/images/M/MV5 ... 00_AL_.jpg

tomatoherd

Re: APOD: The Longer Days (2019 Jun 27)

Post by tomatoherd » Thu Jun 27, 2019 2:32 pm

What i wonder is how the paper keeps from being horribly over-exposed and being completely white (or black, as it applies), given the constant exposure time?

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Re: APOD: The Longer Days (2019 Jun 27)

Post by Chris Peterson » Thu Jun 27, 2019 3:04 pm

tomatoherd wrote:
Thu Jun 27, 2019 2:32 pm
What i wonder is how the paper keeps from being horribly over-exposed and being completely white (or black, as it applies), given the constant exposure time?
Where the Sun is it is highly overexposed. But this film is never developed. We're looking at the direct effects of the light on the emulsion and paper. If you tried to develop the paper, it would be solid black.
Chris

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