Starship Asterisk*

[quote="Chris Peterson" post_id=324141 time=1657634913 user_id=117706]
[quote=Ann post_id=324129 time=1657599863 user_id=129702]
I'm always envious of people who manage to see, and take pictures of, such vividly blue noctilucent clouds. They have never looked so blue when I have seen them.
[/quote]

Don't feel bad. It's because they are not vividly blue to the eye. Rather like blue stars, visually they are bluish white. It takes an image to emphasize the blue.
[/quote]

I’ve never been fortunate enough to see them period. :(

Eric

When I was working in Greenland 13 degrees north of the Arctic Circle, one noon in midwinter with an overcast sky a pure red glow lit up the landscape. It lasted about 15 minutes and vanished quickly. I assume the sunlight was trapped between the snowy earth and the cloud layer and travelled over 1300 km. whereas this isn't noctilucent cloud glow, but it's just as impressive to us, as light starved as we were.

[quote=Ann post_id=324129 time=1657599863 user_id=129702]
I'm always envious of people who manage to see, and take pictures of, such vividly blue noctilucent clouds. They have never looked so blue when I have seen them.
[/quote]

Don't feel bad. It's because they are not vividly blue to the eye. Rather like blue stars, visually they are bluish white. It takes an image to emphasize the blue.

[attachment=2]NoctilucentParis_Kulik_1080.jpg[/attachment]
Kinda does look like a rocket blasting off! :D
[attachment=1]NLCReflectionsAPODheden.jpg[/attachment]
lots of nice photos in today's APOD! 8-)
[attachment=0]istockphoto-1255198816-612x612.jpg[/attachment]
Kity watching the clouds! :mrgreen:

When I loaded this page on my Macbook Air, the screen only held the photo from its top edge to about halfway down the monument. I thought it was a rocket taking off, so it was quite a surprise to see the Eiffel Tower.

[img3="Noctilucent Clouds over Paris. Credit & Copyright: Bertrand Kulik"]https://apod.nasa.gov/apod/image/2207/NoctilucentParis_Kulik_1080.jpg[/img3]
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I'm always envious of people who manage to see, and take pictures of, such vividly blue noctilucent clouds. They have never looked so blue when I have seen them.

In the current Recent Submissions thread, Yann Sainty (YSTY) has posted [url=https://asterisk.apod.com/viewtopic.php?p=323950#p323950]a spectacular closeup[/url] of a noctilucent cloud, where indeed it doesn't look very blue. I hope Yann Sainty will forgive me for posting the same images here that he posted in the Recent Submissions thread:


[float=left][img3="Noctilucent clouds, widefield, by Yann Sainty."]https://live.staticflickr.com/65535/52194255767_694eabe7ae.jpg[/img3][/float][float=right][img3="Noctilucent cloud, closeup, by Yann Sainty."]https://live.staticflickr.com/65535/52195749895_b0c4bbeb46.jpg[/img3][/float]
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Ann

[url=https://apod.nasa.gov/apod/ap220712.html] [img]https://apod.nasa.gov/apod/calendar/S_220712.jpg[/img] [size=150]Noctilucent Clouds over Paris[/size][/url]

[b] Explanation: [/b] It's northern noctilucent cloud season. Composed of small ice crystals forming only during specific conditions in the upper atmosphere, [url=https://apod.nasa.gov/apod/ap190626.html]noctilucent clouds[/url] may become visible at sunset during late summer when illuminated by sunlight from below. [url=https://en.wikipedia.org/wiki/Noctilucent_cloud]Noctilucent clouds[/url] are the [url=https://weather.com/science/weather-explainers/news/2018-06-28-noctilucent-clouds-earth-highest-clouds-view-northern]highest clouds known[/url] and now established to be [url=https://en.wikipedia.org/wiki/Polar_mesospheric_clouds]polar mesospheric clouds[/url] observed from the ground. Although observed with NASA's [url=https://www.nasa.gov/mission_pages/aim/index.html]AIM satellite[/url] since 2007, much about [url=http://science.nasa.gov/science-news/science-at-nasa/2003/19feb_nlc/]noctilucent clouds[/url] remains unknown and so a [url=https://ui.adsabs.harvard.edu/abs/2021EGUGA..23.7863B/abstract]topic of active research[/url]. The [url=https://www.flickr.com/photos/bertrandkulik/52197493369/]featured image [/url] shows expansive and rippled [url=https://www.livescience.com/44815-night-shining-clouds-become-more-common.html]noctilucent clouds[/url] wafting over [url=https://www.youtube.com/watch?v=YPMOce2VdKQ]Paris[/url], [url=https://en.wikipedia.org/wiki/France]France[/url]. This year, [url=http://spaceweathergallery.com/nlc_gallery.html]several northern locations[/url] are already [url=https://media.istockphoto.com/photos/cat-wearing-sunglasses-outdoors-picture-id1255198816?k=20&m=1255198816&s=612x612&w=0&h=niiqSWzKfNileUZRroAhAWShVzYPJhiv6xdgclIxk_g=]reporting[/url] especially [url=https://apod.nasa.gov/apod/ap190726.html]vivid display[/url]s of noctilucent clouds.


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