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Post by wheels59 on Jul 17, 2021 20:54:15 GMT
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Post by wheels59 on Jul 17, 2021 21:20:15 GMT
I think I've done it.
Sorry Acid I've realised after that you had already started this thread earlier.
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Post by acidohm on Jul 18, 2021 5:23:14 GMT
I think I've done it. Sorry Acid I've realised after that you had already started this thread earlier. That's OK Wheelie 😊 Great pics, I haven't seen any this year but I'm glad others are getting the chance! |
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Post by nonentropic on Jul 18, 2021 5:36:59 GMT
They are stunning.
So what do they mean?
are they an artifact of digital photography iso ranges above 10,000 make this stuff possible film was sort of 400s the limit to us plods.
is it an indicator of CO2 doing something to the polar atmosphere, just checking!
Is this a solar cycle thing and an indicator of weak solar magnetism. as per Don Easterbrook.
is this in the bible are some book!! Prophets etc.
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Post by acidohm on Jul 18, 2021 7:14:05 GMT
They are stunning. So what do they mean? are they an artifact of digital photography iso ranges above 10,000 make this stuff possible film was sort of 400s the limit to us plods. is it an indicator of CO2 doing something to the polar atmosphere, just checking! Is this a solar cycle thing and an indicator of weak solar magnetism. as per Don Easterbrook. is this in the bible are some book!! Prophets etc. Truth is we really don't know.... As far as I've seen there are no records of these even during past low solar periods. They are very visible with your own eyes, and yes, also photograph well. They are the result of water vapuor condensing on meteorite dust in the upper mesosphere, hence as the sun falls below the horizon They are the last portion of the sky to be able to reflect light and so visible after or before sunset, sunrise by about an hour or more. Why this phenomena occurs now is not understood. Did our ancestors see them but not appreciate them, were They asleep after sunset, were They not there till now....no one seems to know. This at least gives an idea of spread, although good pictures have been taken in Paris and Italy (see other thread) so last night isn't a widespread event compared to others this season.  |
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Post by blustnmtn on Jul 18, 2021 12:08:08 GMT
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Post by wheels59 on Jul 18, 2021 13:03:48 GMT
Apparently they were seen over Israel recently as well
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Post by nonentropic on Jul 18, 2021 19:50:13 GMT
is it dust or WV or generated by dust??
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Post by blustnmtn on Jul 18, 2021 19:56:41 GMT
is it dust or WV or generated by dust?? This is from the Wikipedia article: “Data from the Aeronomy of Ice in the Mesosphere satellite suggests that noctilucent clouds require water vapour, dust, and very cold temperatures to form.[8] The sources of both the dust and the water vapour in the upper atmosphere are not known with certainty. The dust is believed to come from micrometeors, although particulates from volcanoes and dust from the troposphere are also possibilities. The moisture could be lifted through gaps in the tropopause, as well as forming from the reaction of methane with hydroxyl radicals in the stratosphere.” |
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Post by acidohm on Jul 18, 2021 20:36:36 GMT
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Post by missouriboy on Jul 19, 2021 0:03:27 GMT
is it dust or WV or generated by dust?? This is from the Wikipedia article: “Data from the Aeronomy of Ice in the Mesosphere satellite suggests that noctilucent clouds require water vapour, dust, and very cold temperatures to form.[8] The sources of both the dust and the water vapour in the upper atmosphere are not known with certainty. The dust is believed to come from micrometeors, although particulates from volcanoes and dust from the troposphere are also possibilities. The moisture could be lifted through gaps in the tropopause, as well as forming from the reaction of methane with hydroxyl radicals in the stratosphere.” Are they related to BLM radicals? |
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Post by blustnmtn on Jan 27, 2022 17:48:55 GMT
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Post by acidohm on Jan 28, 2022 8:29:30 GMT
It's quite a seasonal topic for us Boreal types....and there's vert little habitated land in places NLC can be viewed in the south. |
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Post by acidohm on Jun 12, 2022 8:40:59 GMT
They're back, 2022 NLC season northern hemisphere has commenced!
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There was a brilliant display of Noctilucent clouds over Elgin in Morayshire Scotland early hours of Thursday morning this week. My son who works a late shift and finishes at 2am took some great photos and sent them to me via farcebook messenger. Me being an old ludite and IT illiterate can't quite work out how to post them yet, I'll have a word with him to see how to do it and as soon as I'm able I'll post them! 
