Northern NLC Season has started
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Noctilucent clouds are sometimes visible from an hour after sunset to an hour before sunrise. In the NW after sunset and the NE before dawn.
The first clouds for this year have been spotted on the NASA AIM satellite and I have seen reports from Germany as well.
There is an image showing the extent of the clouds as seen from AIM at https://spaceweather.com/ you need to be aware that this can be a bit misleading as the stripes are taken at different time and coverage over the 45 to 55 latitude where NLC may be observed from is not brilliant with large gaps.
I have a page on my website that has more details at http://www.johnmurrell.org.uk/nlc.html. There are also images in The International cloud Atlas as well as on this site
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Great info John on your website. And noctilucent clouds are spotted above England, Belgium and the Netherlands just some days ago. Modest appearances, but nevertheless noctilucent.
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One quick note, my website and others show diagrams that say the maximum height NLC can be seen as they need to be illuminated by the Sun is around 45 degrees. However in 2019 NLC were seen by lots of observers including me at the observers Zenith. The theory says this cannot happen but is based on the assumption that light travels through the atmosphere in straight lines. In reality it is bent by refraction as the air density increases but the amount of refraction is poorly understood particularly at high altitudes so it could be that in 2019 the atmospheric conditions were such that the light bent enough to light clouds overhead.
More observations of the highest angle and the observers location and time are always useful.
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Just for the records, but NLC’s have been visible above the Netherlands on the 9th, the 19th and the 23d of June. Maybe more times but these were the days I saw them myself. Quite surprising to have seen them already three times over here. I am already happy with once a year. This one was yesterday the 23d.
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I saw NLC on the evening of the 23rd June from South London UK but the display was rather obscured by lower normal clouds covering up part of the sky. The sky seemed quite bright though the Sun was around 8 degrees below the Horizon.
No repeat of the 2019 event where NLC were seen at the Zenith even though this is impossible according to the normal illumination model.
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