martinastro
Martin Mc Kenna
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Maghera, N. Ireland
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« on: May 08, 2010, 02:30:38 pm » |
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It's that time of year again everyone!. The NLC seasons typically runs from late May to early August, however displays outside the conventional window period have happened in the past, and will do so again, for this reason it would be a good idea for observers to scan the post-sunset and pre-dawn sky from now on incase there are indeed any early displays. Observations of early and late season NLC displays are of much greater scientific value. Major displays will appear either side of the Summer Solstice and it's particulary during this time period that photographers hope to catch the display of a life time. Let's hope for a season which will be as thrilling and rewarding as the spectacular 2009 season!.
I wish everyone on here the very best of luck and ask that all NLC images, visual reports, discussion, and alerts be posted on this thread so things remain organized. This year, if possible, I hope to be posting alerts on the forum to tip off any new NLC observers to sudden displays. Thanks in advance
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Paul
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« Reply #1 on: May 08, 2010, 02:41:08 pm » |
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It should be an interesting season. Many believe that NLCs are tied into the Solar Cycle in some as yet not understood way, and that increased solar activity may bring a reduction in the number and intensity of NLC displays - we shall see. Of course Solar activity seems to have calmed down a bit recently. I must fess up and admit that I caused this by purchasing a PST recently Paul.
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markt
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« Reply #2 on: May 08, 2010, 04:06:14 pm » |
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I'm really looking forward to this years NLC season - no reports or sightings that i'm aware of globally as of yet. Good to hear you have a PST Paul, I thought this grotty weather was due to somebody buying a new scope though saying that I took delivery of a new camera for solar yesterday so I expect the cloud and rain will carry on for sometime yet. Look forward to hearing your first impressions!
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brianb
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« Reply #3 on: May 08, 2010, 05:31:05 pm » |
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Of course Solar activity seems to have calmed down a bit recently. I must fess up and admit that I caused this by purchasing a PST recently Oh ... I thought it was my Lunt solar wedge ... Anyhow, with the clear sky last night & the twilight persisting almost all night on the northern horizon, I was wondering how long it would be before someone spotted a NLC!
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martinastro
Martin Mc Kenna
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Maghera, N. Ireland
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« Reply #4 on: May 08, 2010, 06:56:41 pm » |
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I was thinking the same thing Brian, the duration of the twilight glow last night was very impressive and I couldn't help but scan the horizon just in case, and my first thought was 'there will be NLCs soon'.
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Roman White
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« Reply #5 on: May 09, 2010, 01:18:41 pm » |
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Hey guys, haven't been at our forum for a long time (much of work). I'm looking forward 2010 NLC season too. I may eventually look at the sky during May 25 - June 15, but I hope I'll be able to monitor activity on each clear night after June 15.
P.S. Does anybody think that recent eruption of Eyjafjallajokull may enchance NLC activity?
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SkyWatcher 130/900mm EQ3, Bresser 76/700mm, 20x90 bino. and other, Olympus SP-550UZ Eclipse & comet chaser, occultation & meteor observer Poltava Astronomy Portal
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brianb
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« Reply #6 on: May 09, 2010, 02:53:44 pm » |
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Does anybody think that recent eruption of Eyjafjallajokull may enchance NLC activity? Can't see why it should, the ash isn't even reaching the lower stratosphere....
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markt
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« Reply #7 on: May 09, 2010, 03:41:21 pm » |
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P.S. Does anybody think that recent eruption of Eyjafjallajokull may enchance NLC activity?
Hi Roman, Good to hear from you again! Don't think the volcano will have any effect on NLC - its been throwing ash anywhere from 3-8km upwards, NLC occur at 75-85km altitude, so quite a range between them. Most likely effect it will have is sunsets tbh... Mark
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Roman White
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« Reply #8 on: May 09, 2010, 05:14:00 pm » |
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Does anybody think that recent eruption of Eyjafjallajokull may enchance NLC activity? Can't see why it should, (...) Is the fact that some of us want it to happen not enough?
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SkyWatcher 130/900mm EQ3, Bresser 76/700mm, 20x90 bino. and other, Olympus SP-550UZ Eclipse & comet chaser, occultation & meteor observer Poltava Astronomy Portal
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martinastro
Martin Mc Kenna
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Maghera, N. Ireland
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« Reply #9 on: May 09, 2010, 09:00:21 pm » |
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Interesting thought Roman, most of the volcanic dust/ash seems to be lower in the atmosphere, however you never know, there could be interesting atmospheric effects. Hard to say but time will tell. Out of interest, here's the link to the 2009 NLC thread on this forum. http://astrophotoweather.smfforfree4.com/index.php/topic,1277.0.html
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paulster78
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Just been scanning through last years NLC thread, some great images and discussions. Im very excited about seeing a NLC display for the first time this year-never even knew about them til I joined this forum, it will be another tick off the list!! Good luck everyone.
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martinastro
Martin Mc Kenna
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Posts: 5182
Maghera, N. Ireland
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You will definitely bag your first displays this year Paul - I hope they put on a good show for you
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martinastro
Martin Mc Kenna
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Posts: 5182
Maghera, N. Ireland
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Here's a few thoughts on the 2010 season sent to me by Ken Kennedy, the European NLC coordinator...
''I feel it will be a very interesting year especially with the Sun returning to activity. Long term reports (Gadsden) of NLC activity certainly show a correlation between solar activity and NLC with maximum NLC sightings about a year or two following solar minimum. Higher levels of solar radiation may well not allow the temperature at the mesopause to drop to the critical temperature for ice nucleation and also the higher UV emissions may dissociate water more quickly so there may be two reasons for the inverse relationship between NLC and solar activity.
As it stands, 2009 was a year of very high frequency of NLC and I don't see much chance of a further increase. I would expect NLC activity to remain possibly as high as last year but it will be interesting to see if frequency decreases over the next year or two. The other area I have explored is a bit more subjective and that is brightness. However, taking a random selection of 198 observations which I received last year (your ones were included), 32 of these gave a brightness estimates of 4 or 5 out of 5. Within this selection, observers saw NLC on 40 nights. Of these 40 nights, 13 were scored as having a brightness of 4 or 5. These figures are considerably higher than in previous years and seem to back up my gut feeling that brightness has also been increasing, especially in 2009. This may be because there is an increase in water vapour at mesopause altitudes perhaps because of dissociated methane which has been increasing since 2007. It may also reflect the slower dissociation of water vapour with low solar activity''...Ken Kennedy.
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markt
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Thats a very intersting report Martin. Lets hope there is lots of bright NLC this year
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martinastro
Martin Mc Kenna
Global Moderator
Hero Member
Posts: 5182
Maghera, N. Ireland
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Negative observation of NLC on May 15/16th during an all-night session, twilight arch is now visible throughout the night.
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