NLCs - May 14/15th May 15, 2008 15:18:48 GMT
Post by martinastro on May 15, 2008 15:18:48 GMT
On the evening of May 14/15th from 23.00 - 23.30 BST I observed yet another NLC display which formed during the twilight hours over N. Ireland. When I left home I was concerned about the bright waxing Moon between Virgo and Leo which could cause a few false alarms but when I got to my high location there was no doubt at all. There was an obvious NLC display in the NW to N sky sector extending 60 degrees in azimuth but only a shy 7 degrees above my local horizon. The display was a fairly conspicuous type 1 very soft veil glowing a blue-white colour which I rated at 2 in magnitude. White was the dominating colour however after 15 min's the display began to rapidly lower in height and fade to a magnitude value of 1. The colour then became blue dominated and it was then that I could make out numerous but very delicate low surface brightness type IIa bands clustered within that blue cut-off point. I text John McConnell who then drove out the road to a good location and confirmed the presence of a very weak NLC display. By 23.30 the display was a very sorry sight and faded from naked eye visibility. This was hardly a spectacular display but shows that Noctilucent Clouds are forming earlier than usual. I hope to be seeing good structured displays by early June.
On the image the blue-white glow above the orange horizon murk are the NLCs. Subtle structure can be seen. This was a 10 second exposure at ISO400, with a lens aperture of F/3.2 using a UV filter. Auriga and Capella are to the L, Perseus at centre with Algol almost 'touching' the NLCs. To the R is Andromeda with Gamma embedded within the NLC. Time of image: 23.24 BST. Cassiopeia is the to the upper R.