Possible NLC display, May 25th 2010

Hi all,

Having seen a hint of an NLC display on Sunday night, I decided to bring my camera with me to maybe be in with a chance of taking a shot of them after midnight on my way home from work Monday night/(early) Tuesday morning. I stopped about a mile outside Tullamore and set up my tripod and camera on the side of the road. Visually, it looked like there was a faint NLC display. There was some very light cloud in the north very low down, made visible by the waxing Gibbous Moon. This was the best of a series of shots of what I think was the faint NLC display:


Canon 350D, 28-80mm lens, 15 seconds, ISO 1600, Tuesday May 25th 00:22hrs. Auriga is the bright star at left.

Again, I say that the Moon interfered with seeing, but as there have been some of you who also claim to have seen Sunday nights display in the West of Ireland with the same Moon on Sunday night, then we may be looking at a very faint NLC display.

I will try again tonight from the same location, the Moon will be brighter but it will be lower down.

Seanie.

Hi Seanie,

I examined your photo in PSE with the levels shifted to throw some more light on the subject. I suspect - though I'd be happy if I were wrong of course - that what we're seeing here is moonlit tropospheric clouds rather than NLCs. Part of my reasoning concerns the camera exposure - NLCs are generally a lot brighter than this needing only a couple of seconds exposure at ISO1600 - certainly not 60, as they are lit by sunlight. I've been looking for a few evenings now and have yet to see anything convincing though it shouldn't be long now, and the sooner the Moon clears off the better it will be

Paul.

Was watching last night for NLC's and nothing was observed under perfect conditions apart from the moon. Martin was also doing a bino sweep so I would have to agree with and say this is not NLC's.

I agree guys, it is rather dubious. Visually, there was that bright horizontal streak along the horizon I am confident was not proper twilight. From my picture above, we're talking just above the horizon. It might be what you described either, Paul.

I read somewhere earlier that the ash content in the sky could be hampering this year's sightings of NLC's. There have been some amazing shots of them from Norway already, which is out of the line of ash cloud.

I fear tonight will not be a better one because of haze - today is very hazy down here despite being mostly cloud-free.

Has anyone got any tips regarding a 350D and taking manual exposures of NLC's?

Seanie.

larneastro wrote:

I examined your photo in PSE ... needing only a couple of seconds exposure at ISO1600 - certainly not 60

Thanks Paul, I just coppped that this one is 15 seconds. I have another one at ISO400 that was almost the same at 60 seconds. I have one of 25 seconds at ISO1600 here in a moment...

Seanie.

With regards to tips Seanie the image looks abit noisey, what iso are you using. I had the 350D too and it was a great camera. Best thing is to focus on a star then switch to manual so the focus is set all night. Then drop the iso pretty low and do longer exposures to compensate for the low sensitivity and also to decrease the noise. Try and capture some foreground in the images ie trees to give a depth to the image.