| Joined: | Mon Apr 2nd, 2012 |
| Location: | South Lakeland, UK |
| Posts: | 4066 |
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I have 147 for you once you've done Roberts!
Didn't realise you weren't seeing it with the naked eye Robert. I do actually see it up here but it is not bright green or anything like it. Most of the time it is a greyish streak in the sky. On Hogmanay it was the brightest I've seen it and actually looked green but it was only a pale minty green. People hike up the saturation on their pics to ridiculous levels and unsuspecting onlookers think the aurora actually looks like that. It may be much greener to the naked eye when an exceptionally strong burst hits the earth or maybe it's much the greener the closer to the pole you get but I have only ever seen a pale streak. The camera exaggerates the green quite significantly. I try to edit my pics so they are reasonably realistic but to bring out the detail in the sea etc in the pic above for example, made the aurora a lot greener than it actually was.
Thanks for the comments Judith, the only way we knew the Aurora was active was a pale green glow in the sky and very occasional faint flares into the sky.
I wasn't even sure which way to point the camera, except in a general sense of course! The right hand edge of the frame is about due North. If I get another chance I will use the 20mm lens to gain better spread, I can of course crop as appropriate at home.
I took several test exposures, established 10 seconds seemed OK and set it off recording time-lapse exposures at 20 second intervals to allow for processing and saving of image to the card. The D300s seemed to take about 7 seconds to process the image before saving it and having a couple of seconds before the next exposure. I don't know if it can make exposures while it is processing and saving images... I suppose it's easy enough to try at home...
As with all these processes there is a trade off between speed and quality. I could have opened up the lens to f1.4and greatly reduced the exposure time at the expense of clarity. This time my emphasis was on good quality images and less on speed.
A shorter exposure would have been good so I could reduce the interval between exposures. As it was I had 90 exposures but 400 over the same period would have been better. I created the moving part of the video at 25% of normal frame rate, so it's a bit rough, jumpy.
Are the 147 made with the intervalometer? If so a movie is pretty easy to make. If you have Lightroom, export them as JPEG's into a new folder, named with sequential numbers. Then open Ps, select workspace 'Motion' and then 'File'>Open, select the first image of the sequence and open it, that will put all your images into the time-line. You can then export as an MPEG4 or QuickTime.
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Robert.