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Photographing the Aurora Borealis

DSLR Acquisition Solar System Earth
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Rick Evans avatar
Rick Evans avatar
I assume for photographing the aurora borealis, a DSLR with a wide angle lens that is wide open makes sense.  Is it best to use an unmodded camera or can you get better results with a Ha modded or full spectrum modded camera?  I assume only a tripod is necesary.  Would you take subs for stacking, do live stacking like EAA, or just individual shots.  I'm assuming the typical total exposure time would be 30 seconds to several minutes and that it might be determined by what the background shadows look like?  I'm assuming maybe an ISO of around 2400?  Does the aurora borealis emit at H-alpha or O-III or S-II?  Is some sort of filter a good idea or a bad idea for aurora imaging?  

Anyone know what a really good setup looks like?

Rick
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andrea tasselli avatar
andrea tasselli avatar
Broadband spectrum is the way to go with AB and full spectrum isn't particularly helpful in this instance. Multiple short exposures would make sense since both the AB and the stars do move. How long depends on the local situation and the focal length of the lens employed and what the effects you want to obtain, as in all landscape photography. Obviously talking of OIII or Ha or even more so SII emission makes no sense here. At all.
Rick Evans avatar
Rick Evans avatar
Yes the emission of the aurora seems to be about 530nm and 640 nm, so regular RGB.  No narrowband.  But auroras do emit in the infrared quite well and so I thought maybe a modded camera would add a sort of luminance effect and enhance the aurora in that way.  Possible?  I agree with stacking shorter subs.  At wide angle maybe you could get away with 30 secs?  Northern Alaska is probably Bortle 1.  Star trails at 15mm FL at 30 sec?  Not sure but doubt it.  Even at 29mm focal length.

Rick
HR_Maurer avatar
HR_Maurer avatar
Hi Rick,
i bookmarked this page some years ago, when i went to Norway with an astro-modified EOS 1000Da, and an unmodified EOS 5DII.
There could be some minor benefits in the molecular nitrogen spectrum, but rather subtle. I didn'd see much of a difference, however i liked the violet cast of the modified camera.

Aurorae can be very diferrent. There are more or less static aurorae, allowing longer exposures. When ist's very active, it is more like disco, and you will obtain some smearing of the details even with 1s exposure. The green luminescence has a decay time of some seconds, so this color does smear naturally. However, you want to shoot with maximum aperture, like f/1.8 or faster, and i'd recommend between 12 and 24 mm focal length. Stacking, from my experience, didn't make a lot of sense. With those focal lengths you can expose ~ 13s. With my 24mm f/1.4 the shortest overexposure was something like 1s at ISO 1000. However, if it's pitch black, you might want to get some additional extra-long exposure for the landscape, or maybe stack that for proper s/n.

Where do you plan to go? Equinoxes?
CS Horst
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andrea tasselli avatar
andrea tasselli avatar
Rick Evans:
But auroras do emit in the infrared quite well and so I thought maybe a modded camera would add a sort of luminance effect and enhance the aurora in that way.


I don't think they emit "quite well" in the band between 700nm and 1000nm and it would be pointless to try to use it as luminance layer (beside the poor QE) as most of the visual effect isn't of the same morphology of the emission in the IR band (not near-IR). Stick with the visual spectrum and you won't be disappointed.

Rick Evans:
At wide angle maybe you could get away with 30 secs? Northern Alaska is probably Bortle 1. Star trails at 15mm FL at 30 sec? Not sure but doubt it. Even at 29mm focal length.

Roughly speaking the length of exposure without trailing is equal to 300 divided by the FL of the lens for modern high-res cameras (pixel less than 4 um). If you aren't picky then 500/FL would work.
Scott Badger avatar
Scott Badger avatar
Fwiw, here are two images I took in Greenland a couple years ago (single shots, not stacked). I hadn't shot auroras before, and haven't since, so can't vouch for the settings, which are actually quite different from each other..... Also, there was a lot of moon at the time.
https://www.astrobin.com/v9tnqr/  --  13"  f2.8  ISO200  20mm
https://www.astrobin.com/7rxbpq/ -- 25"  f2.8  ISO1600  16mm

Cheers,
Scott
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Coolhandjo avatar
Coolhandjo avatar
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Ulli_K avatar
Ulli_K avatar
Hi Rick,Imaging. The aurora borealis is actually quite easy.  one year ago in Finland. I had a chance to see it and that was really impressive. I took some single images with 20 seconds exposure time and a 14 mm wide angle lens. You can find them here: 
https://www.astrobin.com/q7ty9k/B/

Of course, exposure time depends on intensity, which was about medium at that time.Good luck and clear skies.
Ulli
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Rick Evans avatar
Rick Evans avatar
I wanted the information to help a friend who is travelling to northern Alaska and a big part of his trip is trying to photograph the aurora.  He had asked me for some advice and before just telling him what I thought, I wanted to check here and see what other folks experience was.  I had seen the aurora from Iceland a few years ago but where I live now it hardly ever visible and when it is, it is faint.

I've told him to use a regular unmodded DSLR with a wide angle lens between 14mm and 29mm and to base his exposure time also on the appearance of the background.  I told him to use a tripod and that hopefully his exposures would be under 15 seconds at ISO 2400.  I did not suggest taking multiple short images to stack them later, but to try to use one image per shot.  

I hope this was good advice.

Rick
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HR_Maurer avatar
HR_Maurer avatar
Hi Rick,
i think that was a good advice. One more thing to mention: Your friend might run into the quest with the missing autofocus, so he should be able to focus manually in the dark.

CS Horst
by the way, here are some aurora photos i shot in 2015 and 2021:
https://www.astrobin.com/i7d4gq/
https://www.astrobin.com/dxd825/B/
https://www.astrobin.com/7ydm9v/