f4fotografy

f4fotografy OP t1_j21us21 wrote

Honestly I have no idea, I get alerts and updates from a local guy and he posts when the space weather is looking good. He's always talking about things like "need the field strength to shift our way", "this will probably be good for the northern hemisphere but we won't see it" or "the Bz is too far north" or something. I did my undergrad in astrophysics and I still don't understand aurora, when Darren says it's on, I go 🤣

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f4fotografy OP t1_j1yjptv wrote

Photographing the aurora has been a much bigger challenge than I'd originally thought. Everything from knowing (guessing) when it'll happen, finding a location, capture, and processing has turned out to be tricky.
This is the fifth time I've been to this location so far this year, each time the signs for aurora were looking good, only for the magnetic field to collapse, or solar wind to fizzle out, but the good news is that I've found the best place to set up and have level ground for my chair. For this night we were treated to these beams around 10:30 and another show after I packed up (as I had a two hour ride home again).
I wasn't able to see these beams with the naked eye (though others said they did) because I'm extremely colourblind, so it wasn't until I got home and checked through the images that I knew what I'd captured. As I couldn't be sure when the aurora would fire up I had a timelapse running from about 10pm through to 12:30, as I couldn't use the tracking mount I had to use 10" shutter speeds which makes for very noisy images.
Normally for processing astro images I would stack about 10 images for the sky and foreground separately to reduce the noise, but the aurora was changing and shifting so fast that it's completely different in each frame and stacking doesn't work.
Sony A7III, Tamron 17-28 @ 19mm f/2.8, 10" ISO640

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f4fotografy OP t1_j1jjbqt wrote

not quite. You can see everything that's in the image, but your eyes won't pick up the details (everything is just a fuzzy blob), and your eyes won't pick up the colour.

From this location you can make out the dark nebulae like Coalsack and easily see the Magellanic Clouds, but this is a Bortle 3 sky (3rd best rating for darkness, "rural").

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f4fotografy OP t1_j1gtpra wrote

Just a little red and green for christmas (and the Coal Sack).

[Annotated version with POIs on my profile as this sub doesn't allow galleries]

90% of the world's population live in the Northern Hemisphere and cannot see the South Celestial Pole. Down here at -37 degrees lattitude the Magellanic Clouds and the Carina region of the Milky Way never set below the horizon so we have "Galaxy Season" all year 'round.

The layers of green are caused by "Airglow", from the atmospheric molecules which absorb UV radiation all day and glow faintly green as they cool down at night.

The red is from "Diffuse Aurora", caused by high energy charged particles of solar wind being deflected by the Earth's magnetic field towards the poles and slamming into the atmosphere so hard they glow red and green (and sometimes purple) like tiny atomic meteors.

The dark region called the Coal Sack is actually a clump of cold gas and stardust blocking out the light from the stars behind similar to the "Dark Doodad" which is made of the same stuff but has a much funnier name.

The Magellanic Clouds are "Dwarf Galaxies" orbiting outside the Milky Way, they're much smaller than Andromeda but much closer.

The 47 Tuc cluster is the second brightest star cluster and contains more stars within it than can be seen from earth with the naked eye (around 10,000).

The Omega Centauri cluster contains around 10,000,000 stars and looks like a bright fuzzy star to the naked eye.

Sony A7III Tamron 17-28 17mm f/2.8 ISO5000 10"

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f4fotografy OP t1_isnukbl wrote

Unfortunately this wasn't the shot I wanted, but it's not a bad consolation prize.

I drove 3 hours to this location (formerly the 12 apostles but some of them have crumbled), planned for a 4 hour astro shoot with a "full arch" milky way panorama in the west, I got an aurora alert while I was waiting for the sun to set, and there was an ISS pass scheduled during my shoot I planned to capture. But my wife had to work late so I drove 3 hours back home without capturing a single astro image because the dog needed to be let out.

Sony A7III, Tamron 17-28 @ f/9.0, 1/4000, ISO640

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