APOD: All-Sky Steve (2017 Oct 14)

Comments and questions about the APOD on the main view screen.
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APOD Robot
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APOD: All-Sky Steve (2017 Oct 14)

Post by APOD Robot » Sat Oct 14, 2017 4:08 am

[img]https://apod.nasa.gov/apod/calendar/S_171014.jpg[/img] All-Sky Steve

Explanation: Familiar green and red tinted auroral emission floods the sky along the northern (top) horizon in this fish-eye panorama projection from September 27. On the mild, clear evening the Milky Way tracks through the zenith of a southern Alberta sky and ends where the six-day-old Moon sets in the southwest. The odd, isolated, pink and whitish arc across the south has come to be known as Steve. The name was given to the phenomenon by the Alberta Aurora Chasers Facebook group who had recorded appearances of the aurora-like feature. Sometimes mistakenly identified as a proton aurora or proton arc, the mysterious Steve arcs seem associated with aurorae but appear closer to the equator than the auroral curtains. Widely documented by citizen scientists and recently directly explored by a Swarm mission satellite, Steve arcs have been measured as thermal emission from flowing gas rather than emission excited by energetic electrons. Even though a reverse-engineered acronym that fits the originally friendly name is Sudden Thermal Emission from Velocity Enhancement, his origin is still mysterious.

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De58te
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Re: APOD: All-Sky Steve (2017 Oct 14)

Post by De58te » Sat Oct 14, 2017 12:49 pm

It's amazing how scientists figured out how the eye of a fish can see, even out of the water. I remember a Nova science program? or some other science program where they recreated what the compound eye of a fly or bee sees. Hundreds of little separate images all grouped into a large circle. Bring more APOD pictures like this, say how a dog's eye sees the Moon when it howls at it, or how a bird's eye looks at the sky during night navigation.

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Re: APOD: All-Sky Steve (2017 Oct 14)

Post by E Fish » Sat Oct 14, 2017 2:05 pm

How is the fish-eye panorama done? Is it just pictures stitched together in the circle or is there some actual process or camera setting?

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Re: APOD: All-Sky Steve (2017 Oct 14)

Post by neufer » Sat Oct 14, 2017 2:21 pm

E Fish wrote:
How is the fish-eye panorama done? Is it just pictures stitched together in the circle or is there some actual process or camera setting?
https://en.wikipedia.org/wiki/Fisheye_lens wrote:

<<A fisheye lens is an ultra wide-angle lens that produces strong visual distortion intended to create a wide panoramic or hemispherical image. Fisheye lenses achieve extremely wide angles of view. Instead of producing images with straight lines of perspective (rectilinear images), fisheye lenses use a special mapping (for example: equisolid angle), which gives images a characteristic convex non-rectilinear appearance. The term fisheye was coined in 1906 by American physicist and inventor Robert W. Wood based on how a fish would see an ultrawide hemispherical view from beneath the water (a phenomenon known as Snell's window). Their first practical use was in the 1920s for use in meteorology to study cloud formation giving them the name "whole-sky lenses". The angle of view of a fisheye lens is usually between 100 and 180 degrees while the focal lengths depend on the film format they are designed for.
Art Neuendorffer

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Chris Peterson
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Re: APOD: All-Sky Steve (2017 Oct 14)

Post by Chris Peterson » Sat Oct 14, 2017 3:13 pm

E Fish wrote:How is the fish-eye panorama done? Is it just pictures stitched together in the circle or is there some actual process or camera setting?
In this case, it's a single image with a lens like that described by Art. But there are also examples of fisheye panoramas stitched together from multiple images (indeed, my phone can do this automatically). And a group of my colleagues operate allsky cameras that consist of a dozen or more individual cameras all pointing in different directions, with the resulting images automatically stitched in real time.
Chris

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Careful of those acronyms

Post by HellCat » Sat Oct 14, 2017 7:21 pm

As a devote named Steve, I am all for any phenomenon bearing my name.

The problem here is that an All Sky Steve turns into something at the other end of the fish's eye - if you get my drift.

Couldn't we have called it the FULL Sky Steve? Or just Steve?

By the way, those strong thermal emissions we're talking about, they don't have anything to do with eating garlic?

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Re: APOD: All-Sky Steve (2017 Oct 14)

Post by Boomer12k » Sat Oct 14, 2017 10:06 pm

I am a "Mysterious Steve" myself....

Very intriguing phenomenon....

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Re: APOD: All-Sky Steve (2017 Oct 14)

Post by ta152h0 » Sat Oct 14, 2017 10:23 pm

star tracking cupola view on a Boeing B29
Wolf Kotenberg

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Re: APOD: All-Sky Steve (2017 Oct 14)

Post by E Fish » Mon Oct 16, 2017 1:10 pm

Very cool! Thanks, Chris and neufer!

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Ann
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Re: APOD: All-Sky Steve (2017 Oct 14)

Post by Ann » Mon Oct 16, 2017 1:24 pm

I like the name of All-Sky Steve.

To all of you Steves out there, have a good time hunting for Steves in the sky, or for other interesting phenomena!

Ann
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Re: APOD: All-Sky Steve (2017 Oct 14)

Post by bystander » Tue May 08, 2018 2:27 pm

Steve Aurora - May 6, 2018 (4K) -- Alan Dyer, AmazingSky
This 4K video captures the somewhat elusive and unusual form of aurora that has come to been known at Steve, or STEVE -- for Strong Thermal Emission Velocity Enhancement. This was May 6, 2018 from southern Alberta, indeed from my yard in rural Alberta. The time was from 11 pm to midnight.

This night the main aurora to the north was weak and largely inactive as we saw it, but had been very active earlier in the night from more northern locations. Churchill, Manitoba far to the east and north of me had a fabulous display about an hour before I shot Steve, despite the bright twilight sky at their latitude at this time of year.

STEVE usually appears after a major outburst or substorm, and appears as glowing white or grey arc across the sky. The camera records the pink colour, and the brief appearance of slowly moving green fingers in a "picket fence" formation. ...
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