Comments and questions about the
APOD on the main view screen.
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APOD Robot
- Otto Posterman
- Posts: 5549
- Joined: Fri Dec 04, 2009 3:27 am
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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
- Commander
- Posts: 584
- Joined: Mon Sep 30, 2013 6:35 pm
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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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E Fish
- Science Officer
- Posts: 136
- Joined: Thu Mar 09, 2017 2:29 pm
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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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neufer
- Vacationer at Tralfamadore
- Posts: 18805
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- Location: Alexandria, Virginia
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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
- Abominable Snowman
- Posts: 18534
- Joined: Wed Jan 31, 2007 11:13 pm
- Location: Guffey, Colorado, USA
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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.
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HellCat
- Ensign
- Posts: 70
- Joined: Wed Aug 05, 2009 1:30 am
- Location: Cleveland, Ohio USA (Zulu -5)
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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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Boomer12k
- :---[===] *
- Posts: 2691
- Joined: Sun Apr 22, 2007 12:07 am
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by Boomer12k » Sat Oct 14, 2017 10:06 pm
I am a "Mysterious Steve" myself....
Very intriguing phenomenon....
:---[===] *
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ta152h0
- Schooled
- Posts: 1399
- Joined: Mon Aug 29, 2005 12:46 am
- Location: Auburn, Washington, USA
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by ta152h0 » Sat Oct 14, 2017 10:23 pm
star tracking cupola view on a Boeing B29
Wolf Kotenberg
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E Fish
- Science Officer
- Posts: 136
- Joined: Thu Mar 09, 2017 2:29 pm
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by E Fish » Mon Oct 16, 2017 1:10 pm
Very cool! Thanks, Chris and neufer!
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Ann
- 4725 Å
- Posts: 13764
- Joined: Sat May 29, 2010 5:33 am
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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
Color Commentator
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bystander
- Apathetic Retiree
- Posts: 21590
- Joined: Mon Aug 28, 2006 2:06 pm
- Location: Oklahoma
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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. ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
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bystander
- Apathetic Retiree
- Posts: 21590
- Joined: Mon Aug 28, 2006 2:06 pm
- Location: Oklahoma
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by bystander » Mon Aug 20, 2018 11:58 pm
New Kind of Aurora Is Not an Aurora at All
American Geophysical Union | 2018 Aug 20
Thin ribbons of purple and white light that sometimes appear in the night sky were dubbed a new type of aurora when brought to scientists’ attention
in 2016. But new research suggests these mysterious streams of light are not an aurora at all but an entirely new celestial phenomenon.
Amateur photographers had captured the new phenomenon, called STEVE, on film for decades. But the scientific community only got wind of STEVE in 2016. When scientists first looked at images of STEVE, they realized the lights were slightly different than light from typical auroras but were not sure what underlying mechanism was causing them.
In a new study, researchers analyzed a STEVE event in March 2008 to see whether it was produced in a similar manner as the aurora, which happens when showers of charged rain down into Earth’s upper atmosphere. The study’s results suggest STEVE is produced by a different atmospheric process than the aurora, making it an entirely new type of optical phenomenon. ...
The study authors have dubbed STEVE a kind of “skyglow,” or glowing light in the night sky, that is distinct from the aurora. Studying STEVE can help scientists better understand the upper atmosphere and the processes generating light in the sky, according to the authors. ...
On the Origin of STEVE: Particle Precipitation or Ionospheric Skyglow? ~ B. Gallardo‐Lacourt
et al
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
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bystander
- Apathetic Retiree
- Posts: 21590
- Joined: Mon Aug 28, 2006 2:06 pm
- Location: Oklahoma
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by bystander » Tue Apr 30, 2019 5:06 pm
Scientists Discover What Powers STEVE
American Geophysical Union | 2019 Apr 25
The recently-discovered atmospheric glow is both like typical auroras and distinct from them, new research finds
The celestial phenomenon known as STEVE is likely caused by a combination of heating of charged particles in the atmosphere and energetic electrons like those that power the aurora, according to new research. In a new study, scientists found STEVE’s source region in space and identified two mechanisms that cause it.
Last year, the obscure atmospheric lights became an internet sensation. Typical auroras, the northern and southern lights, are usually seen as swirling green ribbons spreading across the sky. But STEVE is a thin ribbon of pinkish-red or mauve-colored light stretching from east to west, farther south than where auroras usually appear. Even more strange, STEVE is sometimes joined by green vertical columns of light nicknamed the “picket fence.”
Auroras are produced by glowing oxygen and nitrogen atoms in Earth’s upper atmosphere, excited by charged particles streaming in from the near-Earth magnetic environment called the magnetosphere. Scientists didn’t know if STEVE was a kind of aurora, but a
2018 study found its glow is not due to charged particles raining down into Earth’s upper atmosphere.
The authors of the 2018 study
dubbed STEVE a kind of “sky-glow” that is distinct from the aurora, but were unsure exactly what was causing it. Complicating the matter was the fact that STEVE can appear during solar-induced magnetic storms around Earth that power the brightest auroral lights.
Authors of a
new study published in AGU’s journal
Geophysical Research Letters analyzed satellite data and ground images of STEVE events and conclude that the reddish arc and green picket fence are two distinct phenomena arising from different processes. The picket fence is caused by a mechanism similar to typical auroras, but STEVE’s mauve streaks are caused by heating of charged particles higher up in the atmosphere, similar to what causes light bulbs to glow. ...
Magnetospheric Signatures of STEVE: Implication for the Magnetospheric
Energy Source and Inter‐Hemispheric Conjugacy ~ Y. Nishimura
et al
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor