APOD: Mysterious Green Patches on the Sky (2013 Sep 30)

[Florian]

A co-worker of mine and I have produced patterns just like that sweeping a green laser pointer through fog or haze. In this case someone standing near the top of the cliff could have done that. One argument for a local light source would be the fairly sharp bottom edge of the glowing patch.

Another possiblity is that the terrain above the cliff allows a narrow sheet of light from a street light or a similar light source to shine across the ocean. If the air was clear early in the evening there wouldn't be any evidence of this in the video, but later during the night as the air got colder a light haze might have formed, making the light visible. The light source could be the same one that causes some of the rocks look green throughout the video.

The strong green tint of the patches in the sky and the rocks may be in part due to the color saturation in the video having been cranked up to eleven.

[Kevin Snair]

Good evening,
I am the photographer who created this video. I'd like to thank everyone for actively helping solve this curiosity. Many questions have been asked so I will try to fill in some of the gaps.
I am a professional photographer who lives and works near The Hopewell Rocks in New Brunswick, Canada. A gentleman was in the park early this season and introduced me to the fun of night photography. I played around with the technique with pleasing results so I decided to try a time lapse video. My first attempt was done during a new moon in early July. I started rather late in the night and went through till dawn. It can be viewed here: https://www.youtube.com/watch?v=_4N5rCm5b7g
I had a small glitch in the evening resulting in me losing 7 minutes of photography. This shows in the video as a jump in the stars just as the milky way passes over Lover's Arch. Being a little on the anal side, this bothered me enough that I felt I wanted to re-do it.
On the evening of August 11th (and into the morning of the 12th) I set up my equipment again. The Hopewell Rocks is situated on the Bay of Fundy which is known for the highest tides on the planet. I set up my camera (Canon 5D mkII) on a tripod down on the shore facing approximately South East. I had the tripod at a height where the tide would rise around it but the camera would be above the high tide mark. I could have set up the tripod above the high tide mark but then I would not be pointing into the sky and still having the Rocks in the foreground. Please keep in mind I was creating this for aesthetics, not a scientific experiment. I set my ISO to 5000, the shutter speed to 30 seconds and the fstop to 4.0 (canon 17-40 mm lens at 17mm focused at infinity). I knew my first hour would be severely overexposed but as the sunset disappeared, the exposure would eventually be right for the remainder of the evening. The results were a gradual fade from white to night sky. I took my first shot at 9:19 pm and continued to take one shot every 40 seconds until 3:08 am. I had set up two small Colman battery powered LED lanterns to illuminate the rocks. They are the source of exposure on the rocks and beach.
It was a beautiful evening, quite warm and no moisture built up on the lens. I was awake and present for the entire event. The camera was being controlled by a laptop and I checked it on occasion to see that everything was working. When opening the laptop, occasionally the screen would add a bit of light to the closest rocks (explaining small fluctuations in foreground exposure). As the tide rose, I did not see the green "clouds" with the naked eye but it was extremely dark and the camera's sensitivity was allowing it to capture more than I was seeing. The tide was coming in with one to two foot waves and I realized that my camera would not survive the entire evening. I stood in water up to my waist, supporting the tripod but eventually the waves forcibly moved the camera and my shoot was over. It is worth noting that as the tide rose, it physically moved my foreground light (changing my foreground exposure as noticeable on the right hand rock surface).

When I got home and processed the photos, I did the following to all 508: Set white balance to 4350, increased the exposure by 15%, added a bit of fill light (midtones +45), and increased the saturation by 10%. When I turned them into the video, I faded to black at the very end to make it more pleasing to the viewer.

[allen ev.]

i believe that we are seeing light from the spots reflecting off of a heavy dew setting in.

[triccare]

My guess: it is the the tide, and specifically a reflection induced by the edge of the water, or water line, being lit by the off-camera light source. The appearance and disappearance of the green glow corresponds exactly with the brightening and then disappearance of the water line behind the rocks on the right as the tide rises. The water line is also the brightest thing in the images, besides the actual light source on the sand.

What is it reflecting off of? The camera lens itself. Being close to the water, there is a good chance of humidity and that there is probably some film on the lens. If not from humidity, from just the lens itself being lit.

[RiverCityKid]

Reflected light from source behind rocks as tide comes in.

[geckzilla]

Good evening,
I am the photographer who created this video.

Thanks, Kevin. I copied your post to the front of the thread since most people do not read the whole thread before contributing.

[lhansen]

that's easy -- the flood lights on the rocks are simply reflected in the incoming tide and thus reflected skyward

[grantjr67]

Yeah, it seems like light clouds that rolled in mixed with bad color mix from the camera. If you watch the rocks on the left throughout the video, you will see the same green effect, just starting sooner.

[mikkykovikky]

It looks like clouds reflecting something off the tide rolling in.

[troy morehouse]

Living along the Bay of Fundy coast line, I know that with the tide comes fog (sometimes just a very light fog), as the warmer waters com in from the ocean, interacting with the cooler air generate mid lying fog/clouds, which dissipate as the sun starts to rise and warm the air.

To me it looks fog-like, with the night sky illuminating it ever-so-slightly (and possibly the back-lighting on the rocks, but it appears too far away fro that).

The Bay of Fundy waters are dark almost green-blue (depending on where you are along the bay), and light reflecting off that water back up would include that hue.

[GunnarNOR]

This looks like Northern Lights to me. I grew up in Northern Norway (70° north), and have seen similar displays of Aurora Borealis several times. This is really fast moving, and sometimes that is the case.

[Britt777]

I believe there would be an obvious correlation between the incoming tide and any reflected light that might cause the "green effect", and any correlation would be at an angle to a specific region of the night sky... if this is what was happening. The "green effect" does not follow any such correlation to reflection off an incoming tide.

It is too late - in the wrong direction - and too diffused (scattered) to be caused by the diamond effect (the "green flash" that occurs over a long horizon on rare occasions right as the sun goes below the horizon. The diamond effect is also a much more brilliant and momentary green flash.

Had a thought about HAARP in Alaska causing this. Discount the thought for several reasons.

That said... am inclined to believe not a direct image of an aurora, but distant reflection that the naked eye could not/would not detect.

[Suddengenesis]

My four-year-old daughter first told me it's the "bush"(or rocks to the left) shining up to the sky. Upon further reflection, she said it might be Oobleck and someone should get Bartholomew.

[BillS]

If the location was equatorial and not Canada I would rule out aurora. I think it may have been a weak effect, while not particularly visible to the eye, perhaps it was brought out by the editing.

[AndyC]

I agree with Curt. The hidden light source to the right is casting a greenish light on the central rock pillar and also on the cliff to the far left of image. I believe the green 'aurora' is actually illuminated sea spray from the rising tide.

[Irene Baron]

Upon checking "Auroranotify.com" for the 11 August date, they predicted auroras to be seen in some areas. That's probably what it was. They suggested the auroras would be seen as streaks.

[KOD]

The Coleman LED fill exposed green, so the fact that the green glow in the sky coincides with the incoming tide suggests illuminated mist. Anyone who has felt the tide coming in at night knows that cool, moist sensation: it's water vapor.

[cyberman]

Although my first impression was that it was some kind of auroral phenomenon, it appears that the green lights are on the bottoms of the clouds indicating that they are either a reflection from the water as suggested in this forum, or perhaps some laser light being used nearby.

[Guest]

Based on the observations made on an APOD from November 19th, 2007, some Aurora light is only visible with photographic equipment.
My vote is Aurora.
http://apod.nasa.gov/apod/ap071119.html

[Badalamenti]

I got a similar effect once, during a photoshoot of the 2009 leonids as a nearby atmospheric lidar laser went on and litup the moist in the air. Considering it to be a perseid night, probably many people was observing the sky, so its possible it could be someone pointing something out with a green laser.

[ElizabethStuMehlin]

Noctilucent clouds.

In the Cloud Appreciation Society photo gallery you can see something similar.

http://cloudappreciationsociety.org/?s= ... clouds&g=1

[youngbloodmark1]

I think the greenish glow is the first part of an aurora borealis. The green haze is followed by an orange one, much like the Northern Lights, I had the pleasure of observing in CT in the 1990s.

[iluxo]

There are two distinctly different phenomena visible:

- a series of green auroral waves (nitrogen/oxygen discharge) - the telltale sign is that the stars are still visible through these green waves, so they are not cirrus clouds;

- followed by high cirrus moving in from the right (different direction); these are grey and obscure the stars, hence they're clouds, not aurora.

[Justin Otter Guess]

Chemicals floating high in the ionosphere put there by governments in secret and acted upon by extremely low pulsing radio frequencies for a plethora of communication atmospheric modification and top secret warfare, crushing economies and destroying the planet.

[Stephan]

looks exactly like the magnificent aurora i saw when i was in new brunswick in august