Is this a cosmic ray?

Vaeltaja

New Member
I already contacted Ursa, that is a Finnish astronomical association. I don't wanna waste their time more with this since I know they don't have too much time. But I photographed this thing and they said that it might be a cosmic ray. What do you think? They also told me that it's possible to take more cosmic ray photos by adding the camera body plug/lens cap and locating your camera in some dark place for taking a very long exposure photo and in some of those photos there might be a change that a cosmic ray hits your camera sensor. I've not yet tried it but seems reasonable.





[Thread info:]

I was in Järvenpää when I took the photo.
Based on the Stellarium time and angle of Ursa Major (Big Dipper) it seems like is UTC+3. So 22:45 UTC Aug 7 2019
 
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jonnyH

Senior Member
I'm no expert, but I would have thought a cosmic ray would appear as a single bright pixel, it would only be picked up by a camera if it struck the sensor directly so it wouldn't show up as a line in the sky.

Is the photo a long exposure? It could be a jet with flashing lights as there seems to be some regularity to the "scintillation".
 

Gerard

Member
I would have thought a cosmic ray would appear as a single bright pixel, it would only be picked up by a camera if it struck the sensor directly so it wouldn't show up as a line in the sky.
Unless the path of the cosmic ray crossed multiple sensor pixels, ie. if its path was approximately in the plane of the sensor array.
 

jonnyH

Senior Member
@Gerard

Maybe, it would seem improbable, but as I said I'm no expert. Why would a cosmic ray produce the pattern of colours we see in the photo?

If you post the location and time the photo was taken there are other members who could say whether or not it is an aircraft. It would be nice to at least rule that out.
 

Vaeltaja

New Member
It cannot be a plane, because there are no flashing lights.
Typically I see this kind of lines in my photos when I take star photos and they are satellites, but this is special because there are clouds behind it. It was a long exposure photo. Also, satellites do not have that kind of colors. That line is made up of all the colors, which is strange.
Exposure time was something between 10- 25 seconds. (can't remember, but if someone really wants to dig into this, I can find the Nikon nef raw file for you later and you can check it all from EXIF.

I can't remember seeing anything there and it was not in the other photo I took from the same place.
 

Mechanik

Member
It’s certainly possible, or even likely, that this is a cosmic ray passing through the plane of the sensor. This must be more common than I would have expected. There is even an open source Android project CREDO (Cosmic Ray Extremely Distributed Observatory) Collaboration that turns your camera phone into a cosmic ray detector by looking for flashes that appear while the lens is covered.
 

Vaeltaja

New Member
But the colors are different compared to some other objects such as satellites. Here is a photo with satellite from my camera

That "foggy" object btw is andromeda.
DSC_4979-3.jpg
 
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Mick West

Administrator
Staff member
It’s certainly possible, or even likely, that this is a cosmic ray passing through the plane of the sensor. This must be more common than I would have expected. There is even an open source Android project CREDO (Cosmic Ray Extremely Distributed Observatory) Collaboration that turns your camera phone into a cosmic ray detector by looking for flashes that appear while the lens is covered.
https://api.credo.science/web/
I don't see any that look like a long thin line though, mostly very short. Like:
Metabunk 2019-09-01 11-56-32.jpg


And the longer ones tend not to be straight.
Metabunk 2019-09-01 11-56-56.jpg

This post discussed some science:
https://astronomy.stackexchange.com/questions/16753/could-this-be-a-cosmic-ray-hit-on-my-cameras-sensor-cmos-dslr

Which suggests a couple of types - perhaps the short wobbly ones are more common.
 

Vaeltaja

New Member
There is also one slightly plausible explanation, which I myself don't believe. But spider web looks quite much like that in photos also. It sounds implausible for me because it's 13 seconds exposure without camera flash and it's crisp sharp line. Also, I was on the pier, so the web would'be been really really long one to be connected into any tree.

Search: "spider web sunlight"
 

Amber Robot

Member
It’s certainly possible, or even likely, that this is a cosmic ray passing through the plane of the sensor. This must be more common than I would have expected. There is even an open source Android project CREDO (Cosmic Ray Extremely Distributed Observatory) Collaboration that turns your camera phone into a cosmic ray detector by looking for flashes that appear while the lens is covered.
I find it exceedingly unlikely that this is a cosmic ray. The probability that one cosmic ray would be traveling almost exactly parallel to the sensor plane and there be no other significant cosmic ray hits on any other part of the array seems vanishingly small. I have seen a lot of long exposure raw images taken by space telescopes and there are always many more single or few pixel cosmic ray hits than long tracks.
 

Z.W. Wolf

Senior Member
Let's back up. Where did you take this photo? And when? And what direction?

I seem to recognize Scorpius, so you wouldn't be in Finland, but much farther south. And it seems to be about 7:30 p.m. local time. Looking toward the south?
 

Trailspotter

Senior Member
This may well be a plane. At least, this suggestion can be explored, if the location and the direction of camera are known, as well as the UTC of the photo.
 

Mick West

Administrator
Staff member
From the raw file above:
 

Trailspotter

Senior Member
From the raw file above:
Yes, I saw this, but it is not clear to me how the time relates to UTC. Can we have a confirmation that it is EEST (UTC+3)?
 

Z.W. Wolf

Senior Member
So the double star is Mizar? Okay. The Aurigids radiant is above the horizon. Active right now, but not very. Three per hour. But the wrong direction.
 

Mick West

Administrator
Staff member
Yes, I saw this, but it is not clear to me how the time relates to UTC. Can we have a confirmation that it is EEST (UTC+3)?
Based on the Stellarium time and angle of Ursa Major (Big Dipper) it seems like is UTC+3. So 22:45 UTC Aug 7 2019
 

Vaeltaja

New Member
Sry guys. I'm in forest taking more photos. Lol.

I'd rather leave my exact location hidden where I was, but it's not very far from Helsinki and I was pointing the camera towards west if I can figure it out correctly from my memory.

And yes, it's not very new photo. I was already emailing with Ursa about this. Then I forget the thing when it now came back to my memory and I made this topic.
 
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Z.W. Wolf

Senior Member



It could be a Perseid meteor, bright enough to shine through the cloud layer. It's the right time of year and it's coming from the right direction. Is the brightness too consistent?

Here are some Perseids and clouds:








 
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Trailspotter

Senior Member
Sry guys. I'm in forest taking more photos. Lol.

I'd rather leave my exact location hidden, but it's not very far from Helsinki and I was pointing the camera towards west if I can figure it out correctly from my memory.

And yes, it's not very new photo. I was already emailing with Ursa about this. Then I forget the thing when it now came back to my memory and I made this topic.
Well, it's up to you. You can use playback option on Flightradar24.com or Planefinder.net to check if at the time of photo there was a plane heading toward your location from the west (or flying to the west away from you). Unfortunately, you would need a paid subscription to either of these flight trackers to go that far back in time.

A Helsinki-bound plane that could have already descended below 5000 m, but was still about 7 to 5 km away from you, would be a good candidate.
 
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deirdre

Moderator
Staff member
A Helsinki-bound plane that could have already descended below 5000 m, but was still about 7 to 5 km away from you, would be a good candidate.
the planes to helinski all seem to go up and turn around before going to the airport.. but they seem to be turning a bit too low for his viewing angle. the Tokyo-paris flights come down past him (at least last weds) but are more NE to SW angle.
upload_2019-9-1_19-34-26.png
 

Z.W. Wolf

Senior Member
It seems to me it would have to be a small plane. The streak looks like a line of single pixels. If it is a plane it's under the clouds, which appear to be thin cumulus; thus not very high.

If it is a plane, I would guess it's a small plane and all that's bright enough to show is the white navigation light on the tail and a single strobe. There does seem to be a beads-on-a-string effect that you'd expect from a strobe. But it's so faint it's hard to tell if it's really there.
 
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Vaeltaja

New Member
The problem with the plane theory is that I don't remember here in Finland seen a plane that is like the one in that lake photo. They always seem to have lights like this:



This is just a random photo from my collection that has a plane in it.
 

Vaeltaja

New Member
Also, the other thing is that typically when I take photos of stars and I see a plane I wait until the plane is gone because those will ruin the photos. Expect if I specifically was trying to have planes in photos, but that's not very often.
I typically only wanna have the stars, landscape, meteors, and satellites in my photos. I didn't see anything moving in the sky when I took the photo.

Also, to be honest. If that line wasn't there I would probably not hesitate to delete that photo.
 

Z.W. Wolf

Senior Member
Wow, looking back through this thread... the time and place was given twice and I missed it twice. I was too sleepy this afternoon to 'bunk.
 

Trailblazer

Moderator
Staff member
Here are some Perseids and clouds:



That second photo looks rather similar to me. Although the cloud in the OP looks possibly too thick for this to be the explanation?

One thing I would say regarding the possibility of a cosmic ray strike in exactly the right plane being “vanishingly small” as @Amber Robot said: well even if it is, how many billions of digital photos are taken every year nowadays? Even if the probability is a trillion to one against, its perfectly possibly we could see it happen.
 

Mick West

Administrator
Staff member
I'm leaning towards the cosmic ray. For a variety of reasons
  • No stars are visible through the clouds, except at the edges. So it would have to be brighter than a star to be seen through the thick part.
  • Forward scattering of the light from a bright light source like a plane landing light or meteor would create a halo around the line. There is no halo.
  • Metabunk 2019-09-01 17-47-14.jpg
  • If it were a plane it would be likewise in front of the cloud, and so low enough to see the navigation lights flashing over 13 seconds.
  • The line is perfectly thin and straight. compare to the trees. It's not just in focus, it's unnaturally in focus, like it didn't go through the lense.
  • Metabunk 2019-09-01 17-51-39.jpg

  • The scintillations seem similar to D7000 sensor noise in their colors
  • Metabunk 2019-09-01 17-46-33.jpg
So I think it's some kind of in-camera sensor thing, like a cosmic ray.
 
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Amber Robot

Member
Go look at http://heritage.stsci.edu/1999/16/images/raw814_600.jpg for a sample raw HST image. You can see that there are many cosmic rays and there are maybe two or so that are actually reasonably long. So, it's definitely possible to have the ray come parallel through the sensor. But I reiterate that the likelihood seems low that if you only had one cosmic ray in your image it would be one that came through parallel when there are so many more angles available to come through your sensor.
 
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