nmarsollier
Member
Hey, darkness is a shadow projected from the sky in the sensor.
In long exposures would show the light in the background a little bit darker that the rest
Night sky long exposure light trail
- Thread starter Pendleton
- Start date
In long exposures would show the light in the background a little bit darker that the rest
nmarsollier
Member
I have another question for you @Pendleton , it is normal to see so many dead pixels in your night exposures ?
[A crop sample from the bottom of the picture]
[A crop sample from the bottom of the picture]
jarlrmai
Senior Member.
Hot pixels are common in long exposuresI have another question for you @Pendleton , it is normal to see so many dead pixels in your night exposures ?
[A crop sample from the bottom of the picture]
nmarsollier
Member
And another curiosity , checking the bottom of the picture, seems that there is an small source of light in the center of the frame, looks like 2 source of lights at the ground. Maybe bugs not sure the light looks pretty soft.
Mendel
Senior Member.
How does that work?
Dave51c
Member
Can we agree on less than or equal to?
This is assuming that only velocity contributes to the brightness.
Well, the shake event could be less than 76 seconds, if I understand you correctly. Apologies if I don't.
Not wanting to assert a full size aircraft, it's worth noting that at a conservative 550mph, a jet aircraft could cover about 11 miles in 76 secs. At a more aerobatic 200mph this drops to only roughtly 4 miles. But, there is a lot of manoeuvring possible within 76 seconds and a few miles of a runway centerline during a military air display. Even if not conjecture, we don't know the distance to the light source (complicated by wide angle lens distortions) and therefore could not argue that the jet sound may have been audible to @Pendleton.
Thanks for your answer - gave me a lot to think about.
So what is the source of light in the image? Is it a meteor trail distorted due to camera shake during the exposure? Independently, wonder what the probability would be of capturing a meteor right at the end of the exposure and the trace is formed by shutter shock and/or mirror slap?
Is it just me or is there a sort of symmetry or parallel offset going on in the trace? It also reminds me of a hysteresis curve
I did a quick google of cosmic ray strikes on cmos sensors in astrophotography, but could not find anything similar. I think I'm overthinking (again).
Mendel
Senior Member.
No, the shake event could be less than 1-2 seconds, because it's not related to the dot navigating the path.
Yes. But what we have here is a loop in under 2 seconds.
This loop:
Mendel
Senior Member.
No. Meteors don't double back. The U-turn rules that out.
JMartJr
Senior Member.
Wondering how sensitive the sensor is -- not in absolute terms, but in terms of what happens if one picks up the camera, say, and moves it without realizing the shutter is still open. Are stars dim enough for the sensor to maybe not register trails if the camera is picked up and moved around? If so, might a brighter light off in some other direction, not in the original shot, say the equivalent of a semi-distant street light, make such a track as the camera is carried in the belief that the shutter is closed (or whatever the analogue for the shutter closing is in digital cameras.)
As is obvious, I don't know a lot about digital cameras -- but I know what happens when I pick up a camera shooting video thinking I've stopped it recording, and the shaky. I can envision it making such an odd track as it happens to pass across some light source -- providing it would not have the stars making similar trails when the camera is first moved.
Of course, that would depend on there being a light available, maybe behind the camera somewhere, and on the photographer picking it up and moving it when the shutter is still open. All of which would have to be discussed, but need not be if picking up the camera and turning it away from the stars would leave obvious star trails streaking all over the place...
As is obvious, I don't know a lot about digital cameras -- but I know what happens when I pick up a camera shooting video thinking I've stopped it recording, and the shaky. I can envision it making such an odd track as it happens to pass across some light source -- providing it would not have the stars making similar trails when the camera is first moved.
Of course, that would depend on there being a light available, maybe behind the camera somewhere, and on the photographer picking it up and moving it when the shutter is still open. All of which would have to be discussed, but need not be if picking up the camera and turning it away from the stars would leave obvious star trails streaking all over the place...
FatPhil
Senior Member.
Absolutely, the first idea that came to mind was that those colours were an artefact of sensor demosaicing.
deirdre
Senior Member.
noone's going to believe me, but i just saw a bright flash of silvery white outside just above the grass. it wasnt yellowish at all, and smaller than i've ever noticed a lightning bug seeming. which i doubt could be here this time of year (i'm near Danbury Ct now, 49 degrees). flash was real short so didnt notice any movement to it. guesstimate like 1/4th the length of a lightning bug flash. Tiny, like 1/8th size of ligtning bug bum.
weird.
weird.
Mendel
Senior Member.
If it did, the long exposure would not be needed.
On the other hand, I don't think that's an easy feat to achieve with a tripod-mounted camera, and the aircraft track may be a better candidate for leaving a streak.
JMartJr
Senior Member.
FWIW, if you start seeing it more often, get your retinas looked at -- I had an episode of weird flashes, tiny seeming, fractions of a second, white, especially at night and when there was a streetlight or other light source out of the corner of my eye. In my case it turned out to be just eyes getting older and the aqueous humor starting the age, and was no big deal. So yay for me! And I'd not worry about seeing one, it might as easily have been a real thing. But if you start seeing it a lot, especially accompanied by floaters, get checked out ASAP. Thus endeth the Public Service Announcement!
I'd tend to agree, especially if we include drone as a category of aircraft. Just wondering if the "camera being moved with the shutter open" was even possible as an explanation. It would account for the slightly odd "flight path" and the lack of navigational flashers, and the photographer not having seen anything flying around.
Do you have any other photos from this night that you could share?
Wondering if any similar exposures from before or after this one might provide some additional context.
Mendel
Senior Member.
Some context, there seems to be a misunderstanding.
I'm referring to the short straight aircraft track in the bottom right corner. Because it is brighter than the stars, it would have been more likely to leave a streak if the camera was moved.
Dave51c
Member
Thanks for sharing your photo. Quick curious question please.
I couldn't see in the specs of a 5D Mk IV if there is a viewfinder shutter to stop light leaks during long exposure. Does the Mk IV have one, and if so, were you using it during exposure? Even if light entered via the viewfinder, I'm not sure it would be so well defined. My own light leaks were not.
Thanks.
Ravi
Senior Member.
Good point. I don't think it has one. The Nikon has it (and darn handy, I used it all the time).
JMartJr
Senior Member.
Clarification noted. Am I reading correctly that your point is that the aircraft-or-whatever that left the lower right streak (presumably as it moved off to the right) might be the light source for the loopy streak IF the camera was moved while still "recording?" Hadn't thought of that...
jarlrmai
Senior Member.
It could be meteor combined with camera shake, a brief bright light at the same time the camera moves.
There appears to be at least one but possibly several other squiggly aberrations that do not appear, to me, to be stars or hot pixels
Here is what looks like another squiggle to the lower left of the main one:
Also here are a handful of "stars" that are not blurred by the same sidereal movement as the nearby stars. Maybe they are hot pixels but they dont look nearly as pin-point as the others.
Here is what looks like another squiggle to the lower left of the main one:
Also here are a handful of "stars" that are not blurred by the same sidereal movement as the nearby stars. Maybe they are hot pixels but they dont look nearly as pin-point as the others.
Mendel
Senior Member.
No, that's not what I meant.
Your idea was that if a camera movement left the mysterious track, then shouldn't other light sources in the picture leave the same track?
My thinking is that the stars are too dark for that, and the brightest source (outside the mysterious track) is that aircraft in the corner.
Mendel
Senior Member.
Let's define some terms for this conversation.
The main feature is a V-track with S-shaped legs:
From afar, it looks smooth, and I expect that the smooth path is one motion: either the motion of the white dot in reality, or a camera wobble, like if someone bumped into the tripod.
Superimposed on this big track are smaller aberrations, see Mick's post (click to enlarge).
These small aberrations (including a small loop) are what I think of as camera shake, caused by wind gusts or ground vibrations travelling through the tripod; or they could be caused by small turbulence affecting a bright airborne speck..
Since a meteor tracks fairly straight in reality, it could only have left a V-track if the camera wobbled for the whole trajectory, forth and back. But then it could've just as well been any other stationary light.
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jarlrmai
Senior Member.
Can anyone identify the patch of sky we are looking at could there be a much brighter star/planet just out of view that a camera knock bought into frame for long enough for it to streak?
Astrometry is failing for me on the image as it which is odd as it is normally pretty good with pure astro photos, although I am trying to enhance the stars to get a match.
Astrometry is failing for me on the image as it which is odd as it is normally pretty good with pure astro photos, although I am trying to enhance the stars to get a match.
deirdre
Senior Member.
thanks, yea had all those during and after covid. been thinking of a better analogy..as bright as, as fleeting as, and about the size of a sparkler bit when you light a sparkler. 10-12 feet from me. grass not wet, very distant light but looked around at the time and nothing that would account really. the dog (sitting out while he pee'd) was 30 feet away to my left. Googled bugs real quick but didnt see any bugs i'd never heard of that do that in November.
no idea.
deirdre
Senior Member.
the only things i can ever pick out is the big dipper and orions belt.. neither of which i see ?? based on their orientation that night. ??
he said he was looking for meteors, can yuo find where the meteors were supposed to be that night?
https://www.timeanddate.com/astronomy/night/@4831725
Alien Chess Fiend
Member
It looks like roughly this field to me. Polaris just left of the lowest part of the trail, Ursa Major just above the horizon slightly left of centre.
Easy Muffin
Senior Member
Oh. I just realised I posted the wrong plane on the previous page. Pretty obvious when you look at the date in the screenshot, it's one day off.
Not that it matters much but I initially confused myself with the UTC conversion and looked at the 14th when it was actually the 13th. I caught the mistake pretty quickly and identified the correct plane but when I pasted the pictures into my post here I mixed them up again and didn't notice until now. This is the correct one (hopefully!)
A Southwest 737, closer and lower but essentially in the same place as the Lufthansa would have been a day later. I suppose them being basically one and the same was what tripped me up to begin with...
So yeah, the streak is a plane, just a different one.
circle - Polaris
square - Beehive Cluster
and parts of Ursa Major
EDIT: For crying out loud. The Stellarium screenshot above is a day out AGAIN. Talk about trying to do things in a rush... Well I got to go in a minute so that'll be it for now! The view a day earlier was virtually the same, anyway.
Not that it matters much but I initially confused myself with the UTC conversion and looked at the 14th when it was actually the 13th. I caught the mistake pretty quickly and identified the correct plane but when I pasted the pictures into my post here I mixed them up again and didn't notice until now. This is the correct one (hopefully!)
A Southwest 737, closer and lower but essentially in the same place as the Lufthansa would have been a day later. I suppose them being basically one and the same was what tripped me up to begin with...
So yeah, the streak is a plane, just a different one.
That's what I see, too.It looks like roughly this field to me. Polaris just left of the lowest part of the trail, Ursa Major just above the horizon slightly left of centre.
circle - Polaris
square - Beehive Cluster
and parts of Ursa Major
Yes, Capella is just out of frame, I think. Something like this?
EDIT: For crying out loud. The Stellarium screenshot above is a day out AGAIN. Talk about trying to do things in a rush... Well I got to go in a minute so that'll be it for now! The view a day earlier was virtually the same, anyway.
I am even more interested to see the raw images taken directly before and after this. There appears to be something else "streaking" in the upper right. Either no light source or very faint. May simply be reflected from lights below.
Definitely a faint light streak. DIfferent to the more apparent one. I'm leaning towards insects.
Can insects fly at those temps?
Also I am trying to find weather station history data for that area but the closest I am seeing is for Danbury, CT and it shows a temp of about 47F around midnight on Oct 12
https://www.wunderground.com/history/daily/us/ct/danbury/KDXR/date/2023-10-12
However the area of the photo is a good 25 miles north of Danbury and appears higher in altitude. Could it have been 20 degrees colder than Danbury?
Mendel
Senior Member.
https://earth.nullschool.net/#2023/...ographic=-72.19,42.15,5689/loc=-73.430,41.833
8.7⁰C ≈ 47F
Edit: wrong month, see below!
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JMartJr
Senior Member.
Thought I had one, but further reading says they tend to walk around on the snow and ice...
Other winter flies and insects I have found are wingless. But some insects are active, at least, and it is certainly possible I'm missing the Abominable Snow Moth or something that doesn't just fold its wings and walk around...
Source: https://blogs.scientificamerican.com/guest-blog/winter-stoneflies-sure-are-supercool/, italics added.
Winter stoneflies are peculiar little creatures. In the dead of winter, the stoneflies’ aquatic immature stages, called larvae or nymphs, crawl from their rocky bottom home up through cracks and crevices in the snow and ice that cover the surface of the stream they’ve inhabited for the last year and emerge as adults. Although in possession of four wings rolled neatly over their elongated abdomens, adult winter stoneflies stay close to the snow and ice, walking rather than flying, in search of mates.
Other winter flies and insects I have found are wingless. But some insects are active, at least, and it is certainly possible I'm missing the Abominable Snow Moth or something that doesn't just fold its wings and walk around...
Thanks
Thats quite a temp difference from 47F to 25F.
deirdre
Senior Member.
not sure "winter " is a good search term. today hit 63 and i had 2 gnats fly around me (and no it was daytime and i saw them clear ..not floaters)
oct 12th in cornwall was a warm day
Sorry, I see the confusion. Photo/Metadata is from 11/12 but I originally posted 10/12. Should I edit the original post to avoid confusion?
Also, I’ll post some of the shots before and after for additional context.
