This may have been a sociological experiment on the rise of religion, science, humour, stupidity (Is there intelligient life here?), ego, cooperation,
communication.
Strange streak discussion: 2004 Dec 7 APOD
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Fred5
streak
In september 2002 I've seen the same "dark"grey couloured line in the Neteherslands. No flashes, or whatsoever. It had been a very cloudy sky, and it seemed to be a part of a circle. As far as I could see, it streched from inland to the horizon, where the sea meets the sky. (I was at the beach).I noticed that it moved with me while walking, but not no more than about 300 meter app. When I later walked back, the same movement. The sun stood near the line. I also took a picture with an anolog camera.
It was definetly not a trail from a plane.
It was definetly not a trail from a plane.
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Boldra
leave it to the kooks
At some point all of the people with the sense to rationally consider the arguments presented will be satisfied that the answer has been found and they will go away. However the kooks and the people who don't bother to read the other posts* will happily keep making loony or already-dismissed suggestions.
FastArtCeeToo seemed to have been the last person posting rational (if sometimes difficult to understand) arguments against the insect theory. Therefore, we can expect that soon the only people posting will be those with ill-thought-out theories that ignore some of the data.
My biggest concern is this: without reading every single page, how do I know this hasn't already happened?
BTW: did anyone eliminate the possibility that the periodicity of the streak was a jpeg artefact, or is the wingbeat/periodicity generally accepted?
* granted I've only read pages 1-12 and 85-107 myself
Boldra
FastArtCeeToo seemed to have been the last person posting rational (if sometimes difficult to understand) arguments against the insect theory. Therefore, we can expect that soon the only people posting will be those with ill-thought-out theories that ignore some of the data.
My biggest concern is this: without reading every single page, how do I know this hasn't already happened?
BTW: did anyone eliminate the possibility that the periodicity of the streak was a jpeg artefact, or is the wingbeat/periodicity generally accepted?
* granted I've only read pages 1-12 and 85-107 myself
Boldra
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Guest
Re: leave it to the kooks
Yes, you seem to prove your point!Boldra wrote:...the kooks and the people who don't bother to read the other posts* will happily keep making loony or already-dismissed suggestions.
My biggest concern is this: without reading every single page, how do I know this hasn't already happened?
BTW: did anyone eliminate the possibility that the periodicity of the streak was a jpeg artefact, or is the wingbeat/periodicity generally accepted?
* granted I've only read pages 1-12 and 85-107 myself
Boldra
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hazeii3
Re: leave it to the kooks
Partially; victorengel posted a simulation which, when subject to the same tests, showed no curvature and no (semi-)periodic behaviour. Also, it's hard to get the relatively low frequency of hte variations from jpg (because it uses 8x8 pixel blocks and the trail is ~33 degrees, artifacts might be expected at around 9 pixels and 14 pixels - too high a frequency for the wobbles). However, victor's simulation used the 'before' (or maybe 'after') picture as his base which therefore doesn't exclude effects due to the background on the main picture. I'm still playing with the software (mainly as a learning exercise now), and am working on my own control test by adding a fake trail parallel to and nearby to the real one, and processing it without rotation; I'll post the result in due course.Boldra wrote:BTW: did anyone eliminate the possibility that the periodicity of the streak was a jpeg artefact, or is the wingbeat/periodicity generally accepted?
Incidentally, the behaviour isn't particularly periodic as in precisely regular (hence I prefer to call it semi-periodic); on the other hand, if the insect was banking or turning that'd cause the period to apparently change in various ways anyway (the path is definitely non-linear, which may have a bearing on this).
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hazeii3
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hazeii3
Thanks! I must admit to being a bit sloppy about the 'methods and materials' part of the report, but even so I don't believe the fire affected the result in any meaningful way (but in the spirit of full disclosure, it was Southern Fried Chicken).Anonymous wrote: Bravo!!! If this doesn't do it for the bug theory I don't know what will... Given the limitations of the experiment, (read your camera) it certainly proves that the bug theory is 100% plausible and since it doesn't require any massive coincidences (like a space shuttle shapped meteorite, or magical contrails)..I don't know what more is needed..Although for the record I feel the exact details of your incinerated dinner needs to be part of the public record..
8) 8) 8) 8) 8)
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Yutacan
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Guest
It's already pretty much excluded because the trail doesn't cross the whole frame, as is pretty obvious in this difference image.Yutacan wrote:shouldn't the meteor theory be absolutely excludeable?
because where's the bow shock ?
you only see a little bit of smoke (the wings) but, a very fast-going comet should leave more smoke or at least a bow shock at the front
Also, the trail isn't as straight as it appears, it's been shown by several people that it wanders around a bit.
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HawaiiArmo
Congratulations hazeii3
At least somone decided to finally go all out and follow the line of empirical science to it's end. It's unfortunate that everyone so caught up in explaining the phenomenon, can't come to grips with the simplest fact of experimentation and support for a working theory. I myself am as equally guilty of trying to conjure up any possible explanation for the image (particularly exploding light bulb, and even less likely, ball lightening), that its' good to see some real evidence at work.
But it wouldn't be science if everyone and their mother didn't throw in their 2 cents worth on the subject. Just broadening the possibilities, and conjuring up an imagination that seems to be taken for granted in this downwad spiral of society.
I think your experiment pretty much clinches the bug theory, at least by 99%. There's still that probabilty something else may have happened, but given the results, and slapping together a working experiment to achieve that, it's honest science as far as I'm concerned. Issue's settled, at least in my book.
But it wouldn't be science if everyone and their mother didn't throw in their 2 cents worth on the subject. Just broadening the possibilities, and conjuring up an imagination that seems to be taken for granted in this downwad spiral of society.
I think your experiment pretty much clinches the bug theory, at least by 99%. There's still that probabilty something else may have happened, but given the results, and slapping together a working experiment to achieve that, it's honest science as far as I'm concerned. Issue's settled, at least in my book.
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Luis
Re: Congratulations hazeii3
Yes, but a good experiment comes only after a lot of thinking and discarding many "thought experiments".It would not be possible to testHawaiiArmo wrote:At least somone decided to finally go all out and follow the line of empirical science to it's end. It's unfortunate that everyone so caught up in explaining the phenomenon, can't come to grips with the simplest fact of experimentation and support for a working theory. I myself am as equally guilty of trying to conjure up any possible explanation for the image (particularly exploding light bulb, and even less likely, ball lightening), that its' good to see some real evidence at work.
experimentally every simple idea that pops up.
The scientific method's steps (as taught in schools, not always true, though) are:
1. Observation,
2. Hypothesis
3. Experimentation
4. Formulation of law
So that is more or less what is been happening, From an observation, many hypothesis were thrown in the basket, discussed and only the more plausible one tried experimentally. I mean... trying the meteorite one is out of the question
Good work everyone!
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victorengel
- Science Officer
- Posts: 158
- Joined: Tue Dec 07, 2004 11:29 pm
Re: leave it to the kooks
Jpeg artifacts were eliminated mathematically, because they align every 8 pixels. Make the appropriate transformation for the angle, and the periodicity should be a harmonic of 14.5 pixels or 9.6 pixels. The periodicity found doesn't match either.Boldra wrote: BTW: did anyone eliminate the possibility that the periodicity of the streak was a jpeg artefact, or is the wingbeat/periodicity generally accepted?
Boldra
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Derek Smith
Photography
1 I have run diff functions on these images (allowing for the mixup in picture order) then run density profiles aross the streak and have identified a problem.
In my analysis, the streak stops at the far horizon, it does not continue in front of the distant land mass nor the bay beyond the bridgehead.
If others can substantiate this observation, then the grey streak is in the sky and extends beyond the horizon, i.e. it does not enter the bay area and is physically a great distace away from both the bay and the flare on the bridgehead.
Does anyone know if Wayne Pryde has been asked if he has higher res images to work with or are the 333k .jpg files posted all that exist. The exif picture information included with the images is a much shortened version of the complete exif data from the camera. This suggess that the images have been processed through some software which has saved a subset of the exif data. if this is the case maybe the original images will not have sharpening and jpg artefacts on them which would allow for a far greater degree of accuracy in the analysis of the trajectory of the gray line to be made (i.e. in front of or behind the horizon). Does anyone have a way to contact Wayne to ask if he has unprocessed original images. Canon have the facility to save the files in .raw format, although these files are very large, they are the most valuable for analysis.
If the line does in fact stop sharply at the horizon, then it strongly indicates the presence in the sky of some rapidly formed and equally rapidly dispersing light reflective media (a vapour shock trail akin to that formed in the sudden depressurisation caused at the tip of a fast moving plane wing - but NO I am NOT suggesting that is the cause, simply describing that the effect is easy to create).
The effect is between the ground and the clouds (it passes in front of all the clouds except the extreem top LHS where it is either behind the clouds or has already dispersed) and is very large (the horizon is miles away yet the effect is still wide by comparison as it passes beyond the horizon.
If the effect is a vapour shock trail, its start may coincide with its junction with suitable air capable of responding to the cause of the effect or it may be that the effect has already faded from this point by the time the image was captured. certainly the fade (or reevapouration of condensed water vapour) is rapid as the effect has gone 15 seconds later. As the effect is not present in the first frame, the whole line (many miles long) must have been created in less than 15 seconds, so its cause was high and very fast.
The effect, if it were caused by the passage of a fast object could not have been due to debris from the object as this could not 'evapourate'. To vanish within 15 seconds the effect would have had to be water condensed from the air by a pressure wave and allowed to reabsorb as soon as the disruption had passed.
The light on the Bridgehead;
If the grey line is in the sky, then the fact that it is 'pointing' at the lamp is an illusion of parralax, there are many things in this image that the line appears to 'point' at, but if in fact the line is travelling across the sky to the horizon, then the fact that it appears to 'point' at the lamp is illusion.
Closeup of the light suggests a small fire and some drifting white smoke. Judging by the state of the surface of the water and the lack of movement in the leaves of the nearby trees there was very little wind during these shots. (1/20 second is a long exposure and would have shown object blur on leaves moving in a wind), so what ever caused the light to fail at that moment was either fluke or an EMP coincidental with the passage of the cause of the grey line.
Note if the line were in fact caused by a very transient water vapour trail, then it would appear grey. Any white material between the camera and the light source ( in this case the clouds, because the sun is behind the clouds) would reflect some of the light from the clouds back towards the clouds, so the amount of light in that region reaching the camera would be reduced and therefore appear greyer than the unaffected areas.
This analysis depends totally on the passage of the grey line to the horizon only, so anyone who can repeat this difference analysis and confirm the cessation of the effet at the horizon will be helping to confirm the high sky, rather than 'Bay Shot' trajectory of this line.
I am not a member of this forum but if anyone wants to PM me they can try on derek@ragwort-uk.com
In my analysis, the streak stops at the far horizon, it does not continue in front of the distant land mass nor the bay beyond the bridgehead.
If others can substantiate this observation, then the grey streak is in the sky and extends beyond the horizon, i.e. it does not enter the bay area and is physically a great distace away from both the bay and the flare on the bridgehead.
Does anyone know if Wayne Pryde has been asked if he has higher res images to work with or are the 333k .jpg files posted all that exist. The exif picture information included with the images is a much shortened version of the complete exif data from the camera. This suggess that the images have been processed through some software which has saved a subset of the exif data. if this is the case maybe the original images will not have sharpening and jpg artefacts on them which would allow for a far greater degree of accuracy in the analysis of the trajectory of the gray line to be made (i.e. in front of or behind the horizon). Does anyone have a way to contact Wayne to ask if he has unprocessed original images. Canon have the facility to save the files in .raw format, although these files are very large, they are the most valuable for analysis.
If the line does in fact stop sharply at the horizon, then it strongly indicates the presence in the sky of some rapidly formed and equally rapidly dispersing light reflective media (a vapour shock trail akin to that formed in the sudden depressurisation caused at the tip of a fast moving plane wing - but NO I am NOT suggesting that is the cause, simply describing that the effect is easy to create).
The effect is between the ground and the clouds (it passes in front of all the clouds except the extreem top LHS where it is either behind the clouds or has already dispersed) and is very large (the horizon is miles away yet the effect is still wide by comparison as it passes beyond the horizon.
If the effect is a vapour shock trail, its start may coincide with its junction with suitable air capable of responding to the cause of the effect or it may be that the effect has already faded from this point by the time the image was captured. certainly the fade (or reevapouration of condensed water vapour) is rapid as the effect has gone 15 seconds later. As the effect is not present in the first frame, the whole line (many miles long) must have been created in less than 15 seconds, so its cause was high and very fast.
The effect, if it were caused by the passage of a fast object could not have been due to debris from the object as this could not 'evapourate'. To vanish within 15 seconds the effect would have had to be water condensed from the air by a pressure wave and allowed to reabsorb as soon as the disruption had passed.
The light on the Bridgehead;
If the grey line is in the sky, then the fact that it is 'pointing' at the lamp is an illusion of parralax, there are many things in this image that the line appears to 'point' at, but if in fact the line is travelling across the sky to the horizon, then the fact that it appears to 'point' at the lamp is illusion.
Closeup of the light suggests a small fire and some drifting white smoke. Judging by the state of the surface of the water and the lack of movement in the leaves of the nearby trees there was very little wind during these shots. (1/20 second is a long exposure and would have shown object blur on leaves moving in a wind), so what ever caused the light to fail at that moment was either fluke or an EMP coincidental with the passage of the cause of the grey line.
Note if the line were in fact caused by a very transient water vapour trail, then it would appear grey. Any white material between the camera and the light source ( in this case the clouds, because the sun is behind the clouds) would reflect some of the light from the clouds back towards the clouds, so the amount of light in that region reaching the camera would be reduced and therefore appear greyer than the unaffected areas.
This analysis depends totally on the passage of the grey line to the horizon only, so anyone who can repeat this difference analysis and confirm the cessation of the effet at the horizon will be helping to confirm the high sky, rather than 'Bay Shot' trajectory of this line.
I am not a member of this forum but if anyone wants to PM me they can try on derek@ragwort-uk.com
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Bob Peterson
- Ensign
- Posts: 35
- Joined: Sun Sep 19, 2004 10:47 am
Re: Congratulations hazeii3
Yes. Experimentation. The spoked bug/wheel produced streak is a good start. I'm not in a position to do an outdoors FLYING BUG experiment. I am growing a little impatient. There's been so much time invested in this thread. Can't someone in a warm climate find a bee keeper willing to place a pre-set Canon PowerShot G3 at one of his/her bee boxes? I know the bug(if it is a bug) can be something other than a bee. Just get those FREE FLYING BUG SHOTS please. It's been 12 days and no FREE FLYING BUG SHOTS.Luis wrote:Yes, but a good experiment comes only after a lot of thinking and discarding many "thought experiments".It would not be possible to testHawaiiArmo wrote:At least somone decided to finally go all out and follow the line of empirical science to it's end. It's unfortunate that everyone so caught up in explaining the phenomenon, can't come to grips with the simplest fact of experimentation and support for a working theory. I myself am as equally guilty of trying to conjure up any possible explanation for the image (particularly exploding light bulb, and even less likely, ball lightening), that its' good to see some real evidence at work.
experimentally every simple idea that pops up.
The scientific method's steps (as taught in schools, not always true, though) are:
1. Observation,
2. Hypothesis
3. Experimentation
4. Formulation of law
So that is more or less what is been happening, From an observation, many hypothesis were thrown in the basket, discussed and only the more plausible one tried experimentally. I mean... trying the meteorite one is out of the question
Good work everyone!
Last edited by Bob Peterson on Sat Dec 18, 2004 4:51 pm, edited 1 time in total.
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Guest
Re: Lack of other streaks and flashes?
This has already been discussed. It's a stuck/hot pixel. It's a falt in the CCD.FastArtCeeToo wrote:If there were many bugs flying about, something of them should have shown up in the photo. If they were just a bit further from the camera we should see a shorter streak and a weaker flash. If they were still further away, we might not see any streak, but we should still see a weak flash. Past some distance, of course, we would see neither streak nor flash even if there were dozens flying about.
But between streaks and/or flashes for some kinds of bugs, and maybe just short streaks (all the way down to just black dots) for larger bugs that were flying either directly toward, or directly away from camera.
I've scanned the photo by eye, and looked at the results of subtracting images, and I can spot only one candidate flash, at location (x=888, y=1346), but it's at exactly the same location in all three photos. Could it be a camera artefact? The colour seems somewhat similar to the main flash. Any close examination is impossible because of jpeg artefacts.
If this is a reflection of some sort, I guess we can't say anything about its true location except to say that it's somewhere along a line from the camera flash to the water surface.
I don't see any obvious dark streak or dark dot candidates, either in water areas of the photos or in the sky areas.
Has anyone else tried to pursue this angle?
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Guest
Amazing. Simply wonderful. Your work has been invaluable. Thank you.hazeii3 wrote:I managed to find some more experimental subjects (I remembered there's a couple of wasp nests in the attic) so I reprised yesterday's experiments, but this time with the advantage of daylight (and a full stomach).
Again, here's the experimental subject (actually photographed post-experiment, looks like it's drooling a bit - not surprising given what it had just been through)
Spinning the wheel around 3 revs/sec (it hurt my fingers too much to go faster) gave a wasp velocity of around 2m/sec. The camera was about 0.6m from the subject, focused on infinity (roughly - it's not an SLR and the built-in screen's not much use), synchro flash and about 1/2 way though its optical zoom range of 8.3 to 24.9mm (Fuji Finepix 6800).
And here you have it.
[
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The Admiral
Streak and flash
I have been posting about this one the Bad Astronomers board but those guys are all so highly educated that they can't entertain a simple explanation.
To begin with, the streak and the flash are unrelated. The streak is a phenomenon that I have seen many times. It's the shadow of a contrail. A jet has just passed overhead leaving a contrail. The sun has cast the shadow of the contrail on the top of the clouds and the overcast is thin enough that the shadow is visible on the ground. Or, it could be that an aircraft has just flown through the clouds and left the streak. It would be interesting to know if there is an airport near the lower end of that streak.
The flash could be the sun shining through an opening in the moving cloud deck but it could also be many other things.
The Admiral
To begin with, the streak and the flash are unrelated. The streak is a phenomenon that I have seen many times. It's the shadow of a contrail. A jet has just passed overhead leaving a contrail. The sun has cast the shadow of the contrail on the top of the clouds and the overcast is thin enough that the shadow is visible on the ground. Or, it could be that an aircraft has just flown through the clouds and left the streak. It would be interesting to know if there is an airport near the lower end of that streak.
The flash could be the sun shining through an opening in the moving cloud deck but it could also be many other things.
The Admiral
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Vayenn
autocorrelation
Did you ever try autocorrelation (mentioned on page 70)? It should be better than FFT at showing any periodicity since it is not as sensitive to phase-shift along the path.hazeii3 wrote:Incidentally, the behaviour isn't particularly periodic as in precisely regular (hence I prefer to call it semi-periodic); on the other hand, if the insect was banking or turning that'd cause the period to apparently change in various ways anyway (the path is definitely non-linear, which may have a bearing on this).
For example (if I get it right): a perfect harmonic tone f inverted (phase-shifted 180 deg) at say each 10th period, would show as zero for f in the fourier transform (frequency domain), but only lose 1/10th of strength for the t = 1/f maximum in the autocorrelation function (time domain). Not until the 5th maximum will it get cancelled.
Presumably you are the expert here, but it may be of interest for both the initial tries with the streak intensity, and the wiggling function.
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Cloudbait
Re: Streak and flash
You should take a lesson from some of that education!The Admiral wrote:I have been posting about this one the Bad Astronomers board but those guys are all so highly educated that they can't entertain a simple explanation.
To begin with, the streak and the flash are unrelated. The streak is a phenomenon that I have seen many times. It's the shadow of a contrail. A jet has just passed overhead leaving a contrail. The sun has cast the shadow of the contrail on the top of the clouds and the overcast is thin enough that the shadow is visible on the ground. Or, it could be that an aircraft has just flown through the clouds and left the streak. It would be interesting to know if there is an airport near the lower end of that streak.
The flash could be the sun shining through an opening in the moving cloud deck but it could also be many other things.
The Admiral
The shadow can't be from a contrail, because the geometry is wrong. The Sun has just set to the right of the camera. There is no place in the sky where a contrail could be to cast a shadow like that seen in the image. It is unlikely that the flash is a reflection, since it can't be from the Sun directly (the Sun is below the horizon), and if from the clouds, it is hard to explain why it is the same brightness. That would require a mirrored surface at least 0.5 meters across. There doesn't seem to be anything like that between the camera and the sea.
The simplest explanation has already been given: a small object passing very close to the camera, probably an insect. It ties together the trail and the flash, it doesn't require any extraordinary coincidences of events, and it is well supported by the evidence.
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victorengel
- Science Officer
- Posts: 158
- Joined: Tue Dec 07, 2004 11:29 pm
Re: Photography
I think you need to do your analysis again. Several people here have made their own diff pictures that clearly show the trail goes in front of not only the distant land mass but also the water. In fact, it goes right up to the bright spot. Of course, at some point, there is a transition from dark to light right at the edge of the bright spot.Derek Smith wrote:In my analysis, the streak stops at the far horizon, it does not continue in front of the distant land mass nor the bay beyond the bridgehead.
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Guest
Re: leave it to the kooks
I guess I'm going to have to work on clarity!Boldra wrote: FastArtCeeToo seemed to have been the last person posting rational (if sometimes difficult to understand) arguments against the insect theory. Therefore, we can expect that soon the only people posting will be those with ill-thought-out theories that ignore some of the data.
Boldra
But I agree: the 'mystery' is solved, and turned (as in wheel) out to bee a natural occurrence.
This discussion can now be left to the believers in stray quarks, wrinkles in time-space, crop circles, ball lightning, alien shooting practice, exploding-self-repairing bulbs, cosmic ray tracks, quantum meteors, and time-traveling micro spaceships to thrash out a few alterative explanations amongst themselves.
It's been nice to politely dialogue with you, various and sundry rationalists, and I've learned a few things about extracting info from images, to boot. I'm outa here! Victor: thanks for your patience!
(I would, however, still like to see some other examples of insects inadvertently caught in flight. Such photos must exist.. mustn't they?
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frustratedtoejam
strange streak imaged in Australia
to victorengel.
appreciate all theoretical objections but still say try it with same type bulb under stated conditions. We may be surprised.
cant reply other than this as am a nonperson stuck in limbo/catch22 on this site; am registered as toejam,(see nonperson# 230 in ascending order) received no activating email & now cannot re-register under another user name as my email already taken (by me!!!!!!) Cannot change password or username, have no other email address, cannot find Administrator or anyone else. Hence frustratedtoejam. I know now how it feels to be the Man on the Stair; You know-
as I was going up the stair
I met a man who wasn't there
he wasn't there again today
I wish to hell he'd go away.
Can anyone help? Or shall I just go away?
appreciate all theoretical objections but still say try it with same type bulb under stated conditions. We may be surprised.
cant reply other than this as am a nonperson stuck in limbo/catch22 on this site; am registered as toejam,(see nonperson# 230 in ascending order) received no activating email & now cannot re-register under another user name as my email already taken (by me!!!!!!) Cannot change password or username, have no other email address, cannot find Administrator or anyone else. Hence frustratedtoejam. I know now how it feels to be the Man on the Stair; You know-
as I was going up the stair
I met a man who wasn't there
he wasn't there again today
I wish to hell he'd go away.
Can anyone help? Or shall I just go away?
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Guest
Re: Streak and flash
And also the streak in this picture is going below the horzion. When have you ever seen a contrail go below the horizon?Cloudbait wrote:You should take a lesson from some of that education!The Admiral wrote:I have been posting about this one the Bad Astronomers board but those guys are all so highly educated that they can't entertain a simple explanation.
To begin with, the streak and the flash are unrelated. The streak is a phenomenon that I have seen many times. It's the shadow of a contrail. A jet has just passed overhead leaving a contrail. The sun has cast the shadow of the contrail on the top of the clouds and the overcast is thin enough that the shadow is visible on the ground. Or, it could be that an aircraft has just flown through the clouds and left the streak. It would be interesting to know if there is an airport near the lower end of that streak.
The flash could be the sun shining through an opening in the moving cloud deck but it could also be many other things.
The Admiral
The shadow can't be from a contrail, because the geometry is wrong. The Sun has just set to the right of the camera. There is no place in the sky where a contrail could be to cast a shadow like that seen in the image. It is unlikely that the flash is a reflection, since it can't be from the Sun directly (the Sun is below the horizon), and if from the clouds, it is hard to explain why it is the same brightness. That would require a mirrored surface at least 0.5 meters across. There doesn't seem to be anything like that between the camera and the sea.
The simplest explanation has already been given: a small object passing very close to the camera, probably an insect. It ties together the trail and the flash, it doesn't require any extraordinary coincidences of events, and it is well supported by the evidence.
skyglow1
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Cloudbait
Re: Streak and flash
I was talking about contrail shadows, which can go below the horizon. See http://www.cloudbait.com/gallery/gallery_sky.html for an example of one that extends right to the ground. (Still, the Darwin image is not a contrail shadow, for reasons that have nothing to do with the fact that it extends below the horizon.)Anonymous wrote:And also the streak in this picture is going below the horzion. When have you ever seen a contrail go below the horizon?
skyglow1
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Derek Smith
victorengel
I have done my analysis four times, each time utilising a different colourspace and parameters. Each time I have seen a clear termination of the profile at the jusnction of the sky with the horizon. That is why I posted asking for others to complete a detailed analysis at the sky/ horizon boundary.
Rather than quote others peoples posts at me could I respectfully suggest that you attempt this for yourself and then report you findings to the deiscussion.
Derek Smith
I have done my analysis four times, each time utilising a different colourspace and parameters. Each time I have seen a clear termination of the profile at the jusnction of the sky with the horizon. That is why I posted asking for others to complete a detailed analysis at the sky/ horizon boundary.
Rather than quote others peoples posts at me could I respectfully suggest that you attempt this for yourself and then report you findings to the deiscussion.
Derek Smith