Starship Asterisk*

Unusual path was caused by the gravitation influence of the rouge planetoid BP.

I can picture a dynamics similar to those wartime photos of parts of an airplane spiraling toward the sea, except in this case ablation rounds off the air-catching surface(s) thus damping the spiral.

Thanks for all your comments and thoughts about the meteor image. Let me add something which I mentioned briefly in my second comment. The assumption that the camera was jarred was mentioned by several people I contacted before I sent the photo to the APOD people. A camera vibration was also my very first thought. If you look at the "left" part (which is assumed to be the beginning of the lumnous trail) you can see a bit of a faint straight trail until the point where the
sinusoidal trail starts and the brightness becomes higher. So it seems that the meteor (space junk re-entry or whatever) started fainter than it was during the "wobbling part". While a sudden start of a vibration might be explained by a wind gust (which I did not feel but cannot be excluded), the coincidence with the brightness increase would be highly unlikely. So it is to some extent similar to Jeremie's Quadrantid image of 2008 where the deviation from the straight trail also occurs during the meteor's motion. Again, this is no proof, but it made me curious. Juergen Rendtel

Some thoughts that, in my mind, kill all of the "vibration" theories are these:

In order for meteors to leave a trail bright enough to be captured in the manner in which this one was, it would have to be moving VERY quickly, which means that either:
a.) it left a VERY bright trail, that faded quickly, or
b.) it left a somewhat dimmer trail, that faded away very slowly, or
c.) possibly, but not likely, the camera caught the actual meteor itself, and not the trail. That, however, would have to be SOME camera!

In either case, if it were either camera or tripod vibration, it would act upon the entire trail, not just the earliest visible part. The characteristics of vibration distortion cannot act upon selectively specific portions of a captured image, but must act upon the entire image.

As I had pointed out earlier, the angle of distortion at the "tail" of the motion trail varied from the angle of distortion noted in the bright stars nearest the trail. What I had failed to notice at the time is that the "butterfly wing" distortion (as some earlier posters called it) is consistent around the outer edge of the image, with all the brighter stars, and that the effect is concentric to the center of the image, which convinces me that this is an artifact effect of the lens itself, because for it to be a vibration effect, the vibration would have to be torsional in nature, with the center of the torsional vibration being the exact center of the detector plate, which would be a serious "WTF" moment if there ever was one; not to mention that the meteor's trail would be similarly affected, which it's not.

Also worth mentioning one characteristic of the fish-eye lens, which is that as you decrease proximity to the center of the lens, you conversely increase the amount of radial distortion toward the edges. Bearing this in mind, if it were, indeed, any sort of vibration distortion, it would be more pronounced toward the outer edges of the image, and this is just not evident at all.

You may have seen the photo I took myself just a few weeks ago. You can find it on page 5 of this thread. I took that photo by simply putting my camera on its back on a table outside and opening the lens for 40 seconds.

If you look closely at the star trails you'll see that they are crooked when I bumped into the table. Yet the meteor trail is not crooked (it must have come over before or after I hit the table). And even tho the meteor trail shows a distinct corkscrew pattern, the star trails do not.

Since, no movement of the camera could make the meteor do a corkscrew and leave the star trails untouched I conclude that the corkscrew pattern must be caused by the meteor's path itself.

I subscribe to the theory that it is caused either by the irregular shape of the meteor causing it to tumble when it entered the atmosphere, or by parts of the meteor being of a volatile material that evaporates unevenly causing a force to act on the meteor. Or perhaps both.

Craine wrote:Since, no movement of the camera could make the meteor do a corkscrew and leave the star trails untouched I conclude that the corkscrew pattern must be caused by the meteor's path itself.

Not so. In most images of meteors, the meteor itself is much brighter than most of the stars. That's how it can show a similar brightness to stars despite having a much shorter total exposure time. The light from each star accumulates in the sensor pixels for the entire exposure- typically on the order of a minute. The light from the meteor is only present for around a second. If you jar the camera and if vibrates for a few seconds (coinciding with the meteor), the meteor image will show a damped sinusoidal pattern just like we see in this APOD, and the stars will show practically no effect at all, since only a small fraction of their light ends up on adjacent pixels during the vibration period.

I subscribe to the theory that it is caused either by the irregular shape of the meteor causing it to tumble when it entered the atmosphere, or by parts of the meteor being of a volatile material that evaporates unevenly causing a force to act on the meteor. Or perhaps both.

It is not physically realistic to think a particle a few millimeters across can follow a zig-zag or spiral trajectory several kilometers across, oscillating at a few hertz. The forces the particle would experience in that case are greater than the material strength of the body. It would fragment- something not seen in this image.

Your image shows something quite different, which might be explained by camera vibration, but also by jetting or rotation of the body. I don't see lateral motion, only a variation in the light curve.

Chris Peterson wrote:This image has been widely discussed in the meteoritics community. The consensus (unanimous as far as I've seen) is that the camera got jarred by wind or maybe an animal. The same effect has been seen on other images where that happened.

They maybe experts on meteoritics but that doesn't necessarily make them experts on astrophotography!

Camera shake etc has been mentioned and the symetry of star shake in adjacent stars,
the one thing that no one has mentioned is that Mount Teide is a volcano.

While it is 101 years since the last erruption, dormancy does not mean seismic quiescence.
Since there appears less "shake" on the buildings, which would be in seismic syncrony with the camera,
than the stars direct shake to the tripod/camera, is inlikely

If the photographer knows the precise time of the picture this could be correlated with
the seismic records to eliminate this theory.

Hypothetically, if the metoer trails duration was 1/10th of a second any seismic trace
should have an identical wave form if time interval of its recording could be adjusted to the same duration.

€z

adastragrl wrote:They maybe experts on meteoritics but that doesn't necessarily make them experts on astrophotography!

Sometimes true, sometimes not. Many are experts on meteor photography, however. Many are systematically operating meteor cameras and have collected thousands of meteor images. And regardless of how much they know about astroimaging, they are well qualified to assess whether a meteoroid is physically able to move in the way the image suggests. And if the conclusion is "no", that is useful even if they are unable to explain for certain how the meteor image was actually produced.

jrendtel@aip.de wrote:If you carefully look at the left end of the trail, it seems that is started before the sinusoidal motion started and the brightness increased.

It's compatible with an hurt of the second curtain (?) of the camera shutter, happened after the uncovering of the sensor and in coincidence with the passing of the meteor.
After the analysis of the impossible physical reality of the track, now I'm completely convinced of this theory.

Marcopie wrote:It's compatible with an hurt of the second curtain (?) of the camera shutter

Sorry, the FIRST curtain (?), the one uncovering the sensor...

Both meteor trails are twisted....seismic occurance that shook camera?

Guest wrote:Both meteor trails are twisted....seismic occurance that shook camera?

As has been stated several times already...
There are not two meteor trails. There is just one. The smaller one in the lower-right was copied and enlarged and pasted over the upper-left to make the detail more visible.

Rob

Camera shake seems plausible--it would be interesting to estimate the time duration of the meteor trail then look at the peak to peak distance of the wobble to calculate the frequency. Based on the speed of meteors I've seen, I would think the wobble is at least at an audible frequency. Maybe a gang banger was driving by with his stereo up during the exposure?

During the Leonids meteor shower a few years back we looked at the trails of the big ones with our 22" dob and every one was twisting and turning as it disapated.

Bob wrote:During the Leonids meteor shower a few years back we looked at the trails of the big ones with our 22" dob and every one was twisting and turning as it disapated.

You were looking at the train, the trail of dust and ionized gas left after bright meteors pass. Trains get blown around by high altitude winds. This image appears to show a meteor trail, the actual illuminated path of the meteor. Meteor trails are almost always straight (by which I actually mean always, but with a tiny element of doubt since I am a scientist <g>).

vegaskt wrote:Camera shake seems plausible--it would be interesting to estimate the time duration of the meteor trail then look at the peak to peak distance of the wobble to calculate the frequency. Based on the speed of meteors I've seen, I would think the wobble is at least at an audible frequency. Maybe a gang banger was driving by with his stereo up during the exposure?

A reasonable estimate for the duration of a meteor like this is one second. That makes the frequency of the wobble around 10 Hz, which is right in the area you might expect for vibrations in the camera setup.

The camera was obviously jarred. All the bright nearby stars show an oval "diamond ring" effect. The meteor trail records the pattern of the jarring clearly. An initial (possibly pre-exposure) strong jolt which is damped rapidly and leaves a slight residual wobble. The strong jolt causes the faint limbs of the diamond ring, whereas spending most of the exposure with very little vibration causes the bright "diamond".

I am surprised this was considered an interesting question.

zink -- 6 pages don't lie. i 2 am surprised that there is so much discussion about so little. must be something in the air. sniff - sniff - sniff----AH-choo

What about a meteor that splits and loses a bit of mass that goes one direction and the other goes equal and opposite but does not burn up due its composition?

The object was more nearly ellipsoidal and asymmetric having a knob/protrusion at the leading end of the major axis and orthogonal to this axis. Rapid rotation about the long axis with a leading-end protrusion including a wobble similar to a poorly thrown football would generate a spiral trail, as in image the pitch of the spiral is quite constant. Disintegration of leading-end
protrusion results in diminishing spiral due to tendency toward higher symmetry (ellipsoidal to spherical) and decay of wobble. Trail substructure would yield more information. Nonuniform
composition and structure may play their roles.

For me it seems to be the reaction induced by the flipping mirror of an DSLR-camera. At the beginning of the exposure the effect is more pronounced and fadinng away during the long exposure. The camera aparently was mounted on a tripod that was not sturdy enough. As allready noted by others the captured stars at the photograph show eliptical spiral "smearings" of the same amplitude that result from the same motion. May be that some meteors make a snakeing trail due to their irregular shape, for me this one most probably not...

Greetings!

Please see this post for another "curvy" meteor trail, this a recent submission for APOD and captured in Edmonton, Alberta.

I took some trial images last summer, checking out hardware and software for astro imaging with my Nikon D70 camera. I happened to catch what also appears to be a spiral-trajectory meteor near Vega on one frame. The angular frequency appears relatively constant, but the amplitude varies, increasing or decreasing over the short trail, depending on which direction it was heading. The trajectory is not sinusoidal, but appears to be a projection of a spiral path which is asymmetric. The camera was pointing straight up attached to a Leica tabletop tripod, 6 inches tall altogether. The table I had the camera on might have vibrated, but it would have to have vibrated in X and y at the same frequency to create the image seen, probably unlikely. Two other images from other frames during the same session show airplane trails and they exhibit a stair-step artifact (only X-and Y- steps) caused by the Bayer filter and reconstruction, but no trace of the spiral sort of artifact seen in the meteor trail.

I vote for a meteor doing a barrel roll: "A barrel roll is an aerial maneuver in which an airplane makes a complete rotation on its longitudinal axis while following a helical path, approximately maintaining its original direction." Normally done by a pilot using rudder & stick, but in this case by an odd shape that results in asymetric drag (similar to constant aileron & rudder input) & then gets ablated to a symetrical shape. The trail appeart to be more of a helical path than than a sprial motion or some giggle of the camera. Such a path does not seem unreasonable since all the meteors I saw in the Chicago Field Museam did not have nice symetric shapes.