I'm pretty certain I captured a shooting star in a sub frame. Thoughts?

[Spedz]

On the morning of 30/10/2022 I was out doing some DSO astrophotography in Cassiopeia and Perseus on the Heart and Soul nebulae and the Double Cluster, which would have been located in the west-northwestern part of the sky at that time.  My location is in Northumberland and I am 55 degrees latitude.  

My gear used was a Canon 700D astro modded, Samyang 135mm f2, star adventurer 2i and the exposure length was 70s.

At 03:34:38 in the morning (the clocks went back that night so my camera read 04:34:38) I saw a bright green flash streak across the sky near the constellations I was shooting, I'm 100% certain it was a shooting star.  When I went to check my camera after it had finished the exposure it was on I saw the most recent image had a streak through it that was extremely bright, I think it is the shooting star I saw.  I'm trying to find a definitive answer however because i'm not certain if it was just a coincidence. 

It can't be the ISS because it wasn't visible from my location at the time of the photo, it looks absolutely nothing like a plane flying through an exposure, some people on other forums suggested a starlink train since there was a launch recently, however I checked a map of their satellites and they are almost all south of 55 degrees north and therefore surely don't appear in the northern side of the sky for me?  Also satellite trails tend to be really thin at the focal length I shoot at of 135mm and this streak is very thick, changes in thickness across the picture and turns from a single streak into multiple streaks within the same picture. I checked heavens-above.com for any possible bright satellites flying overhead at exactly that time through exactly that small part of the sky and there were none, however I'm not sure how comprehensive a list of satellites that site has.

I'll upload some images in varying states of processing, the streak is so bright that when the data is linear it is by far the brightest object in the picture and has a distinct yellowish colour to it.  When I did the starxterminator and created a star image it had a very distinct green colour to it too.

Attached are the Linear data that was calibrated in Pixinisight with PCC,

A stars only image that was colour calibrated > automatic background extraction > noisexterminator > SCNR > starxterminator > EZsoftstretch > slight saturation boost

The image as it appeard on my camera.  Note the top left corner where it splits into multiple lines, towards the middle of the line near the soul nebula there is a fuzziness coming off the line and at the very bottom centre of the line it becomes noticeably thinner.

IMG_1578.CR2

Edited November 1, 2022 by Spedz

[vlaiv]

Looks more like passing airliner.

Several light streaks are visible next to each other - which could be tail and wing fin lights. Also changing colors can indicate blinking lights.

[Tomatobro]

I agree with vlaiv. Definitely a aeroplane

[Elp]

Usually a shooting star unprocessed on camera looks like the image has been scratched with a fine needle in a line, it's a clean, sharply defined line which is very thin one end and getting slightly thicker then thinner again as it fades.

[Spedz]

9 hours ago, vlaiv said:

Looks more like passing airliner.

Several light streaks are visible next to each other - which could be tail and wing fin lights. Also changing colors can indicate blinking lights.

A plane is one of the things I'm sure it is not.  It's far too bright in the linear image and there aren't any blinking lights indicating wing or a tail lights.  The object in question is a solid line and ridiculously bright and there are more than 3 distinct lines in the section in question.  Is it possibly deorbiting space junk and if so do you know if there would be a way to confirm it?

I'll attach a comparison shot from the same night of a very bright plane in its linear state and as it appeared in the camera.

 

Edited November 1, 2022 by Spedz

[Spedz]

4 hours ago, Elp said:

Usually a shooting star unprocessed on camera looks like the image has been scratched with a fine needle in a line, it's a clean, sharply defined line which is very thin one end and getting slightly thicker then thinner again as it fades.

Is it possible that because I was imaging in a relatively narrow fov (relative to how long shooting stars can be) that I caught the middle section and the taper at the end of the fireball happened out of frame?  Most images of shooting stars you see are super widefield.

There is a very clear change in thickness at the end near the centre of the picture.

Edited November 1, 2022 by Spedz

[vlaiv]

46 minutes ago, Spedz said:

A plane is one of the things I'm sure it is not.  It's far too bright in the linear image and there aren't any blinking lights indicating wing or a tail lights.

Brightness of the streak depends on relative speed of object (as well as its brightness).

Airliner that is far away (high altitude) will slowly traverse the frame and it will leave brighter trail.

Image that you linked second is typical on lower flying airplane that is on approach to airport or getting ready to land (or maybe just took off). I used to get such trails when I was shooting at about 60-70Km from airport.

However, when airplane is much higher in the air - it is also much smaller and there is less distance between wing tips. Blinking will actually "join" to form wavy pattern rather than being separate dashes.

In any case, if you don't think it is an airplane and want to investigate further - here are some pointers.

Try calculating speed based on exposure length, direction of exposure and atmosphere thickness if you think it is space debris falling down. Then compare that with possible terminal velocity of such object.

Look at this website for info on satellites or other things that orbit:

https://www.heavens-above.com/

 

 

[Spedz]

I've checked that site extensively for any satellites that might have passed through my camera fov at both 03:34 and 04:34 ± 5 mins and there weren't any that passed anywhere close to the heart and soul nebulae (I'm not sure if that site accounted for clocks changing on that night so I checked both times).

Also it was a 70s exposure so if a plane was flying that high that its wing and tail lights became one line it would surely not cross the field of view in a single exposure.

[Leo S]

I agree. It looks like a bright meteor to me. I have come across very similar images of meteors in the past.

I suspect either this event, or this.

[Spedz]

2 minutes ago, Leo S said:

I agree. It looks like a bright meteor to me. I have come across very similar images of meteors in the past.

I suspect either this event, or this.

I've made a report to the United Kingdom Meteor Observation Network, waiting to hear back from them.

[vlaiv]

5 minutes ago, Spedz said:

Also it was a 70s exposure so if a plane was flying that high that its wing and tail lights became one line it would surely not cross the field of view in a single exposure.

That can be calculated.

We can take say 10Km as fight level - you can get alt/azimuth from time of recording, your location and target RA/DEC

We also have sensor size and lens FL - which will give us field of view

And so on...

If you suspect meteor (shooting star) - then color is important part of the puzzle as is multiple / single trails.

Meteor can not go from multiple to single trail, while airplane can (change of angle we look it at as it moves across the sky / any banking to execute heading adjustment).

Meteor can usually go from single streak to multiple as it falls apart from friction in atmosphere.

Color is indicator of temperature. Red/Orange/Yellow/white/blue - that is ascending temperature color - or this diagram:

Meteor usually heats up as it enters atmosphere.

From multiple / single streak point of view - logical trajectory of meteor would be from right to left (single streak to multiple)

From color point of view - logical trajectory of meteor would be from left to right (Red/orange towards white and bluish).

These two contradict each other.

[vlaiv]

Another important aspect of meteor is that it has uneven brightness. As it enters atmosphere it is slowed down. This change of velocity will produce change in brightness.

It can have relatively even brightness only if you captured part of its trajectory in FOV.

[Leo S]

7 minutes ago, vlaiv said:

Color is indicator of temperature. Red/Orange/Yellow/white/blue - that is ascending temperature color - or this diagram:

 

Not true. The colours in meteors are produced when elements are ionized. Each element corresponds to a specific wavelength of light emitted, depending on how much energy is input. Faster meteors for example are good at ionizing oxygen, which emits light @ 557.7 nm (green) higher up, and when they get lower down nitrogen is ionized producing red light. The elements within the meteoroid itself can also contribute (sodium, iron, magnesium, and calcium often have strong spectral lines), complicating the picture, but it seems they don't contribute significantly till the meteoroid has a large mass.

Velocity is also important, and will determine what colours are made. Some spectral lines are not strongly emitted unless there is enough energy input (the OIII forbidden emission line of oxygen mentioned above for example), and this is directly dependent on velocity.

This Orionid that one of my cameras recently captured has the classic green 557.7 emission that many of the faster meteors (eg. Leonids, and Perseids) have.

[vlaiv]

29 minutes ago, Leo S said:

Not true. The colours in meteors are produced when elements are ionized. Each element corresponds to a specific wavelength of light emitted, depending on how much energy is input. Faster meteors for example are good at ionizing oxygen, which emits light @ 557.7 nm (green) higher up, and when they get lower down nitrogen is ionized producing red light. The elements within the meteoroid itself can also contribute (sodium, iron, magnesium, and calcium often have strong spectral lines), complicating the picture, but it seems they don't contribute significantly till the meteoroid has a large mass.

Velocity is also important, and will determine what colours are made. Some spectral lines are not strongly emitted unless there is enough energy input (the OIII forbidden emission line of oxygen mentioned above for example), and this is directly dependent on velocity.

This Orionid that one of my cameras recently captured has the classic green 557.7 emission that many of the faster meteors (eg. Leonids, and Perseids) have.

I think we are talking about different things, but please do correct me if I'm wrong as I'm only applying common knowledge and don't have any specific details on processes involved.

You are talking about color of trail and not the color of "head".

In long exposure image - streak is formed by bright head - which is much brighter than the tail.

Here is screen shot from your video:

tail is indeed green as it consists out of ionized oxygen that is left in trail behind meteor itself - but we can clearly see that meteor itself is shining with yellow color - which would indicate temperature of about 5000K.

 

[Leo S]

2 hours ago, vlaiv said:

I think we are talking about different things, but please do correct me if I'm wrong as I'm only applying common knowledge and don't have any specific details on processes involved.

You are talking about color of trail and not the color of "head".

In long exposure image - streak is formed by bright head - which is much brighter than the tail.

Here is screen shot from your video:

tail is indeed green as it consists out of ionized oxygen that is left in trail behind meteor itself - but we can clearly see that meteor itself is shining with yellow color - which would indicate temperature of about 5000K.

 

My understanding of the process is that ionized plasma is generated at the head of the meteor, which is where most of the light is produced. This same plasma becomes the wake or train. So it's the same process generating light at the head, as it is in the wake/train, but emission of light is delayed in the wake/train depending on element in question. One of the great (still unanswered as far as I'm aware) questions in meteor science is how can the trains persist for so long - it should not be possible.

It does seem to be quite a complex picture of how colours are generated in some cases, with many factors that can influence it, so I certainly do not understand all the details.

Regarding the yellow -  a very "watered down" green, watered down by other emissions (see link I posted previously) at the red/orange end of the spectrum is likely the cause for that.

Edited November 1, 2022 by Leo S
typo

[Elp]

Isn't it just a case of matter burning at a high temperature? Like a spark is hot material which cools very quickly but you see the spark and it appears to disappear once it's cooled.

[Leo S]

14 hours ago, Elp said:

Isn't it just a case of matter burning at a high temperature? Like a spark is hot material which cools very quickly but you see the spark and it appears to disappear once it's cooled.

It's not quite that simple, but there are some similarities in processes going on I'm fairly sure. Thinking about this has made me realise that I don't have a deep understanding of exactly what is going on at an atomic scale when something burns or is heated, so I can't be 100% sure.

That said, what I do know, and have to point out here is that there is no combustion involved when a meteoroid enters the atmosphere. Although oxygen is present, there is not enough to support combustion - combustion is hard even at the top of Everest (a few km?), and we are talking 50-150 km for most meteors, and perhaps as low as ~10 km for the rarer deep-penetrating events.

In meteors light is essentially generated by their very high velocity, usually between 10-74 km/s. When a meteoroid slams into a molecule of air, that extreme speed translates to a very high energy impact - enough to split molecules into their ions (ionization). In this process electrons are raised into higher/unstable orbits around the nucleus, and when they decay back to their lower orbits, photons of specific wavelength are emitted, depending on which element is involved.

The process is more akin to what goes on in a neon sign tube, where very high voltages (lots of energy) is used to ionize neon gas, giving the characteristic colour/wavelength neon has.

Temperature has very little to do with it. Ions/plasma can exist at any temperature, but here in Earth's atmosphere (vs the vacuum of space) plasmas can't easily last except at high temperature (or with constant energy input like in a neon sign), so there has to be some temperature involved in these energetic processes. What is different is that for example, if you heat copper, it gives off a characteristic green. In the case of ionization, depending on the energy involved, the same element can be made to produce different wavelengths/colours - red and green for example. So colours in meteors essentially depend on the elements involved (meteoroid composition + air composition) AND velocity, with things like size also playing a part or at least influencing what is observed.

This means that meteor showers with different physical characteristics take on different characteristic colours/sequences of colours as thy pass through different layers of atmosphere that have different compositions of gas.

So fast meteors typically look like this Perseid (~59 km/s) I caught a few years back (see attached image "IMG_8957_cl"), starting out green (oxygen), then yellow (probably sodium, which is orange peaking through as levels of oxygen and nitrogen equal each other), and then red (nitrogen).

Because of their speed, Perseids become visible at around 110 km altitude, but slower speed meteors become visible much lower down in the atmosphere, and the colours are very different, essentially due to velocity (different high speed showers all tend to have the same colour profile for example). Here (attachment "JavorKac-TAH_2") is a tau Herculid (~14 km/s - not sure what altitude off hand, but it's under 85 km that they become visible IIRC) from this year's outburst for example - note this is NOT my image (credit to Javor Kac) and I'm posting without permission, but will be happy to remove it if required to do so:

There is probably more going on (I've observed colours that don't make sense), but I think in most cases the above fits the observations!

[Leo S]

One last image, again NOT mine (please let me know if it's yours and I'll be happy to remove it if you would like me to), but one of the images of bright meteors I came across and saved as it is a text book example. Looks like a good match for the OP's image IMHO.