What the heck was that!

[Leo S]

From Twitter, it's looking like it was either Russian Angara or Chinese Longmarch 2C rocket.

I've uploaded a clip from my camera. It starts off at ISO 25600 but I upped that by a notch to 32000 (which was probably overkill looking back on it). Unfortunately I lost it as it went behind the house, although I did go out of the front to continue to observe it visually. My wife also got some mobile phone footage at that point, which I have yet to see.

Watch: https://vimeo.com/704874126
Download: https://vimeo.com/user83167831/download/704874126/d0506bcbfe

Equipment/settings: Sony a7SII + Sigma Art 20/1.4 @ f1.4 - 1/30s, ISO 25600/32000, 30 FPS - Ninja V recorder/monitor recording in 4K pro-res, Slog2 (vivid setting set on camera).

[JeremyS]

Seems there might have been two events: https://britastro.org/forums/topic/spacecraft-burn-propellant-dump-at-2306-ut-2022-04-29

[Astro Noodles]

Sounds like it was very busy out there last night.  People firing rockets all over the sky.

Unfortunately I missed it as I was indoors for a few minutes. 🙄

[SuburbanMak]

4 hours ago, wulfrun said:

I'll be happy to know if anyone can give a definitive answer, I'm intrigued & it was an odd sight. First glance I thought "the moon looks seriously hazy" then a double-take because it couldn't be the moon!

Pretty much exactly my experience - was out in a very isolated spot alone & was slightly freaked for a few minutes by it’s “otherness”.  Was pretty sure it wasn’t a ground-based light & had a “noctilucent cloud” like quality to it.   Like you I noted it’s similarity to the moon viewed through cloud, the angular size I think similar, but know there was neither moon nor cloud so added to the sense that something odd was going on… 

[Jp114]

5 hours ago, wulfrun said:

I'll be happy to know if anyone can give a definitive answer, I'm intrigued & it was an odd sight. First glance I thought "the moon looks seriously hazy" then a double-take because it couldn't be the moon!

I saw this too, I was kicking myself for not grabbing a camera before it faded. 

[Jonk]

I've gone back and had a look at the images for this and yep, I have it too!

Here's an animation and startrails.

 

[DavidR100]

Sounds like what I saw - a faintish disc of light about 2 degrees across (fingertip width) that travelled north from the vicinity of Polaris through the eastern side of Perseus before it disappeared over the horizon, taking about 3 minutes from 00:07 to 00:10.  Looking through binoculars I saw a central bright dot surrounded by a halo filled with fainter light.  Viewed from North Wales.

At around 2 degrees across, the light disc was 3 or 4 times the diameter of the full moon, and easily the biggest night time celestial light source I can remember seeing, excluding the Milky Way and Aurora Borealis!

Thanks Leo S for the explanation, video and links.

This is my first "deorbit burn" in countless hours of night sky observing.  Bet I see another next time out!  At least I'll not be spooked...

Edited May 1, 2022 by DavidR100

[Leo S]

You're welcome David.

It was also a first for me to see something like this, although I have seen similar footage before, and I did observe a Dragon supply craft over the UK back in about 2014 if memory serves, but that was devoid of the fuel/exhaust cloud which accompanied the craft this time.  Without the "cloud" this would probably have gone unnoticed. I have specialized in observing meteors/fireballs for 20+ years, so I'm always after a good view of the sky with minimal obstruction, and have also notched up a fair few hours. I guess it's a sign of the times that these things are becoming more common. There was another similar occurrence over mainland Europe just over two weeks ago.

[PhotoGav]

I caught this event on my all sky camera too, here are the composite still and the whole night's video.

Amazing to hear that it was the deorbit burn / fuel dump from the Russian Angara rocket mission to place the Kosmos 2555 satellite in orbit. So, what exactly has happened here? Has the third stage of the Angara lit its engines to consume all the fuel before reentering the atmosphere or has it just dumped its fuel to make it less dangerous as it comes back to Earth?

 

 

 

 

[DavidR100]

From the Twitter link supplied by Leo S it would appear to be a deorbit burn.  I'm no expert, but it's easier to imagine hot exhaust gases generating light rather than cold dumped gas doing so.

Leo S's link to the DPREVIEW forum contained an interesting link to CENAP, a German site for registration of unknown phenomena in the sky (AKA UFOs, but I guess they have a bad rap).  Before searching Stargazerslounge I unsuccessfully googled for a UK version of CENAP.  The nearest I could find were sites for reporting meteors and fireballs, which interestingly is where Leo S is coming from, though his useful links were in a different direction!

I now suspect that orbiting crafts/rockets/stages, without plumes, have accounted for several unexplained phenomena I have seen over the years - typically a surprisingly bright point of light (to the naked eye) travelling in a straight line across the sky at an approximately constant speed.

Edited May 2, 2022 by DavidR100

[Chaz2b]

Personally I reckon you lot are taking/ consuming something! What ever it is….can I have some?!

chaz

Edited May 2, 2022 by Chaz2b

[skybadger]

Here's my contribution to this - seen from RIseley in South Berks /Hampshire border south of Reading, at 29 April 2302 to 2309Z. 

North is 20 degrees from top towards E, South is 20 degrees from bottom towards W.

All SKy camera takes exposures for 5 seconds every 5 seconds with a 50ms delay for read from an ASI 120mm camera. 

I'll have a fully annotated video once ASC processes it. 

 

2022Apr29 2302_2309Z 2nd stage capture.avi (205MB)

 

 

Edited May 2, 2022 by skybadger
Added avi embedded

[Leo S]

5 hours ago, DavidR100 said:

From the Twitter link supplied by Leo S it would appear to be a deorbit burn.  I'm no expert, but it's easier to imagine hot exhaust gases generating light rather than cold dumped gas doing so.

Leo S's link to the DPREVIEW forum contained an interesting link to CENAP, a German site for registration of unknown phenomena in the sky (AKA UFOs, but I guess they have a bad rap).  Before searching Stargazerslounge I unsuccessfully googled for a UK version of CENAP.  The nearest I could find were sites for reporting meteors and fireballs, which interestingly is where Leo S is coming from, though his useful links were in a different direction!

I now suspect that orbiting crafts/rockets/stages, without plumes, have accounted for several unexplained phenomena I have seen over the years - typically a surprisingly bright point of light (to the naked eye) travelling in a straight line across the sky at an approximately constant speed.

The clouds of gas these events generate are not self-luminous, and would not be visible if they were not illuminated by sunlight.

While this particular event was a surreal experience to behold, it slightly pales in comparison compared to others, like this launch for example:

 

Probably the leading authority on these type of events is James Oberg, who is an ex-NASA employee. Among other things, his report on the "Norway Spiral" incident is worth a look if these type of phenomena interest you.

Can you be sure the "point of light" you observed was not a meteor? Assuming it was not just an ordinary satellite too..

[DavidR100]

3 hours ago, Leo S said:

The clouds of gas these events generate are not self-luminous, and would not be visible if they were not illuminated by sunlight.

While this particular event was a surreal experience to behold, it slightly pales in comparison compared to others, like this launch for example:

 

Probably the leading authority on these type of events is James Oberg, who is an ex-NASA employee. Among other things, his report on the "Norway Spiral" incident is worth a look if these type of phenomena interest you.

Can you be sure the "point of light" you observed was not a meteor? Assuming it was not just an ordinary satellite too..

 

Well I did say I wasn't an expert!  I know a little more now though, thanks.

Next time I'll know to just momentarily salute the passing space vehicle and then resume my galaxy hunting.

[PhotoGav]

11 hours ago, Leo S said:

The clouds of gas these events generate are not self-luminous, and would not be visible if they were not illuminated by sunlight.

So… I am still not completely clear as to how these events occur, what exactly is going on? (The video you linked to is amazing!) Is this correct: The rocket stage in question activates an engine burn to alter its orbit to bring it back down to Earth. The burn involves production of a substantial quantity of exhaust gases that are illuminated by sunlight and hang eerily in the sky, shining away to create a display for us here on Earth?!

[Leo S]

9 hours ago, PhotoGav said:

So… I am still not completely clear as to how these events occur, what exactly is going on? (The video you linked to is amazing!) Is this correct: The rocket stage in question activates an engine burn to alter its orbit to bring it back down to Earth. The burn involves production of a substantial quantity of exhaust gases that are illuminated by sunlight and hang eerily in the sky, shining away to create a display for us here on Earth?!

Yes, that is essentially it. Ice crystals/moisture reflecting sunlight. It's similar to NLCs, albeit the source is different.

[DavidR100]

5 hours ago, Leo S said:

Yes, that is essentially it. Ice crystals/moisture reflecting sunlight. It's similar to NLCs, albeit the source is different.

NLCs - Noctilucent Clouds (I had to look it up).

Here's a quote from the Wikipedia article on NLCs: "They are most often observed during the summer months from latitudes between ±50° and ±70°. Too faint to be seen in daylight, they are visible only when the observer and the lower layers of the atmosphere are in Earth's shadow, but while these very high clouds are still in sunlight."

That description fits our situation very well.

Further down the article: "In August 2014, a SpaceX Falcon 9 also caused noctilucent clouds over Orlando, Florida after a launch".

How the pieces fit together.

Leo S - you know some stuff!

Edited May 3, 2022 by DavidR100

[Leo S]

1 hour ago, DavidR100 said:

NLCs - Noctilucent Clouds (I had to look it up).

Here's a quote from the Wikipedia article on NLCs: "They are most often observed during the summer months from latitudes between ±50° and ±70°. Too faint to be seen in daylight, they are visible only when the observer and the lower layers of the atmosphere are in Earth's shadow, but while these very high clouds are still in sunlight."

That description fits our situation very well.

Further down the article: "In August 2014, a SpaceX Falcon 9 also caused noctilucent clouds over Orlando, Florida after a launch".

How the pieces fit together.

Leo S - you know some stuff!

David, I'd like to think I have a basic working knowledge of all known atmospheric phenomena. I probably got into astronomy by the most unorthodox route possible - after it rained fireballs for most of the night of Nov. 16 1998! That got me started on meteors/fireballs, and if you observe meteors properly (from somewhere with good/great all round views) you tend to catch more stuff going on up there in the sky than others (this event we are discussing here is a good example), so I have tried to arm myself with as much knowledge about what goes on up there as possible, as I don't like getting caught out! Plus it's a fascinating/much overlooked part of our environment, considering it completely surrounds us - many of the less common phenomena are still understudied, and there are still mysteries to solve.

I'm nearing the limit in my knowledge of rocket exhaust/fuel dump phenomena, but my understanding is that liquid oxygen is or was the fuel of choice for rockets, and oxygen + hydrogen produces H2O (not sure where the H comes from?), so water ice crystals are likely what we are seeing with the Falcon 9 launches. In the case of satellites, they usually use hydrazine (sp?) propellant, which I presume would also create H2O (?), but if this was a satellite fuel-dump before being deorbited then the cloud we saw would just be liquid hydrazine I guess.

There are also many connections between even unrelated atmospheric phenomena, which in my experience leads from one thing to another, so I keep finding myself getting sidetracked from my main interest, meteors, to things like this. For example, NLC's are normally seeded with the fine particles that are left behind when a meteor ablates in our atmosphere.

[PhotoGav]

Excellent stuff, thank you for the various explanations and thoughts.

As for NLCs, they are one of the finest displays we can enjoy here on Earth! We are now entering the time of year when they occur, so fingers crossed for a few displays over the coming couple of months.

Regarding rocket propellant, Leo, the fuel is liquid hydrogen (or kerosene in the case of the Russians) that is mixed with the oxidising agent, liquid oxygen, to give much combustion, expelling exhaust gases, serious thrust and some H2O!

[Leo S]

On 04/05/2022 at 06:55, PhotoGav said:

Excellent stuff, thank you for the various explanations and thoughts.

As for NLCs, they are one of the finest displays we can enjoy here on Earth! We are now entering the time of year when they occur, so fingers crossed for a few displays over the coming couple of months.

Regarding rocket propellant, Leo, the fuel is liquid hydrogen (or kerosene in the case of the Russians) that is mixed with the oxidising agent, liquid oxygen, to give much combustion, expelling exhaust gases, serious thrust and some H2O!

Thanks for filling in some of the blanks Gav.

Agree that NLCs are a beautiful sight. I managed to image a couple of strong displays in the past few years, and they seem to get stronger every year.