APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

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APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by APOD Robot » Mon Dec 27, 2021 5:05 am

Image Comet Leonard behind JWST Launch Plume

Explanation: Which one of these two streaks is a comet? Although they both have comet-like features, the lower streak is the only real comet. This lower streak shows the coma and tail of Comet Leonard, a city-sized block of rocky ice that is passing through the inner Solar System as it continues its looping orbit around the Sun. Comet Leonard has recently passed its closest to both the Earth and Venus and will round the Sun next week. The comet, still visible to the unaided eye, has developed a long and changing tail in recent weeks. In contrast, the upper streak is the launch plume of the Ariane V rocket that lifted the James Webb Space Telescope (JWST) off the Earth two days ago. The featured single-exposure image was taken from Thailand, and the foreground spire is atop a pagoda in Doi Inthanon National Park. JWST, NASA's largest and most powerful space telescope so far, will orbit the Sun near the Earth-Sun L2 point and is scheduled to start science observations in the summer of 2022.

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by Major Oz » Mon Dec 27, 2021 6:46 am

Launch plume from.............Thailand ??

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by Ann » Mon Dec 27, 2021 7:30 am


Who would have guessed that the JWST launch plume is like a spherical planetary nebula with stuff going on inside it? :D

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by XgeoX » Mon Dec 27, 2021 11:48 am

Nice catch Ann!

At first glance I thought I was looking at Paris :ssmile:

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by orin stepanek » Mon Dec 27, 2021 1:53 pm

CometJwst_Matipon_1080.jpg
Nice catch by the photographer! :D
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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by neufer » Mon Dec 27, 2021 3:56 pm

APOD Robot wrote:
Mon Dec 27, 2021 5:05 am

Explanation: In contrast, the upper streak is the launch plume of the Ariane V rocket that lifted the James Webb Space Telescope (JWST) off the Earth two days ago. The featured single-exposure image was taken from Thailand, and the foreground spire is atop a pagoda in Doi Inthanon National Park.>>
The last stage of the Ariane V rocket stopped firing at about 1,000 km altitude over East Africa
and might possibly have still been seen some 30º (= cos-1[R/(1000+R)]) further East.

So is this a composite of a photo of the launch plume of the Ariane V rocket taken
(from Africa?) somehow Thai'd in with a comet Leonard photo from Thailand :?:
https://en.wikipedia.org/wiki/Thai_National_Observatory wrote:
<<Thai National Observatory (TNO) is in Doi Inthanon National Park, Chom Thong District, Chiang Mai Province, Thailand A top Thailand's highest mountain, Doi Inthanon, this observatory is part of the National Astronomical Research Institute of Thailand, and is its main facility. The TNO has of two sections—the main observatory, and an auxiliary station lower on the mountain with offices and lodging for astronomers, facilities for public outreach activities (like school groups), and a small permanent exhibition for the public. Because the observatory is located in a national park, it was built to minimize environmental impact.>>
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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by Dsamva » Mon Dec 27, 2021 4:53 pm

As I understand it, the boost phase of the Ariane 5 completed 26 minutes after launch at about 1000km altitude over Africa. How did people see the “plume” in Thailand?? I would think the plume would be below the western horizon in Thailand.

Does anyone know the exact time and exact location that the photo was taken?

Is this a composite photo?

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by jfgout » Mon Dec 27, 2021 4:55 pm

neufer wrote:
Mon Dec 27, 2021 3:56 pm
The last stage of the Ariane V rocket stopped firing at about 1,000 km altitude over East Africa
and might possibly have still been seen some 30º (= cos-1[R/(1000+R)]) further East.

So is this a composite of a photo of the launch plume of the Ariane V rocket taken
(from Africa?) somehow Thai'd in with a comet Leonard photo from Thailand :?:
Not sure at all about that. There seems to be quite a few other pictures showing the plume from Thailand.

I suspect that the plume remains visible for some time after the burn ends. During that stage of the flight, the JWST's altitude was increasing very quickly. So, it might not have taken too long after the end of the burn for it to become visible from Thailand?
I also seem to remember from the stream that the upper stage was supposed to perform a small burn after separation (to avoid any risk of collision?). Maybe what we see is the result of this burn?

Anyways, I see no evidence that this image is a composite. There are plenty of bad composite out there, let's not blame the pictures that are actually true single shot images!

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by jfgout » Mon Dec 27, 2021 5:02 pm

The author gave more information on facebook: https://www.facebook.com/photo.php?fbid ... 865&type=3

Very little doubt in my mind: this is a real, single shot image. And a great one!

(Unlike this one for example: https://apod.nasa.gov/apod/ap211025.html)

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by neufer » Mon Dec 27, 2021 8:31 pm

jfgout wrote:
Mon Dec 27, 2021 4:55 pm
neufer wrote:
Mon Dec 27, 2021 3:56 pm

The last stage of the Ariane V rocket stopped firing at about 1,000 km altitude over East Africa
and might possibly have still been seen some 30º (= cos-1[R/(1000+R)]) further East.

So is this a composite of a photo of the launch plume of the Ariane V rocket taken
(from Africa?) somehow Thai'd in with a comet Leonard photo from Thailand :?:
Not sure at all about that. There seems to be quite a few other pictures showing the plume from Thailand.

I suspect that the plume remains visible for some time after the burn ends. During that stage of the flight, the JWST's altitude was increasing very quickly. So, it might not have taken too long after the end of the burn for it to become visible from Thailand?
I also seem to remember from the stream that the upper stage was supposed to perform a small burn after separation (to avoid any risk of collision?). Maybe what we see is the result of this burn?

Anyways, I see no evidence that this image is a composite. There are plenty of bad composite out there, let's not blame the pictures that are actually true single shot images!
The JWST itself (not the Ariane) was supposed to have its first burn at around launch time plus 12 hours (i.e., just prior to sunrise at the Thai National Observatory in Doi Inthanon National Park). Since burns are most effective near perigee (i.e., maximum velocity) presumably the JWST has almost completed its ~12 hr orbit #1 and is getting its first perigee boost to a higher orbit.
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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by jfgout » Mon Dec 27, 2021 9:36 pm

neufer wrote:
Mon Dec 27, 2021 8:31 pm
The JWST itself (not the Ariane) was supposed to have its first burn at around launch time plus 12 hours (i.e., just prior to sunrise at the Thai National Observatory in Doi Inthanon National Park). Since burns are most effective near perigee (i.e., maximum velocity) presumably the JWST has almost completed its ~12 hr orbit #1 and is getting its first perigee boost to a higher orbit.
Sure, but this is not relevant to this picture. Clearly, the picture was taken in the evening (comet Leonard visible), so this is not the JWST MCB1a.

Not sure why you are having so much trouble believing that this picture shows the final burn from the Arian 5 upper stage...

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by neufer » Mon Dec 27, 2021 10:25 pm

jfgout wrote:
Mon Dec 27, 2021 9:36 pm
neufer wrote:
Mon Dec 27, 2021 8:31 pm

The JWST itself (not the Ariane) was supposed to have its first burn at around launch time plus 12 hours (i.e., just prior to sunrise at the Thai National Observatory in Doi Inthanon National Park). Since burns are most effective near perigee (i.e., maximum velocity) presumably the JWST has almost completed its ~12 hr orbit #1 and is getting its first perigee boost to a higher orbit.
Sure, but this is not relevant to this picture. Clearly, the picture was taken in the evening (comet Leonard visible), so this is not the JWST MCB1a.

Not sure why you are having so much trouble believing that this picture shows the final burn from the Arian 5 upper stage...
  • Because, the Ariane shouldn't have been visible from Thailand some 55º further East:
neufer wrote:
Mon Dec 27, 2021 3:56 pm

The last stage of the Ariane V rocket stopped firing at about 1,000 km altitude over East Africa
and might possibly have still been seen some 30º (= cos-1[R/(1000+R)]) further East.
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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by Pon » Mon Dec 27, 2021 11:23 pm

Hi, the original photographer here. Allow me to explain some of the issues that have been raised.

The image was shot exactly at 12:57 UTC from Chiang Mai, Thailand. The coordinate is (if anybody's asking): 18.55387688510697, 98.48196698124625

Yes, this is a single shot. Barely any processing was done on this image. Besides the overall adjustment there was only one brushing tool to lower the overblown highlight of the plume.

And yes, the plume indeed belong to Ariane 5 that boosted JWST. I've shot another Ariane 5 from this same location before (750 m away, to be exact). You can actually find it from past APOD https://apod.nasa.gov/apod/ap140212.html. So when I heard of JWST launch being 19:20 local time, I knew that it's within the right window to see JWST and comet at the same time. I had already planned to go there to shoot comet at some point anyway so I arranged for that date hoping to see both. Although, I figured it would be highly improbable for both of them to line up in the same shot. Boy, am I glad to be wrong.

Now, on to the question: How is it possible that the rocket that ended over Africa is seen by Thailand? You're right to ask that question. I had the exact same question when I first spotted the rocket 7 years ago. The answer is that you're not seeing the upper stage of JWST as it BURNS. You saw the upper stage after it has already separated from JWST. What you see in this image is not JWST itself, but the spent upper stages and its exhaust.

You see, the purpose of the upper stage is to boost JWST to elliptical trajectory to reach L2, after which JWST will gain enough velocity to just coast there. (Let's keep in mind that in order to do so it must also do some crazy maneuver tilting down towards the atmosphere to graze it a bit, too) Now, right at separation both the upper stage and JWST would have the exact same trajectory. Since there was no other burns that's going to happen until the first course correction some 12 hours later, the upper stage would also have the same elliptical trajectory that JWST has, minus some kick it gained during separation. This along with all the rocket engine exhaust would just float along with JWST, and that's exactly what was seen all across Thailand. (It made quite a headline over here).

What I observed with naked eye was a bright comet-like object traveling almost head on from SW direction. West made sense because rocket were coming from French Guiana. And South, because we are slightly North of the equator. First it had a highly visible circular plasma "envelope", likely from atmospheric glow from the exhaust shocked into it. Then it drifted upward rather quickly (satellite speed) and as it does the plasma envelope just fade away. Then it slowly drifted upwards towards constellation Cetus and slowly fade away. I kept tracking it with my telescope (that I brought to shoot Leonard) for a while before I stopped. It disappeared almost straight up from where we were. This kind of make sense considering it was doing elliptical trajectory with apogee aimed at L2, it would have to "depart" Earth somewhere on the night side, but towards the terminator. So perhaps something like 20:00 local time which was exactly when it was observed.

It's definitely once-in-a-lifetime experience (and a crazy amazing shot to get). I don't think I'll ever be able to observe comet Leonard with JWST launch ever again!
Last edited by Pon on Tue Dec 28, 2021 2:03 am, edited 1 time in total.

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by Pon » Mon Dec 27, 2021 11:29 pm

I've attached some photos of the images that were also shot that night. Here are some close up of the (spent) upper stage rocket and its plume. The plume is probably lit by sunlight but you can also see the glowing heat from the rocket engine as it spiraled out of control.
_DSC1196.jpg
_DSC1233.jpg
_DSC1237.jpg
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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by johnnydeep » Tue Dec 28, 2021 12:19 am

On the “where is JWST now” link, the ruler shows the distance from L2 as much less than the indicated 29 percent that the number shows. Am I reading this wrong?

158F04D3-4FDC-4B77-BA65-E3EA74AE0B5A.jpeg
EDIT: D’oh! Yes I am - the ruler shows days not distance! Post left undeleted as a testament to my stupidity.
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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by RJN » Tue Dec 28, 2021 1:06 am

FYI today's APOD and image were featured in an article in the Daily Mail.

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by alter-ego » Tue Dec 28, 2021 1:50 am

Pon, nice response to the questions. I was similarly puzzled about what we're looking at in your image. I also was thrown by the listed facebook time (7:12pm, 8 min before launch :). I had your location, and the sky field looked right, and the comet was the key to nailing down the day (Dec 25). I decided, that if no other plumes occurred, the only sensible answer was the plume must have traveled with/near JWST. I also thought its relatively large size was consistent with a burn occurring earlier.
My last question (which I now may know the answer to) is: How did the plume get to 25° altitude in 10 minutes? Separation occurring 55° SE of you puts the plume well below your horizon. Ten minutes isn't enough time it seems. I think the answer is, at separation, the altitude (above sea level) was increasing very fast. In the last minute before separation, the altitude was changing at 216 km/min. You said the actual image time was 12:57 UTC (10 minutes after separation). This works out to be ~2100 km change in altitude, and a subsequent 4600 km change in horizontal distance (assuming travel stays linear). Bottom line, the position change after 10 minutes brings the plume well into Thailand's view.

Thanks for the details, Pon. I understand the image, and what a good catch it was!
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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by Pon » Tue Dec 28, 2021 1:59 am

alter-ego wrote:
Tue Dec 28, 2021 1:50 am
Pon, nice response to the questions. I was similarly puzzled about what we're looking at in your image. I also was thrown by the listed facebook time (7:12pm, 8 min before launch :). I had your location, and the sky field looked right, and the comet was the key to nailing down the day (Dec 25). I decided, that if no other plumes occurred, the only sensible answer was the plume must have traveled with/near JWST. I also thought its relatively large size was consistent with a burn occurring earlier.
My last question (which I now may know the answer to) is: How did the plume get to 25° altitude in 10 minutes? Separation occurring 55° SE of you puts the plume well below your horizon. Ten minutes isn't enough time it seems. I think the answer is, at separation, the altitude (above sea level) was increasing very fast. In the last minute before separation, the altitude was changing at 216 km/min. You said the actual image time was 12:57 UTC (10 minutes after separation). This works out to be ~2100 km change in altitude, and a subsequent 4600 km change in horizontal distance (assuming travel stays linear). Bottom line, the position change after 10 minutes brings the plume well into Thailand's view.

Thanks for the details, Pon. I understand the image, and what a good catch it was!
I think you might also be forgetting the curvature of the Earth. The Greeks noticed that ship's pole poke above the horizon way before the ship does. Well this pole happens to be hundreds of kilometers tall. And we're talking about things that are many thousands kilometers away, the curvature definitely matters here.

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by alter-ego » Tue Dec 28, 2021 2:32 am

johnnydeep wrote:
Tue Dec 28, 2021 12:19 am
On the “where is JWST now” link, the ruler shows the distance from L2 as much less than the indicated 29 percent that the number shows. Am I reading this wrong?


158F04D3-4FDC-4B77-BA65-E3EA74AE0B5A.jpeg

EDIT: D’oh! Yes I am - the ruler shows days not distance! Post left undeleted as a testament to my stupidity.
Stupidity is not at play here at all. Misreading an occasional technical graph is common. I'm constantly reminding myself not to make assumptions!
In this case, my first thought is to choose the more precise numbers. The digital distance numbers yield the simplest and most accurate result:
[259172]/[259172+639536.5] = 28.83827%
:)
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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by alter-ego » Tue Dec 28, 2021 3:06 am

Pon wrote:
Tue Dec 28, 2021 1:59 am
alter-ego wrote:
Tue Dec 28, 2021 1:50 am
Pon, nice response to the questions. I was similarly puzzled about what we're looking at in your image. I also was thrown by the listed facebook time (7:12pm, 8 min before launch :). I had your location, and the sky field looked right, and the comet was the key to nailing down the day (Dec 25). I decided, that if no other plumes occurred, the only sensible answer was the plume must have traveled with/near JWST. I also thought its relatively large size was consistent with a burn occurring earlier.
My last question (which I now may know the answer to) is: How did the plume get to 25° altitude in 10 minutes? Separation occurring 55° SE of you puts the plume well below your horizon. Ten minutes isn't enough time it seems. I think the answer is, at separation, the altitude (above sea level) was increasing very fast. In the last minute before separation, the altitude was changing at 216 km/min. You said the actual image time was 12:57 UTC (10 minutes after separation). This works out to be ~2100 km change in altitude, and a subsequent 4600 km change in horizontal distance (assuming travel stays linear). Bottom line, the position change after 10 minutes brings the plume well into Thailand's view.

Thanks for the details, Pon. I understand the image, and what a good catch it was!
I think you might also be forgetting the curvature of the Earth. The Greeks noticed that ship's pole poke above the horizon way before the ship does. Well, this pole happens to be hundreds of kilometers tall. And we're talking about things that are many thousand kilometers away, the curvature definitely matters here.
Indeed, in detail, I took spherical geometry into account assuming a constant altitude (which is not correct). Assuming a constant, 1392-km separation-altitude and 10-min earlier image time, the plume was not visible. After incorporating the constant dv/dt approximations into the hybrid spherical analysis as a bookend calculation, I realized there was a path to explaining your image, likely overestimating the plume's elevation with the hybrid analysis. Anyway, that's as far as I wanted to pursue that calc since the details were getting complicated. After reading your account, I was enough convinced the image made sense, so I ended the exercise.
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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by Pon » Tue Dec 28, 2021 3:33 am

alter-ego wrote:
Tue Dec 28, 2021 3:06 am
Pon wrote:
Tue Dec 28, 2021 1:59 am
alter-ego wrote:
Tue Dec 28, 2021 1:50 am
Pon, nice response to the questions. I was similarly puzzled about what we're looking at in your image. I also was thrown by the listed facebook time (7:12pm, 8 min before launch :). I had your location, and the sky field looked right, and the comet was the key to nailing down the day (Dec 25). I decided, that if no other plumes occurred, the only sensible answer was the plume must have traveled with/near JWST. I also thought its relatively large size was consistent with a burn occurring earlier.
My last question (which I now may know the answer to) is: How did the plume get to 25° altitude in 10 minutes? Separation occurring 55° SE of you puts the plume well below your horizon. Ten minutes isn't enough time it seems. I think the answer is, at separation, the altitude (above sea level) was increasing very fast. In the last minute before separation, the altitude was changing at 216 km/min. You said the actual image time was 12:57 UTC (10 minutes after separation). This works out to be ~2100 km change in altitude, and a subsequent 4600 km change in horizontal distance (assuming travel stays linear). Bottom line, the position change after 10 minutes brings the plume well into Thailand's view.

Thanks for the details, Pon. I understand the image, and what a good catch it was!
I think you might also be forgetting the curvature of the Earth. The Greeks noticed that ship's pole poke above the horizon way before the ship does. Well, this pole happens to be hundreds of kilometers tall. And we're talking about things that are many thousand kilometers away, the curvature definitely matters here.
Indeed, in detail, I took spherical geometry into account assuming a constant altitude (which is not correct). Assuming a constant, 1392-km separation-altitude and 10-min earlier image time, the plume was not visible. After incorporating the constant dv/dt approximations into the hybrid spherical analysis as a bookend calculation, I realized there was a path to explaining your image, likely overestimating the plume's elevation with the hybrid analysis. Anyway, that's as far as I wanted to pursue that calc since the details were getting complicated. After reading your account, I was enough convinced the image made sense, so I ended the exercise.
Actually, now that I think about it, the curvature would only made the altitude worse, not the other way around... So my mistake on pointing it out. I didn't look carefully into your details (I have no need to. I was there to see it in person after all) but I assume your math is probably correct.

But you're right to be skeptical about authenticity of my image, or any image really (we should all be). I get annoyed by all those "fake" images, too. Sometimes I just wish an average layman is a bit more skeptical about the images they are sharing. Even more so against photographers who flat out lie about how they obtain their images. A composite is a composite, there's no shame in admitting it.

And I don't really mind being called a "fake". Honestly, I consider it among the greatest form of flattery.

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by jfgout » Tue Dec 28, 2021 3:45 am

neufer wrote:
Mon Dec 27, 2021 10:25 pm
jfgout wrote:
Mon Dec 27, 2021 9:36 pm
neufer wrote:
Mon Dec 27, 2021 8:31 pm

The JWST itself (not the Ariane) was supposed to have its first burn at around launch time plus 12 hours (i.e., just prior to sunrise at the Thai National Observatory in Doi Inthanon National Park). Since burns are most effective near perigee (i.e., maximum velocity) presumably the JWST has almost completed its ~12 hr orbit #1 and is getting its first perigee boost to a higher orbit.
Sure, but this is not relevant to this picture. Clearly, the picture was taken in the evening (comet Leonard visible), so this is not the JWST MCB1a.

Not sure why you are having so much trouble believing that this picture shows the final burn from the Arian 5 upper stage...
  • Because, the Ariane shouldn't have been visible from Thailand some 55º further East:
neufer wrote:
Mon Dec 27, 2021 3:56 pm

The last stage of the Ariane V rocket stopped firing at about 1,000 km altitude over East Africa
and might possibly have still been seen some 30º (= cos-1[R/(1000+R)]) further East.
Maybe I should have written "shows the aftermath of the final burn". It's true that the burn itself was already finished when this picture was taken. But the JWST, Ariane 5's upper stage and all the gases around it don't just disappear when the burn ends :) They keep on going on their trajectory (as the author of the image explained) and became visible from Thailand a few minutes after the end of the burn.

jf

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by johnnydeep » Tue Dec 28, 2021 2:31 pm

I didn't follow all the technical back and forth discussion above, and maybe I missed it, but what's the significance of the plume being surrounded by an almost perfect sphere, seemingly centered on the point of the cone of what I would call the plume proper?

jwst plume from tailand.JPG
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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by Pon » Tue Dec 28, 2021 3:57 pm

johnnydeep wrote:
Tue Dec 28, 2021 2:31 pm
I didn't follow all the technical back and forth discussion above, and maybe I missed it, but what's the significance of the plume being surrounded by an almost perfect sphere, seemingly centered on the point of the cone of what I would call the plume proper?


jwst plume from tailand.JPG
That would be the glow of plasma in the atmosphere. I would guess it's the upper atmosphere being shocked by the rocket exhaust glowing. It glow into a very noticeable sphere even to the naked eye. Looked like a giant cloud or something. It got brighter, bigger, and then slowly fade away. The bigger part probably came from it being closer to us, and fading away is probably due to the plume gaining altitude being much farther away from the atmosphere.

A lot of these explanation is my personal speculation, but it's definitely not lens artifact as it was visible to the naked eye. Maybe someone could dig up explanation someone else mentioned from other rocket launch?

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Re: APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

Post by neufer » Tue Dec 28, 2021 7:38 pm

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