A Briefly Famous Star (and calibrating the JWST) - Sixty Symbols
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- Опубликовано: 19 мар 2022
- An unassuming star is thrust into the spotlight during calibration of the James Webb Space Telescope.
More links and info below ↓ ↓ ↓
Featuring Professor Mike Merrifield.
Mike's Twitter: / astromikemerri
The JWST website: www.jwst.nasa.gov
The star is 2MASS J17554042+6551277
Deep Sky Videos: / deepskyvideos
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More Professor Merrifield talking about JWST please
More, of every single one of them, please.
Yes and yes!
More Professor Merrifield talking about anything....
Yes please, Nottingham alumni represent
🥺 please
Great video
Destin!
If you say so i have to agree! 😅👍
why hello there!
Dustin!
Your videos are great too Destin!
I think a fun fact from an engineering perspective that was left out is that the focusing is done by physically deforming the mirror segments, not just by rotating them about an axis. Often we think of the mirrors as this static, large flat piece (i.e. the hubble mirror) but these ones can be deformed microscopically to adjust for any errors.
Oh. So they can correct themselves without another corrective lens, like Hubble had to have (not that there is a place for any lens in JWST)? Or just to adjust angles?
@@OmateYayami Hubble uses corrective aspherical mirrors, not a lens. Webb will never need anything like that (or have the budget to install it anyway, a million miles from Earth), precisely because it can change the curvature and orientation of its own mirror segments remotely. Of course, if Hubble's primary mirror had been ground correctly in the first place, it also wouldn't have needed later correction.
@@EebstertheGreat Thanks, I dunno why I thought it's a lens. I also thought problem was surface roughness, to the cruvature, thus I wondered how complex JSWT make it's mirror surface. Physical intervention on a system that is like 3x the moon distance is not going to be as easy as visiting ISS. It has to be robust enough on it's own.
@@OmateYayami 🌍👍🤝
🌍👍🤝
Since lots of stars have lots of different name (Arcturus, for instance has seven) poor old J17554042 should obviously get the additional name *_JWST1_* .
How about Calibrator?
@@klausolekristiansen2960 That sounds like a He-Man villain. Calibrator: Evil Master of Geometry!
@@klausolekristiansen2960 Or perhaps Garrus :)
Arcturus has far more than seven names as it was known to many cultures. However, the only officially-recognised (by the International Astronomical Union) one is Arcturus. It is also known by many catalogue designations (the most widely known is probably α Boötis). Most stars have no names, just various designations. 2MASS J17554042+6551277 has two other designations. '2MASS' signifies it is an entry in the Two Micron All-Sky [infra-red] Survey; 'J' refers to the Julian reference epoch, and the numbers are the co-ordinates -- right ascension and then declination (the '+' indicates it is in the Northern celestial hemisphere) - of the star's position in the sky.
Yes!
Prof Merrifield: "This is a boring star deserving of its obscurity."
Aliens living on a planet orbiting that star: "HEY! >:("
'Mostly harmless'
They won't get the message for 2000 years. By then, humans will be extinct.
First thing I noticed were the galaxies as well, and I was amazed at just how much detail they still have in a crappy jpeg version of the image.
Glad You talked about telescope artifacts - this is the first time I've seen it explained.
I agree...the spikes were the first question I had!
This is why I came here, glad it's covered
I would guess that they will process them out in the final images.
@@self-transforming_machine-elf kkkkooookook ooh k kkkkooookook kk KKK of o kk KKK on k on of kk KKK of kkkkooookookok of of course k kkkkooookooko kk OVH k ooh ooh ooh kkkk of
@@self-transforming_machine-elf kokoookkokokokkokokookkkoo
"Has it got a name?"
"No, it's got a telephone number."
Well we should ring it then
Right now, that star is getting 5 calls a day: "Stop, don't hang up. The IRS has issued a warrant for your arrest. Press 1 now to learn how you can...."
Wouldn't it be funny if around that star there was an Earth-like planet, with a human-like civilisation, who are calibrating a Webb-like telescope on Sol?
spiderman pointing at himself
347 years from now we're looking at this comment and wondering how you made such an accurate prediction. We visited their planet and shared our knowledge.
telling themselves, that it is a rather nondescript uninteresting star ;o)
UNDERRATED COMMENT
LOL
I love the 6-symmetry of the diffraction spikes. it makes for an interesting variation from the 4-symmetry I see from a lot of other telescopes
Telescopes with three vanes will produce six diffraction spikes. They are not uncommon with many of the cheaper newtonian telescopes.
@@NGC6144 I'm sure I'd see more of that if I were better acquainted with the amateur astronomy scene. Perhaps someday
My points of comparison are mainly the published photos collected from large observatory telescopes -- which if memory serves most frequently show 4 spikes.
Nah mate, it's just ugly. I'd rather have no spikes at all.
Love listening to Professor Merrifield.
for a calibration image to look that spectacular - what we will see this year will blow the worlds mind - I'm excited.
I think forever more it should simply be known as Webb's Star.
My thoughts exactly!
It was chosen because there are very few bright stars in the field of view that would influence or negatively impact calibration of the optics and sensors.
Sixty Symbols is back!
With all the terribleness going on in the world, it's nice that there is some positive, happy news that even folk who know nothing about the subject can celebrate.
Hey man, don’t jinx it!
I was thinking the same thing. This telescope is one of the few things allowing me to retain some hope for the human species.
Stop watching the news
When even such a boring star makes such a pretty picture, then there is much to expect from the JWST.
The calibration images that my printers make rarely make my jaw drop like this. Amazing achievement by the whole team!
And this also shows really well that delaying a project to perfect it CAN actually pay off BIG time. I'm glad they took the time they needed.
What an exciting time for astronomy!
It's been an exciting time for astronomy for the past hundred years.
@@michaelsommers2356 Well I wasn't alive 100 years ago, hence my current excitement.
@@michaelsommers2356 Ii is only getting exciter.
@@S.... Yet another space telescope is more exciting that discovering that the Milky Way is not the only galaxy?
@@JCW7100 Neither was I alive back then, but I can imagine the excitement of discovering that there are other galaxies out there.
OMG, i was hoping you would have a video on this and there it is!
From now on that star shall be called THE CALIBRATOR!
The diffraction spikes are mathematically definable, so image processing should be able at least reduce them considerably, if not eliminate them.
That's what I was thinking the first images of Jupiter were very ordinary until they were processed. It may improve after they get the over all convexity of the mirror perfect, what amazes me is they could null out any rotation of the space craft so perfectly.
Also, as they said, most of what they will eb observint is much dimmer/farther away, so the spikes will be much less prominent on most JWST images of interest.
But would software be able to reconstruct what they may be obscuring?
@@bobschaaf2549 Surprisingly, yes. You derive the exact amplitude shape of the radials and mathematically null it. You don't just blot out the bright bits that are lines. Small details that were hidden by them appear. It is almost like magic.
@@donepearce I think it's more complicated than that, you deconvolve and basically collect the light for every point from its own spikes.
It's been a while since I've watched your videos, but boy they are still great!
Wouldn’t it be ironic if at some point in the distant future we find life at that star
Yes
iirc it's one of plot in Liu Cixin's Three Body Problem series. The unremarkable star turned out to have a habitable planet. It's in 2nd / 3rd book. It would be interesting if real life follows fiction.
@tom louis - I was thinking the same thing.
except everything in that photo is at least 2,000 years in the past. The galaxies much more than that.
"Do you see anything?"
"I see wonderful things!"
That picture truly is something special, and marks the start of a new era. Can't wait for what comes next, like all the redshifted galaxies furthest away we couldnt see before.
Been waiting decades for that photo from JWST. Worth it
I'm a simple man... I see Sixty Symbols... I click!
Breaking taps has made a wonderful video about those pistons behind the mirror segments.
We should call it Webb's Star! 🌟
it finally cooled down enough to calibrate, looking forward to more pics, with so many more primary mirrors and their surface area being so much more than Hubble the photos should be astounding.
I am obsessed with space. Don’t know how I’m finding a channel today but better late than never. I cannot wait for when James Webb is putting out photos on a daily basis and everyone is making videos about them. I think some pictures are just going to be unimaginable.
10:11
I was waiting for him to address this the whole time.
It's the only thing I could see!
I fall asleep listening to sixty symbols videos for 8 years now 🤷🏻♂️
This was a very informative and all around excellent video about the jwst. Thank you very much for making it and to Professor Merrifield for the explanations. I appreciated the immense detail about each step as I have not heard this information from other sources before. Please keep up the great work as I check out your other videos.
I think they should rename this the Discovery Star.
Can't wait to see what we are about to discover.
thanks' so much fur clearing out this diffraction issue! I was getting worried..
That star won't be forgotten, now that we've been told to forget about it.
All stars were famous
His enthusiasm is infectious
Exciting times indeed. I look forward to the years ahead with Webb.
I believe it's possible to remove the spikes from the picture by computing a deconvolution if you determine the impulse response of the telescope and know the approximate distance to the star you observe.
I'm not sure if I saw this in the last video of Dr. Becky or Launchpad Astronomy, but if you try to correct it you end up with a different kind of artifact...
Thanks for the update!
Can't wait to see a JWST Deep Field shot
Thank you for the explanation. This is most informative, and exciting.
These videos are always the best! Thank you :))
Professor Merrifield refers to the actuators as 'pistons'. However, the actuators operate by turning a lead screw, similar to the read/write head of a DVD drive being moved by a lead screw. It is the *thread* on the actuator rod that transfers the turns of the servo motors to the mirror section.
The word piston is appropriate in the context of, say, hydraulic pistons, in which oil pressure is used to transfer force.
So it's safe to say the use of the term pistons has made you a bit pistoff?
@@jhonbus 👏👏👏
The lead screw is the coarse alignment mechanism. But there is also a flexing structure inside it that you could potentially referee to as a piston
The word piston is entirely accurate.
A piston is displaced by any number of methods, including threaded rod. It may be change in pressure of gas or liquid, volumetric phase change of solid/liquid (wax motor), or a connecting rod which changes position by offset rotating shaft.
@@wiregold8930 I checked encyclopic descriptions. The word 'piston' is consistently described as a part that fits in some cilinder with small tolerance (often achieved with piston rings) such that the piston is either moving fluid (liquid or gas), making it a pump, or is being moved by fluid, making it an engine part.
Obviously Professor Merrifield was using the word 'piston' generically for any part that, while guided in some sleeve, moves another part. The point is: the more generic word is 'actuator'.
Mirrors having 7 axis of movement is a curious reality. There was a lovely video on how the actuators can work with fine and corpse adjustments by using a single motor. And then having 3 of them in a delta configuration to give 6 axis.
What also surprised me is that there were galaxies resolved in the same image and some researchers attempted to do science on them.
Amazing upgrade to astronomy!
Fascinating (and moving, too).
The most interesting thing about this picture is not the star itself but all the galaxies visible in the background
Being waiting 20 years,this is a exciting moment for mankind.
Amazing..cant wait for more discovery 👍👍
The JWST star should now be known as "PM Clement Attlee"- after Winston Churchill's famous quip:
"Atlee; is a modest man; indeed, he has much to be modest about..."
Thanks well explained enjoyed watching
I love this!! I'm so excited for jwst to show off.
I suggest we try to rename 2MASS J17554042+6551277 to “The Parker Star”. As it is a star and it has put in a lot of effort to become a star but not made it all the way to something worth naming.
Helt enig!
What like the Parker solar probe
ie it is JWST a star
..its the goldie locks star....just right...:D
That first image is awesome.
We aint seen nothing yet.
This is truly amazing!
Yeesss I was hoping for this exact video!
Great video.
I feel breathless when I look at this uncalibrated picture and see the crazy detail of 100 galaxies already lol
Thank you !
I'm gonna make it my life mission! Loved it!
Great video 👍
Can’t wait for images of galaxies.
Was thinking the same thing about all the galaxies you can see in the background...it's insane!
Very nice.
Thank you.
"It's stardom as a star..." Classic.
Brilliant!
Surely, if the physics of the diffraction spikes is so well known; you could write a piece of software to analyse the data from the scope to subtract the diffraction effects.
Yes by a process called deconvolution, it is definitely possible, but a little computationally intensive. In this instance it is not useful because there is information in the spikes. If you look closely the spikes feature diffraction patterns. I'm pretty sure they must have used those for extra-precise calibration.
Since they know the shape of the mirror, they can somewhat remove the diffraction pattern, but it mathematically only works perfectly in certain circumstances and only without the presence of noise. Real images always have noise, so the process of removing the diffraction artifacts is always going to destroy some information and only be "close" to the real image.
I bet you that star is gonna turn out to be incredibly and inconceivably remarkable.
That's what you get for trash talking it.
Thank you
Can’t wait to zoom in on the raw images late at night 😂
It's the David Mitchell of stars. A star so unremarkable that it in itself is remarkable.
Having 30 years of preparations is paying off
I must admit, surprisingly very interesting news!
I'm really confused about the spikes, doesn't 3 legs create 6 spikes in an hexagonal pattern exactly like the 6 created by the mirror geometry ? why the legs create just a single spike ?
edit: I just now realized that the 2 bottom legs are not symmetric with the middle leg, they are aligned with the edge of the hexagonal mirrors, that means the diffraction spike they create is aligned with the spike created by the mirror geometry, meaning the extra 2 (or 4) spikes are there but behind the other spikes. but since the middle leg is aligned with the line of the hexagons, it creates a spike between the two edge spikes
its a spider!
Yea, you figured it out.
Spot on with your edit! I was frustrated that he explained it incorrectly (or at least over simplified it a bit for the audience). Presumably he knows his Fourier optics :). He also made it sound like the full shape of the mirror causes the main spikes but looking at the angles makes it very clear that it's due to the individual segment edges.
Would love to see more JWST content
In honour of the telescope that calibrated on it, I think we should name it the James' Star or James Webb Star.
It all worked out better than expected.
thank you
JWST made that star a Star of stars
We've seen your star on the Webb and have come to calibrate you!
Amazing
Coherent 🌞
They should continue to use that star for any future telescope calibrations to make it famous as the calibration star.
hahahaha "it's got a telephone number." that's a great way to put it.
If JWST comes back to this star I wonder how tiny radial velocities it would detect. How small of a planet at what distance?
Send all the politicians there boring start boring planet.
Thank you for asking about the spikes. I guess they will have a way to filter out the spikes?
Probably try not to aim at such a bright star.
11:21 We can be Heroes, just for one day
I’ve meant so much in a few minutes.. All in layman’s terms, a perfect fit for me.
Thanks.
Once JWST is focused, does it stay fixed or will there ever be situations where they have to adjust the focus? Thank you as always Prof. Merrifield for a clearly explained and entertaining video.
The telescope is focused at infinity, no need to adjust between observations. They'll check the calibration every few months to check for drift.
The star used for calibration is called HD 84406 (featured in all black and white photos). The final image taken with a red filter is a different star 2MASS J17554042+6551277 (much dimmer than HD 84406). I assume the original star was too bright and it saturated the JWST sensors after calibration was done, so they opted for another dimmer star in order for the final image to look nicer.
They used about 25 different stars during calibration, with HD 84406 as the first and ..77 as the last.
Looking forward to seeing and hearing about more planet Discovery and I read an Interesting article about A possible Dark universe with Time that goes backwards and not forwards. I've seen U.F.Os as A child so I'm open to an infinite universe.
that must have been an intense job being on the committee to pick out the most perfect, average star for the job. no pressure 🤣
~2000 light years away, that means this image might have been fired off whilst ol JC was flippin tables 💖
Wonder if they cut down the outer portion of hexagonal mirron & made that round would that have helped to get pic without any spike .