I really like the Rubin because I think a lot of people focus too much on "deep" seeing (IE, looking at individual or several objects with very high magnification only once). The Rubin does much more "wide" seeing and this actually produces a ton of useful data- basically, enough data to collect reliable statistics about things. This helps refine cosmological models in ways that smaller individual observations cannot.
What's amazing to me is just how long it took to get to first photo- I was working on the design of the LSST scope well over 10 years ago, and the project had been underway for some time before that. It's hard to keep attention on projects for that long when a company can IPO and make billions in just a few years.
Deep is still interesting in understanding the origins of the universe. Rubin seems highly practical on the flip side. It'll be a super helpful tool in predicting asteroid impacts.
Also new planets! Planet Nine should likely be resolved within months, one way or another.
> "Probably within the first year we’re going to see if there’s something there or not,” says Pedro Bernardinelli, an astronomer at the University of Washington."
The image of the woman holding the model of the sensor is nice because it includes a moon for scale.
Question I was curious about is whether or not the focal plane was flat (it is).
This is an interesting tidbit:
> Once images are taken, they are processed according to three different timescales, prompt (within 60 seconds), daily, and annually.
> The prompt products are alerts, issued within 60 seconds of observation, about objects that have changed brightness or position relative to archived images of that sky position. Transferring, processing, and differencing such large images within 60 seconds (previous methods took hours, on smaller images) is a significant software engineering problem by itself. This stage of processing will be performed at a classified government facility so events that would reveal secret assets can be edited out.
They are estimating 10 million alerts per night, which will be released publicly after the previously mentioned assessment takes place.
>The prompt products are alerts, issued within 60 seconds of observation, about objects that have changed brightness or position relative to archived images of that sky position. Transferring, processing, and differencing such large images within 60 seconds (previous methods took hours, on smaller images) is a significant software engineering problem by itself.[64]
>This stage of processing will be performed at a classified government facility so events that would reveal secret assets can be edited out.
I expect a lot of events to get filtered that foreign governments expect to stay reasonably secret, even if they aren't friendly with the US. It's a game.
The thing that really saddens me is that the military gets to filter the data first and scientists only get to see the already manipulated data instead of a raw feed from their own instrument.
"Let's look for spy satellites / orbiters" was an "application" I wondered about. My second thought about this was: maybe the US (and possibly other countries) already have something like this, but classified?
If it has the potential to wipe out our entire species, but there's something we could do to prevent it (which I'm not sure about w/r/to asteroids), then it's worth looking out for the black swan event.
Doing some extremely rough math along these lines to double check myself:
* Gemini says that a dinosaur-extincting asteroid hits Earth about once every 100 million years. So in any given year that's 0.000001%.
* Economists say a human life is worth about 10 million dollars. There are about 8 billion people on Earth. So the total value of all human life is $80,000,000,000,000,000 (or 8e+16).
* So in any given year, the present value of asteroid protection is $800,000,000 (likelihood of an impact that year times value of the human life it would wipe out).
* The Guardian says the Vera Rubin telescope cost about $2,000,000,000 (2 billion).
By that measure, assuming the Rubin telescope prevents any dinosaur-extinction-level asteroid impacts, it will pay for itself in three years.
Back in January 2010 I went on a blind date with a lady who’s now my wife — an astrophysicist. We talked about this instrument and how Google would shuffle petabytes of raw observations, then distilling them into datasets researchers could actually use (don't know if Google is still involved?). We’ll celebrate 15 years of marriage this January, and I have been following the progress of this telescope since 2007 or so. It's amazing how long it takes for these instruments to come online, but the benefits are significant.
Here's the SDSS view[0] of this featured[1] section from the Virgo Cluster, in comparison, to put the staggering depth of these exposures in their proper context,
Thanks for the link, I didn't know one can do this with Aladin Lite!
But to be fair, if we compare to DESI LS, it looks much less impressive. I.e. all the shells/tidal debris are basically visible in DESI.
The amount of data this thing will be putting out every night is insane. For years now the community has been building the infrastructure to be able to efficiently consume it for useful science, but we still have work to do. Anyone interested in the problem of pipelining and distributing 10s of TB of data a night should check out the LSST and related GitHubs.
I've followed this project for over a decade and the amount of data they are moving around is fairly routine, given their budget size and access to computing and networking resources. The total storage (~40-50PB) is pretty large, but moving 10TB around the world isn't special engineering at this point.
It's not about the size of the data in bytes, it's also the amount of changes that need to be detected and alerts that need to be sent out (estimated at millions a night). Keep in mind the downstream consumers of this data are mostly small scientific outfits with extremely limited software engineering budgets.
I've worked on quite a few large-scale scientific collaborations like this (and also worked on/talked to the lead scientists of LSST) and typically, the end groups that do science aren't the ones handling the massive infrastructure. That typically goes to well-funded sites with great infrastructure who then provide straightforward ways for the smaller science groups to operate on the bits of data they care about.
Personally, I have pointed the grid folks (I used to work on grid) towards cloud, and many projects like this have a tier 1 in the cloud. The data lives in S3, metadata in some database, and use cloud provider's notification system. The scientists work in adjacent AWS accounts that have access to those systems and can move data pretty quickly.
So stoked for this observatory to go online! One cool uses it'll excel at is taking "deltas" between images and detect moving stuff. Close asteroids is one obvious goal, but I'm more interested in the next Oumuamua / Borisov like objects that come in from interstellar space. It would be amazing to get early warnings about those, and be able to study them with other powerful telescopes we have now.
(For those who haven't noticed, you can just simply paste 186.66721+8.89072 or whichever target you're curious about in an astronomy database like Aladin[0], and there right-click on "What is this?")
They look like they're roughly in the same plane. Is it safe to assume they're roughly in the same plane, or could they be really distant along the line of sight? The similarity in size makes me think they are, but I don't have any reason to be confident in that judgment.
Every set of deep field imagery reminds me that any point of light we see could be a star, a galaxy, or a cluster of galaxies. The universe is unimaginably vast.
For observatories like Rubin, is there a plan for keeping them open after the funding ends? Is it feasible for Chile to take over the project and keep it going?
On a practical note, what happens to a facility like this if one day it's just locked up? Will it degrade without routine maintenance, or will it still be operational in the event someone can put together funding?
Even one zoom-in and I find something interesting.
What's that faint illuminated tendril extending from M61 (the large spiral galaxy at the bottom center of the image) upwards towards that red giant? It seems too straight and off-center to be an extension of the spiral arm.
EDIT: The supposed "Tidal tail" on M61 was evidently known from deep astrophotography, but only rarely detected & commented upon.
The zoomed images look grainy as one would expect from raw data, but I would have expected them to do dark field subtraction for the chips to minimize this effect. Does anyone know if that's done (or expressly avoided) in this context, or why it might not be as helpful (e.g., for longer exposures)?
Those are diffraction spikes, caused by how the light interacts with the support structure holding the secondary mirror. Each telescope has different patterns, hubble, jwst, etc. I think they only happen for stars, and not for galaxies (an easy way to know which is which), but I might be wrong on that (there's a possibility for faint stars not to have them IIRC).
This one's extra-special! The pattern is multiple + shapes, rotated and superimposed on top of each other. And they're different colors! That's this telescope's signature scanning algorithm—I don't know what that is, but, it's evident it takes multiple exposures, in different color filters, with the image plane rotated differently relative to the CCD plane in each exposure. I assume there's some kind of signal processing rationale behind that choice.
edit: Here's one of the bright stars, I think it's HD 107428:
This one has asteroid streaks surrounding it (it's a toggle in one of the hidden menus), which gives a strong clue about the timing of the multiple exposures. The asteroids are going in a straight line at a constant speed—the spacing and colors of the dots shows what the exposure sequence was.
I think this quote explains the reason they want to rotate the camera:
> "The ranking criteria also ensure that the visits to each field are widely distributed in position angle on the sky and rotation angle of the camera in order to minimize systematic effects in galaxy shape determination."
https://arxiv.org/abs/0805.2366 ("LSST [Vera Rubin]: from Science Drivers to Reference Design and Anticipated Data Products")
No, they happen for absolutely every externally-generated pixel of light (that is, not for shot noise, or firelflies that happen to fly between the mirrors). Where objects subtend more than one pixel, each pixel will generate it's own diffraction patterns, and the superposition of all are present in the final image. Of course, each diffraction pattern is offset from the next, so they mostly just broaden (smear out), not intensify.
However, the brightness of the diffraction effects is much lower than the light of the focused image itself. Where the image is itself dim, the diffraction effects might not add up to anything noticeable. Where the image supersaturates the detector (as can happen with a 1-pixel-wide star), the "much lower" fraction of that intensity can still be annoyingly visible.
The same effect is used for Bahtinov focusing masks. From what i know, all light will bend around the structures, but stars are bright and focused enough to see; in theory galaxies would too
"Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."
“Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.” -Douglas Adams
I really like the Rubin because I think a lot of people focus too much on "deep" seeing (IE, looking at individual or several objects with very high magnification only once). The Rubin does much more "wide" seeing and this actually produces a ton of useful data- basically, enough data to collect reliable statistics about things. This helps refine cosmological models in ways that smaller individual observations cannot.
What's amazing to me is just how long it took to get to first photo- I was working on the design of the LSST scope well over 10 years ago, and the project had been underway for some time before that. It's hard to keep attention on projects for that long when a company can IPO and make billions in just a few years.
It does wide through image stacking/repeated visits. The speed and FOV is the key here.
Deep is still interesting in understanding the origins of the universe. Rubin seems highly practical on the flip side. It'll be a super helpful tool in predicting asteroid impacts.
Also microlensing events, supernovae, and many other things in our very dynamic universe.
Also new planets! Planet Nine should likely be resolved within months, one way or another.
> "Probably within the first year we’re going to see if there’s something there or not,” says Pedro Bernardinelli, an astronomer at the University of Washington."
https://www.nationalgeographic.com/science/article/is-there-...
nice
Or detecting more unusual interstellar objects like 'Oumuamua.
The wikipedia article is quite good - https://en.wikipedia.org/wiki/Vera_C._Rubin_Observatory (Edit: Treasure trove of details in the references if any of your interests are adjacent to this)
The image of the woman holding the model of the sensor is nice because it includes a moon for scale.
Question I was curious about is whether or not the focal plane was flat (it is).
This is an interesting tidbit:
> Once images are taken, they are processed according to three different timescales, prompt (within 60 seconds), daily, and annually.
> The prompt products are alerts, issued within 60 seconds of observation, about objects that have changed brightness or position relative to archived images of that sky position. Transferring, processing, and differencing such large images within 60 seconds (previous methods took hours, on smaller images) is a significant software engineering problem by itself. This stage of processing will be performed at a classified government facility so events that would reveal secret assets can be edited out.
They are estimating 10 million alerts per night, which will be released publicly after the previously mentioned assessment takes place.
>The prompt products are alerts, issued within 60 seconds of observation, about objects that have changed brightness or position relative to archived images of that sky position. Transferring, processing, and differencing such large images within 60 seconds (previous methods took hours, on smaller images) is a significant software engineering problem by itself.[64]
>This stage of processing will be performed at a classified government facility so events that would reveal secret assets can be edited out.
Interesting, I'm guessing secret spy satellites?
it’s spy satellites (mainly domestic). In some cases, they don’t actually need to be removed, just embargoed until orbital change.
I expect a lot of events to get filtered that foreign governments expect to stay reasonably secret, even if they aren't friendly with the US. It's a game.
The thing that really saddens me is that the military gets to filter the data first and scientists only get to see the already manipulated data instead of a raw feed from their own instrument.
"Let's look for spy satellites / orbiters" was an "application" I wondered about. My second thought about this was: maybe the US (and possibly other countries) already have something like this, but classified?
The US already has a very sophisticated system for this.
https://en.wikipedia.org/wiki/United_States_Space_Surveillan...
.. and aliens, of course ...
The asteroid detection capability is amazing: https://rubinobservatory.org/news/rubin-first-look/swarm-ast...
And supernovae: https://m.youtube.com/watch?v=Ch18t9cz-JU&pp=ygUETHNzdA%3D%3...
Among many other uses: https://m.youtube.com/watch?v=h6QYjNjivDE
That is likely the most unexcitedly unsettling video I have ever seen. Amazing storytelling really.
I was just coming back to comment on the existential dread elicited by that video.
Whoa that's incredible.
(And amazing production of the actual video as well)
Pretty sure you can see some kind of masking for satellites in some of the frames of the asteroid videos.
This is really going to revolutionize our ability to detect and predict asteroid impact.
And just in the nick of time!
Wow, they should have led with this.
Which also tells the astronomical low odds of asteroids hitting earth even with “so many” of them. To me it changes nothing
If it has the potential to wipe out our entire species, but there's something we could do to prevent it (which I'm not sure about w/r/to asteroids), then it's worth looking out for the black swan event.
Doing some extremely rough math along these lines to double check myself:
* Gemini says that a dinosaur-extincting asteroid hits Earth about once every 100 million years. So in any given year that's 0.000001%.
* Economists say a human life is worth about 10 million dollars. There are about 8 billion people on Earth. So the total value of all human life is $80,000,000,000,000,000 (or 8e+16).
* So in any given year, the present value of asteroid protection is $800,000,000 (likelihood of an impact that year times value of the human life it would wipe out).
* The Guardian says the Vera Rubin telescope cost about $2,000,000,000 (2 billion).
By that measure, assuming the Rubin telescope prevents any dinosaur-extinction-level asteroid impacts, it will pay for itself in three years.
https://www.npr.org/transcripts/835571843
Back in January 2010 I went on a blind date with a lady who’s now my wife — an astrophysicist. We talked about this instrument and how Google would shuffle petabytes of raw observations, then distilling them into datasets researchers could actually use (don't know if Google is still involved?). We’ll celebrate 15 years of marriage this January, and I have been following the progress of this telescope since 2007 or so. It's amazing how long it takes for these instruments to come online, but the benefits are significant.
Here's the SDSS view[0] of this featured[1] section from the Virgo Cluster, in comparison, to put the staggering depth of these exposures in their proper context,
[0] https://aladin.cds.unistra.fr/AladinLite/?target=12%2026%205...
[1] https://rubinobservatory.org/gallery/collections/first-look-...
With an opacity slider, for easy comparison:
https://aladin.cds.unistra.fr/AladinLite/?baseImageLayer=CDS...
Thanks for the link, I didn't know one can do this with Aladin Lite! But to be fair, if we compare to DESI LS, it looks much less impressive. I.e. all the shells/tidal debris are basically visible in DESI.
The amount of data this thing will be putting out every night is insane. For years now the community has been building the infrastructure to be able to efficiently consume it for useful science, but we still have work to do. Anyone interested in the problem of pipelining and distributing 10s of TB of data a night should check out the LSST and related GitHubs.
I've followed this project for over a decade and the amount of data they are moving around is fairly routine, given their budget size and access to computing and networking resources. The total storage (~40-50PB) is pretty large, but moving 10TB around the world isn't special engineering at this point.
It's not about the size of the data in bytes, it's also the amount of changes that need to be detected and alerts that need to be sent out (estimated at millions a night). Keep in mind the downstream consumers of this data are mostly small scientific outfits with extremely limited software engineering budgets.
Again, nothing special. The small outfits aren't going to be doing the critical processing.
…they do the science
I've worked on quite a few large-scale scientific collaborations like this (and also worked on/talked to the lead scientists of LSST) and typically, the end groups that do science aren't the ones handling the massive infrastructure. That typically goes to well-funded sites with great infrastructure who then provide straightforward ways for the smaller science groups to operate on the bits of data they care about.
Here's the canonical example: https://home.cern/science/computing/grid and a lab that didn't have enough horsepower using a different grid: https://osg-htc.org/spotlights/new-frontiers-at-thyme-lab.ht...
Personally, I have pointed the grid folks (I used to work on grid) towards cloud, and many projects like this have a tier 1 in the cloud. The data lives in S3, metadata in some database, and use cloud provider's notification system. The scientists work in adjacent AWS accounts that have access to those systems and can move data pretty quickly.
Is this not the same problem high resolution spy satellites have? Seems like a fair bit of crossover at least?
Spy sats are more bandwidth and power constrained. For low earth, you also can’t usually offload data over the target.
So stoked for this observatory to go online! One cool uses it'll excel at is taking "deltas" between images and detect moving stuff. Close asteroids is one obvious goal, but I'm more interested in the next Oumuamua / Borisov like objects that come in from interstellar space. It would be amazing to get early warnings about those, and be able to study them with other powerful telescopes we have now.
> So stoked for this observatory to go online!
Second this, but other areas are of great interest too. Kuiper Belt discoveries and surveys FTW!
Counter-rotating spiral galaxies. Super neat! https://skyviewer.app/embed?target=186.66721+8.89072&fov=0.2...
> "?target=186.66721+8.89072"
(For those who haven't noticed, you can just simply paste 186.66721+8.89072 or whichever target you're curious about in an astronomy database like Aladin[0], and there right-click on "What is this?")
[0] https://aladin.cds.unistra.fr/AladinLite/?target=12%2026%204...
I wonder if there's some kind of gravitational lensing going on. A lot of the galaxies look similar, but in different orientations.
https://skyviewer.app/embed?target=186.66721+8.89072&fov=0.2...
https://skyviewer.app/embed?target=185.46019+4.48014&fov=0.6...
https://skyviewer.app/embed?target=188.49629+8.40493&fov=1.3...
(Quick side note, if you go to /explorer instead of /embed you can zoom out so you can see the whole image at once)
https://skyviewer.app/explorer?target=187.69717+12.33897&fov...
That is interesting!
They look like they're roughly in the same plane. Is it safe to assume they're roughly in the same plane, or could they be really distant along the line of sight? The similarity in size makes me think they are, but I don't have any reason to be confident in that judgment.
Those are NGC 4411 a+b and they're indeed right next to each other,
https://noirlab.edu/public/images/iotw2421b/ ("thought to be right next to each other — both at a distance of about 50 million light-years")
What's going on directly above with what looks to be 3-4 galaxies interacting?
something green: https://skyviewer.app/embed?target=186.82033+8.25479&fov=0.0...
Every set of deep field imagery reminds me that any point of light we see could be a star, a galaxy, or a cluster of galaxies. The universe is unimaginably vast.
For observatories like Rubin, is there a plan for keeping them open after the funding ends? Is it feasible for Chile to take over the project and keep it going?
On a practical note, what happens to a facility like this if one day it's just locked up? Will it degrade without routine maintenance, or will it still be operational in the event someone can put together funding?
Even one zoom-in and I find something interesting.
What's that faint illuminated tendril extending from M61 (the large spiral galaxy at the bottom center of the image) upwards towards that red giant? It seems too straight and off-center to be an extension of the spiral arm.
EDIT: The supposed "Tidal tail" on M61 was evidently known from deep astrophotography, but only rarely detected & commented upon.
My God, it's full of stars
brings up that old paradox - should any line of sight ultimately end up at a star?
https://en.wikipedia.org/wiki/Olbers%27s_paradox
The zoomed images look grainy as one would expect from raw data, but I would have expected them to do dark field subtraction for the chips to minimize this effect. Does anyone know if that's done (or expressly avoided) in this context, or why it might not be as helpful (e.g., for longer exposures)?
Seems this will be done on the 'nightly' release cadence. Found on page 11 in this doc that I found from the wikipedia page:
https://docushare.lsstcorp.org/docushare/dsweb/Get/LSE-163/L...
I was surprised by how many lensed objects I could spot.
Related: https://www.nytimes.com/2025/06/23/science/vera-rubin-scient...
(via https://news.ycombinator.com/item?id=44352455, but no comments there)
https://skyviewer.app/
Why are there lens-flare-like artifacts around some of the bright objects?
Those are diffraction spikes, caused by how the light interacts with the support structure holding the secondary mirror. Each telescope has different patterns, hubble, jwst, etc. I think they only happen for stars, and not for galaxies (an easy way to know which is which), but I might be wrong on that (there's a possibility for faint stars not to have them IIRC).
> "Each telescope has different patterns"
This one's extra-special! The pattern is multiple + shapes, rotated and superimposed on top of each other. And they're different colors! That's this telescope's signature scanning algorithm—I don't know what that is, but, it's evident it takes multiple exposures, in different color filters, with the image plane rotated differently relative to the CCD plane in each exposure. I assume there's some kind of signal processing rationale behind that choice.
edit: Here's one of the bright stars, I think it's HD 107428:
https://i.ibb.co/HTmP0rqn/diffraction.webp
This one has asteroid streaks surrounding it (it's a toggle in one of the hidden menus), which gives a strong clue about the timing of the multiple exposures. The asteroids are going in a straight line at a constant speed—the spacing and colors of the dots shows what the exposure sequence was.
I think this quote explains the reason they want to rotate the camera:
> "The ranking criteria also ensure that the visits to each field are widely distributed in position angle on the sky and rotation angle of the camera in order to minimize systematic effects in galaxy shape determination."
https://arxiv.org/abs/0805.2366 ("LSST [Vera Rubin]: from Science Drivers to Reference Design and Anticipated Data Products")
No, they happen for absolutely every externally-generated pixel of light (that is, not for shot noise, or firelflies that happen to fly between the mirrors). Where objects subtend more than one pixel, each pixel will generate it's own diffraction patterns, and the superposition of all are present in the final image. Of course, each diffraction pattern is offset from the next, so they mostly just broaden (smear out), not intensify.
However, the brightness of the diffraction effects is much lower than the light of the focused image itself. Where the image is itself dim, the diffraction effects might not add up to anything noticeable. Where the image supersaturates the detector (as can happen with a 1-pixel-wide star), the "much lower" fraction of that intensity can still be annoyingly visible.
The same effect is used for Bahtinov focusing masks. From what i know, all light will bend around the structures, but stars are bright and focused enough to see; in theory galaxies would too
Those are stars, they create those lens flares because they are so bright.
All the dim fuzzy objects are galaxies much further away.
"Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."
Jesus H Christ, the Universe is big.
“Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.” -Douglas Adams
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Sometimes I feel like a diatom floiting in the ocean
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