Giant, all-seeing telescope is set to revolutionize astronomy

https://www.science.org/content/article/giant-all-seeing-telescope-set-revolutionize-astronomy

by gammarator • 1 year ago

192 67 1 year ago

science.org

gnabgib• 1 year ago

Discussion a year ago (75 points, 22 comments) https://news.ycombinator.com/item?id=39927682

taylorportman• 1 year ago

The mirror coating timelapse video is pretty awesome https://www.youtube.com/watch?v=Gg9UPS7ndRA

fastball• 1 year ago

Why is the substrate glass? Lack of reactivity? Ability to remove imperfections? As a layman with almost zero knowledge of telescope construction, I feel like a heavy amorphous solid would not be my first choice for the base layer underneath the reflective/mirror coating.

idontwantthis• 1 year ago

Has this not been affected by USA science cuts?

viraptor2• 1 year ago

It's been over 10 years since they started. I don't know what the funding details are, but overall this is not really working on a scale that 5 months would change.

hermitcrab• 1 year ago

It looks like the current administration may kill other projects mid-mission:

"Among the other programs set to lose funding are a craft already on its way to rendezvous with an asteroid that's expected to pass close to Earth in 2029, and multiple efforts to map and explore the acidic clouds of Venus. Researchers worry that abandoning missions would mean investments made by earlier generations might be lost or forgotten."

https://phys.org/news/2025-06-trump-dozens-nasa-missions-thr...

So I'm not sure any US government-funded science project is safe.

IAmBroom5• 1 year ago

The time the tree has spent growing is only loosely correlated with the time it takes to fell it.

perihelions2• 1 year ago

No, but its space-based counterpart was cancelled (the 2.4 meter wide-field survey telescope).

https://en.wikipedia.org/wiki/Nancy_Grace_Roman_Space_Telesc...

zanecodes• 1 year ago

It has not been cancelled as of now, the cancellation has only been proposed, not passed.

walrus01• 1 year ago

Is there a figure somewhere on how many TB of images this will produce per day when running in automated sky survey mode?

Jgrubb• 1 year ago

The vast archive, growing by 20 terabytes each night, will after 1 year contain more optical astronomy data than that produced by all previous telescopes combined.

9dev• 1 year ago

73 PB over the full runtime of the survey. That’s a nice new datacenter filled to the brim with images.

ethan_smith• 1 year ago

The Rubin Observatory will generate approximately 20TB of raw image data per night, with an annual data production of about 15PB for the 10-year survey.

blop2• 1 year ago

I found this pdf presentation with lots of great technical details about data management and a devops infra oriented view of this telescope: https://ci-compass.org/assets/602137/2025jan23_cicompass_rub...

Worth a read for the devops guys around here!

  - about 20TB per day, around 100PB expected for the whole survey
  - 0.5PB ceph cluster for local data
  - workloads on 20 nodes kubernetes cluster/argocd
  - physical infra managed with puppet/ansible
  - 100Gbs(+40Gs backup) fiber connection to US-based datacenter for further processing

Melatonic• 1 year ago

Insanity - love it

newpavlov2• 1 year ago

I wonder if they could reduce the data size at rest by using specialized compressing techniques. Your probably could build an averaged "model" of the sky observed by the telescope (probably with account for stellar parallax and bright planets) and store only compressed diffs, not full images.

But I guess, since storage is relatively cheap, it's simply impractical to bother with such complexity.

blop2• 1 year ago

actually the telescope devops guys were hiring a couple years ago on HN: https://news.ycombinator.com/item?id=38101085 :-D

viraptor2• 1 year ago

Q for astronomy people: This is tracking the sky movement as it takes the pictures right? Also, with the atmosphere moving, is there a limit of how large the telescope can be and take photos from earth, before it can't get more quality?

ddahlen3• 1 year ago

The atmosphere is always an issue, we can correct for many of the effects using adaptive optics, but there are always limits. The advantage you get from going bigger on the ground is that you are making a bigger "bucket" to put photons in. More photons = fainter objects are visible, this is the motivation for projects like:

https://en.wikipedia.org/wiki/Extremely_Large_Telescope

Typically for non-adaptive optics telescope the atmosphere will limit you to the scale of about an arcsecond. Meaning objects which take up less than an arcsecond of the sky will appear as points. Adaptive optics telescopes however have much better resolving power.

prpl3• 1 year ago

The seeing in Chile is closer to .7 arc seconds. Sub-arcsecond seeing for Rubin has already been achieved across the focal plane.

joshvm• 1 year ago

At some point you'll be diffraction limited even at the scale of Earth. The larger your effective aperture, the better you can resolve. Adaptive optics helps get big telescopes closer to diffraction limited performance. That's the best you can do with a given optical system, barring some funky microscope setups. Trying to beat the diffraction limit has occupied a lot of very smart minds.

https://en.m.wikipedia.org/wiki/Diffraction-limited_system

Practically to go really big you need to use interferometry. There are radio experiments that can do this at Earth scale - the Event Horizon Telescope can image very small objects (black holes) by making simultaneous observations from all over the world. The telescopes point at the same place and use very very good timestamping. At the South Pole we have a hydrogen maser for that. Then all the data gets sent somewhere for correlation and a lot of processing. The analogy I like most is imagining you have a big mirror (Earth) but you've blacked out almost the entire surface except a few points where the telescopes are.

Radio is particularly amenable to this because you can build big dishes more easily than for visible light, and the diffraction limit is lower because it's proportional to wavelength/aperture. So in addition to big dishes, you're observation wavelength is much much longer (mm vs nm).

There's a log-log plot on that wiki page which is quite difficult to read, but the important point is that radio is all the way at the top and the best we have is the VLBA.

Visible interferometry is much harder...!

prpl3• 1 year ago

it tracks the sky. The exposures here are never longer than 30 seconds for the normal survey mode. They bounced around a lot, it was going to be 2 15s images so you can do cosmic ray rejection (and other things)

abound• 1 year ago

If you're just here looking at the HN comments: check out the article. It's really well-written and has a bunch of nice visualizations if you like astronomy things.

vincnetas• 1 year ago

The last picture made a bit sad and feel pity for astronomers : "Satellite swarms mar Rubin’s pristine view"

I imagine these are like mosquitos in photoshoot where you try to capture a super hot model.

soco• 1 year ago

I guess Rubin will be the last telescope built on the Earth surface right? Little use to have stronger eyes only to have them blinded...

BotJunkie2• 1 year ago

I visited there a few months ago, and satellites are not a big concern for Rubin in particular. It will visit every part of the sky over 800 times and add all those images together, and since the satellite trails won't cover the same things every time the overall impact on data is minimal. They estimate less than 1%, so the plan is to just run the survey for 1% longer.

ddahlen3• 1 year ago

I have been working in astronomy for a few years now and I recently have gone back to school for a PhD in orbital dynamics.

Rubin is going to make a big difference in our knowledge of the asteroid belt, it will likely more than triple the size of our known catalog of asteroids. Its actually somewhat difficult to know exactly how much it will increase our knowledge. The bigger the telescope we build, the fainter the asteroids we see. The difficulty is that while we can make a pretty educated guess as to how many smaller ones there are, this is such a jump that the error bars on that guess is quite large. I am quite excited to see how the catalog of asteroids changes, I expect we will be finding a LOT of smaller rocks near the Earth.

Asteroids have a broad range of albedo, basically the brightness of the surface can vary from the blackest coal (like 3-5% of the light reflecting) to concrete (up to about 50%). All visible range telescopes will be susceptible to a bias in their observations, since a big black rock will be as bright as a smaller paler rock. We know that the asteroid belt favors the dark material.

In a couple of years, the Near Earth Object Surveyor (NEOS) space telescope will launch. NEOS is an IR telescope and will not have the same albedo bias. The trade off is that it will measure the black body radiation, meaning asteroids have to be nearer the sun. Broadly these are very complementary surveys, Rubin will be fantastic for filling out the main belt, and NEO Surveyor will do a great job on our neighborhood.

Source: I worked at Caltech on NEOS, I wrote the code they use to predict known asteroid orbits:

https://github.com/dahlend/kete

Edit: I failed to mention that Rubin is a big deal for a lot of time-domain astronomy, I'm just being selfish talking about asteroids only.

sdoering• 1 year ago

I love your selfishness. Learned a lot, while sipping my second coffee and eating my breakfast before diving into work. Thanks kind stranger.

I loved astronomy as a kid and the town I grew up in has a "solar system way", basically a long street where a kind fellow (who in his freetime taught astronomy to nerds like myself and had built his own oberservatory in his backyard) had - with the blessing of the city - built a scale model of the solar system on a length of about 1.5 kilometers (a bit less than a mile).

I always found it fascinating when walking "through our solar system" with about 13 times the speed of light (normal walking translated into the distance at that scale) how veeeeeeeeeeery far apart things get in the solar system.

Sadly only in German: https://www.muenchberg.de/erleben/tourismus/tourismus-und-fr...

Edit: And yes - Pluto is still in there. It was built before the demotion - and they kept him in when doing the renovation last year (I was not in my home town since then - I so need to see it, when I visit the next time).

teekert2• 1 year ago

Selfishness tends to work well for everyone when practiced by a rational individual ;)

SiempreViernes• 1 year ago

Good luck with cleaning out the Musky foreground!

IAmBroom5• 1 year ago

Took me a bit to derive "Elon-Musk-created" from "Musky".

In the meantime, I imagined high-jumping muskelunges...

realityfactchex2• 1 year ago

For anyone passionate about orbital dynamics: IMO it would be great to get more eyes on and thorough critiques of the Tychos model put forth at https://www.tychos.space where there is a book, visual simulator, forum, etc.

The sincere claim put forth appears to be that Tycho Brahe was almost right, and that something like this is in fact true:

  - The planets except for the Earth orbit around the Sun
  - The Sun orbits around the Earth
  - The Earth has its own small orbit

It is pretty dense information, but seems important if true. I believe that the Tychos model is claimed to be just as consistent with observation as the conventional model, if not more so (with some arguments in the favor of the Tychos model as more likely, which escape me).

The best intro to cut to the chase may be at https://book.tychos.space/chapters/4-intro-tychos but I think that the writers would do well to summarize their main arguments somewhere.

colonCapitalDee• 1 year ago

What is this, flat Earth theory for people with bachelors degrees? There is a 0% chance this is true.

jl62• 1 year ago

The starlink streak issue is real, but isn’t this type of survey uniquely well suited to compensate for it, because it takes repeated exposures in relatively quick succession, meaning the odds of a given pixel being obscured by a streak in successive images get very low? Still not ideal but seems manageable compared to other telescopes running non-automated surveys.

BurningFrog2• 1 year ago

As I understand it, the orbit for each satellite is very precisely known.

Which I think/hope means you can remove/identify known satellites in the images mechanically.

Kye3• 1 year ago

That doesn't help if the distant light you're interested in was blocked. It's not an aesthetic concern. You can't remove the satellite and put the interesting light back. It's just gone. That could be a supernova or some as yet unidentified phenomena that only exists for a moment.

Kye3• 1 year ago

This sounds so cool. I sure hope this isn't one of the projects threatened by impending cuts to science funding.

aragilar2• 1 year ago

I suspect the better question is "how badly affected are project science goals by the funding uncertainty". I'm not US-based, but from what I've heard no astro projects are unaffected.

IAmBroom5• 1 year ago

Holy shazbot! I thought the author was being a bit hyperbolic about the "built for speed" part...

"The test drive shows off just 20% of Rubin’s maximum speed. At full tilt, a runner wouldn’t be able to keep up.

Presumably measured at the edge of the platform, but still... WOW!

inasio• 1 year ago

I see some parallels with magnetic resonance imaging. I worked on a project optimizing MRI scans a few years back. I remember the PI in the project essentially acknowledging that analyzing single MRI images is absolutely more art than science, but there's a ton of value in getting periodic MRIs (say yearly) and looking at the diffs. I imagine a lot of the value coming from Rubin will be due to this, as well as the reason it was built for speed.

vivzkestrel• 1 year ago

fictional question: how much detail would we see if we could somehow make a telescope with a 1 million km diameter

me_again• 1 year ago

Not exactly the same, but https://en.wikipedia.org/wiki/Very-long-baseline_interferome... is a technique used in radio astronomy which uses two receivers a long way apart and a very accurate clock to approximate having a radio telescope the size of the distance between them. By putting one receiver on a satellite, measurements have been made with a separation of 300,000km.

asinno• 1 year ago

I visited the cleanroom where they manufactured and assembled the lens and processing unit before shipping to Chile. world’s largest digital camera at 3200-megapixel image in a few seconds.

kristianp• 1 year ago

alerts for each new “transient”—as many as 10 million every night

How are astronomers going to deal with that many alerts?

BotJunkie2• 1 year ago

There are automated "alert brokers" that will filter these alerts to make them manageable- you can subscribe to phenomena that you're interested in and get only those alerts.

Giant, all-seeing telescope is set to revolutionize astronomy

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