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Can You Find the Comet?
- w-ll 6mo agoif i could imagine what a Sophon from 3 body problem would look like. this is kind of it.
- ragebol 6mo agoYeah, I kinda get why astronomers are not particularly happy with satellite constellations.
- HumblyTossed 6mo agoDoesn't matter. We, as a society, have said we're willing to give up nature in exchange for money machines the go brrrrr.
- adev_ 6mo agoAnd this is just the visible spectrum. The situation is one order of magnitude worst in radio-astronomy. It is fair to state that satellite constellations will certainly be the main obstacle to multiple major scientific discoveries in the next decade.
- ultratalk 6mo agoOpinion: We need to move our astronomical observation equipment off of Earth and onto other bodies, especially radio astronomy, which, unlike telescopes that operate in other wavelengths, is still affected by Earth's emissions in LEO/near-Earth space. We should put a radio telescope on the far side of the moon [0] to benefit from the thousands of kilometers of lunar material separating Earth's emissions from telescopes. [0] https://doi.org/10.1109/AERO50100.2021.9438165 https://doi.org/10.1109/AERO50100.2021.9438165 [1] https://en.wikipedia.org/wiki/Lunar_Crater_Radio_Telescope https://en.wikipedia.org/wiki/Lunar_Crater_Radio_Telescope
- christophilus 6mo agoAgreed. It’s the only solution short of a ban on constellations.
- silon42 6mo agoIMO, everyone that launches/operates a constellation should pay for launch of large telescope every 5-10 years (assuming science organizations can fund/build them).
- maxnoe 6mo agoOur telescopes actually need the (or at least an) atmosphere to function. There are some classes of observatories, which you cannot build in space but which are still affected by satellites to some degree.
- ultratalk 6mo ago> Our telescopes actually need the (or at least an) atmosphere to function. What about Hubble, Chandra, Spitzer, JWST, etc? As of my understanding, the only reason we haven't built radio and and other long-wave telescopes in space is because of their impractical size preventing them from being deployed in orbit. > There are some classes of observatories, which you cannot build in space but which are still affected by satellites to some degree. Examples?
- voidUpdate 6mo agoI believe we haven't built radio telescopes in space because we don't need to, and building them in space would be a lot more expensive. https://commons.wikimedia.org/wiki/File:Atmospheric_electromagnetic_transmittance_or_opacity.jpg https://commons.wikimedia.org/wiki/File:Atmospheric_electrom... This shows that wavelengths between ~10cm and ~10m are largely unaffected by the atmosphere, so you wouldn't gain much from putting receivers of those wavelengths in space. Spitzer and JWST (IR), and Chandra (x-ray) operate in bands that are generally blocked by the atmosphere, and Hubble gets better images than a similarly sized earth-based telescope because of the atmospheric distortion (stars don't "twinkle" when you're in space), however there are still earth-based visible light telescopes because you can more easily build a massive one on earth than in space
- chris_va 6mo agoNot to disagree, but stacking a series of exposures with a sigma-clipped mean (or similar) should still get a nice image.
- oofbey 6mo agoExactly. It’s not that hard to remove the satellites. It’s almost easier than whining about it. But whining is more fun.
- adrian_b 6mo agoIt is not hard to remove the satellites, but that is not free. It reduces the signal-to-noise ratio of the image, making more difficult the detection of faint objects.
- MarkusQ 5mo agoIt _increases_ the signal to noise ratio. It's a denoising technique, and that's what they do. Compared to the processing already done to get data from astronomical data, yeah, it's essentially free.
- oofbey 5mo agoTrue. But that’s never the framing you hear from astronomers. It’s how the satellites are “ruining” the pictures, like this whole thread. The SNR degradation isn’t even very much. Noise goes down by 1/sqrt(N) samples. In a stack like this might have 5-40 images depending on how they did it. Typically a satellite will only show up on one of those images for a given pixel. So by excluding that image from the stack that pixel’s noise would go up by a ratio of sqrt(N/(N-1)) which for 5-40 images is between 12% more noise and 1% more noise. Only the pixels with satellite tracks. True there’s more noise if you remove the satellites. But it’s probably only a few percent noisier, and only in the places where the satellite flew. Add a few more images to the stack and accept that the world is changing.
- oofbey 6mo agoComputational photography has long been table stakes for astronomers. They just need to up their game on satellite rejection algorithms. Satellites look nothing like stars, and as such are pretty easy to remove with software. Pictures like this which leave them in are just there to make a point.
- MagicMoonlight 6mo agoSo what? Astronomy doesn’t actually produce anything meaningful. Hell, astronomers were telling us the sun orbited the earth for 99% of human history. Shoot forward to the present day and they can tell us… the universe started at some point somehow. Great job guys. Really earning those billions in grants. Actually going to space has far more value.
- ragebol 6mo agoHave you heard of Kessler Syndrome? More satellites means higher risk on that happening and not going to space until all the debris of a collision deorbits.
- ciroduran 6mo agoI'm rebuilding my RSS feed collection, and having pretty astronomy pictures is a fine addition. Thanks!
- originalvichy 6mo agoI fear this is only the start of it. A minimum of 3-4 constellations more will probably be launched in the near future (Russia, China, EU). Their obvious dual-use nature makes them tempting, and a military target if a large conflict will take place in the near future. I hope their lower orbit will help any space junk burn up fast.
- aaron695 6mo ago[dead]
- mark-r 6mo agoIf you blow up a satellite, half of it will end up going slower and half will go faster. The slower bits will probably burn up nicely, but the faster bits will just elevate their orbit.
- bluGill 6mo agoI doubt they will elevate their orbit by enough to be a problem. Some bits will come down in hours, some will come down in a year - even in the worst case where it takes out everything in low earth orbit in 5 years everything will be clear and we can start over. Higher orbits are the real worry, even the things slowed down mostly stay in orbit for centuries - but higher orbits are mostly a lot higher.
- moffkalast 6mo agoDon't be so sure: https://stuffin-space.vader.zone/ https://stuffin-space.vader.zone/ The Iridium-Kosmos collision fragments have been up there since 2009, and that's a massive spray of junk just from one disintegration in LEO.
- zamadatix 6mo ago"LEO" is a big place, those satellites collided ~1.5x higher than e.g. the maximum Starlink altitude and the debris lifetime relationship is not a linear one.
- renerick 6mo agoThat looks so cool, ngl!
- gasi 6mo agoSo cool! Zoom in to find out: https://zoomhub.net/0w8pN https://zoomhub.net/0w8pN
- khazhoux 6mo agoIs this all / mostly Starlink?
- albert_e 6mo agoWhy are satellite trails not continuous lines Is the camera exposure taking a few seconds of break between takes that get stacked later with some "missing" moments in between?
- deleted 6mo ago[deleted]
- debugnik 6mo agoMy guess is the camera itself was taking photos of shorter exposure and the final image was composed in post-production, yes.
- pedvide 6mo agoI've taken long exposures using film (analog, so no stacking or any other funny business) and saw the same thing. I always thought they were planes but now it seems they may have been satellites. I'm curious if someone knows why this happens
- deleted 6mo ago[deleted]
- mark-r 6mo agoI'm not aware of a digital camera that can take a 10 minute continuous exposure, but maybe there are special astronomy cameras that can?
- deleted 6mo ago[deleted]
- zimpenfish 6mo agoDo iPhones count? I've taken multi-hour continuous exposures on my iPhone + iPad (both "normal" and "light trail" variants.) By the looks of [0], you can do at least 90 seconds on the Olympus E-M5 MK II - which is what I have and I'll see if it can do 10 minutes tonight. [0] https://www.olympuspassion.com/2019/08/26/long-exposures-with-olympus-gear/ https://www.olympuspassion.com/2019/08/26/long-exposures-wit...
- aa-jv 6mo agoHot take: We're in the first stages of building our own Dyson sphere and therefore comets are only useful in the context of capturing them for that purpose. ;)
- ButlerianJihad 5mo agoThe idea of a Dyson sphere is that it's built around a star, in attempting to capture and utilize 100% of its energy output. So a shady shell around the Earth is not "the first stages" of a Dyson sphere, because our energy source is on the other side of the shell, and the orbits are completely different.
- aa-jv 5mo agoSure it is - we build a sphere around our planet to harvest every erg of energy hitting it, and then use that to create and flatten the disc that is one of many we'd need to build to construct the sphere ..
- 1970-01-01 6mo agoI, a taxpayer, would rather have a cellphone signal in a remote location than lots of amazing pictures of a comet. And I just don't see a solution or compromise that could work. The utility of neat picture vs full cell signal in a Montana canyon cannot be won by taking more pictures and showing me the problem. I made my decision already.
- hrldcpr 6mo agoWhy gaze up at the vast cosmos when we can stare down at a little screen
- 1970-01-01 6mo agoWhy have cheap radio safety when you can die under the stars?
- fluoridation 6mo agoHow is it relevant that you're a taxpayer?
- 1970-01-01 6mo agohttps://www.cnbc.com/2020/12/07/spacex-starlink-wins-nearly-900-million-in-fcc-subsidies-auction.html https://www.cnbc.com/2020/12/07/spacex-starlink-wins-nearly-...
- fluoridation 6mo agoWell, isn't that good for you? The other seven and a half billion of us just get to deal with having our skies skidmarked like this with no choice on the matter.
- gowld 6mo agoYou can use satellite Internet too. It's strange to call it "skid marked" when the "skid marks" only appear when you apply complicated technology setups, and those setups can easily remove the "skid marks" also. "Now, the orbiting satellites themselves only appear as streaks because of the long camera exposure, over 10 minutes in this case. On the contrary, to the eye, satellites appear as points that drift slowly across the night sky and shine by reflecting sunlight -- primarily just after sunset and before sunrise. " See https://apod.nasa.gov/apod/ap191014.html https://apod.nasa.gov/apod/ap191014.html for example
- AntiUSAbah 6mo agoWe do not need Starlink! It only provides service to 9 Million! People We are a planet with 8 Billion People. Do i want cheap and reliable internet everywhere and perhaps work remote? Yes. Should someone like Musk destroy our look into space for just me and my use case? No.
- giancarlostoro 6mo agoI do wonder if in 100 or 200 years if we do become interplanetary as a species, and technology advances if many of these satellites will just disappear from the night sky and it would be long since forgotten or if remembered only as a steppingstone towards an interplanetary future. In the meantime, Starlink is the only thing that gives my sister in Puerto Rico access to the internet when the grid gets completely nerfed by a hurriance so she can tell us she's alright, well, that and landlines if she gets a power generator, otherwise, we're left to wonder how my sister and nephews are doing.
- AntiUSAbah 6mo agoYou don't need starlink to get a message out of Puerto Rico. We also don't need starlink as a stepping stone. What we need is food for the planet, resiliance infrastructure, proper health care, stable energy grids.
- giancarlostoro 6mo agoI sure hope you never have to wonder if your relatives are safe and doing well after they have no way to communicate with you for weeks.
- AntiUSAbah 6mo ago1. to keep this argument properly, you still need to see what the overall benefit for the whole society is and not just your little bubble. And putting a lot of satelites in sky, affects 8 billion people. 2. As i said, robust infrastructure would fix that too. Fiber under earth, backup energy etc.
- jharohit 6mo agoDone its beautiful https://imgur.com/a/tH39FAS https://imgur.com/a/tH39FAS (telescopes in space looking outside should have happened long ago, lets just get it done man)
- mlmonkey 6mo agoWhy doesn't the comet "streak" also, given the Earth's rotation? 10 minutes is a long enough window to have an appreciable impact on the comet's image. Or is it the case that the telescope is stabilized to the Earth's rotation?
- advisedwang 6mo agoLow earth orbit satellites orbit about once per 90 minutes, so in 10 minutes they go about 40 degrees across the sky. The comet is not even orbiting the earth, it's essentially fixed in the sky. The earth only rotates about 2.5 degrees in 10 minutes. So the satellites streak is 16 times longer than the comets.
- NooneAtAll3 6mo ago40 degrees around Earth (central angle) but it increases to much more when you are much closer to the arc
- advisedwang 5mo agoGreat point!
- dangond 6mo agoGiven that the moon is about 0.5 degrees in diameter from Earth, shouldn't we expect to see the stars and comet much more blurred than they are here though? Or the ground if it's stabilized against the rotation?
- ButlerianJihad 5mo ago> essentially fixed in the sky Let's start with "fixed in the sky" and qualify your frame of reference as the field of distant stars, or the celestial sphere. The common coordinate system is right ascension (RA) and declination (dec). The GP question was about the Earth's rotation, which would be in terms of azimuth and altitude, and that question's been asked and answered. The key terms there: "equatorial mount" and "clock drive". The comet C/2025 R3 (PanSTARRS) is in fact near its highest velocity (with reference to the Sun especially), being near perihelion while this photograph was taken. The comet is swinging around the Sun, and it was about 0.49 AU from Earth at the time of the photograph. https://en.wikipedia.org/wiki/C/2025_R3_(PanSTARRS) https://en.wikipedia.org/wiki/C/2025_R3_(PanSTARRS) I chose an approximate time on April 27: in 10 minutes of wall-clock time, with the J2000 epoch, the comet's apparent motion is from RA 02h 49m 07.1s, dec +06° 02' 56.5" to RA 02h 49m 15.4s, dec +06° 02' 13.3" That is a distance of 2' 11.13" across the celestial sphere. For reference, Venus is 11.6" wide in the sky as we see it this week. 24 hours later, we find it at RA 3h 08m 44.1s, dec +04° 19' 27.8". Its apparent motion was 5° 10' 46.02", which is approximately the width of your three middle fingers held together, at arm's length. So, "fixed in the sky" is not a scientifically useful description of astronomical objects: we need to put that in terms of at least one frame of reference, and "apparent motion" which is how an observer perceives it. https://soho.nascom.nasa.gov/data/LATEST/latest-lascoC3.html https://soho.nascom.nasa.gov/data/LATEST/latest-lascoC3.html (grab this today; scroll between 4/23 and 4/27)
- signorovitch 6mo agoFWIW, if you actually want to photograph a comet or anything that doesn’t move in the sky, you’d take multiple exposures that would make the moving light sources like satellites disappear. Taking HDR photographs like this has an number other benefits as well.
- andsoitis 6mo ago> can you find the comet? You mean the obvious object (ball shaped head with a tail) in the center of the image? That was super hard.
- LuckyBuddy 6mo ago[flagged]