Done its beautiful https://imgur.com/a/tH39FAS
(telescopes in space looking outside should have happened long ago, lets just get it done man)
Yeah, I kinda get why astronomers are not particularly happy with satellite constellations.
And 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.
Opinion: 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
[1] https://en.wikipedia.org/wiki/Lunar_Crater_Radio_Telescope
Unfortunately, that seems to be the only solution.
However, it has serious disadvantages. It will exclude the poorer from astronomical research, except within the limits enabled by whatever cooperation the richer will be willing to do with them.
For the richer, that will make astronomical research much more expensive. When even USA, who claims to be the richest country, cuts a lot of the scientific funding, this makes likely a great reduction in the research targets that could be accomplished, even if a Lunar array of telescopes and radiotelescopes and communication relays for them were approved.
While professionals might still be able to do some work, the amateurs will be able less and less to enjoy the sight of the distant Universe.
There are already many years since I have become unable to see the sky that I enjoyed looking at when young, because it cannot be seen from the city where I live, due to light pollution (and high buildings). To see it again, I would have to go somewhere up in the mountains, far from a city or village, but I have not succeeded to do this recently. Even there now you can hardly look at the sky without seeing satellites, and it will only become much worse.
Nowadays there are many children who have never seen even once the sky that our ancestors were seeing every night, so many passages from old texts that mention the sky are unintelligible for them.
I get what you're saying, but poor people want cheap internet/phone connectivity. They can't afford telescopes anyways.
And starlink (and the like) have more uses beyond good remote connectivity. They're a big reason why Ukraine didn't lose to Russia. They're also a potential avenue for people in oppressed nations to talk to the rest of the world (eg: Iran has a death penalty for starlink usage to counter this point).
> It will exclude the poorer from astronomical research, except within the limits enabled by whatever cooperation the richer will be willing to do with them.
Isn't it the case that most astronomical research uses source data from large telescopes and sky surveys? An example is the Rubin Science Platform [0] which makes available images and metadata from the Rubin Observatory along with compute and APIs?
Or even out past the heliosphere/heliopause
Its still worth while for every normal human to have access to space if the benefit of this stuff is not relevant for most people.
And with 9 million customers its not.
Our 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.
> 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?
I 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_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
What? The atmosphere gets in the way. Ever heard of an (amateur/)astronomer talking about 'good seeing'? That's when the atmosphere is hindering you less than usual.
The limiting factor of passive optical telescopes on earth is the atmosphere.
They are talking about very high energy gamma-ray telescopes, the Imaging Cherenkov Telescopes.
Agreed. It’s the only solution short of a ban on constellations.
IMO, everyone that launches/operates a constellation should pay for launch of large telescope every 5-10 years (assuming science organizations can fund/build them).
Any chance of CubeSat style of telescopes at some point?
Sure, there have already been some launched and predictably they are only adequate to look at the bright stuff we already knew about from the big telescopes.
A small telescope is just a small telescope even when you put it in 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.
Do you really think a starlink style installation won't be put in orbit of the moon before such a telescope could be funded?
> Do you really think a starlink style installation won't be put in orbit of the moon before such a telescope could be funded?
There are ITUs rules that forbid that and the far side of the moon is declared as radio quiet.
Those rules won't last long once (IF) there are significant numbers of people on the moon. The rules are easy to agree to today (50 years ago) because nobody could do anything otherwise anyway. Once the rules are getting in the way of a significant number of people they will change.
I make no predictions how they will change, but the current rules are obviously unworkable if significant numbers of people live in space. I also make no predictions on if we will ever get significant numbers of people living in space - there are a lot of hard/expensive problems that may not be solvable.
Starlinks are already spewing out into supposedly protected radio bands on Earth, good look getting these rules respected on the Moon when they aren't here.
Not to disagree, but stacking a series of exposures with a sigma-clipped mean (or similar) should still get a nice image.
Exactly. It’s not that hard to remove the satellites. It’s almost easier than whining about it. But whining is more fun.
Computational 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.
Doesn't matter. We, as a society, have said we're willing to give up nature in exchange for money machines the go brrrrr.
So 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.
Have 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.
Why 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?
My time to shine! I've spent yesterday morning to track the photo down and answer this question. The APOD description is lacking. Yes, this was an exaggerated stack of 153 four-second exposures (the rejection map of the satellite trails was added on top of the image), and the gaps happened when the camera took its time to save between two exposures.
Here is a link to the original photo and it's description (German) by Uli Fehr: https://www.facebook.com/groups/Nachtfotografie/posts/264063...
Probably exactly that. If you take a single 10 minute exposure (or really, anything more than a few seconds) you'll get noticeable star trails if you don't put your camera on a rotating mount. Stacking multiple exposures also has other nice benefits such as noise canceling itself out and being able to remove satellite trails.
Last time I did astrophotography was a few years ago, before Starlink made the problem considerably worse, but satellite trails were relatively easy to remove with stacking. I'm sure it's harder now but definitely still possible, so I'm assuming in this case leaving them in was done on purpose to highlight the problem.
EDIT: Looking better at the picture, I belive this was taken with a star tracker and then composited with a shorter exposure of the foreground. Notice how the foreground, even far away, looks considerably blurrier than the stars, and how the tower in the background has some light streaks. This is exactly what you'll see if you use a star tracker. Rather than star trails, you'll have "foreground trails". This would explain why there are relatively few gaps in the satellite trails, since the exposures can be much longer.
My guess is the camera itself was taking photos of shorter exposure and the final image was composed in post-production, yes.
I am guessing, but I think it likely has to do with the shape and orientation of the satellite with respect to the sun and the camera. Depending on the relative positions, the brightness reflected off the satellite and reaching the camera will change over time.
I'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
I'm not aware of a digital camera that can take a 10 minute continuous exposure, but maybe there are special astronomy cameras that can?
Pretty much every DSLR/DSLM camera out there has a "bulb" mode that keeps the shutter open as long as you hold down the shutter button. I think my personal record is a 20-minute exposure.
As for actually holding down the button, you can either use an external wired shutter button that has a mechanical lock to hold it down, or you use a wired controller that has an electronic timer, or you use a software feature in the camera to set the bulb timer.
For anybody wondering, the reason not to do a single ultra-long exposures is noise.
There's an equilibrium between exposure duration, aperture, and ISO that gives the best results for the conditions with a minimum amount of sensor noise, and getting close to the equilibrium and stacking the images typically gives better results than one massive exposure.
I believe your claim about noise and long exposures is false. To start, I posit that there are three sources of noise:
0) Photon shot noise from the object that you want to photograph. This is an inherent and unchangeable quantum-mechanical fact.
1) Sensor read noise per photo taken. This increases with the number of subexposures.
2) Dark current noise per time and per temperature.
#0 and #2 only depend on the total exposure time, not the number of subexposures. #1 actually gets worse with more subexposures, but what you gain are the ability to reject satellite trails, bad mount tracking, cosmic rays, wind gusts, rolling clouds, and other transient artifacts. Whereas if you took a single hour-long exposure, it's essentially guaranteed to be ruined by something.
The trade-off in how many / how long subexposures to take has been analyzed and discussed to death by astro imagers. To cite a few videos I enjoyed: https://www.youtube.com/results?search_query=astrophotograph... , https://www.youtube.com/watch?v=T_k9B01AeFM , https://www.youtube.com/playlist?list=PLaDi49CzWbrYhWEKxWiwB... , https://www.youtube.com/watch?v=mj5zn_Jz3dE , https://www.youtube.com/watch?v=n1RbyswFUqs
As for ISO, it is very commonly misunderstood. ISO amplifies photon noise and dark current noise, and changing the ISO doesn't make your images better or worse in these aspects. ISO in the form of analog gain can help boost the signal above the analog-to-digital converter noise, and that's what it's useful for. The MinutePhysics video explains excellently: https://www.youtube.com/watch?v=ZWSvHBG7X0w . More and more sensors these days approach "ISO invariance", where analog amplifier gain has about the same effect as digital gain (i.e. multiplying the measured numbers on a computer).
Exactly what I'm refuting:
> exposure duration
In astronomy, more is better. Get as much total exposure time as you can afford (e.g. time being at a suitable location, time spent monitoring the equipment, time under clear skies).
> aperture
In astronomy, more is better. Buy the biggest aperture you can afford - obviously, subject to constraints such as cost, weight, mountability, focal length. Also, telescopes don't have adjustable aperture blades, unlike general photographic lenses. You could put a disc cut-out in front of the telescope to close down the aperture, but that's just a waste of light.
> minimum amount of sensor noise
You get the least amount of sensor noise by reducing the exposure time and reducing the temperature (dedicated astro cameras have Peltier cooling). Note that although noise increases with time, signal increases with time faster, so the signal-to-noise ratio is proportional to the square root of time. So 100× more exposure time gives you a 10× better SNR.
> stacking the images typically gives better results than one massive exposure
This is the main falsehood that I wanted to address. Taking multiple images actually gives more noise overall, even if it's a tiny bit. But multiple images gives you much more processing flexibility and the ability to selectively reject things.
Do 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-wit...
My Canon can do this without modification and its 8 years old. Switch to bulp and have an external mini device which you connect with a microphone cable and it creates the signal for shutter off after x minutes.
For extra long exposre its recommended to use also a stable powersource.
How is a 10 minute continuous exposure functionally different from 10 minutes of video with every frame stacked? In the former, each photodiode acts as a compositor for each pixel instead of whatever algorithm is chosen to combine frames in the latter?
You pay the read noise every time you read out the sensor and digitize the values. Also, you lose a tiny bit of time between exposures as the sensor resets itself. And you might have a bottleneck in moving the data off the sensor and saving the image. Furthermore, if you perform lossy compression on the video, then your digitally stacked image will differ significantly from analog stacking on the silicon sensor.
Maybe, but also a lot of satellites rotate and so their brightness changes over time.
Passing clouds?
I 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.
Add a black umbrella to each satellite: when they pass through the critical region where they are visible in the night sky while still being sunlit, pop the brollies up. We will fly them in the shade!
You could paint them black but they’d probably get quite hot.
Won't the shade then reflect the light instead? It's nighttime, so sunlight will be aimed up, from the Earth-based observer's point of view, so the shade will need to be pointed down in order to shade the satellite.
If 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.
I 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.
Don't be so sure: 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.
It'll elongate the orbit, which is a bit better of a scenario than elevating it wholesale.
In either case, you will increase the section area / volume ratio, what makes the fragments fall from LEO faster.
I'm rebuilding my RSS feed collection, and having pretty astronomy pictures is a fine addition. Thanks!
So cool! Zoom in to find out: https://zoomhub.net/0w8pN
if i could imagine what a Sophon from 3 body problem would look like. this is kind of it.
Is this all / mostly Starlink?
It's a set of network satellites for sure either by Eutelsat or Starlink in 70:20 ratio 10% being other providers
But all of them being LEO for sure.
70% of all satellites are Starlink. So probably.
Hot 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.
;)
We 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.
I 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.
You 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.
I 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.
That looks so cool, ngl!
I, 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.
Why gaze up at the vast cosmos when we can stare down at a little screen
Why have cheap radio safety when you can die under the stars?
I, a taxpayer, wish that we could significantly reduce light pollution so we could see the stars on a typical clear night.
Then give up streetlights. Although crime and road accidents will massively increase and women won’t feel safe outdoors. So is it really worth it?
Women would feel less safe yes but there is no evidence that crime and road accidents would increase.
How is it relevant that you're a taxpayer?
Well, 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.
You 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 for example
