Impacts of Large Satellite Constellations on Astronomy

[eeergo]

The reason why astronomers care about this and few others is because the vast majority of people can’t even see it.

So even calling it aesthetic is a bit of a misnomer. It’s an annoyance for large ground based survey telescopes. That’s it.

No it's not, as has been amply demostranted analytically, observationally (within the as-of-yet low status of deployment of such systems) and quantitatively. That's not it. Again, feel free to continue spreading these easy-fire misinformation and think to have the high ground because factual rebuttals need more nuance than your sweeping statements.

[abaddon]

Let's just hope Amazon is as willing to work with astronomers as SpaceX has been.  Active pursuit of mitigations is critical to reduce the impact, and that isn't cheap.

[Robotbeat]

... but the deployed constellation is essentially invisible to 95% of people...

That's because our skies are so polluted.  Using this argument is like saying it's fine to throw plastic into the ocean because there's already a lot of plastic in the ocean so it doesn't matter, and it helps the less fortunate get rid of their trash.

No,

Yes, that analogy was correct.

it’s like saying flying a silent electric airplane is fine because the visual impact is really not a problem (oh look, I can see an airplane! Oh, the humanity!). That’s literally what we’re talking about here.

No, we're talking about something different here.

But you have to massively exaggerate the issue using hyperbolic analogies for anyone to care.

That's because most people don't care about the environment in which they live.

To see much of the wonder of the night sky, you need long exposure photography.  Heck, even Andromeda looks like a blurry blob through a decent sized telescope until you expose for a few tens of seconds, and ideally over an hour.

We literally aren’t talking about something different here. A plane being visible is exactly the same as a satellite being visible, except a satellite is only visible a tiny fraction of the time and much dimmer and doesn’t blink disconcertingly whereas an airplane is (for safety purposes) visible at all times other than being obscured by clouds. Heck, aircraft often leave thick contrails that, if conditions are right, can cover a massive portion of the sky persistently.

And sure, modern tech has put sensitive instruments in the hands of amateurs. So we can detect stuff in space better. That doesn’t change the visual aesthetics argument one bit.

[Robotbeat]

The reason why astronomers care about this and few others is because the vast majority of people can’t even see it.

So even calling it aesthetic is a bit of a misnomer. It’s an annoyance for large ground based survey telescopes. That’s it.

No it's not, as has been amply demostranted analytically, observationally (within the as-of-yet low status of deployment of such systems) and quantitatively….

Oh really? In what way we’re my statements contradicted? They weren’t. Yes, it makes it a bit more annoying to analyze data from some of the large survey telescopes. But for the rest, it has very little if any impact on the science. And for everyone else just looking at the night sky, the only time it’s really noticeable is soon after launch. After deployment at operational altitude, it’s barely visible even at the best of times.

It’s important to take a step back from the hyperbole and get some sense of perspective, here.

[Robotbeat]

Let's just hope Amazon is as willing to work with astronomers as SpaceX has been.  Active pursuit of mitigations is critical to reduce the impact, and that isn't cheap.

Agreed. I think we need some reasonable regulations, globally, because someone most certainly COULD design and launch a constellation which is more visible for longer.

Like at 1000km altitude with much larger satellites than OneWeb and No Starlink-like sun-shield.

[Robotbeat]

Kuiper will operate at slightly higher altitudes but will have twice the mass. That means that, assuming the shape is similar, they will need a Starlink-like sunshield to be similarly low visibility. And even then, they’ll be visible for later into the night, further from dusk/dawn.

[Lee Jay]

It’s important to take a step back from the hyperbole and get some sense of perspective, here.

Just because you don't care about this doesn't make it hyperbole.

[Lee Jay]

... but the deployed constellation is essentially invisible to 95% of people...

That's because our skies are so polluted.  Using this argument is like saying it's fine to throw plastic into the ocean because there's already a lot of plastic in the ocean so it doesn't matter, and it helps the less fortunate get rid of their trash.

No,

Yes, that analogy was correct.

it’s like saying flying a silent electric airplane is fine because the visual impact is really not a problem (oh look, I can see an airplane! Oh, the humanity!). That’s literally what we’re talking about here.

No, we're talking about something different here.

But you have to massively exaggerate the issue using hyperbolic analogies for anyone to care.

That's because most people don't care about the environment in which they live.

To see much of the wonder of the night sky, you need long exposure photography.  Heck, even Andromeda looks like a blurry blob through a decent sized telescope until you expose for a few tens of seconds, and ideally over an hour.

We literally aren’t talking about something different here.

You might want to look up what "literally" means, because you're not using it correctly.

A plane being visible is exactly the same as a satellite being visible, except a satellite is only visible a tiny fraction of the time and much dimmer and doesn’t blink disconcertingly whereas an airplane is (for safety purposes) visible at all times other than being obscured by clouds. Heck, aircraft often leave thick contrails that, if conditions are right, can cover a massive portion of the sky persistently.

For now.  Around 10,000 planes are in the air at a time.  But if all these constellations get to full deployment, they will out-number the planes by an order of magnitude.

And sure, modern tech has put sensitive instruments in the hands of amateurs. So we can detect stuff in space better. That doesn’t change the visual aesthetics argument one bit.

Not "one bit", many bits.

[daedalus1]

To be fair Lee Jay the writing was on the wall for uninterrupted visible light telescope viewing since aeroplanes became a thing and sputnik 1 was launched. Good luck with telling China that they can't do what Russia and the west have been doing for 70 years with increased numbers of orbital objects. LEO is becoming a cheap place to place a satellite even poor countries are having them built. Ground based astronomy will have to learn to live with it.

[Robotbeat]

Visibility of something in the sky from active objects doing something useful = Visibility of something in the sky from active objects doing something useful. It’s the same kind of impact. If any property is “literally the same,” this is.

Visibility of something in the sky from active objects doing something useful. IS NOT throwing plastic trash that isn’t being used for anything into the ocean.

[abaddon]

I don't know that this back-and-forth on analogies is going to convince anyone of anything, so maybe it's best we drop it and move on.

[woods170]

To be fair Lee Jay the writing was on the wall for uninterrupted visible light telescope viewing since aeroplanes became a thing and sputnik 1 was launched. Good luck with telling China that they can't do what Russia and the west have been doing for 70 years with increased numbers of orbital objects. LEO is becoming a cheap place to place a satellite even poor countries are having them built. Ground based astronomy will have to learn to live with it.

Agreed. I can vividly remember a certain Dutch-based astronomer cursing a satellite for spoiling one of his long exposures. When we bothered to identify the North-South orbiting satellite the astronomer suddenly clammed shut.

You see, the satellite that had dared to invade his image was IRAS, the Infra-Red Astronomical Satellite.

Certain forms of astronomy are only capable of being done from orbit. Yet astronomers (you know: the guys and gals practicing astronomy) go ape over satellites spoiling their exposures. How hypocritical of them, because over the course of six decades of spaceflight they actually added to the problem themselves. The finest example being the Hubble Space Telescope. Which is big and so bright that it regularly shows up in astronomical shots from around the equator.

The undisturbed night skies ended over 75 years ago, when humankind started flying at night. The problem intensifiied, starting 5 decades ago, when humandkind started launching things into EO. The current rise of megaconstellations does not add a new problem. It just vastly increases an already existing problem.

The ultimate solution will be to move Earth-based astronomy off-planet. I hear one has a lovely undisturbed view of the heavens from the backside of the Moon. No atmosphere to worry about either. And no, that is not a silly suggestion. The idea was first proposed in the 1950s, even before spaceflight began.

[JayWee]

The ultimate solution will be to move Earth-based astronomy off-planet. I hear one has a lovely undisturbed view of the heavens from the backside of the Moon. No atmosphere to worry about either. And no, that is not a silly suggestion. The idea was first proposed in the 1950s, even before spaceflight began.

Agreed. There's a whole thread about one of the options - https://forum.nasaspaceflight.com/index.php?topic=49461.80

It's just the usual fight between NIMOs and YIMOs... (Not In My Orbit)

[MarcPol]

Sad perspective as Europe has also fallen prey to the hard cash with the Kuiper deal. My critiques, should this project go forward as advertised, are unchanged -or even heightened considering the slight orbital altitude increase- from those discussed for Starlink's case.

https://mobile.twitter.com/Spicey_Spiney/status/1510951865927753738

So how long was the exposure? Most of the clutter here appears to be aircraft. How many of the satellite trails are starlink? This is simply meaningless.

Street lighting is a far more serious desecration of the night sky for most of the human race. I live well out in the country and I can only see a few dozen stars.

I have been working on all-sky meteor detection cameras for quiet some time.  The image Mary posted to Twitter is the composite image output of an entire night's worth of observations from RMS, a raspberry pi based meteor detection system.  This composite image spans from dusk to dawn, and is not at all related to the detection and astrometric aspects of the software.  Each detected meteor is cataloged and saved into a separate archive, along with various still images and video of the detection. 

TLDR: This image is great for shock value, but to some degree misrepresents the effects planes, satellites, etc. have on meteor detection applications.  It's an entire night's worth of sky traffic, and not indicative of sky conditions over short periods of time. 

[eeergo]

Sad perspective as Europe has also fallen prey to the hard cash with the Kuiper deal. My critiques, should this project go forward as advertised, are unchanged -or even heightened considering the slight orbital altitude increase- from those discussed for Starlink's case.

So how long was the exposure? Most of the clutter here appears to be aircraft. How many of the satellite trails are starlink? This is simply meaningless.

Street lighting is a far more serious desecration of the night sky for most of the human race. I live well out in the country and I can only see a few dozen stars.

I have been working on all-sky meteor detection cameras for quiet some time.  The image Mary posted to Twitter is the composite image output of an entire night's worth of observations from RMS, a raspberry pi based meteor detection system.  This composite image spans from dusk to dawn, and is not at all related to the detection and astrometric aspects of the software.  Each detected meteor is cataloged and saved into a separate archive, along with various still images and video of the detection. 

TLDR: This image is great for shock value, but to some degree misrepresents the effects planes, satellites, etc. have on meteor detection applications.  It's an entire night's worth of sky traffic, and not indicative of sky conditions over short periods of time. 

I appreciate your experience but the poster made it clear the image was a stack of 90 mins centered around 3 am, not an entire night.


On the other hand, she uses much stronger language than I do on this thread to describe megaconstellations, and she also appears to have 'some' experience with these observations.

[JayWee]

The real question is: Can astronomers adapt? If so, adapt and stop complaining as noone is going to ban megaconstellations, they are just so much useful.

[eeergo]

To be fair Lee Jay the writing was on the wall for uninterrupted visible light telescope viewing since aeroplanes became a thing and sputnik 1 was launched. Good luck with telling China that they can't do what Russia and the west have been doing for 70 years with increased numbers of orbital objects. LEO is becoming a cheap place to place a satellite even poor countries are having them built. Ground based astronomy will have to learn to live with it.

"Good luck telling Brazil it cant chop down and burn the Amazon, so those ivory tower biologists and botanists might as well learn to live with savage deforestation anywhere else on the planet. Cannot deny people worldwide wood to heat up their homes".

"Good luck telling Japan not to kill whales or release tritiated water from Fukushima into the Pacific, so those pesky oceanographers might as well learn to live with industrial drag fishing worldwide and radioactive barrel dumping in the high seas, 50s-style. Can't deny people of healthy food, for Pete's sake are you a monster? Plus the economy needs cheap nuclear, are you a luddite?"

[eeergo]

The real question is: Can astronomers adapt? If so, adapt and stop complaining as noone is going to ban megaconstellations, they are just so much useful.

For many so much useful things, like you know, hazardous asterioid detection, no they cannot.

What about you stop complaining about ground infrastructure with remote-area backup from minimalistic sat services (also LEO) not currently being able to support gaming-standard connectivity and invest in such a system, which can easily do the trick sustainably, for less money, with more resiliency and less environmental footprint? That'd be so much more useful too!

[MarcPol]

I appreciate your experience but the poster made it clear the image was a stack of 90 mins centered around 3 am, not an entire night.


On the other hand, she uses much stronger language than I do on this thread to describe megaconstellations, and she also appears to have 'some' experience with these observations.

I don't see a reference anywhere to it being a stack of 90 mins- the original tweet references "Overnight on 2nd3rd April 2022", and the curves called out as star trails in the image are unambiguously longer than 90 minutes worth of exposure. 

[su27k]

... but the deployed constellation is essentially invisible to 95% of people...

That's because our skies are so polluted.  Using this argument is like saying it's fine to throw plastic into the ocean because there's already a lot of plastic in the ocean so it doesn't matter, and it helps the less fortunate get rid of their trash.

No, it's not because sky is polluted, it's because with proper mitigation, the visibility of LEO satellite can be reduced to at or beyond the limit of what human eye can see even in the best conditions.

Starlink VisorSat is already at 6.8 magnitude in operational orbit per ZTF study, the dimmest star human eye can see is between 6.5 to 7.0 magnitude, this is under the best conditions, without light pollution, without moonlight.