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How satellite ‘megaconstellations’ will photobomb astronomy images

nature.com

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Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#271

Post by PeterisP »

reitzensteinm wrote: post #142
vanderZwan wrote: post #126

Earlier quoted context omitted.

> I was picturing some of the places I've been in Africa that don't have mobile reception and may well never get it if it means laying fiber. When was the last time that you were in Africa? And in which country, because it's an entire continent. EDIT: So I guess HN doesn't like being called out on https://africasacountry.com/ issues? Well sorry not sorry, but as someone born in Ghana I'm more a little tired of the se…

This isn't about being able to afford infrastructure. It's about population density in rural areas. North America and Australia (where I'm from) have the exact same issue. No country is going to spend a million bucks to lay fiber to ten person towns in the middle of nowhere.

If we're talking about population density in rural areas, then the poor countries of Africa (excluding Saharan desert) have a much higher rural population density than middle of USA, and there rolling out cell coverage is quite feasible, definitely more feasible than rolling out an electricity grid - there's already something like a hundred million people in sub-Saharan Africa who don't have electricity connections but do have mobile phones and coverage.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#272

Post by dheera »

verytrivial wrote: post #15

The article covers the mitigations already in place and how they only partially resolve the issue. These satellites are low, bright (at dawn/dusk) and very soon to be incredibly numerous. Yes, it is possible for data workflows to post-process these streaks away, but not all configurations allow this, and whereas previous intrusions were somewhat rare and could be ignored that simply won't be the case due to three com…

I do a lot of astrophotography as a hobby and for visual/infrared images, these satellites are a non-issue and extremely easy to deal with by simple outlier rejection techinques. One of the most basic techniques is sigma clipping, in which you stack a bunch of sky-tracked images, and for each pixel, you throw away data points that are more than a sigma or two away from the mean before actually averaging.

I already have to do this for aircraft, and aircraft do a LOT more photobombing than satellites.

The satellite trail images people post all over the internet to fear monger the public are actually processed exactly the OPPOSITE way that astrophotographers would process an image stack. They are processed by taking the max at each pixel stack to emphasizing the outliers in the stack instead of eliminating the outliers and averaging the rest. No astronomer would ever do that.

I can imagine they might be a bigger threat to radio astronomy, though.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#273

Post by astrophysician »

valuearb wrote: post #206
vanderZwan wrote: post #124

Earlier quoted context omitted.

> which I would say is trivial I'm frankly amazed at the arrogance on display here. Do you honestly think you know better then the entire field of astronomy?

If the entire field of astronomy is so educated on the subject, why do most not know Starlink was never visible except at dawn or dusk, and it’s already implemented successful mitigations for those tones with visors?

...wow.

(1) astronomers are pretty darn aware of everything going on, and it's really shocking as an astronomer to see these sorts of claims. There have been close collaborations with Space X to try to mitigate some issues, but these are partial mitigations and the most important ones are only planned, not implemented. The "successful" mitigations I think you're referring to is their "DarkSat" coating, which is not actually a successful mitigation. It is still ~2x as bright as the ~maximum level of acceptable brightness for e.g. LSST.

(2) Space-X did not release any details about brightness characteristics, and they themselves claim that they were "surprised" by the brightness. To people that work in space rather routinely, that is staggeringly incompetent.

(3) > why do most not know Starlink was never visible except at dawn or dusk

Near earth object (NEO) detection only happens during these times. NEO includes "asteroids that threaten human life" so I would hope you agree that this is pretty important. Also, depending on latitude and time of year, "dawn or dusk" can constitute your entire observing window. So this doesn't really make things better.

(4) all of these mitigations should be done before companies can start doing ~10,000 satellite launches. The only reason this isn't done is outdated legislation that never conceived of this being possible.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#274

Post by HumblyTossed »

verytrivial wrote: post #15

The article covers the mitigations already in place and how they only partially resolve the issue. These satellites are low, bright (at dawn/dusk) and very soon to be incredibly numerous. Yes, it is possible for data workflows to post-process these streaks away, but not all configurations allow this, and whereas previous intrusions were somewhat rare and could be ignored that simply won't be the case due to three com…

> Yes, it is possible for data workflows to post-process these streaks away, but not all configurations allow this, and whereas previous intrusions were somewhat rare and could be ignored that simply won't be the case due to three companies from one country.

Not to mention there will be far fewer non-processed photos. Most people won't care, but it just seems like nothing we see anymore is real.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#275

Post by astrophysician »

dheera wrote: post #272
verytrivial wrote: post #15

The article covers the mitigations already in place and how they only partially resolve the issue. These satellites are low, bright (at dawn/dusk) and very soon to be incredibly numerous. Yes, it is possible for data workflows to post-process these streaks away, but not all configurations allow this, and whereas previous intrusions were somewhat rare and could be ignored that simply won't be the case due to three com…

I do a lot of astrophotography as a hobby and for visual/infrared images, these satellites are a non-issue and extremely easy to deal with by simple outlier rejection techinques. One of the most basic techniques is sigma clipping, in which you stack a bunch of sky-tracked images, and for each pixel, you throw away data points that are more than a sigma or two away from the mean before actually averaging. I already ha…

Not just radio astronomy but any other type of research astronomy. Astrophotography has different goals. If you want a good picture, this isn't a huge deal. If you're measuring pixel-level brightnesses using state of the art equipment, the story is completely different. The "fear mongering" you state is not fear mongering, it's an illustration of just how much of a research image is ruined by these tracks.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#276

Post by oh_sigh »

verytrivial wrote: post #15

The article covers the mitigations already in place and how they only partially resolve the issue. These satellites are low, bright (at dawn/dusk) and very soon to be incredibly numerous. Yes, it is possible for data workflows to post-process these streaks away, but not all configurations allow this, and whereas previous intrusions were somewhat rare and could be ignored that simply won't be the case due to three com…

This is a silly hill to die on. Did you complain(or would you have complained) when tax dollars were building space probes, meanwhile people are starving to death on earth?

"Won't somebody please think of the astronomers!" is a moral panic that I just can't get behind.

Astronomy is great. But world-spanning wireless internet is great too. If 5% of astronomical observations get messed up because 100% of people can now have access to the internet, then that is just a big shrug from me.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#277

Post by simion314 »

ColanR wrote: post #270
simion314 wrote: post #45

Earlier quoted context omitted.

Will those american billionaires pay say for more European satellites to compensate? What if this were Chinese satellites would you have the same opinion? It would be great if this billionaires would also launch scientific satellites payed from their pocket to compensate, then I would change my mind.

> It would be great if this billionaires would also launch scientific satellites payed from their pocket to compensate, then I would change my mind. They don't owe you anything.

We need a sky pollution tax. They owe the public not me personally.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#278

Post by beached_whale »

reitzensteinm wrote: post #142
vanderZwan wrote: post #126

Earlier quoted context omitted.

> I was picturing some of the places I've been in Africa that don't have mobile reception and may well never get it if it means laying fiber. When was the last time that you were in Africa? And in which country, because it's an entire continent. EDIT: So I guess HN doesn't like being called out on https://africasacountry.com/ issues? Well sorry not sorry, but as someone born in Ghana I'm more a little tired of the se…

This isn't about being able to afford infrastructure. It's about population density in rural areas. North America and Australia (where I'm from) have the exact same issue. No country is going to spend a million bucks to lay fiber to ten person towns in the middle of nowhere.

Funny, Canada, even less dense, is doing exactly that. Maybe not 10, but at multiple levels of government there have been up to half the capital without many strings attached to get broadband out to rural areas. My understanding though, it's not work the time even with the fibre there for the larger companies in many cases. This is the latest program https://www.canada.ca/en/radio-television-telecommunications...

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#279

Post by oh_sigh »

q3k wrote: post #52
reitzensteinm wrote: post #42

Earlier quoted context omitted.

I personally believe that pervasive high speed internet even in remote locations will do more for humanity than the scientific cost of these satellites. However, this conversation has basically been skipped over. Maybe you're right and I'm wrong. The constellations are being launched, and there's zero chance of shutting them down once they're serving a commercial role. Considering the abundant red tape in the modern…

> I personally believe that pervasive high speed internet even in remote locations will do more for humanity than the scientific cost of these satellites. I've had faster Internet than the average Starlink speedtest says, in rural Romania, at the foot of a mountain, wild bears and all: https://twitter.com/q3k/status/1172621386977861632 . Internet access in rural areas is pretty much a solved problem, it just now hing…

"There's food in my refrigerator. Ergo, world hunger is pretty much a solved problem."

If we are just going to completely ignore costs, then I can say that getting great astronomical observations is solved as well, since we can just launch satellites to take the observations instead of doing ground-based observations. So it's not clear what the big deal about these satellites is anyway.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#280

Post by oh_sigh »

vanderZwan wrote: post #126
reitzensteinm wrote: post #69

Earlier quoted context omitted.

I've been there, it's beautiful. Although under ten kilometers from a town of tens of thousands wasn't exactly what I had in mind; I was picturing some of the places I've been in Africa that don't have mobile reception and may well never get it if it means laying fiber. A solar powered base station that relayed mobile internet, even if slow, would make a meaningful difference. The point of my comment isn't to defend…

> I was picturing some of the places I've been in Africa that don't have mobile reception and may well never get it if it means laying fiber. When was the last time that you were in Africa? And in which country, because it's an entire continent. EDIT: So I guess HN doesn't like being called out on https://africasacountry.com/ issues? Well sorry not sorry, but as someone born in Ghana I'm more a little tired of the se…

Would you have had a second thought if someone said "Some of the places I've been in North America don't have great reception"? OP never claimed or implied Africa was a country.
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