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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

#131

Post by weego »

ImaCake wrote: post #116
51Cards wrote: post #114

Earlier quoted context omitted.

As I noted on a similar thread the issue is not removing the streaks, it's what data is lost behind those. If you take a look at this image you'll see that it can be a non-trivial amount of interference in some cases and that data can't just be filled in with "black". https://i.imgur.com/Qdt0N2g.png The interference also causes a "glow" effect on the CCD which corrupts the data well beyond the edges of the main strea…

I guess you could statistically impute that data. But it is the long tail of unlikely readings which are generally interesting, and imputation will not find those.

This is a logic flaw I see everywhere. Making a proposition for what might have been there is not a useful scientific instrument. And especially not when unseen anomalies are an integral part of pushing your field forward. If you're inferring what might have been there you're explicitly filling in based only on what you already know.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#132

Post by Turing_Machine »

rimliu wrote: post #60
pfdietz wrote: post #50

Earlier quoted context omitted.

Why do astronomers own the skies? I don't remember when they got title to that property.

I don't remember the sky being awarded to America either.

Other countries can, and do, put satellites up all the time.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#133

Post by [deleted] »

vanderZwan wrote: post #124
0-_-0 wrote: post #117

Earlier quoted context omitted.

It seems to be around 1-2%, which I would say is trivial. This can be further reduced if you use multiple exposures because then only 1 contains the streak. Getting satellite data from SpaceX about satellite positions and turning off the receiver for a few seconds would also mitigate the issue. I don't understand how this is treated as a problem that's worth halting satellite launches over.

> 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?

[deleted]

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#134

Post by totetsu »

modeless wrote: post #57
Thlom wrote: post #53

Earlier quoted context omitted.

Maybe, but with tens of thousands of satellites, each with a life expectancy of about 3-5 years then Space X will have to re-fill the constellation constantly.

Sure, you'll be able to see the most recent launch, just as you can now. But you won't see 30,000 in the sky, which is what everyone assumes. Also note that you can't see them at all in the middle of the night; only for an hour or so around sunset and sunrise.

Isn't sunrise and sunset the prime time for people looking at the sky for aesthetic reasons?

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#135

Post by rimliu »

dharma1 wrote: post #66

ok, so 30k satellites from SpaceX, 60k from OneWeb. I anticipate this is just the beginning, other US companies and other countries will want to launch similar amounts. What will the impact be when there are 500k+ satellites in LEO, who decides who can launch more?

I hope not many other countries would want to do so, because many have solved internet problem already.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#136

Post by tom-khagai »

DoingIsLearning wrote: post #36
tom-khagai wrote: post #9

I believe it would be difficult to further prevent this from happening since there is so much more demand for global, low-latency wireless internet than for astronomical observations.

> there is so much more demand for global, low-latency wireless internet than for astronomical observations. This is very much not true and a remarkably narrow utilitarian view. I understand US folks are poorly served in terms of ISP infrastructure and competition but please don't try to project those issues as a 'global' problem. Internet service is a solved problem, you have transoceanic cables and distribution net…

The demand is not limited to americans, most third-world countries will benefit from having high speed internet unconstrained by local infrastructure and lack of investment. Having stayed in South East Asia I know the locals would very much appreciate having more than one option: pay-as-you-go mobile data bundles.

Even in rural parts of Scandinavia where I spent my vacation, 4G signal was too weak and ISP's refuse to lay fiber unless the whole neighborhood commits to subscribe.

This may concern millions of people who need basic or better internet access, meanwhile there are only a few thousand astronomers in the world.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#137

Post by mikro2nd »

tssva wrote: post #92
gambiting wrote: post #48

Earlier quoted context omitted.

Exactly, if China launched thousands of satellites ruining everyone's astronomy efforts I'm sure there would be an uproar. But US doing it? Fine, business as usual.

The US isn't doing it. Companies are doing it. As stated in the article the company which is currently planning to place satellites at a height likely to have the greatest impact is OneWeb which is a UK company. It is soon to be controlled by the UK government and an Indian conglomerate. The satellites it launches are built by a joint venture which includes Airbus.

The USA is doing it: The permitting authority is a US government agency taking unilateral decisions that affect the entire globe.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#138

Post by pas »

jobigoud wrote: post #122
0-_-0 wrote: post #115

Earlier quoted context omitted.

Is it a difficult problem to solve though in software? On its face it seems trivial, and something that should be part of an astronomer's job description. The cost of not having internet satellites seems to be many orders of magnitude higher than writing software to get around the problem.

> On its face it seems trivial To me it seems completely impossible. How exactly do you expect to replace the missing information? Statistically from the neighboring pixels or frames? That works if your goal is to make an image prettier, but if you want to make measurements on the data "inventing" the background is not good enough.

Take many short expo images, and integrate them. This way you will have smaller streaks.

Yes, the sats will occlude things anyway, and their brightness is a big problem, but they are fast moving, they can be mitigated by moving to may short expo images combined. Yes, it's an undue burden, SpaceX should do more, but they can't solve it completely.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#139

Post by natch »

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…

The first few are bright, but as you said only at dawn or dusk. The vast majority of future ones are intended to be dark, with partial mitigations (not perfect, nobody is making that claim) like dark coating applied by SpaceX at their own expense.

With plentiful availability of orbital delivery, we can also expect more earth-orbiting space telescopes in our future, including private ones and with numbers possibly several orders of magnitude higher than what we have today. These will have higher orbits so that will help, and they will be largely immune to atmospheric effects.

I would suggest the astronomy community ask SpaceX and others to commit to giving key projects free or low cost launch services or ride sharing to orbit, to help compensate for some of the costs you allude to. If asked directly, Elon is often responsive.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#140

Post by 0-_-0 »

welterde wrote: post #125
0-_-0 wrote: post #117

Earlier quoted context omitted.

It seems to be around 1-2%, which I would say is trivial. This can be further reduced if you use multiple exposures because then only 1 contains the streak. Getting satellite data from SpaceX about satellite positions and turning off the receiver for a few seconds would also mitigate the issue. I don't understand how this is treated as a problem that's worth halting satellite launches over.

CCDs are not really receivers that can be turned off for a couple seconds. A physical shutter moves in front of the detector and covers it (for most instruments as they exist right now).

Can you move the shutter in front of the receiver when you know a satellite will transit?
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