
Astronomers Despair as Starlink Train Ruins Observation of Nearby Galaxies - SubiculumCode
https://www.forbes.com/sites/jonathanocallaghan/2019/11/18/this-is-not-coolastronomers-despair-as-spacex-starlink-train-ruins-observation-of-nearby-galaxies/#4601f3666538
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modeless
> if we’re going to go into a future where you end up losing 30 to 60 minutes,
> that would be a significant chunk of our observing time through the night

As this comment implies, the worst case impact to astronomy is only going to
be about 30 to 60 minutes lost per night right after dusk and before dawn.
There will still be uninterrupted viewing time in the middle of the night
because the satellites will be in Earth's shadow and not visible at all.

Personally, I think the benefit of truly global broadband internet from space
is worth the cost of an hour of observing time per night. Even in the worst
case, ground based astronomy can still happen. "Despair" is not warranted.

On a related note, I made a website to predict when the Starlink satellites
will be visible for you. They look pretty cool if you can catch them, but
viewing opportunities are limited because of that limited time window before
they enter Earth's shadow.
[https://james.darpinian.com/satellites/?special=starlink-201...](https://james.darpinian.com/satellites/?special=starlink-2019-11)

~~~
pulisse
> Personally, I think the benefit of truly global broadband internet from
> space is worth the cost of an hour of observing time per night.

SpaceX isn't the going to be the last company or nation state to put up a
network of satellites like this.

~~~
sbierwagen
Do you have any reason to believe that additional satellites would alter the
geometry of the Earth so that they would be visible for longer after sunset?

~~~
mtnGoat
would larger objects, or ones at a larger orbit be visible longer?

admittedly, i dont know much about space stuffs. :)

~~~
scrumbledober
at a higher orbit their brightness will be less, but they will be illuminated
longer and visible from more of the planet. Assuming a constant average
reflectivity, larger objects will be more visible.

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robcohen
I understand that the astronomers are disappointed, but isn’t that because the
period we are in right now is immediately before it becomes 10x cheaper to
launch telescopes into space? Won’t it be so much better to observe directly
from space as opposed to from the earth?

Can anyone comment on this?

~~~
cstross
How much do you think all the sunk infrastructure costs of existing telescopes
cost, and how many years did it take to build them?

The bigger telescopes today have primary reflectors that are _vastly_ bigger
than the James Webb Space Telescope: for example the Large Binocular Telescope
with its 8.4 metre mirrors, or the Extremely Large Telescope (currently under
construction: first light due in 2024) with its 39.2 metre segmented priary.
Even the segmented designs weigh hundreds of tons; these instruments are too
big and heavy to put in orbit even with SpaceX's Superheavy/Starship.

If the light pollution from Starlink can't be mitigated, it'll be necessary to
replace dozens of hundred million dollar to billion dollar instruments which
took years or decades to build, at a post potentially greater than the entire
consat cluster.

~~~
deevolution
What's more important? Global internet access for the rest of the world
population or a few dozen telescopes? Imo internet access is going to have
immediate positive impact for billions of global disconnected poor.

~~~
cstross
I'm sure I could make better use of your home by demolishing it and erecting a
homeless hostel. Isn't that more important than your prior claim to live
there?

(This is a m-e-t-a-p-h-o-r, not a literal proposal, but what Starlink is doing
to astronomy on a global scale is pretty much equivalent. The onus should be
on Starlink to (a) not do that, or (b) pay for complete relocation or
replacement of the telescopes they've just wrecked. Yes, that's a lot of
money. Boo hoo ...)

~~~
shadowgovt
> The onus should be on Starlink to (a) not do that

Why? Astronomers have no more claim to ownership of the sky than Starlink
does.

~~~
pintxo
Astronomers are not changing anything IN the sky, Starlink does?

~~~
shadowgovt
The sky changes all the time. Astronomers are observers, and it seems the onus
should be on the observer to change the way they interpret the observation if
the observable changes. We didn't kill radio stations (or microwave ovens) to
make sure that radio telescopes can do their jobs
[[https://xkcd.com/2226/](https://xkcd.com/2226/)].

~~~
pintxo
Isn't there a "security-zone" around the large radio-telescopes where usage of
most electronic devices is forbidden?

------
lionheart
So I'm confused, because according to
[https://caseyhandmer.wordpress.com/2019/11/02/starlink-
is-a-...](https://caseyhandmer.wordpress.com/2019/11/02/starlink-is-a-very-
big-deal/)

"Based on the Starlink website, that all satellites will be deployed below
600km. In this case, satellites may be visible during twilight but not after
nightfall, greatly reducing the potential impact to astronomy."

Can anybody verify this?

~~~
shadowgovt
It's the physics of the arrangement of satellite, sun, and Earth. The
satellites are only visible due to reflected sunlight, and they're flying
quite low for satellites, i.e. near to Earth. The nearer an orbital object is
to Earth, the larger percentage of the arc of its orbit is occluded by the
Earth's shadow.

Given their close proximity to Earth, they can reflect sunlight at dawn and
dusk (when the sun is shining "along" the surface relative to the observer)
but when an observer is in nighttime (i.e. within Earth's shadow), Earth
blocks the path of light to reflect off the satellites and they won't shine.
Hypothetically, they could still pass in front of distant objects and occlude
them, but I'm assuming based on the way the problem is described that flooding
a telescope with reflected light is more of a problem than occluding a distant
object for a few moments.

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smabie
Laws to protect astronomy? Really? Talk about the strong needs of the few
outweighing the weak-moderate needs of the many. If I was an astronomer I
would be pissed, but let’s have some perspective here: vastly more people are
going to be helped by this than hurt.

Moreover, this sky pollution has already happened with light and eventually
will become a problem with satellites. There’s just no stopping it and we
should recognize that things change, sometimes for better or for worse. But
mostly, better for some and worse for others.

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Mobius01
I worry about the precedents being created. There is little in the way of
other companies or governments adding more to Earth’s orbit. Eventually there
could be enough objects there that one single incident could cause a chain
reaction and blanket Earth on debris making launches dangerous or impossible.

~~~
bpodgursky
All the SpaceX satellites are in LEO, low enough that even in the absolute
worst case scenario (which, FWIW, is not realistic), they will all de-orbit in
a couple years.

~~~
Rebelgecko
That is technically true for this batch of satellites. However at the next
shell out that they're planning on using (1150km) it can take a really long
time for an orbit to decay (decades or centuries depending on the size of the
thing). There's still radioactive crap in orbit from Soviet satellites that
were orbiting at 900km more than 40 years ago.

~~~
nickik
All of these automatically fly themselves to destruction. So we are really
only talking about a few defect ones.

Once we are launch 1000s of satellites we are defiantly going to have
servicing satellites out there. Refueling, orbital maneuvers and so on.

Even in the worst case, decades is still not that crazy. The locations are
known and can be avoid.

This is a problem, but really not any kind of gigantic issue that should stop
progress.

------
ksaj
Light pollution is probably a bigger problem, except on the tallest mountains,
or ironically, in orbit.

These astronomers seem to be obsessed with one guy, when there are way more
than just his satellites up there. It makes me think it's more of a lobbying
effort than a clear-sky thing.

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duaoebg
The noise looks very predictable, should be super simple to filter out

~~~
ISL
Super simple == many people-centuries sapped from funding-strapped research.

Furthermore, astronomy is just entering a paradigm where the entire sky can be
imaged multiple times per night with great optical depth. Transients are going
to be the next frontier, and that is precisely what these constellations will
create. A few lost satellites with improperly-documented orbits can fake
optical transients.

Furthermore, radio astronomers have moved to the outback of Australia to get
away from rare radio transients. A zoo of satellites is precisely something
they don't need.

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nickik
Once we have that man things in space we will have the launch capacity to
launch gigantic/multi satellite space overvaluation platform for gravitational
and 'normal' astronomy. Astronmy will benefit from this overall.

And what the alternative, for the rest of time not using this capability?

I understand that they are sad, but since this doesn't even effect the
majority of astronomers, I really think this is kind of a non-issue.

~~~
ISL
It will affect the majority of earth-based astronomers -- science these days
comes from the concordance of experiments.

------
oh_sigh
I'm extremely pro-space research, but if I had to weigh the benefits of some
astronomers observations being obscured sometimes versus getting hundreds of
millions of people onto the internet, I think the choice is pretty clear.

~~~
Uhuhreally
there are other ways to deliver internet

~~~
shadowgovt
there are other ways to do astronomy

~~~
Uhuhreally
from Earth there's only one way: telescopes

~~~
shadowgovt
Starlink hasn't rendered telescopes inoperative, nor will it. They still work
for 99+% of viewing time, and the satellites in question are invisible on most
of the radiation band telescopes can operate on.

This is a tempest in a teapot complaint. Ground-based telescopes already need
to account for the existence of satellites, airplanes, birds, the ISS, etc.
The Starlink constellation is just increasing the number of the things; it's
not changing the nature of the challenge.

Or would you recommend we ban microwave ovens because they deliver noise near
the radio spectra we use for Internet communication?

~~~
ISL
Banning microwave ovens (and RF transmission in general) is precisely what is
done near radio-astronomy sites (see Green Bank, the SKA, etc.)

~~~
shadowgovt
... but not throughout the whole town housing the telescope.

~~~
ISL
Including the town housing the telescope:
[https://greenbankobservatory.org/the-land-where-the-
internet...](https://greenbankobservatory.org/the-land-where-the-internet-
ends/)

~~~
shadowgovt
Do you propose to pass laws to turn the world into Green Bank, W.Va?

Because I, for one, kinda enjoy being able to have the conversation we're
having right now.

~~~
ISL
We are having this conversation now without significantly impeding the work of
astronomers.

~~~
oh_sigh
Is there anything that trumps the needs of astronomers in your book? If we
could go to 100% carbon free energy, but severely reduce ground based
astronomical observations, would you be against that?

~~~
ISL
Astronomers are way behind on this -- it has never been a problem before --
but launching a huge constellation of satellites _before_ considering the
potentially irreversible impact on a branch of science seems unwise to me.

Global internet sounds awesome, and has undeniable benefit to humankind.
Uncoordinated launches of large constellations will have some detriment to
humankind. The thing I'd like to see is a clear-eyed assessment of the impacts
and mitigation strategies _before_ there are billions more in sunk costs
deployed in launching these constellations. Once they're up, they're up, and
large companies will lose huge if the constellations have to come back down.

Motorola's bankruptcy came from insufficient monetization of Iridium. SpaceX
will be in the same boat, if they aren't already.

I'm an experimental physicist, not an astronomer. Limiting systematic
uncertainty is what I do all day. When I see these constellations, what I see
is a zoo of uncontrolled systematics and a shrinking opportunity to address
them before they become permanent.

As someone who looks at the stars, I want generations in the future to look at
the stars and have their imaginations captured by distant pinpricks of burning
hydrogen, not a visual screen of our own construction. Our children's
understanding of our place in the universe may depend upon it.

~~~
shadowgovt
FWIW, nothing about the SpaceX constellation is going to make the visible
pinpricks of burning hydrogen go away. They orbit too close to the Earth to be
visible at night in most of the sky.

How much astronomy relies upon sunrise / sunset observation windows?

------
ilaksh
Could something like Starship carry a large mirror?

Or could it ever be feasible to manufacture a large mirror on the moon, if a
large enough one can't be flown?

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colek42
Starlink is the way SpaceX is funding exploration to Mars. Please stop
complaining about your minor inconvenience. Someone in the government might
listen and cause needless regulation halting space exploration progress.

------
Uhuhreally
the view of the night sky is about to be destroyed by companies

~~~
shadowgovt
Not really. The satellites will be too small to see unaided in general, and
their proximity to Earth means that outside of twilight hours, they're
generally invisible.

(Also, "destroyed" is a matter of perspective. I think it'd look kind of cool
if every twilight you could look up and see a web of satellites drifting
quietly overhead ;) ).

~~~
Uhuhreally
no that would not be cool. Not at all

~~~
shadowgovt
Difference of opinion.

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kd3
What SpaceX should do is equip every satellite with a camera and lens
specialized for astrophotography pointed away from Earth to the sky. Then give
every one of them a unique ip address and interface that astronomers and
anyone else can connect to and take pictures and videos. Some of them could
even get equipped with bigger telescopes.

~~~
mturmon
The telescope in the OP whose observations were interrupted has a 4m primary
mirror. Hubble has a 2.4m primary mirror.

The optical corrector lens -- just the corrector lens alone -- that is part of
the camera instrument of OP has a diameter of 1m, with a mass of about 200kg.
([https://www.darkenergysurvey.org/the-des-
project/instrument/](https://www.darkenergysurvey.org/the-des-
project/instrument/)). The entire Starlink satellite mass is 227kg.

I don't think SpaceX is going to be putting instruments of this class on its
satellites.

~~~
kd3
That is not what I am suggesting either. Smaller telescopes and cameras but on
every satellite which can then be combined computationally as well. Tons of
possibilities. Of course, like I said, they could also equip some of them with
more powerful and larger hardware. But the smaller ones would already provide
lots of capabilities for very little extra cost relatively.

~~~
mturmon
OK, but that's not addressing the problem raised in the OP.

Dedicated CubeSats have largely filled the smallsat niche. I would expect the
Starlink mass has been carefully optimized already.

There _are_ interesting mission concepts (telescope + star shade; NEO
detection [1]) that are in the works with dedicated CubeSat constellations,
but yoking them to another spacecraft bus with its own constraints doesn't
sound likely to succeed.

[1]
[https://www.aanda.org/articles/aa/full_html/2017/07/aa29809-...](https://www.aanda.org/articles/aa/full_html/2017/07/aa29809-16/aa29809-16.html)

