
Stacked images of the comet, photobombed by Starlink satellites - _Microft
https://twitter.com/djulik/status/1286053695956881409
======
irthomasthomas
It's trivial to erase these things from photos. The photographer no doubt
knows this, but that isn't the point.

It's perfectly reasonable for scientists to want to capture accurate data on
the space surrounding the main subject being imaged. Simply erasing the
satellites from photos does not recover the data on the space behind. Any data
from behind the satellites is lost forever. This photo keeps the satellites in
order to visually demonstrate this problem.

Remember that astronomy today is often done on a single pixel of data.
Starlink blocks multiple pixels, and even ruins entire exposures when they
flare up. This will make astronomical research, like searching for exoplanets,
far harder and more expensive than it is today. Space telescopes are, and will
always be, orders of magnitude more expensive than ground telescopes to
launch, maintain and operate.

~~~
kbenson
If the images are stacked, doesn't that mean that there's plenty of images
with the parts that are occluded in others not occluded?

I understand for any specific image, there's going to be some lost background
because of Starlink satellites, but that's not what this is showing, this is
showing something that's not possible, right? Shifting all the satellites
temporally so they appear together, _arbitrarily maximizing the problem beyond
what is real_ isn't an accurate depiction of the problem, IMO.

Put another way, if you erase the Starlink satellites from the images _before_
stacking them, you then get a fairly accurate representation of the sky
without any Starlink satellites, and you still have the data behind them (from
the other pictures where that portion of the sky was not occluded). You can
also probably fix the intensity of anything occluded in a few of the pictures
but not others through some math.

~~~
mturmon
Not an actual astronomer, but somewhat aware of detector issues for space-
based telescopes.

Typically, you want to use one single integration time, if possible. Doing so
can limit readout noise, for one thing. (Note that ground-based
astrophotographers, with consumer cameras, often take multiple exposures to
cool down the detectors. This is not a factor with the actively-cooled
detectors in astronomical telescopes.)

For instance, the observations leading to the recent discovery of the two-
planet exosystem [1] used roughly 15-minute integration times [2, sec. 2]
across an 8 meter (!) aperture. This is a longer integration time than the 17,
30-second integrations that produced OP.

I think the above considerations about stacking vs single exposures are a side
issue, though.

The saving grace is that many astronomical observations are narrow-field-of-
view, and are done away from the _illuminated_ part of the StarLink
constellation. But, surveys or wide-field images could really be affected
strongly, at the 30-40% level [3].

[1]
[https://news.ycombinator.com/item?id=23917559](https://news.ycombinator.com/item?id=23917559)

[2]
[https://academic.oup.com/mnras/article/492/1/431/5680498](https://academic.oup.com/mnras/article/492/1/431/5680498)

[3]
[https://www.eso.org/public/archives/releases/sciencepapers/e...](https://www.eso.org/public/archives/releases/sciencepapers/eso2004/eso2004a.pdf)

~~~
rimliu
There are plenty of amateurs using actively cooled specialized
astrophotography cameras with total integration times reaching hours (2-3 are
typical). Readout noise can be cancelled by taking so called bias frames.
Shorter exposures are sometimes preferable because of the light pollution and
to minimize the possibility of an exposure being rendered usles by some plane
or satellite: it is less painful to throw away three minutes of exposure time
than 15.

~~~
mturmon
> Readout noise can be cancelled by taking so called bias frames.

That’s not what bias frames [1] are doing. Bias frames measure a systematic
effect in the conversion of stored charge to a digital number in the CCD
device. You can then subtract it out.

The calibration offered by bias frames does not fix readout noise, which is a
_random_ , not systematic, effect that is inherent in the same conversion.

You can use the bias frames to compute the strength of the readout noise
(i.e., the rms magnitude of its random part) but you can’t remove the random
noise itself.

See sec. 1.1 of the linked reference for more.

[1]
[https://users.astro.ufl.edu/~lee/ast325/handouts/ccd.pdf](https://users.astro.ufl.edu/~lee/ast325/handouts/ccd.pdf)

~~~
rimliu
The point of bias frames is what you take them without accumulating any
charge. Well yes, you cannot eliminate random noise, but you can reduce it.
Also, most popular deidcated astrophotography cameras are now CMOS not CCD and
readout differs in these. Your link does not work, and probably for the
better. See this instead:
[https://www.youtube.com/watch?v=O6oGyFlZgAc](https://www.youtube.com/watch?v=O6oGyFlZgAc)

------
sparker72678
Anec-data, but in my shots of the comets there were 0 satellites and about 12
airplanes with flashing lights that I had to remove. ¯\\_(ツ)_/¯

I get the frustration, and no doubt I'll be pissed when I have a shot that's
more affected, but amateur astrophotography seems like the least-important
reason to be concerned about Starlink.

But then, the photo is going to get more attention, for sure.

~~~
autokad
It doesnt matter the impact of amateur astrophotography's work, starlink
doesn't have the right to take that from them. I do think we need to evaluate
whether these costs are worth it.

I go further.

I myself think we need to take a second look at city light. I'd like us to
begin working on making the milky way visible again.

~~~
animal_spirits
I agree. Vast populations of people can't know their place in the universe
because they physically can not see it. What can we do to avoid that? In
suburbs it seams feasible to stop building / start removing streetlamps in
neighborhoods that don't necessarily need them, but I don't know how that
would work in bigger cities

~~~
kergonath
Better, more directional street lamps help, even in large cities. We can tune
their wavelength to be less blinding as well. They do not need to illuminate
the sky. More of them, and less powerful, would provide better light where
it’s actually needed.

The other side is to reduce emissions of aerosols and particles that scatter
light in the atmosphere.

------
kbenson
Flipped on its head, I would say Starlink, or at least the underlying
technology that makes it feasible (and it's all related, since it's all
SpaceX) may be _good_ for astronomy... _eventually_.

Space based telescopes give a much clearer picture than land based ones. You
can't have ubiquitous and/or (relatively) cheap space based telescopes without
a thriving launch industry that reduces costs. You can't have that without
innovation and competition in the space launch industry. You are unlikely to
innovation or competition in that industry the without a market need. Starlink
_is_ the market need right now.

Want lots of space telescopes to give you even better pictures? Don't kill off
what's going to take you there before it begins. The astronomy industry needs
to work with SpaceX to minimize the problem while also encouraging them (and
anyone else working to drop costs to launch something into orbit) to succeed,
not killing off or greatly delaying the oncoming age of ubiquitous and easy
access to space telescopes because they are short sighted.

~~~
rumanator
> Space based telescopes give a much clearer picture than land based ones.

Aren't those far more expensive to launch and operate?

~~~
kbenson
Right now? Yes. As I understand it you get much more capability for your size
of telescope if in space, because you don't have to look through the
atmosphere. If launch costs go down (which they are), and satellite components
and labor to build operate become cheaper (because of increased general
experience, supply of parts and labor, etc), then space satellites become
cheaper. If we get better at assembling things in space (which we're only
going to do after demand and experience in doing it), it might even be easier
to make a larger telescope in space than on land eventually, and the stresses
of gravity on the structure for the mirror are greatly reduced or eliminated.
It looks like all the recent large telescopes are with segmented mirrors now
anyway.[1]

1:
[https://en.wikipedia.org/wiki/List_of_largest_optical_reflec...](https://en.wikipedia.org/wiki/List_of_largest_optical_reflecting_telescopes)

~~~
rumanator
It seems you're basing your assertion on projections based on wishful
thinking. It's like saying to a cancer patient that he shouldn't worry about
having cancer because in the future you believe there will be wonder drugs
that fix everything. Well, perhaps there will be wonder drugs in the future,
but what about real life, and real life solutions to real life problems? I
already have a ton of money invested in earth telescopes. What good does it do
me if you argue that in the future I might gain some capabilities if I scrap
everything and buy a whole new infrastructure?

Moreover, you only need a guy with a wrench to fix a telescope on the ground.
If your telescope is in orbit then the problem is a tad more expensive to fix.

~~~
kbenson
> It's like saying to a cancer patient that he shouldn't worry about having
> cancer because in the future you believe there will be wonder drugs that fix
> everything.

Is the field of astronomy facing death because of Starlink? That seems a bit
excessive.

I would say it's more like a national healthcare system covering only poor
quality glasses for vision for a decade while they pump money into research
and training for laser corrective surgery to both reduce the downsides and
make it much more affordable, in preparation for covering laser reconstructive
surgery at the end of that period.

> I already have a ton of money invested in earth telescopes. What good does
> it do me if you argue that in the future I might gain some capabilities if I
> scrap everything and buy a whole new infrastructure?

Again, telescopes aren't scrapping everything, astronomers aren't going to
disappear. They're at most some percentage less useful than they thought they
would be prior to this. That sucks, but homeowners have complained about other
people moving in and obstructing their perfect view for a long time, so it's
not entirely new. I don't support Starlink because I think SpaceX has some
right over astronomers, but because I think humanity as a whole benefits from
more industry in space, and there's a solution for astronomy on the other side
of this, and I don't want humanity held back because astronomers feel it
infringes on a domain with a problem they've generally not had to worry about
(even if they would probably argue that they are doing it for the benefit of
humanity by providing knowledge).

Bottom line, I think the benefit to humanity from increased space industry is
greater than the benefit unhampered astronomy provides in a case where we
impede that industry.

~~~
astrophysician
To be honest, I understand where you are coming from, and share your opinion
that many issues are more important than astronomy, including humanitarian
issues. I think actually most astronomers would agree with that (the ones that
I know, anyway).

But the problem here is with the _way that this debate is being framed_. There
is a false dichotomy that has been repeated here which I sum up as basically
"Space-X is trying to solve humanitarian problem A, and astronomers are
getting in the way! Deal with it astronomers, you are not more important than
humanitarian issue A." but that's not at all what's actually happening. This
is a monumentally impactful project undertaken by Space-X in secret, with
enormous ramifications on science that -- despite the simplistic claims here
-- are _not_ something that can be worked around (LSST and other projects
_cannot_ be done in space, regardless of the cost of space delivery). Instead
of responsibly investigating the impact, consulting with scientific agencies
to either mitigate them, or prepare for the impact (as they are doing now
after a huge outcry, but there is little that can be done now), they have
instead opted to completely blindside entire branches of science, ruining
decades of work around the globe and impacting tens or hundreds of billions of
dollars in R&D. Even their press releases now say things like they are
"learning how astronomical detectors work" \-- that is extremely disturbing.
That should basically never happen. There are responsible ways to do what
Space-X has done, and they have shirked those responsibilities.

------
ortusdux
Each starlink group is inserted at a low orbit, booted up and tested, and then
they boost themselves to a higher orbit over a period of a month or so. During
this boost, they orient their panels horizontally to minimize drag. Once they
reach their final orbit, they rotate their panels vertically, at which point
their visibility goes way down (mag 5 (prior to the new coating) down from a
mag 0).

I've seen plenty of people saying some variation of "there are only 600 of
these now, imagine what it will be like when there are 42k of them..." If I
understand correctly, the number of bright satellites will be proportional to
the launch rate, not the total quantity in orbit. Going off Wikipedia, they
have launched about 1/8th of their 2024 goal, and the majority of the
remaining satellites are destined for much higher (and dimmer) orbits.

[https://en.wikipedia.org/wiki/Starlink#Constellation_design_...](https://en.wikipedia.org/wiki/Starlink#Constellation_design_and_status)

~~~
Rebelgecko
>If I understand correctly, the number of bright satellites will be
proportional to the launch rate, not the total quantity in orbit.

Because the constellation needs constant replenishment, the launch rate (and
hence the # of brighter satellites) will have to reach a steady state that is
directly proportional to the size of the constellation.

We can extrapolate that in the future this rate will actually be
_significantly_ higher than it is currently:

They currently have permission to launch around 12,000 sats. They're launching
around 250 per year. The current launch rate is only sustainable if each
satellite lasts for _50 years_.

If you expand that to the proposed 42,000 constellation, 250 new satellites
per year is only sustainable with a MTBF of around 150-200 years per
satellite, which is nigh impossible in low Earth orbit. Using a lower (but
still very generous and optimistic) MTBF of 10 years, Starlink will need to
launch 4,200 satellites every year, about ~15x _higher_ their current launch
cadence.

> the majority of the remaining satellites are destined for much higher (and
> dimmer) orbit

Just about all of the satellites they've orbited so far are hanging out around
550km. SpaceX initially got permission to go as high as 1300km, but they've
since changed their mind. The new plan (still pending FCC approval I believe)
is to keep all of the satellites between 300-550km. So the future satellites
will be as low or lower than the current ones.

------
Nikkau
It's bad faith, a normal stacking would have made them completely disappear,
it's one of main reasons to do stacking, remove things which are not on all
images, and it's works flawlessly.

You have to actively tweak your settings to create this kind of photo.

~~~
vilhelm_s
I guess the most basic way to stack (just add the images together) would leave
them in, but

> Almost every modern astronomical post-processing program has a rejection
> process (sometimes referred to as sigma-reject) to remove unwanted signals,
> though the exact sequence will depend on which program you use.

[https://skyandtelescope.org/astronomy-blogs/imaging-
foundati...](https://skyandtelescope.org/astronomy-blogs/imaging-foundations-
richard-wright/satellites-begone-how-to-remove-satellite-trails-from-your-
astrophotography/)

~~~
woko
From your link:

> The way this process works is that, while averaging all of the pixels in a
> series of, say, 10 images, the program mathematically calculates which
> pixels fall far away from the mean value because they're much brighter (or
> much fainter) compared to the same pixels in other frames. The algorithm
> then discards those out-of-range pixel values so they don’t affect the final
> image.

Wouldn't this process remove part of the comet trails as well as the satellite
trails?

I mean, I get how it works if all you care about is relatively static like
distant stars, but would it work for this specific use case?

~~~
Sharlin
No, because the comet does not perceptibly move in the sky during the
acquisition. All comet pixels are present in every image.

~~~
_Microft
The comet does not change but its position in the sky does btw. Longer
exposure times turn points into streaks if the object is not tracked to
compensate for this.

~~~
Sharlin
Yes, I assumed tracking as it's basically a mandatory requirement when you do
telephoto astrophotography, and definitely used in the OP photo. The
alternative is to shoot wider angle and align the images during stacking, but
either way you have to get your subject's pixels aligned or the result is just
blur.

------
ianmcgowan
Apart from all the comments about this being a bad faith post, I wonder about
the utilitarian argument, if you take it at face value. If you could provide
decent internet at low cost to large parts of the world that are underserved,
at the cost of ruining ground-based telescopes, is that a good trade-off? What
if it's just certain kind of telescopes, or certain classes of astronomers (as
this seems to be)?

~~~
marcus_holmes
I think this is useful if we also consider that part of SpaceX's plan is to
make launching satellites cheap (in fact, launching anything cheap). So while
ground-based astronomy will suffer, space-based astronomy will get cheaper and
easier.

Presumably to the point where people who want to can subscribe to a Hubble-
like satellite service and get all the space photos their hearts desire.

Also, we made a similar trade-off a long time ago - most people live in
heavily light-polluted cities, because we value having street lighting more
than being able to see the stars.

~~~
justapassenger
Cost of launch is not really main reason why we don’t see more space based
astronomy.

1\. Space is a hostile place, and developing telescope that works there is
much harder. 2\. There are very real limits on size and weight of what can be
put there right now, and rocket equation is ruthless. 3\. Any type of
maintenance or upgrades are basically impossible, compared to earth based. 4\.
Adaptive optics were such a huge breakthrough, that basically negated need for
most of space based telescopes.

~~~
TeMPOraL
Reasons 2 and 3 are big part of why launches of expensive.

There's a feedback loop in space launches: they're expensive, therefore you
launch less, so you need to add redundancies and spend more time ensuring the
payload will work, which raises the development cost and increases mass, which
makes launches less frequent and more expensive.

Conversely, reducing the cost of access to space means you can send more stuff
that's less robust, which shortens development time and makes it less
expensive, and of course makes technological progress faster.

Which translates to: suddenly space telescopes may be more affordable, and
more of them will be launched.

~~~
gammarator
Some ground-based observatories have been productively operated for nearly a
_century_, with improvements in instrumentation providing leaps forward in
sensitivity. That amortizes the cost of the observatory (mirror, site, etc.)
across many years.

Even with cheaper launches it's much harder to get that benefit in space--
servicing missions are much more expensive than driving up a mountain...

------
whoopdedo
The truth is most people will never notice the Starlink satellites. Because
light pollution obscures the night sky so much you can only see the brightest
of stars and nearly nothing close to the horizon. How many kids are hearing
about this comet in the sky, rush out at sunset, and are then disappointed to
only see the haze of city lights?

~~~
daveslash
Truth is, _most people_ never look at the night sky, period. But this isn't
about _most people_ ; this is specifically about people who look at the sky _a
lot_ \-- and those people typically seek out darker skies anyway.

~~~
catalogia
> _Truth is, most people never look at the night sky, period._

Truth is people never look at the sky _period_. Ask people when the moon is
visible and most will say _" during the night."_ But about half of the time,
the moon is actually visible during the day. Wouldn't people realize this if
they simply looked up?

~~~
cnity
That's because what they mean is that the moon appears more brightly at night,
and I suspect you know this. You don't _actually_ think these people have
never seen the moon during the day, surely?

~~~
catalogia
> _That 's because what they mean is that the moon appears more brightly at
> night, and I suspect you know this._

No, I don't think that's the reason. The moon is frequently very bright during
the day, not even remotely hard to see. Moreover, people are mostly outside
during the day, meaning that most of the time they have the opportunity to see
the moon will be during the day.

I think the reason is that a supposed sun/moon - day/night dichotomy is
perpetuated by culture (for instance, clock dials that use an image of the
moon to symbolize the night) and that culture has a stronger impact on
people's perception of the moon than their personal observations of the sky. I
think they have seen the moon during the day, but the moon is very rarely the
object of their attention. They see it, but rarely do they notice it.

The reason for such a culture emerging seems obvious to me; the Sun's presence
in the sky obviously correlates with daylight perfectly, making the sun an
obvious symbol to associate with the day. But then what symbol would you use
for the night? There's a clear day/night dichotomy, creating a demand for a
symbol that's inverse of the sun. However there's no object in the sky that
correlates so perfectly with the night. The moon isn't there half the time,
but neither is any particular star. You could use generic stars, and sometimes
that's done, but stars aren't necessarily visually distinctive. The moon is
visually distinctive and so it's pressed into the roll of being the symbolic
opposite of the Sun, even though a trivial glance into the sky reveals that it
isn't actually opposite of the sun.

~~~
savoyard
“And God made two great lights; the greater light to rule the day, and the
lesser light to rule the night.”

------
Alupis
I find it astounding that just any old for profit company can decide to ruin a
world-wide public resource just to turn a few bucks. In 2020.

I'd expect that from something like the East India Company in the 1700's or
something. Not a modern company in a modern society.

~~~
oh_sigh
Do you shake your fist at every airplane that flies overhead too?

~~~
Alupis
The country agreed to that. One day the country may decide against it. No-Fly
Zones can be created.

A US company airplane passing over my house doesn't impact people in India,
for example.

Airplanes have proven utility. Airplanes proved their utility before bothering
people worldwide.

~~~
oh_sigh
The country agreed to the starlink satellites as well, considering they
received FCC approval.

The country can still decide against it and now allow any more launches, and
the satellites that are up there will come down naturally in a few years time.
You may even be able to forcibly deorbit them if they still have propellant
left (not sure if they do or not).

No-fly zones are almost always created for the government to do government
things, and not for the direct benefit of the public (ie reducing airport
noise for nearby residents).

A US plane passing over your house doesn't impact people in India either
negatively or positively(except for the consequences of global warming). These
satellites passing over the US and India can equally benefit people in the US
and India. It's not like starlink is a US only service and SpaceX is going to
prevent anyone in India from having access.

Satellites also have proven utility, as does the internet, which is why groups
like the UN General Assembly HRC declared access to the internet as a basic
human right.

~~~
Alupis
What is not proven is if Starlink will work the way it's been sold to you as
an idea. What is also no proven is if it can be profitable even if it does
work. People in these remote places of the world are unlikely to be able to
afford internet... not have a need or desire for it. They have other
priorities.

Not to mention there's already ways to get very high-speed internet to remote
villages that want it. The only barrier is cost - but for motivated villages
and/or governments, it's not very expensive ($10's of thousands up front cost,
trivial long-term costs). I've sat in many conferences with people building
out wireless networks in remote regions - very fascinating work.

There's some pretty non-trivial chance Starlink was only approved because of
the Cult of Elon.

SpaceX wants to put 1,584 satellites in orbit[1] to the cost of around $10
Billion USD, and will need to replace these routinely due to orbital decay.

There's only 2,666 satellites in orbit currently[2]. 1,327 of which are from
the US[2].

Re: No fly zones - they can be established for all sorts of things. There's no
fly zones around many amusement parks, for example, and not just because of
the remote possibility of some terrorist attack.

> UN General Assembly HRC declared access to the internet as a basic human
> right

That seems simply to be virtue signaling. Of course everyone should have
access to information and knowledge, but that's not exclusive to the internet.

It costs money to provide internet access. Basic Human Rights don't cost money
to exercise. The Right to be Free doesn't require a monthly payment to some
mega-corp. If it did, you would not be free, would you?

[1]
[https://en.wikipedia.org/wiki/Starlink](https://en.wikipedia.org/wiki/Starlink)

[2] [https://www.ucsusa.org/resources/satellite-
database#:~:text=...](https://www.ucsusa.org/resources/satellite-
database#:~:text=In%2Ddepth%20details%20on%20the,purpose%2C%20and%20other%20operational%20details).

~~~
oh_sigh
Literally anything that hasn't been done yet hasn't been proven, so I don't
really understand how you can use that as an argument against it. At worst, if
it is unsuccessful, then the satellites will just stop getting launched and
will all fall back to earth after a few years, and Elon et al will be out a
few billion dollars.

> People in these remote places of the world are unlikely to be able to afford
> internet... not have a need or desire for it. They have other priorities.

Not my experience visiting some remote areas of India, Nepal, and Tibet. A
single anecdote, but I gave a man a ride to the top of a mountain near Ganden
monastery so he could use his cell phone. He went with a list of messages of
various people in his family and who to send the messages to. He would
normally walk 3 hours uphill in order to get service to send those messages
(This was in 2007, maybe things have changed since then).

> The only barrier is cost - but for motivated villages and/or governments,
> it's not very expensive ($10's of thousands up front cost, trivial long-term
> costs).

Many places in the world wouldn't be able to drum up tens of thousands of
dollars, and it isn't for a lack of motivation. But they might be able to drum
up $500 and then $60/mo.

> There's some pretty non-trivial chance Starlink was only approved because of
> the Cult of Elon.

The FCC isn't composed of the twitter mob or the spacex subreddit.

I'm not really interested in debating positive or negative rights, or whether
the UN was virtue signaling. My point was that many people view internet
access as extremely important for humanity, and starlink and other projects
may be an incredible boon for the world, at the expense of _some_ astronomy
observations.

~~~
thewalkeroo
“This was in 2007, maybe things have changed since then).“

So before 3G, when AT&T had an exclusive deal to sell a locked iPhone.

I mean I remember having to use dial up for the first time in years when I
lived in Spain in 2005!

------
dvxvd
im 100% against that commercial project is destroying my night sky.. its like
building highway through my yard.. our already overglobalized world will be
even more 'globalized' in the hands of few.. w t f..

------
todd3834
What are some of the potential consequences of this? I’m curious if stars
getting photobombed is a signal pointing to a greater issue? If they can coat
them in a way to not be reflective then will most astronomers be satisfied?

~~~
pmontra
We will exchange white lines for black lines. We won't be able to see through
the satellites.

Actually maybe a white line is simpler to remove than a black one on a black
background.

~~~
sp332
Black lines are far preferable because they do not contribute to the total
amount of light collected. A momentary flash from a bright light can swamp the
sensor, but a brief moment of blackness will leave the pixels' state much less
disturbed.

~~~
Kye
This is why long exposure photographs of roads have light trails with no cars.

------
toohotatopic
Wait till we have the first moon bases and there will never be a new moon
again.

~~~
f00zz
Can't wait!

------
LeChuck
I wonder if these things will have any effect on astronavigation. It would be
sad to see such a cool practice become impossible.

~~~
catalogia
I don't see why they would. The stars typically used for astronavigation are
very bright; brighter than starlink satellites. A brief web search leads me to
believe typical starlink satellites have a magnitude of around 5 or more,
while the stars typically used for astronavigation have magnitudes of less
than three
([https://en.wikipedia.org/wiki/List_of_stars_for_navigation](https://en.wikipedia.org/wiki/List_of_stars_for_navigation))

Even if that weren't the case, it's easy for the human eye to distinguish a
star from a LEO satellite; the satellite is the one that's moving fast. I see
no reason the sailors couldn't simply ignore the satellites.

~~~
LeChuck
It was the brightness I was worried about, yes. Should've probably just looked
it up myself!

I don't think astronavigation is used in any serious capacity anymore, so in
that sense it's a moot point. Still, it's a cool practice and it would've been
too bad to see that go away.

------
ineedasername
There's a tension here, and I'm not saying that I know where the appropriate
balance is-- but it's a tension between the positive societal impact that
inexpensive and ubiquitous broadband may have, vs. the societal impact of
scientific knowledge from ground-based observatories.

I'm sure there's other ways of solving the broadband problem. I'm sure there
are other ways of getting the astronomical data. I'm also pretty sure that all
of them would have their own trade offs. Everything does.

In this case, I think the unilateral approach that Musk is taking has hurt
perception of the project as much as the trade offs represented by the project
itself.

------
asdfk-12
Perhaps to remedy the situation, SpaceX would do well to introduce a large
fleet of freely-accessible amateur astronomy platforms with some kind of
timeshare credit component? I ordered several images through a university
terrestrial telescope as part of an astronomy course and it was a great
experience to refine the object's orbital parameters based on the
observations.

------
valuearb
This is pretty much a cherry picked worst case scenario. The comet is only
visible right above the horizon after sunset for a brief period.

Starlink satellites are also only visible low on the horizon, and only for
brief periods after sunset and before sunrise, because their low orbits keep
them in the Earths shadow the rest of the night.

~~~
asdfadsfgfdda
Yeah its basically optimized to look bad. The satellites are relatively close
to each other. In normal operation, there's no reason to have 30 different
satellites in view. I suspect these satellites were very recently launched, so
they are not in the normal sun-tracking orientation.

Also, the comet is a wide object. A wide image is just more likely to have any
satellite in view.

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tinus_hn
That’s odd, I took a bunch of pictures of that same comet and saw no
satellites at all. Did I do something wrong?

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shadowgovt
That looks so cool.

------
zelon88
The OP posted this in the ensuing Twitter argument...

> Why (on Earth) do you want to become a multi planetary species??

That's just an un-neccesarily foolish question. Why does a dog swim when you
place him in a lake?

> Have you ever tried to live in Antarctica or in the Atacama desert (I have)?
> I support science, exploration, tech development but not foolishness. Do you
> surround your house with roads to explore distant locations?

Isn't that exactly what we've done as a society already?

~~~
time4hn
> That's just an un-neccesarily foolish question.

On Twitter there seem to be a lot of people on who expect to _live_ in other
worlds soon, and not just to explore and study them. He's likely rhetorically
responding to that idea. And I think it's worthwhile to confront those ideas
critically. IMO as well, living off of Earth sounds hellish, given what we
know now.

The person the Twitter poster is talking with is now suggesting that many
people will abandon their physical bodies, and those that won't will live in
cylindrical space colonies. He's speaking fantasies.

~~~
crowbahr
Twitter OP is also arguing that there will never be human settlements off this
Earth, which is bullshit.

Assuming humanity exists long enough, it will expand throughout the solar
system. At very least to the moon.

We can argue about how long that might take, but not about it ever happening.

~~~
dhosek
_> Assuming humanity exists long enough_

That's a big assumption.

There's also the _why_ question. What's on the moon that would make it worth
all the difficulty to get there? I suppose we might have a semi-permanent
research station on the moon or even Mars, but colonization? Unless we make
some really unlikely discovery like unobtanium is only found on Europa and
it's really super useful, we're not going to have space colonies.

~~~
dwaltrip
The moon will be a good source of water for spacefaring endeavors of the
future, due to the large quantities of ice it has at the poles. With 1/6 the
gravity of earth and the appropriate infrastructure in place, it will likely
be cheaper to get that water off of the surface of the moon than from the
Earth. The most promising use here is actually for producing methane fuel from
this water. An industrial base of sorts could develop around this.

The other potential industry will be moon tourism. It could become something
like the new Mt Everest. Obviously only for the very rich at first.

Once it becomes a real possibility and not some crazy sci-fi project,
governments may start competing, so as to not get “left behind”, even if it is
not immediately profitable.

One way or another, unless we destroy ourselves, it will happen eventually.
There’s a percentage of people who are just absurdly curious and adventurous,
and want to go where no one has gone before, even if the cost is immense.
Hell, for some, I’m sure even just desire to get away from their situation on
Earth will be a big part of why they go for it. People like this will build
the first settlements and bases on the moon and elsewhere in the solar system.

Edit: sorry for the constant edits. It’s a bad habit — I don’t always get my
thoughts out on the first try.

~~~
dhosek
So, going to space to the moon is useful because it enables going further out
to space.

And I'm not entirely sure how you turn water (H₂O) into Methane (CH₄). Granted
I barely passed freshman chemistry 33 years ago so my chemistry knowledge
isn't so good, but as near as I can recall, there is no process that will turn
that input into that output.

And again, even if the moon is a source of water, there's not a significant
need for any water mining operation at the poles to have a colony around it or
even any human staffing. Putting people there on even a semi-permanent basis
would likely eliminate any gains to be had from using the moon as a source of
water.

Even the space tourism doesn't call for settling the moon. No one lives on top
of Mount Everest either.

~~~
gmanley
Could you simply separate hydrogen from the water, using electrolysis, or
other methods and then use the Sabatier reaction? [1] Carbon dioxide in bulk
may be harder to come by on the moon, however.

Also, the Lunar Gateway [2] is a key part of the plans by NASA/SLS. It's not
about settling on the moon, it's about making it a stop off point to refuel or
pickup supplies before going on to a further off destination like Mars.
Instead of having to have all your fuel and payload when taking off from
Earth, you can have a lot of your supplies and weight on the Moon. This means
your trip off Earth can be cheaper. Getting out of Earths gravity and getting
to escape velocity is the hard part. Getting off the moon is a lot easier.

[1]
[https://en.wikipedia.org/wiki/Sabatier_reaction](https://en.wikipedia.org/wiki/Sabatier_reaction)
[2]
[https://en.wikipedia.org/wiki/Lunar_Gateway](https://en.wikipedia.org/wiki/Lunar_Gateway)

~~~
dhosek
The Sabatier reaction relies on carbon dioxide. For the concept of using it to
generate rocket fuel, there's a reliance on atmospheric CO₂ which is viable on
Mars but not the Moon (which is why the section in the Wikipedia article is
called “Manufacturing propellant on _Mars_ ”). And the Lunar Gateway is
irrelevant to what I'm arguing, which is that there's not really any reason to
settle off-planet.

------
kome
i can't believe people are suggesting to edit this away with photoshop... you
are pointing at the moon and they are looking at the finger...

~~~
catalogia
That the image tweeted is a product of photoshop in the first place should be
obvious to anybody who _looks up._ Go outside tonight and look up. Does the
sky appear as it does in that tweet? Obviously not.

~~~
nimih
And how about that black hole photo from last year? Definitely a hoax--black
holes are supposed to be _black_ , dummies!

~~~
catalogia
The image being the product of a computer program processing data does not
mean that it's a hoax. That's moronic, and it's not even remotely what I'm
talking about.

Fixing the image is not a matter of "editing it out in photoshop". It's a
matter of processing the data correctly in the first place, e.g. _not editing
it in_. The author of the tweet stacked his images to show every satellite
instead of removing every satellite, which is ass-backwards.

------
gpm
Easily solved in software by removing the small part of each frame that has a
satellite in it. Satellite tracks are completely predictable. This is not
novel.

~~~
Kye
Somehow I get the feeling people who do this professionally understand what's
possible and what effect this has better than you.

~~~
gpm
They undoubtedly do, but this is an opinion formed by talking to people in
person in the industry. Random twitter users who manage to get there tweet on
HN is not even close to an unbiased sample of professionals in the industry.
My sample undoubtedly also has its biases, but is not selected for
sensationalist views at least.

~~~
Kye
This is "I talked to some people" vs the linked tweet from a person in the
industry. I think you can understand my skepticism. I also understand you
probably don't have a convenient way to prove your side of it.

------
aaron695
How did we get to this cargo cult where sitting on our behinds taking photos
of the stars and un-ironically posting on the internet supersedes mastering
space.

It's mostly the media, who care's not for science at all pushing this 'we
should be outraged', but we eat it up.

Starlink and others helping the world will also create a whole new genre for
ground based space photography the super rich can get into, but this drama is
so tiring.

------
mchusma
If you want humans to become a space faring people, you need to accept the
idea that there will be at least 1000x more things in space.

People's comments here are generally insane to me.

Let's go to other planets. Let's build a Dyson swarms of O'Neil cylinders with
a quadrillion humans living in luxury. Let's keep the light of consciousness
alive.

Some things will change along the way, like amateur photography.

------
hombre_fatal
How much sympathy can I really spare for a purely leisurely hobby like
backyard astronomy vs. satellites, Starlink, and our space tech?

To me it's like complaining that your photography hobby is harder now that
more people can afford to travel and they get in the way of your favorite
tourist shots.

I'm sure there are good examples of trade-offs that matter here like the
impact on terrestrial research telescopes, but a guy snapping a pic of a comet
and ranting about it on Twitter frankly has the opposite effect on me.

~~~
dmitriid
True, because professional astronomers, lucky them, are provided a completely
different sky devoid of satellites, debris and other man-made objects.

~~~
marcus_holmes
If we can make space travel cheap enough to get more Hubble-like telescopes up
there, then yes, this.

I believe that's part of the goal of SpaceX

~~~
wbronitsky
Yes, but the point is that we should do that first before polluting the night
sky.

There are also reasons for humans and animals to not want new, moving stars
for reasons other than pure utility. At the very least, these shiny beacons
are an insulting advertisement for Musk.

Next, people will be defending a Pepsi ad on the moon or something.
[https://www.theatlantic.com/science/archive/2019/04/pepsi-
ad...](https://www.theatlantic.com/science/archive/2019/04/pepsi-
advertisement-space/587608/)

