> I'm not an astronomer but I'm not convinced that that's the case.

I'm not entirely certain what the balance is here. I don't think my post made it clear that I'm not certain how big the effect would be, only that there is a tradeoff here which is hard to quantify.

I do know there is a lot of significant astronomy done by space telescope and that the importance of space astronomy is only growing.

Seems to me the answer is that those who benefit from the new satellite constellations (SpaceX, etc) should finance additional investment in astronomy to mitigate the effects.

> I do know there is a lot of significant astronomy done by space telescope and that the importance of space astronomy is only growing.

Former astronomer here. I would argue that the importance of space astronomy is actually decreasing. Satellite telescopes are most important at wavelengths that the Earth's atmosphere absorbs like IR, UV, and X-ray. At visible wavelengths satellite telescopes have been much less important over the past couple of decades due to the development of adaptive optics.

The main reason to put a visible wavelength telescope in space is that you avoid the smearing out of the source by the atmosphere. Adaptive optics solves this problem by correcting for the distortions induced by the atmosphere and bringing images to resolutions that are comparable to (though still not quite as good as) what you can achieve in space.

Since space telescopes no longer have the advantage of much greater resolution, there's much less of a compelling reason to use them for most research problems. (Some questions, of course, can only be tackled by using the highest resolution available.) On every other dimension space-based telescopes are inferior to ground-based telescopes. They are more expensive by many orders of magnitude, much, much smaller, and they cannot be changed once they're up (at least not easily). By contrast a ground based observatory can get substantially better over the course of a year by installing better detectors.

Adaptive optics have zero issues if you’re looking to make a cool picture, but they do introduce bias which is an issue for scientific instruments. That’s largely offset by more and larger telescopes for the same price, but it is very much a tradeoff based in launch costs which are falling.

IMO, over the next 30 years space based telescopes are going to play an ever larger role.

What about amateur astronomy? Are we now saying that only those with the means to afford space telescopes or expensive software can participate?

Are you an amateur astronomer or just trying to be the devil's advocate?

I'd be curious to know what the impact is on impactful amateur astronomy (as opposed to backyard hobbyists who are just engaged for personal pleasure). I know some amateurs use images created by public telescopes, I'm not sure how much meaningful work is done by amateurs using backyard equipment anymore.

Not being dismissive, genuinely curious.

Variable star observing is actually a place where amateurs really help, since it's about observation time, and not necessarily some hugely powerful telescope. And the more powerful a telescope is, the more people want to use it to point at all sorts of things, which makes it kind of expensive to use those telescopes for variable star observations which take a lot of time.

"Since professional astronomers do not have the time or the resources to monitor every variable star, astronomy is one of the few sciences where amateurs can make genuine contributions to scientific research." [0]

[0] https://en.wikipedia.org/wiki/American_Association_of_Variab...

And the Betelgeuse deathwatch!

In recent news, the only confirmed interstellar comet in our solar system was found by a dude who worked at an observatory (not as an astronomer) and decided to build own telescope for fun in his spare time. It's one of only two known interstellar visitors we've had, and because he found it early enough the pros were able to make very detailed observations.

A decent number of asteroids and comets are still found by backyard astronomers.

If SpaceX works out, we'll probably see a lot more telescopes in space. Wouldn't be that expensive at that point for, say, a school class to launch a telescope cubesat.

I'd trade amateur ground astronomy for that.

I'm not entirely sure how you think looking at an image on a computer screen compensates for the experience of doing observations with your own eyes.

There are plenty of good pictures on wikipedia already, do looking at those compare to going out on a clear night and looking at the stars yourself?

A LEO satellite constellation will absolutely not prevent you from looking into the night sky with a telescope and seeing stars.

"Seeing a star" is a low bar to pass, especially if you get a telescope to help you.

The dead of night will be fine. But during (astronomical) twilight, the time when you are most likely awake and looking up, it will have ugly extra dots.

Also I'm sorry but I really, really don't care about a hobby if it gets in the way of the progress of the entire human race.

Imagine if a painter in Greece in some century BC convinced his fellow Grecians that building a harbor in the cove by their town was a bad idea because it ruined his paintings of the cove. How was he supposed to look at the marine life if you stuck wood and industry in the water???

This. Every change has some negative effect. The question is whether the net effect is positive or negative.

What makes a dot ugly?

Can adaptive optics be applied to filter out objects like Starlink satellites?

Don't think so. Adaptive optics works by changing the physical shape of the mirror. If you measure the atmosphere continuously and bend the mirror the right way, you can remove atmospheric distortion from the image. If anything, AO just gets you sharper images of the starlink satellites (or significantly worse ones if a satellite flies in front of the guidestar that you're using as a reference point to measure atmospheric distortions).

You can filter them out computationally without adaptive optics with enough frames captured.

Modern astronomy works at the edges of whats possible, a single frame might take hours. Needing multiple frames would mean multiple days per observation. It would mean no longer seeing faint and distant objects, limiting us to younger, closer and frankly far more boring objects. It would make observing variability impossible for certain timescales.

You need old distant objects for cosmology, observing the structure if the universe, big bang and stuff. You need variability for finding exoplanets, measuring distance and observing transitions such as supernovae.

Oh, and then a huge part is taking spectra, which means bouncing the light directly off a grating. Filtering transients is hard to impossible there. You need spectra for relative motion, magnetic fields, composition of matter and radiation and of course temperature.

Needing such filters would set astronomy back a few decades

> pay for a resource they’ve been getting for free (unobstructed sky)

Wow.

If someone doesn’t manage or govern it with economic incentives, no one does (see: most of the “public good” rainforest slashed and burned in South America and Asia that we desperately needed managed better, through private ownership and conservation management, to avert climate change).

You’re shocked at my statement, as if StarLink is entitled. Consider the alternative argument: why should astronomy slow global comms progress? If astronomy is more valuable than the ~$30 billion/year global comms market, shouldn’t someone bear that cost?

Because ultimately, arguments relying solely on economics are moot.

Technically, a human life has an economic value. And yes such value is used every day to decide health policies and insurance coverage. Would this mean that SpaceX killing N humans (where N=30B*number of years of operation planned for starlink/value of a human live) is ok? Absolutely not.

That's exactly the calculus a company like Tesla does before taking a mass consumer product like a car to market.

No it doesn't. If you know something will kill people, economic arguments are not considered sufficient. This was famously decided when it was revealed Ford elected not to recall the Pinto on the basis of paying compensation was cheaper then the fleet maintenance they had to do.

Not considered sufficient to avoid penalties in a court of law. But even that example can be reframed as a failure to calculate total risk in the cost / benefit analysis (i.e. they should have factored in the risk of a lawsuit and federal fine).

Hot take: Because Starlink is a shitty answer to ISPs being run by shitty people.

Well then, we should also have Elon pay rent for use of space...

I think it’s hard to argue it belongs to you if you can’t get there. If you can’t defend it or control it, you can’t stake a claim to it.

https://en.wikipedia.org/wiki/Extraterrestrial_real_estate

This is actually one of the more interesting questions in space exploration in general. It has been ever since someone tried charging NASA for parking on the section of the moon they claim ownership of.

Defense would actually be quite easy. Just undesirable. There are working antisat weapons in the major powers' arsenals. However, they would produce nasty debris clouds.

And then there is also the vulnerability of the lauch site and control center...

And it is probably significantly cheaper to take down a sat than putting it up. So it would be a losing battle.

Not in general. A kinetic striker would require as much energy to reach the satellite as the satellite used to get there. Something fancier, like a targeted laser, to my knowledge doesn't exist with anything like the wattage needed to punch through atmo and still have effective kill on anything that far out (assuming you could solve the targeting problem to resolve the beam that tightly in the first place).

The satellite is in orbit. It requires significantly more energy to put something in orbit than merely reachin that altitude. Satellite killers are relatively small rockets that can use a small supersonic fighter jet as first stage, while it requires a much bigger rocket to put a satellite in space (it would depend on the orbit of course).

It is true that spacex can put a significant amount of satllites in orbit witha single launch though, so it probably evens it out.

That makes the relationship sound adversarial, when really there's mutual benefit to SpaceX and the international astronomy community. Astronomy can use cheap lifting capabilities.

And why does SpaceX get the privilege to rule the sky and the radio waves simply because they could stream Seinfeld somewhat cheaply?

It's a complicated question, but there are echoes of it in "Why does the US get the privilege of having their flag on the moon, just because they could get it there and nobody can take it back down?" or "Why do people have any right to the land they occupy, merely because they got there before other people did?"

First-mover advantage is real.

It’s not complicated. The answers to your questions are, “Because they can.” Possession, control, and force carry much more weight than some would like. It just makes those without power, authority, or any other stakeholder equity uncomfortable.

The US is not a super power because it asked politely and a committee granted it permission. Similarly, SpaceX will move forward because anyone with the authority to challenge them allows them to proceed.

What is the SpaceX constellation enabling that others aren't? Hint: theirs is not for consumers.

You're not wrong! The US DoD is already paying StarLink for proof of concept work for low latency, high bandwidth connectivity services.

Hey you're back! I asked you previously "That might work for imaging, but what's your fix for spectroscopy?" here: https://news.ycombinator.com/item?id=21577081

You replied "Optical, RF, or Xray?"

Then I said, "Let's start with optical." but then you disappeared!

So, what's your solution for long-slit optical spectroscopy?

Hey! I'm still waiting to hear back from the astronomer I paid to do the research. I still intend to report back with their DOI from the resulting paper. I recognize when I've exceeded my domain knowledge and need an expert.

To be clear, I think we're well in the realm of academic discussion; no one is stopping any global constellation due to astronomy concerns. As I've said many times in this thread and elsewhere, I think it's a growth opportunity for the astronomy community to move towards space based observation platforms, and with the plummeting cost of lift (ie SpaceX Falcon and Starship) I don't think that's an unreasonable position to hold.

No, they are too bright and will saturate the detector with even very short exposures. Best you can do is just discard the affected area, at worst you have to discard several exposures because the saturation effected the readout electronics.

Arecibo and VLA aren't affected by starlink at all. Those are radio telescopes. They don't even need to wait until nighttime to observe. It's only an optical/ir problem.

Starlink uses radio to communicate with the ground. A common complaint from radio astronomers is new radio satellite operators promising to not interfere with radio astronomy and then making no effort to follow through in that promise.