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SpaceX satellites could blight the night sky, warn astronomers

theguardian.com

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Re: SpaceX satellites could blight the night sky, warn astronomers

#41

Post by batbomb »

perilunar wrote: post #39
batbomb wrote: post #37

Earlier quoted context omitted.

The amount of light will still be appreciable and will affect many kinds of observatories around the world, even at magnitudes less brightness. You also can't slew a telescope in space like you can on ground, it would be extremely cost prohibitive in terms of fuel. "moving telescopes to space" is the equivalent of "let them eat cake" comment in this funding environment. It sounds like a wonderful proposition until yo…

>You also can't slew a telescope in space like you can on ground, it would be extremely cost prohibitive in terms of fuel. You can use reaction wheels instead for zero fuel use.

not quickly

Re: SpaceX satellites could blight the night sky, warn astronomers

#42

Post by perilunar »

This is such an incredibly short-sighted view from astronomers. The same tech that is going to enable SpaceX to launch thousands of satellites is exactly what will enable (and fund) the expansion of humans into space — which will be more of a boon to astronomy in the long term than any number of large ground-based telescopes.

I'm perfectly happy to permanently screw over ground-based astronomy if that's what it take to get us into space.

Just build the damn telescopes in space. And stop thinking single-mirror scopes like Hubble — you could build huge multiple-segment mirrors in space — much bigger than anything on earth.

Re: SpaceX satellites could blight the night sky, warn astronomers

#43

Post by maxander »

From a minute of googling, there’s roughly 5k satellites in orbit right now. Most of those are in a slightly higher orbit than Starlink’s (LEO) so they’re incrementally farther away, but would be in a better position to catch sunlight in the night sky.

And yet I, probably like everyone else who isn’t an astronomy enthusiast, haven’t ever looked at a light in the sky and known it was a satellite. They’re subtle, not dominating the night sky by any means, at least insofar as an untrained modern human can tell. Starlink would up the number of satellites by ~2x, perhaps, but would that be enough to change the basic equation?

Re: SpaceX satellites could blight the night sky, warn astronomers

#44

Post by dingaling »

maxander wrote: post #43

From a minute of googling, there’s roughly 5k satellites in orbit right now. Most of those are in a slightly higher orbit than Starlink’s (LEO) so they’re incrementally farther away, but would be in a better position to catch sunlight in the night sky. And yet I, probably like everyone else who isn’t an astronomy enthusiast, haven’t ever looked at a light in the sky and known it was a satellite. They’re subtle, not d…

> at least insofar as an untrained modern human can tell

Perhaps, but that's irrelevant to this discussion which was initiated by competent experts in their field. Not like protests against 5G which are based on dodgy YouTube videos.

Starlink will have a significant impact on the global night sky based solely on the approval of one agency of one country of 8% of the World's population. Even if you as a layman don't perceive it to be a problem in your daily life, doesn't that just seem... wrong? If North Korea had taken such a step there would be sanctions.

Re: SpaceX satellites could blight the night sky, warn astronomers

#45

Post by autocorr »

nonnontrivial wrote: post #11

Wondering if these satellites follow a fixed path. If so, and there are few enough of them, the nextgen land-based optical telescopes will just have to factor this into scheduling. Has SpaceX said anything about the paths they will follow? Can they change mid-deployment?

Interestingly (if somewhat unfortunately), this is already done for some radio telescopes. Some satellite down-links are strong enough to damage the receivers, so their visibility has to be taken into account when considering what frequencies to observe at what times.

Re: SpaceX satellites could blight the night sky, warn astronomers

#46

Post by perilunar »

maxander wrote: post #43

From a minute of googling, there’s roughly 5k satellites in orbit right now. Most of those are in a slightly higher orbit than Starlink’s (LEO) so they’re incrementally farther away, but would be in a better position to catch sunlight in the night sky. And yet I, probably like everyone else who isn’t an astronomy enthusiast, haven’t ever looked at a light in the sky and known it was a satellite. They’re subtle, not d…

There's also 10,000+ aircraft (and over a million people!) in the air at any time, and those planes have nav lights and strobes that are much brighter than satellites.

Re: SpaceX satellites could blight the night sky, warn astronomers

#47

Post by aeternus »

batbomb wrote: post #37
aeternus wrote: post #31

Earlier quoted context omitted.

The video in the article is not representative. Solar sails were not in the final position and the satellites were not in their final (higher) orbit. It was also taken during the short time-window that the sun was still illuminating the satellites. Regardless, we should be moving our telescopes to space. Much less interference of all kinds.

The amount of light will still be appreciable and will affect many kinds of observatories around the world, even at magnitudes less brightness. You also can't slew a telescope in space like you can on ground, it would be extremely cost prohibitive in terms of fuel. "moving telescopes to space" is the equivalent of "let them eat cake" comment in this funding environment. It sounds like a wonderful proposition until yo…

>there's no reason to expect SpaceX to be a good citizen of the night sky.

Seems like they are willing to do more than most:

https://twitter.com/elonmusk/status/1132908915144794113

https://twitter.com/elonmusk/status/1132908689860415488

https://twitter.com/elonmusk/status/1132902372458418176

Re: SpaceX satellites could blight the night sky, warn astronomers

#48

Post by [deleted] »

Robotbeat wrote: post #10
vbuwivbiu wrote: post #9

Earlier quoted context omitted.

after their shelf life SpaceX will send more up. That's our night sky ruined as long as SpaceX exists and any competitors.

That's not accurate unless you think the current satellites (many of which are far brighter, such as ISS and Iridium flares) already "ruin" the night sky. I watched a recent pass of the Starlink satellites, and now that they're oriented near their operational directions, I could barely see them. I only noticed them because I knew right where to look. Unlike the flashing lights of passing aircraft which were a lot mor…

[deleted]

Re: SpaceX satellites could blight the night sky, warn astronomers

#49

Post by akvadrako »

sdinsn wrote: post #21

> His estimates suggest that once the first 1,584 satellites are launched, for which the trajectories have already been made public, there will be about 15 satellites clearly visible above the horizon for three to four hours after sunset and before sunrise. Oh no, 15 tiny lights in the sky. Not really a blight.

Actually, this is a good point.

I care about light pollution a lot and think most people are missing what I had when I grew up (Canadian/American border in the 90's). I wish cities had strict codes and But dark skies are not dark at all - there are about 10000 visible stars. A few moving dots is not going to ruin the experience.

Re: SpaceX satellites could blight the night sky, warn astronomers

#50

Post by pfdietz »

Rebelgecko wrote: post #36
pfdietz wrote: post #17

Earlier quoted context omitted.

The importance society places on something can be judged by how much money it's willing to spend on it. The NSF budget for astronomy is $250M/year. Revenue projections for Starlink reach as high as $50B/year.

The global market for ice cream is already $60B/year.

Your point? If the world had to choose between astronomy and ice cream, it would choose the latter.
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