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Posted by ColinWright 1 day ago

Can You Find the Comet?(apod.nasa.gov)
69 points | 25 comments
albert_e 1 hour ago|
Why are satellite trails not continuous lines

Is the camera exposure taking a few seconds of break between takes that get stacked later with some "missing" moments in between?

rcxdude 3 minutes ago||
Maybe, but also a lot of satellites rotate and so their brightness changes over time.
mark-r 6 minutes ago|||
I'm not aware of a digital camera that can take a 10 minute continuous exposure, but maybe there are special astronomy cameras that can?
pedvide 12 minutes ago|||
I've taken long exposures using film (analog, so no stacking or any other funny business) and saw the same thing. I always thought they were planes but now it seems they may have been satellites. I'm curious if someone knows why this happens
debugnik 1 hour ago|||
My guess is the camera itself was taking photos of shorter exposure and the final image was composed in post-production, yes.
AlgorithmicTime 39 seconds ago||
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ragebol 3 hours ago||
Yeah, I kinda get why astronomers are not particularly happy with satellite constellations.
adev_ 2 hours ago|
And this is just the visible spectrum.

The situation is one order of magnitude worst in radio-astronomy.

It is fair to state that satellite constellations will certainly be the main obstacle to multiple major scientific discoveries in the next decade.

ultratalk 2 hours ago||
Opinion: We need to move our astronomical observation equipment off of Earth and onto other bodies, especially radio astronomy, which, unlike telescopes that operate in other wavelengths, is still affected by Earth's emissions in LEO/near-Earth space. We should put a radio telescope on the far side of the moon [0] to benefit from the thousands of kilometers of lunar material separating Earth's emissions from telescopes.

[0] https://doi.org/10.1109/AERO50100.2021.9438165

[1] https://en.wikipedia.org/wiki/Lunar_Crater_Radio_Telescope

adrian_b 1 hour ago|||
Unfortunately, that seems to be the only solution.

However, it has serious disadvantages. It will exclude the poorer from astronomical research, except within the limits enabled by whatever cooperation the richer will be willing to do with them.

For the richer, that will make astronomical research much more expensive. When even USA, who claims to be the richest country, cuts a lot of the scientific funding, this makes likely a great reduction in the research targets that could be accomplished, even if a Lunar array of telescopes and radiotelescopes and communication relays for them were approved.

While professionals might still be able to do some work, the amateurs will be able less and less to enjoy the sight of the distant Universe.

There are already many years since I have become unable to see the sky that I enjoyed looking at when young, because it cannot be seen from the city where I live, due to light pollution (and high buildings). To see it again, I would have to go somewhere up in the mountains, far from a city or village, but I have not succeeded to do this recently. Even there now you can hardly look at the sky without seeing satellites, and it will only become much worse.

Nowadays there are many children who have never seen even once the sky that our ancestors were seeing every night, so many passages from old texts that mention the sky are unintelligible for them.

inquirerGeneral 49 minutes ago||
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Aboutplants 38 minutes ago||||
Any chance of CubeSat style of telescopes at some point?
christophilus 2 hours ago||||
Agreed. It’s the only solution short of a ban on constellations.
maxnoe 1 hour ago||||
Our telescopes actually need the (or at least an) atmosphere to function.

There are some classes of observatories, which you cannot build in space but which are still affected by satellites to some degree.

ultratalk 1 hour ago||
> Our telescopes actually need the (or at least an) atmosphere to function.

What about Hubble, Chandra, Spitzer, JWST, etc? As of my understanding, the only reason we haven't built radio and and other long-wave telescopes in space is because of their impractical size preventing them from being deployed in orbit.

> There are some classes of observatories, which you cannot build in space but which are still affected by satellites to some degree.

Examples?

voidUpdate 28 minutes ago||
I believe we haven't built radio telescopes in space because we don't need to, and building them in space would be a lot more expensive.

https://commons.wikimedia.org/wiki/File:Atmospheric_electrom...

This shows that wavelengths between ~10cm and ~10m are largely unaffected by the atmosphere, so you wouldn't gain much from putting receivers of those wavelengths in space. Spitzer and JWST (IR), and Chandra (x-ray) operate in bands that are generally blocked by the atmosphere, and Hubble gets better images than a similarly sized earth-based telescope because of the atmospheric distortion (stars don't "twinkle" when you're in space), however there are still earth-based visible light telescopes because you can more easily build a massive one on earth than in space

iso1631 32 minutes ago|||
> . We should put a radio telescope on the far side of the moon [0] to benefit from the thousands of kilometers of lunar material separating Earth's emissions from telescopes.

Do you really think a starlink style installation won't be put in orbit of the moon before such a telescope could be funded?

adev_ 5 minutes ago||
> Do you really think a starlink style installation won't be put in orbit of the moon before such a telescope could be funded?

There are ITUs rules that forbid that and the far side of the moon is declared as radio quiet.

originalvichy 3 hours ago||
I fear this is only the start of it. A minimum of 3-4 constellations more will probably be launched in the near future (Russia, China, EU).

Their obvious dual-use nature makes them tempting, and a military target if a large conflict will take place in the near future. I hope their lower orbit will help any space junk burn up fast.

mark-r 9 minutes ago||
If you blow up a satellite, half of it will end up going slower and half will go faster. The slower bits will probably burn up nicely, but the faster bits will just elevate their orbit.
aaron695 3 hours ago||
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ciroduran 3 hours ago||
I'm rebuilding my RSS feed collection, and having pretty astronomy pictures is a fine addition. Thanks!
gasi 3 hours ago||
So cool! Zoom in to find out: https://zoomhub.net/0w8pN
aa-jv 1 hour ago||
Hot take: We're in the first stages of building our own Dyson sphere and therefore comets are only useful in the context of capturing them for that purpose.

;)

w-ll 4 hours ago||
if i could imagine what a Sophon from 3 body problem would look like. this is kind of it.
khazhoux 2 hours ago||
Is this all / mostly Starlink?
vednig 2 hours ago|
It's a set of network satellites for sure either by Eutelsat or Starlink in 70:20 ratio 10% being other providers

But all of them being LEO for sure.

renerick 3 hours ago|
That looks so cool, ngl!