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?
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Can You Find the Comet?
31–40 of 119 posts
Re: Can You Find the Comet?
#32Earlier quoted context omitted.
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 telescop…
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.
What? The atmosphere gets in the way. Ever heard of an (amateur/)astronomer talking about 'good seeing'? That's when the atmosphere is hindering you less than usual.
The limiting factor of passive optical telescopes on earth is the atmosphere.
Re: Can You Find the Comet?
#33Why 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?
Passing clouds?
Re: Can You Find the Comet?
#34Earlier quoted context omitted.
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 telescop…
Any chance of CubeSat style of telescopes at some point?
Sure, there have already been some launched and predictably they are only adequate to look at the bright stuff we already knew about from the big telescopes.
A small telescope is just a small telescope even when you put it in space.
Re: Can You Find the Comet?
#35Earlier quoted context omitted.
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.
What? The atmosphere gets in the way. Ever heard of an (amateur/)astronomer talking about 'good seeing'? That's when the atmosphere is hindering you less than usual. The limiting factor of passive optical telescopes on earth is the atmosphere.
They are talking about very high energy gamma-ray telescopes, the Imaging Cherenkov Telescopes.
Re: Can You Find the Comet?
#36Earlier quoted context omitted.
> . 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?
> 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.
Starlinks are already spewing out into supposedly protected radio bands on Earth, good look getting these rules respected on the Moon when they aren't here.
Re: Can You Find the Comet?
#37I 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.
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.
I doubt they will elevate their orbit by enough to be a problem. Some bits will come down in hours, some will come down in a year - even in the worst case where it takes out everything in low earth orbit in 5 years everything will be clear and we can start over. Higher orbits are the real worry, even the things slowed down mostly stay in orbit for centuries - but higher orbits are mostly a lot higher.
Re: Can You Find the Comet?
#38Earlier quoted context omitted.
> . 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?
> 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.
Those rules won't last long once (IF) there are significant numbers of people on the moon. The rules are easy to agree to today (50 years ago) because nobody could do anything otherwise anyway. Once the rules are getting in the way of a significant number of people they will change.
I make no predictions how they will change, but the current rules are obviously unworkable if significant numbers of people live in space. I also make no predictions on if we will ever get significant numbers of people living in space - there are a lot of hard/expensive problems that may not be solvable.
Re: Can You Find the Comet?
#39I 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.
Add a black umbrella to each satellite: when they pass through the critical region where they are visible in the night sky while still being sunlit, pop the brollies up. We will fly them in the shade!
You could paint them black but they’d probably get quite hot.
Re: Can You Find the Comet?
#40Why 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?
Probably exactly that. If you take a single 10 minute exposure (or really, anything more than a few seconds) you'll get noticeable star trails if you don't put your camera on a rotating mount. Stacking multiple exposures also has other nice benefits such as noise canceling itself out and being able to remove satellite trails.
Last time I did astrophotography was a few years ago, before Starlink made the problem considerably worse, but satellite trails were relatively easy to remove with stacking. I'm sure it's harder now but definitely still possible, so I'm assuming in this case leaving them in was done on purpose to highlight the problem.
EDIT: Looking better at the picture, I belive this was taken with a star tracker and then composited with a shorter exposure of the foreground. Notice how the foreground, even far away, looks considerably blurrier than the stars, and how the tower in the background has some light streaks. This is exactly what you'll see if you use a star tracker. Rather than star trails, you'll have "foreground trails". This would explain why there are relatively few gaps in the satellite trails, since the exposures can be much longer.