Can You Find the Comet? • Hacker News Board

Re: Can You Find the Comet?

#61

Post by marcosdumay » Tue, Apr 28, 2026, 2:41 PM UTC

mark-r wrote: post #27

originalvichy wrote: post #5

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.

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.

In either case, you will increase the section area / volume ratio, what makes the fragments fall from LEO faster.

Re: Can You Find the Comet?

#62

Post by nayuki » Tue, Apr 28, 2026, 2:49 PM UTC

mark-r wrote: post #28

albert_e wrote: post #15

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?

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?

Pretty much every DSLR/DSLM camera out there has a "bulb" mode that keeps the shutter open as long as you hold down the shutter button. I think my personal record is a 20-minute exposure.

As for actually holding down the button, you can either use an external wired shutter button that has a mechanical lock to hold it down, or you use a wired controller that has an electronic timer, or you use a software feature in the camera to set the bulb timer.

Re: Can You Find the Comet?

#63

Post by MagicMoonlight » Tue, Apr 28, 2026, 2:53 PM UTC

ragebol wrote: post #3

Yeah, I kinda get why astronomers are not particularly happy with satellite constellations.

So what? Astronomy doesn’t actually produce anything meaningful.

Hell, astronomers were telling us the sun orbited the earth for 99% of human history. Shoot forward to the present day and they can tell us… the universe started at some point somehow. Great job guys. Really earning those billions in grants.

Actually going to space has far more value.

Re: Can You Find the Comet?

#64

Post by MagicMoonlight » Tue, Apr 28, 2026, 2:54 PM UTC

projektfu wrote: post #55

1970-01-01 wrote: post #42

I, a taxpayer, would rather have a cellphone signal in a remote location than lots of amazing pictures of a comet. And I just don't see a solution or compromise that could work. The utility of neat picture vs full cell signal in a Montana canyon cannot be won by taking more pictures and showing me the problem. I made my decision already.

I, a taxpayer, wish that we could significantly reduce light pollution so we could see the stars on a typical clear night.

Then give up streetlights. Although crime and road accidents will massively increase and women won’t feel safe outdoors. So is it really worth it?

Re: Can You Find the Comet?

#65

Post by AntiUSAbah » Tue, Apr 28, 2026, 3:01 PM UTC

We do not need Starlink! It only provides service to 9 Million! People

We are a planet with 8 Billion People.

Do i want cheap and reliable internet everywhere and perhaps work remote? Yes. Should someone like Musk destroy our look into space for just me and my use case? No.

Re: Can You Find the Comet?

#66

Post by AntiUSAbah » Tue, Apr 28, 2026, 3:02 PM UTC

mark-r wrote: post #28

albert_e wrote: post #15

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?

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?

My Canon can do this without modification and its 8 years old. Switch to bulp and have an external mini device which you connect with a microphone cable and it creates the signal for shutter off after x minutes.

For extra long exposre its recommended to use also a stable powersource.

Re: Can You Find the Comet?

#67

Post by AntiUSAbah » Tue, Apr 28, 2026, 3:03 PM UTC

ultratalk wrote: post #12

adev_ wrote: post #11

Earlier quoted context omitted.

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.

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…

Its still worth while for every normal human to have access to space if the benefit of this stuff is not relevant for most people.

And with 9 million customers its not.

Re: Can You Find the Comet?

#68

Post by Miraltar » Tue, Apr 28, 2026, 3:13 PM UTC

MagicMoonlight wrote: post #64

projektfu wrote: post #55

Earlier quoted context omitted.

I, a taxpayer, wish that we could significantly reduce light pollution so we could see the stars on a typical clear night.

Then give up streetlights. Although crime and road accidents will massively increase and women won’t feel safe outdoors. So is it really worth it?

Women would feel less safe yes but there is no evidence that crime and road accidents would increase.

Re: Can You Find the Comet?

#69

Post by ragebol » Tue, Apr 28, 2026, 3:14 PM UTC

MagicMoonlight wrote: post #63

ragebol wrote: post #3

Yeah, I kinda get why astronomers are not particularly happy with satellite constellations.

So what? Astronomy doesn’t actually produce anything meaningful. Hell, astronomers were telling us the sun orbited the earth for 99% of human history. Shoot forward to the present day and they can tell us… the universe started at some point somehow. Great job guys. Really earning those billions in grants. Actually going to space has far more value.

Have you heard of Kessler Syndrome?

More satellites means higher risk on that happening and not going to space until all the debris of a collision deorbits.

Re: Can You Find the Comet?

#70

Post by jlarocco » Tue, Apr 28, 2026, 3:50 PM UTC

nayuki wrote: post #62

mark-r wrote: post #28

Earlier quoted context omitted.

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?

Pretty much every DSLR/DSLM camera out there has a "bulb" mode that keeps the shutter open as long as you hold down the shutter button. I think my personal record is a 20-minute exposure. As for actually holding down the button, you can either use an external wired shutter button that has a mechanical lock to hold it down, or you use a wired controller that has an electronic timer, or you use a software feature in th…

For anybody wondering, the reason not to do a single ultra-long exposures is noise.

There's an equilibrium between exposure duration, aperture, and ISO that gives the best results for the conditions with a minimum amount of sensor noise, and getting close to the equilibrium and stacking the images typically gives better results than one massive exposure.