171–180 of 200 posts
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Yes we also had a population of 50 million and 10% of them starved to death every time a volcano burped, they were great times.
And 9 million starve to death annually because it isn't profitable to feed them, what's your point?
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For professional astronomers, it really sucks if you only have, say, an hour of observing time on a big telescope, and then a few of your precious frames are ruined because of a satellite. And you don't always even know that the frame is ruined until later, or have the flexibility to take more frames if needed (because you submit the full observation plan ahead of time, and just get the results later), in which case…
That's what I don't understand, how are they ruined? If you're so deep that you need minutes or hours of exposures, that satellite will blip past the frame so fast it's not going to matter. And if the exposure time is less than that, you stack.
2. If you are doing photometry (measuring the brightness of something), even if the relative brightness isn't very much, it can introduce a lot of noise to the data. For many things, even the dimmest satellite is going to add more light than the change in brightness you are looking for.
Now to be fair for scientific research typically you can use the frame if the streak isn't too close to your object(s) of interest. And for pretty pictures you can often edit out the streaks. But even so, it's a problem more than you would think.
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> Most people didn't care about dark skys in the first place and still don't. Most people were never given the opportunity to care.
Very true, but isn't that exactly what the parent is suggesting? That even a ship full of sailors given the opportunity to care, very few do? Or are you suggesting that by the time they are in the Navy, it's after the age where one might be most easily encouraged to care?
There's another aspect to it, though — parent was in a navy ship, surrounded by sailors. That's a very specific population, in a very specific situation, and it's not necessarily true that that's the right crowd or situation to care (though it baffles me how a sailor at sea might look up at the stars without being in awe of the thought "damn, my predecessors navigated based on those")
> “… gives the illusion, without the reality, of safety” This actually isn’t true. Having done physical security work before, a weird fact is that one of the best physical deterrents is lighting; even over CCTV. I don’t say that to take away from this, this is great work and I’d love to see the lighting toned down for multiple reasons. However, this should be framed as a security tradeoff not an outright win. Source:…
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That's what I don't understand, how are they ruined? If you're so deep that you need minutes or hours of exposures, that satellite will blip past the frame so fast it's not going to matter. And if the exposure time is less than that, you stack.
1. The satellite is usually significantly brighter than the thing you are observing. Often bright enough to saturate pixels (which can spill over to adjacent pixels). 2. If you are doing photometry (measuring the brightness of something), even if the relative brightness isn't very much, it can introduce a lot of noise to the data. For many things, even the dimmest satellite is going to add more light than the change…
I wondered if a city-wide synchronised Pulse-Width-Modulation of LED lights could allow astrophotography (or even naked-eye astronomy) to be possible again, with a filter synchronised to the off-cycle.
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1. The satellite is usually significantly brighter than the thing you are observing. Often bright enough to saturate pixels (which can spill over to adjacent pixels). 2. If you are doing photometry (measuring the brightness of something), even if the relative brightness isn't very much, it can introduce a lot of noise to the data. For many things, even the dimmest satellite is going to add more light than the change…
Is this what you do? Because I'm at least an intermediate with astrophotography with a camera, and even airplanes are a total non issue. If you're so deep into the sky that you actually need many minutes or hours on the same spot, the teeny tiny time that satellite is there is a non issue and easy to remove with math.
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Those are probably 50-60 hz flickering from the mains frequency rather than PWM. (Or 100-120 hz due to the rectifier). Actual PWM ICs drive LEDs over 10,000 hz, which is truly imperceptible to the human eye.
Surely a PWM of 10,000Hz wouldn't allow for night sky photography. With full exposure it can already take minutes of hours to take a night sky a photo. And it's usually recognized that 1,000hz is the bare minimum to spare sensitive individuals from symptoms, with 2,500 usually used for safety margin. Then you have to account for some jitter in the synchronized network so you're looking at at best a 1/5,000 exposure.…
Regardless, I agree with your larger point that the proposed system would be entirely impractical!
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> but if there aren't population centers, you'll have to have plans to create them in order to support the rail system itself. This is such a misanthropic point of view. Nobody "creates" population centers. People aren't created out of raw clay, they already exist. If population centers are "created" it's because people already exist and want to live in a specific place, often time urban. And if they wouldn't go to t…
Many cities and settlements have been created intentionally rather than as a result of populations organically reproducing on the spot. Colonies, chartered towns/cities/etc, company towns, etc. It's a very common thing throughout history to the present day.
All you're describing is population redistribution, not population creation. Urban centers have very low fertility rates, which actually reduces populations...