What Major World Cities Look Like at Night, Minus the Light Pollution • Hacker News Board

Re: What Major World Cities Look Like at Night, Minus the Light Pollution

#61

Post by jt2190 » Sat, Mar 30, 2013, 4:37 PM UTC

I'm surprised nobody has mentioned the International Dark Sky association [1]:

  > Once a source of wonder--and one half of the entire
  > planet's natural  environment—the star-filled nights of
  > just a few years ago are vanishing in a yellow haze.
  > Human-produced light pollution not only mars our view of
  > the stars; poor lighting threatens astronomy, disrupts
  > ecosystems, affects human circadian rhythms, and wastes
  > energy to the tune of $2.2 billion per year 
  > in the U.S. alone.

You may want to check out their Practical Guide [2] for homeowners who want to reduce their light pollution.

[1] http://darksky.org/ [2] (PDF) http://www.darksky.org/assets/documents/PG3-residential-ligh...

Re: What Major World Cities Look Like at Night, Minus the Light Pollution

#62

Post by handzhiev » Sat, Mar 30, 2013, 5:41 PM UTC

Camillo wrote: post #35

They would look nothing like those photos. The city would look much, much darker. You can really tell that those are day shots of the cities with the brightness and saturation reduced. The sky would look much, much less impressive. Photographers like to perpetuate a fantastic idea of the night sky by taking overexposed pictures, and this one is no exception. I have been in the middle of the savannah in Africa, with n…

Was it cloudy? Obviously stars wouldn't shine like this through clouds, but if the sky is clear, they could

Re: What Major World Cities Look Like at Night, Minus the Light Pollution

#63

Post by Sharlin » Sat, Mar 30, 2013, 5:51 PM UTC

_delirium wrote: post #24

danso wrote: post #14

If you were in New York City during Hurricane Sandy, in the lower half, at least, you got a taste of this first hand. I had to walk home into the unpowered section of Manhattan every night from work. I took some photos during that time. Unfortunately, as it was still overcast, we never did get a chance to see the stars from downtown Manhattan: http://tumblr.eyeheartnewyork.com/post/37636219209/i-finally...

An interesting difference between your photos and the renditions linked here is that the buildings in yours are black silhouettes, while the ones here are fairly well lit up. That's the first thing that stuck out at me: if there is no light pollution, what is lighting the foreground buildings? If you look at the Hong Kong photo, for example, it looks like there is a ton of light pollution: all the buildings, plus the…

To get the kind of starry skies shown in those pictures, you'd need an exposure of at least tens of seconds if not more. With that long an exposure, the starlight will be quite sufficient to bring out detail in the environment.

Re: What Major World Cities Look Like at Night, Minus the Light Pollution

#64

Post by Zak » Sat, Mar 30, 2013, 6:01 PM UTC

pbhjpbhj wrote: post #52

officemonkey wrote: post #50

Earlier quoted context omitted.

I grew up in rural New York and once, when camping, we stayed up very late with all the lights off. You would be amazed at how much your eyes eventually see after a couple hours in darkness. We could see Satellites, the Milky Way, and even the "Horse and Rider" ( https://en.wikipedia.org/wiki/Horse_and_Rider ). Nowadays, with phones and ipod, it's nearly impossible to let your eyes adjust that long without light. But…

There's probably an app (that has probably been done) in there for making the screen show in hues of red. Or, if not an app then a screen protector that's a gel ( https://en.wikipedia.org/wiki/Color_gel ).

There's an app for that: http://stereopsis.com/flux/

Re: What Major World Cities Look Like at Night, Minus the Light Pollution

#65

Post by tanzam75 » Sat, Mar 30, 2013, 7:32 PM UTC

joeyh wrote: post #33

danso wrote: post #14

If you were in New York City during Hurricane Sandy, in the lower half, at least, you got a taste of this first hand. I had to walk home into the unpowered section of Manhattan every night from work. I took some photos during that time. Unfortunately, as it was still overcast, we never did get a chance to see the stars from downtown Manhattan: http://tumblr.eyeheartnewyork.com/post/37636219209/i-finally...

I live 30+ miles from any town of any size and there's still sufficient light pollution seeping over the horizon to make the hills stand out black against the sky. I'm lucky I can see the milky way at all, although somewhat washed out. Being in the lower side of Manhatten, there would still be sufficient light pollution from all the areas nearby that still had power, that I'd doubt you'd see more than a few stars. Yo…

Acadia National Park has a decent night sky. That's because Maine is very sparsely populated -- half of the population lives in the 10% of the land area that's closest to Massachusetts. It gets even better if you go farther. Take I-95 up, and exit about halfway between Bangor and Canada.

The Michigan Panhandle is also not too bad. It helps that two sides are surrounded by water, which leads to little light pollution.

Re: What Major World Cities Look Like at Night, Minus the Light Pollution

#66

Post by tanzam75 » Sat, Mar 30, 2013, 7:38 PM UTC

SoftwareMaven wrote: post #4

jcr wrote: post #2

I doubt I'm the only one who read the article with the hope of finding some new technique to remove light pollution from images to show off the stars... and was mildly disappointed to find out the beautiful images were just cut-n-paste jobs (albeit outstanding ones). I'm wondering what kinds of techniques exist for removing light pollution? Spectrum sensitivity? Spectrum filtering on exposure? Post processing?

Tucson, Arizona uses sodium vapor lighting for all its street lighting specifically to allow the nearby observatories easily filter the light pollution.

It helps that sodium lights produce more lumens/watt than the alternatives.

Re: What Major World Cities Look Like at Night, Minus the Light Pollution

#67

Post by tanzam75 » Sat, Mar 30, 2013, 7:47 PM UTC

hippobravo wrote: post #15

hobb0001 wrote: post #6

Earlier quoted context omitted.

Whew. I was wondering if I was the only one who has been out in the mountains and other rural areas, but have never seen a night sky like these.

If there is literally no light pollution in your vicinity (like in the middle of northern canada, hundreds of kilometers away from the nearest small town) on a very very clear night it does look something like this. I've never seen the milky way with that much color, but the amount of stars and the star clouds of the milky way are not that far off. The title is not just removing light pollution, it is removing most o…

I remember the Milky Way looking very ... milky. It's just a dim white haze -- much dimmer than the stars surrounding it.

The reason it doesn't really look like the photos is that we don't have CCDs in our eyes. When things get dim enough, we lose a lot of color perception. (That's why night scenes look practically monochrome.)

Re: What Major World Cities Look Like at Night, Minus the Light Pollution

#68

Post by JumpCrisscross » Sat, Mar 30, 2013, 8:58 PM UTC

"“It is impossible not to read these pictures the way the artist wants them read: cold, cold cities below, cut off from the seemingly infinite energies above.”

I see unity: humanity's improbable citadels cradled by the beckoning infinity of the universe. Not everything has to be framed in conflict.

Re: What Major World Cities Look Like at Night, Minus the Light Pollution

#69

Post by enjo » Sat, Mar 30, 2013, 9:51 PM UTC

Camillo wrote: post #35

They would look nothing like those photos. The city would look much, much darker. You can really tell that those are day shots of the cities with the brightness and saturation reduced. The sky would look much, much less impressive. Photographers like to perpetuate a fantastic idea of the night sky by taking overexposed pictures, and this one is no exception. I have been in the middle of the savannah in Africa, with n…

I love driving up into the mountains here in Colorado on a clear night. The stars are just..dazzling. They very much look like one of those photographs.

Re: What Major World Cities Look Like at Night, Minus the Light Pollution

#70

Post by drexel » Sat, Mar 30, 2013, 10:57 PM UTC

JumpCrisscross wrote: post #68

" “It is impossible not to read these pictures the way the artist wants them read: cold, cold cities below, cut off from the seemingly infinite energies above. ” I see unity: humanity's improbable citadels cradled by the beckoning infinity of the universe. Not everything has to be framed in conflict.

I had a feeling of coziness and was reminded of human cohesion looking at what I presumed to be millions of people coming together to sleep at the same time preparing for the next day. It seemed so peaceful.