Dark Site Finder: tracking light pollution to find locations for stargazing | Hacker News Reader

Dark Site Finder: tracking light pollution to find locations for stargazing

darksitefinder.com

322 pointskibwen76 comments

I use this site frequently. Whenever I travel on assignment, I look up what the seeing will be like in that area. This sight quickly lets me know what kind of imagery will be possible. I then use other sites to get an actual seeing forecast that includes info like temperature, expected cloud coverage, wind speeds, moon phase, etc.

I recently visited Australia and New Zealand, and using this site I knew I was in for a treat at night.

Here's an example from NZ from a location that is represented by the first blue color after green: https://vimeo.com/246328898

Here's an example from Australia also in the same blue color on the map. However, this one starts while the moon is below horizon, and continues until the almost full moon gets pretty high in the sky to the point it looks like day light: https://vimeo.com/241600503

By comparison, here's a video where all of the footage was taken from a totally dark sky area of the map: https://vimeo.com/157779663 The difference from blue to black on the map is pretty significant.

I am quite the fan of this site. I'm not sure on the status of the site currently, but when I first started to use it, I believe the data was many years old at the time. Based on that, you can pretty much assume that if it is old data, then it will only have gotten brighter in any given area. Very few places take light pollution into consideration with new development.

Wait... Stars are visible during the day with time-lapsed photography?

To be clear, no, that was not taken during the day. In that one clip from Australia, the light is 100% only from the nearly full moon. With a DSLR and a long exposure, that light will completely light up the area to the point that it looks like day light. The only thing to give away that it is not taken during the day are the stars being visible and the smoothness of the water. The smoothness of the water gives away the long exposure.

On a full moon in dark sky locations, it is possible to walk around without the need of a flashlight. Of course, you need to give your eyes time to adjust. It is definitely bright enough to cast shadows. I've even seen shadows cast from the light of the Milky Way on new moon nights. It is hard to believe how bright starlight can be.

I live in a "dark blue" area per the map, with a ~1h drive to absolute black. Mind you, I'm not sure I've noticed that much difference between my back yard and deep in the middle of Yellowstone.

Anyway, the thing that surprised me about long exposure DSLR dark photography is that you get pretty decent color rendition. For some reason I didn't expect that. You can very clearly see the different color temperature of the stars in Orion, and if you have a very dimly illuminated foreground as you mention, you see it in accurate full color. I guess I didn't expect it because human eyes don't register color in low light. DSLR sensors are doing it photon by photon through the Bayer filter..

Mmm..nope. The Milky Way cannot cast shadows visible to the human eye, it’s around magnitude 5. Even if it was possible (and it isn’t) there are many much brighter stars in the sky that would cast a stronger shadow. I saw a shadow cast from a meteor that was around -7 magnitude, so brighter than Venus, but I don’t think I ever saw a shadow cast by a star, even Sirius that is -1.6 if I recall correctly. Although I have never been in an area mapped as black, the darkest that I have been for star gazing was the dark green accordingly to the map.

That’s awesome! I lived most my life in nz and I still long for the stars there (living in the uk now).

I recently moved to a tiny village in the uk and the darkness is amazing. After years in London it still surprises me on a daily basis.

10 years ago I spent a month at sea and it will be hard to beat stargazing in the middle of the Atlantic Ocean :-)

Beautiful work!

Can you share the equipment you used to create these videos?

Thanks. I appreciate that. I use my handy Canon 5DmkII. I pretty much only shoot timelapse on that body, and it has over 250,000 shutter clicks. The lenses change depending on what I have with me. I've used Canon 24mm f/1.4, 35mm f/1.4, 20mm f/2.8, Rokinon 14mm T/1.5, 24mm T/1.5. I have a couple of sliders that I use for timelapse. One I hand built using an Arduino and different components on a 1000mm rail driven by a lead screw, and I also have a Syrp Genie I use with a cheap 24" sub $100 carbon fiber rail kit that fits nicely in my suitcase for trips involving checked luggage. I also have a collection of wired intervelometers. I also run MagicLantern firmware on the Canon. I use it for the ETTR abilities for handling bulb-ramping sunset/sunrise setups, but I will still use an external intervelometer for the shutter release. I have found that the MagicLantern intervelometer is not reliable, especially for intervals less than 5 seconds between shots. However, even at a 5 second setting, it will randomly take 2 shots in quick succession and then goes back to the desired interval. Never had an issue with an external controller.

edit: corrected one of the lens focal lengths

Thank you for the detailed reply! I want to try my hand at this at some point. Living in a city, I miss the stars.

This https://youtu.be/kNfRIkP0kgM is from Bellevue WA, less than 15 miles from Seattle, WA. Get a Hoya intenfifer filter, they’re about $50 and the results speak for them self https://www.lonelyspeck.com/hoya-intensifier-review-an-affor...

Were the colors altered in your last video? Specifically the ones showing a very colorful sky?

Sorry for the naive question but I live in a city and despite having traveled a lot, it was mostly to cities as well. I cannot imagine such a sky in real life.

http://www.lightpollutionmap.info has much higher resolution data, down to tens of metres. You can also choose the dataset by year - choose the "VIIRS 2017 March" dataset for the best detail. Data comes from the Visible Infrared Imaging Radiometer Suite (VIIRS) satellite [1].

For example, with the extra resolution I managed to find a dark patch near the train line in between Waterfall station and Helensburgh south of Sydney - the darkest sky until you go far past Wollongong.

[1]: https://jointmission.gsfc.nasa.gov/viirs.html

Is there a reason they default to the 2015 dataset instead of the 2017 dataset? Is it more complete?

It's been a really long time when I saw the milkyway in the urban area. I don't expect I can see the milkyway in the city (maybe at the total blackout?), but I hope to see it within 30min drive. Also, I hope to see more nebular in my backyard w/ decent telecope, I only could see a few famous nebular such as Orion, Omega, faint veils...

Too bad for little people to be able to see that amazing nightsky .

I love looking at sites like this. My favorite is:

https://www.lightpollutionmap.info

One thing I've always been curious about is there are 3 points of brightness off the coast of Newfoundland. Does anyone know what they are?

https://www.lightpollutionmap.info/#zoom=6&lat=5811787&lon=-...

This is the one my astronomer friend recommends.

From the location of those light sources, I suspect they are from drilling rigs extracting oil from several large oil fields around the Grand Banks of Newfoundland.

There's a map of the largest fields in this article:

http://www.cbc.ca/news/canada/newfoundland-labrador/husky-we...

I was on a boat crusing through the Galapagos Islands and went topside to look at the southern skies. I've never been is so dark an area. The Southern Cross and the Jewel Box appeared almost 3-dimensional and the Milky Way was visible from horizon to horizon. It was the most amazing night of star watching I've ever had.

I was once on a beach in the southern part of Crete in Greece, many hundreds of kilometers away from the nearest city. There was no moon, and when we turned off the flashlights we could barely make each other out, but the sky was full of stars. It was glorious.

This might just look like an alternative visualization of those composite images of the Earth from space at night, but what's nifty about this is that it purports to also show just how far from populated areas one would need to travel in order to maximize darkness.

Not seeing that feature. Maybe it's somewhere on the website, but the linked page seems to just be a visualization of the common light pollution map.

What common light pollution map is this referring to? The only images that I've seen of this nature are photographs of the Earth from space at night, which do a good job of showing where the light is but a less good job at showing where the darkness is. Though I doubt this map is taking geography into account, it appears to be a clearer indicator of the distance from well-lit areas such that e.g. one could reason that in order to see a dark sky in the US one would need to be no farther east than Nebraska. I can't argue as to its true accuracy, I just submitted it to see if anyone else might find it useful. :)

Just google "light pollution map", NOAA has been producing them since at least the 90's. We used it for our astronomy club when we purchased property for our observatory in 2000. At the time it was the only blue area on the map within 1 hour drive. Unfortuatley there's no blue areas within a 2 hour drive now :(.

Thanks for the info! Like I said, I'm not an expert, and I live in the NE US so my prospect of ever seeing stars is pretty much nil regardless. :P

The entire map is the light pollution. The key there at the top of the screen. Find where you are, and look at what color the area is around you on the map. From personal experience, if you're in a downtown metropolitan area that the map shows as white, then you'll be lucky to make out Betelgeuse or Rigel in Orion, Sirius would be visible, as well as Venus, Saturn and Jupiter. Anything fainter than that will be difficult. Using binoculars will improve things quite a bit though. As you start to get into the orange colors, all of the stars in Orion would be visible. I have been able to make out the Milky Way in yellow areas. In the blue areas, I can see the Milky Way quite clearly. In the black areas, it takes me a bit of time to adjust to find Orion/Big Dipper/etc because there are now so many stars visible that the very obvious constellations are harder to see immediately.

I live in the middle of the giant cancer of light pollution that is the Netherlands/Belgium/Germany triangle. Most of Belgium is on the white-ochre spectrum. There are no dark spots to speak of within any reasonable distance. It's depressing.

DarkSiteFinder is a great tool in addition to this website:

http://cleardarksky.com/csk/

Ex: Sierra Vista, AZ: http://www.cleardarksky.com/c/SierraVistaAZkey.html?1

Which uses various models to calculate night sky visibility. Avoiding light pollution is only one part of the game.

You can see most large metropoles having a white core. In Rotterdam and The Hague (Netherlands), this white core is in between.

Very interesting. I live on the southern outskirts of The Hague, Netherlands. Between The Hague and De Nieuwe Waterweg is the Glass City [0] located, a large area (~20x20km) with mainly greenhouses. These greenhouses use artificial light to spur growth in plants, causing the white core in the light pollution heatmap.

When I look out on my balcony to the south, the sky never turns dark. Only when there is heavy rain clouds, the light from the greenhouses dims a bit. The sky is always in an orang-y darkish glow.

[0]: https://translate.google.nl/translate?sl=auto&tl=en&js=y&pre... (translated dutch wiki page, english page is only stub)

There should be a movement to restore darkness.

Nightlife has completely changed, music gigs are extremely well lit, where before you had a dark room and the musicians illuminated.

Old lights have been replaced one for one by much brighter LEDs.

There is a big push by dark sky advocates to have cities rethink their lighting. Nobody really expects metropolitan areas to just suddenly go replace existing lighting, but at least for new lighting installs to use dark sky friendly lights. These just keep light shining where it's needed (shining down) versus wasting energy by lighting upwards. Some cities are positively responding, and considering this when replacing/updating lights.

The astronomy campus I frequent works closely with the local and county government to replace lights to be more dark sky friendly as they are working to be officially recognized as a dark sky location.

There is a big push by dark sky advocates to have cities rethink their lighting.

Do you have any links for formal or informal organizations or individuals working on this? thanks

http://www.darksky.org

https://en.wikipedia.org/wiki/Dark-sky_movement#List_of_grou...

I saw that someone else provided links to good info. As an anecdotal piece of evidence, I know that big box home improvement places like Home Depot have a dark sky category in their outdoor lighting department. I was flabbergasted the first time I saw that. I would love to see the affect of all homeowners replacing light fixtures with these types of lights. As an example, in the last video I linked earlier today, there are small lights on the horizon that shine very brightly in the video clips. There's one light source in particular that is a single lamp on a pole located on a ranch that is several miles away. If you multiply that by the output of every lamp in a city, it doesn't take a lot of imagination to quickly understand why we can't see the sky at night.

I don't like the key on this map. The actual map has some kind of alpha overlay that seems to go to fully transparent for the darkest parts, while the key is 100% opaque black for the darkest parts. In parts of the map it's hard to tell if you're in the darkest area. A hover info window would be helpful.

Use the slider at the top right. It controls the overlay transparency. It's not ideal but it works to identify the darkest parts.

Anybody knows why there is such a large area with light in nothern/central russia?

Came here to ask this. What the heck! Here it is: https://imgur.com/a/vXwqO

EDIT: Never mind, apparently it's oil and gas refineries! https://www.reddit.com/r/answers/comments/4x0v1e/why_is_ther...

That's where the oil is as well as relatively cheap electricity. The area is quite developed for the purpose of extraction.

And the coast of Nigeria has some odd lights as well.

edit: and in the middle of their national forest o_O

I was surprised by that too. It's huge. First I thought it's the Moscow area.

This map must be a little out of date - North Dakota is now an explosion of light from natural gas venting in its oil fields:

https://worldview.earthdata.nasa.gov/?p=geographic&l=Referen...

This is Ural - https://en.m.wikipedia.org/wiki/Ural_(region)

Metal heart of Russia. Industrial core of country.

You can see updated nightly images of what is presumably the source imagery (Suomi NPP VIIRS) on NASA's satellite imagery viewer:

https://worldview.earthdata.nasa.gov/?p=geographic&l=Referen...

Does the legend not match the actual colors used on the map, or is the entire surface of the planet light polluted? I don't see a single area on the Earth that's as dark as the three darkest colors on the legend.

If you switch the map to full opacity (slider underneath the full screen button at the top right), the colors match the legend. There are areas in the darkest categories-- look in Nevada, for example, or just about anywhere in central Africa or Siberia.

The legend isn't a perfect match - there is an opacity on the color overlays that makes the black side of the legends instead be lighter shades of grey when on the map.

Sorry to reply on this thread but I wasn't sure how to contact you otherwise. Thank you for your comments regarding my landing page copy. I think you are right, and I was assuming my bad experiences were what others would experience. I revised my page based on your feedback. So thanks.

I use this site when trying to find good places to go camping. When I moved back to Chicago, I was pleasantly surprised to find a few decent stretches of night sky within a 4 hour drive from the city.

I think this would be more useful if the color bar had a slider that tracked the user's mouse across the map.

Also, where does the color bar information come from? Is it from observational data of the dimmest magnitude stars or objects visible at a particular location or is it just integrating data from satellite based night-time passes to show light received on clear-sky passes?

Seems to be moderately useful but the actual utility of anything like this is dependent on the source and processing of the data used to create it.

I like it but i want to know that the colors represent. For instance, what is eliminated from view in the night sky because i'm in a white, red, or green region.

From personal experience using this map, if you're the worst areas designated by white on the map, you will be able to make out only the brightest of objects like Venus, Jupiter, Saturn, Rigel, Betelgeuse, Sirius. Anything fainter will be difficult with the naked eye. As you get into the reds/oranges, you'll be able to see most of the more visible constellations. I can find all of Orion and the Big Dipper. In the yellow areas, the Pleiades cluster is pretty visible. In the green areas, you might be able to make out a faint shape of the Milky Way, but the time you're in a blue area you will definitely see it. In the black areas, it's almost overwhelming how much can be seen.

If you live in an area any where from red to white and are not usually prone to looking up, then I'd venture a guess that you might be pretty impressed by visiting a yellow to green spot on the map. Being bold and visiting a blue to black area will just blow you away.

These are all naked eye examples. Using any type of seeing aide will improve things dramatically. A simple pair of binoculars in a white part of the map will reveal so many more stars. The entire constellation of Orion can be seen in binocs. You just need a few visible starts to find your way. Any of the apps like StarWalk or StarChart will help you find your way. However, in the white parts of the map, I can never see Polaris bright enough to properly align my telescope for accurate guiding. I usually just use my phone's compass to point in the general direction of North, and go from there. In those areas, I can easily see the rings of Saturn and a few moons, make out the belts on Jupiter and several moons, and have even seen the different phases of Venus. I even took the scope out to a roof top bar a few years ago to let people see one of the PanStar comets.

It seems like there's another factor of altitude or maybe humidity that makes a difference. In my experience, Atlanta is like you describe - a handful of stars and planets. But in Denver, which is colored the same as Atlanta, I can easily make out Orion for example this time of year.

Altitude and humidity definitely play a factor in the seeing clarity. There's a reason the really big telescopes are built on top of mountains. The thinner the air, the less atmospheric distortion. The current favorite location for observatories is the Atacama Desert in Chile. Extremely high altitude and humidity in the 0%-1% range. I'd guess only Hubble gets better views.

Sea level beach locations are horrible for imaging with the ocean mist and humidity. However, visually, watching the stars rise/sink into the horizon of the ocean is one of my favorite sites for just watching. The power of ocean waves and the enormous sky just helps put into perspective our place in the universe.

I wonder if http://www.darksky.org/idsp/communities/ can be discerned on this map? I can't at a glance, but of course it'd be hard to tell unless the difference were pretty stark and it's hard to tell what the right comparisons are for a given community.

What stood out for me; how divided the US is. And also (expectedly), how dark North Korea is on this map in comparison to South Korea.

The Gila National Forest is a pretty good-sized dark blob on that map and it truly is amazing. Midnight in March showed me an abundance of stars that I'd forgotten even existed, having lived in cities for almost 15 years. The massive fireball that lit up our campground so much we were able to turn around in time to see it was just icing on the cake.

I like this site:

http://www.jshine.net/astronomy/dark_sky/

The UI isn't as nice, but it has pins for recommended dark spots. I've found several of my favorite stargazing spots this way.

What is that big bright area, with some very bright spots, in Russia? North of Kazakhstan.

Gas flares. IIRC about half percent of world's CO2 emissions are from here.

This is a great resource for astrophotographers. I always check it prior to traveling somewhere new (particularly the western US) to see if it's worth packing equipment and taking a detour for photo opportunities.

This is really useful, especially since you can view satellite images. Here in the Pacific NW, just having clear dark skies is not enough.. you also need a clear-cut on top of a hill!

There's a popular spot north of LA where a lot of the amateur astronomy groups meet up that sounds similar. It's the top of a mountain, but the viewing is severely limited because of the height of all of the trees surrounding the area, but it's the only/best place within a 90 minute drive of downtown LA. Beautiful drive up to the location too.

I guess that's Mount Pinos. You can go a little further north from there into the desert and it's really dark there to see the whole Milky Way across the sky.

Ojai used to be that way when I was growing up. Normal summer night could see so much.

I was shocked to be able to see Orion quite clearly from the West Village area of NYC. Many days the sky is this brownish color, no stars.

As someone living in Frankfurt, this site encourages another trip to Scotland or Norway. I miss seeing stars.

Is there a way to make one of these maps show RF pollution at different frequencies using similar models?

This is a very interesting idea. In locations where serious radio astronomy is conducted, there are restrictions on radio emissions in a large area around the antenna. No wifi, no bluetooth, no cellphones, no anything.

An RF pollution map would be useful to see not only where a candidate spot to build a new radio antenna might be, but would also be interesting to see the areas around existing sites.

This is awesome! What data does this use? Does it correlate population density with light pollution?

I don't think so. It probably uses imagery from some space based system.

That's a lot of wasted energy.

Most people sleep at night anyway - no need to keep the lights on.

Poor western Europe!

Basically all of northern Canada

This is spectacular.

https://xkcd.com/1138/

Please see my other comment as to what this map is useful for. Furthermore, on a global scale, light pollution is not equivalent to population; consider the light levels of Indonesia, the world's fourth most populous country.

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