Wednesday, July 9, 2014

How to find pictures of cities at night

Astronauts have taken over a million photographs of Earth from the International Space Station. Many of them have been taken at night, like this one of Berlin:

Berlin at Night from the ISS, original image ISS035-E-17210 available here.

NASA has made all of the images freely available through its "Gateway to Astronaut Photography of the Earth". But when you've got a haystack of 1.2M photos and you just want to find the original of the one Chris Hadfield took of Calgary at Night, you could use some help to find what you're looking for.

A group of ISS photo enthusiasts and light pollution researchers have solved your problem by putting together an Atlas of nighttime images of the Earth. This post is a short note to help you use a feature of the Atlas that's not necessarily very obvious from the main page.

When you go to the main page, scroll down to "Gallery of cities at night". Here you can scroll and zoom over the Earth to find a city (like Calgary). When you click on the dot, it will pop up some information about the photo, as well as a thumbnail:

The thumbnail has a link to the photo at the NASA gateway - but if you click on it you'll notice that it's not the one that Commander Hadfield tweeted! The problem is that multiple photos of Calgary have been taken.

While the Atlas website is super for finding cities that have been imaged, it's not what you want to use if you're looking for all photos of a given city. To do that, you want to click below where it says "Original at"

When you click there, you will get to a google spreadsheet that looks like this:

Now click on "Table of data" near the top left, type the city you're looking for in the box at the top left, and then click "Find":

Now you can see more detailed information about the photos, including thumbnails and links to the NASA site if you scroll way over to the right. The photo that Chris Hadfield took is the top one on the list, and now you can go to the NASA site and get the link to the full resolution photograph of Calgary at night.

The last step is to scroll down on the NASA page to the two "view" buttons. Click on the bottom one:

and voila, here is your full resolution image:

Calgary at Night from the ISS, ISS034-E-44268

The images from the NASA site are all free to use, provided you acknowledge the photo source (there is a recommended citation at the bottom of the page). To make it easier for other people to find the photo in the future, be sure to always include the image designator that starts ISSxxx.

If you use the Atlas to find a photo and then publish the photo somewhere, then please also cite this paper: Alejandro Sánchez de Miguel, et al., Atlas of astronaut photos, of Earth at night, Astronomy & Geophysics, Vol. 55 no4. August 2014 (in press).

Going forward

The best part about the Atlas website is that it includes three citizen science projects to ensure that future photos are cataloged, and to find other older images "hidden in the dark of the database".

Dark Skies of ISS allows citizens to sort images between different types: Images of cities, images of stars, and other images. It requires no previous knowledge, and is only available online. It is the simplest of the three projects.

Night Cities aims to allow citizens to apply their lay knowledge of local and international geography. The project shows paired images of cities with maps. Project volunteers identify points in the night images and match them to positions on the maps. With this help we can generate light maps of cities.

Lost at Night is the stiffest challenge for citizens with good geographical knowledge of a region. Their goal is to identify which city is in an image without any identification. The position of the cities in this case is only known to within about 500 km.

Note: If this is your first-ever visit to the blog, welcome! The blog is about a citizen science app called "Loss of the Night". We need your help to understand how changes in street lighting technology are changing the night sky. You can read our introduction to the blog here, and instructions on how to use the app here.

There's lots more to see, including:

You can see bring up our entire photo series via this link. Thanks for visiting!  

Tuesday, July 1, 2014

A travel to dark sky places in the USA

Astronomer and natural night sky campaigner Andreas Hänel recently returned from the USA where he traveled 7600 km in order to see the sky at a number of pristine and polluted sites in the American Southwest.

Andreas wrote up his observations, so you can read about his trip (and see dozens of great photos) here (pdf).  When he got back to Germany, he took this great photo in the Black Forest:

Galactic center viewed from the Black Forest by Andreas Hänel
is licensed under a Creative Commons Attribution 4.0 International License.

The view may not be as good as in the parks in the USA, but at least it's good to know that such views still exist in some places in the South of Germany. Maybe 30 years from now, better lighting will help clear the skies further towards the horizon.

Wednesday, June 25, 2014

Short film about the Loss of the Night project

A short documentary film about our interdisciplinary "Loss of the Night" research project is now available on youtube!

The part about the Loss of the Night app starts at 14:29.

Please share it with anyone you think might be interested!

A German version of the video is also available.

Tuesday, May 27, 2014

Universe in a Box

I just found out about a really excellent Kickstarter project, called "Universe in a Box":

I backed them, and if you want to encourage kids in underprivileged communities worldwide to reach for the stars, maybe you'd like to back them too! Information about the project is available on the Kickstarter page, and you can read a longer post about the project by Markus Pössel here.

When I first heard the title "Universe in a Box", I wondered if it was going to be related to something that blew my mind when I was in grade 5 or so. One of my teachers brought a great big box into the class, and asked us how much we thought could fit in it. After our guesses, she claimed that it was possible to get the entire school building into the box. After we expressed our disbelief, she revealed the trick by getting someone to climb inside, and closing the lid on them. The point was that the "inside" and "outside" of the box are actually relative concepts, and if you want to enclose the entire universe, all you have to do is climb into a big enough box.

Tuesday, May 20, 2014

Aerial images of Berlin at night

It was recently asserted to me that when you look at cities from an airplane you see only lit streets, not dots corresponding to street lamps. My job often involves flying at low altitude over Berlin, and in my experience, there are massive numbers of individual lamps visible from the air. I decided to share some of the photos I've taken that show the "dots". If you're interested in pretty images of monuments from the air at night, look here instead.

The first example is what we'd like to see - the street is lit, but you don't see any dots corresponding to the lamp:

The rest of the examples show that in many places you can see street lights from the air:

Finally, here's an example of the kind of lamp that's a problem - because of the curved glass a lot of light is directly emitted into the sky:

Thursday, May 8, 2014

Possible meteor shower on May 24

Mark your calendars: May 24 is probably the best night of the year to make Loss of the Night app and Globe at Night observations. The reason? Earth is going to pass through the debris ejected by comet 209P/LINEAR in the 1800s.

Leonid Meteor

Since it's not known what the comet was doing in the 1800s, there's a lot of room for surprises. The peak is forecast between 2-4 o'clock in the morning Eastern Daylight Time (8-10 am Berlin time) on May 24th. Since there is considerable uncertainty on when exactly the peak will occur, depending on your location it may be worth going out on both May 23 (late evening), May 24 (early morning) or the early evening of May 24. Use this applet to figure out the most likely best times to observe at your location.

I have seen a number of meteors while using the app, and even once a fireball over Berlin! The next moon free phase runs from approximately May 19-28.

Lighting strategies in England

A number of English councils are experimenting with replacing dusk-till-dawn lighting with a different lighting regime, either involving dimming of lamps, or else switching them off. The Campaign to Protect Rural England has done a survey of councils to try to understand how widespread this practice is, what the councils reasons are, and to learn more about what types of strategies are being used. They've produced a 32 page report summarizing their findings that you can download for free. They've also made the short slideshow below to present the main findings:

Lighting survey results from cpre

If you found that interesting, you may also be interested in a related report submitted to the Department for Environment, Food, and Rural Affairs: A review of local authority road lighting initiatives aimed at reducing costs, carbon emissions and light pollution.

Finally, my group recently published a paper discussing recommendations that we suggest policymakers should adopt in order to reduce energy consumption, and reducing light levels during periods of little activity was one of our recommendations. The paper is unfortunately not open access, but you can download an author's copy from my personal website, Redefining efficiency for outdoor lighting.