Thursday, August 28, 2014

15,000th observation submitted!

The Loss of the Night app project passed another milestone today, with the 15,000th observation being submitted early this morning. The observation was made by an anonymous user in New Jersey, USA under partly cloudy skies. The naked eye limiting magnitude was about 4, with 5 of 7 stars observed.

As I noted when we passed 10,000 observations, most submitted observations are not made under ideal conditions. Sometimes people test or demonstrate the app indoors, sometimes the moon is up, and very often (as in the case of observation #15,000) the sky isn't clear. But through the dedication of our participants, we are continuously building up a record of how skyglow is changing worldwide.

Now the race is on to observation #20,000. To celebrate that milestone, I will again send a holographic postcard to the registered user who makes a complete observation (7 or more stars, no moon, no twilight, no clouds) with the observation number closest to 20,000.

Tuesday, August 19, 2014

New version of the app is coming soon - we need your help this week!

An updated version of the Loss of the Night app is currently in development. The most exciting changes will include:

  • iPhone version!
  • Improved feedback: We fit your data and tell you the estimated naked eye limiting magnitude, approximately how many stars are in your sky, and how consistent your observations were.
  • Smoother behavior: Phones that had problems with an unstable star field should now be fixed.
  • More customization: You can change font sizes and switch the screen brightness between a city/country mode. Pinch zooming will replace the zoom buttons.
  • Better night mode: Removal of gray backgrounds and replacing orange with red in many places.
  • Faster GPS convergence
  • Expanded language support
  • More accurate measurement technique
  • Better set of stars used

We can still use your help with that last point!  The new version has removed stars that are so close together that it's difficult to tell which we're asking for, for example the Pleiades and Alcor. But we have also built in a new list of "easy" stars. These are stars for which you, the users, were able to make decisions on quickly and decisively. We have lots of data about bright Northern Hemisphere stars, but we've had far fewer observations of faint stars, and much less data from the Southern Hemisphere.

The final list of "easy" stars needs to be completed by Monday, so there's one week left for you to help us learn which stars are the best! If you have clear skies at some point this week, please take a moment to go outside and use the app. The more stars you observe, the better, so if you are enjoying yourself, please continue after you've reached seven stars.

This could be you this weekend!

Thank you to everyone who has used the app in the last year!
We appreciate everyone who provided valuable feedback through email or comments!
Dankeschön to our translators!

And finally, if you've told other people about the app, then we can't thank you enough! The more people that take part, the better and more accurate our results will be.

Watch for the official announcement of the new version here in the fall.

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: