Friday, October 25, 2013

Moon free observing period has started

We're back into a period where the moon sets early enough to allow moon-free observations of the sky brightness in the evening. This can be done using either the Loss of the Night app (Android) or Dark Sky Meter app (iPhone). The moon-free observing period will last until November 7 (exact dates depend on your latitude).

After November 7, the next observing periods this year will be:

November 21 - December 6
December 20 - January 4 (2014)

The dates are based on Berlin sun/moon rise/set times, and will be slightly different depending on where you live and what time of night you intend to make your observation.

Please try to make observations especially in urban areas with lots of light pollution, and please encourage your friends in urban areas to do the same!

If the weather co-operates, we are going to hold two "Flashmob for Science" events next week as part of the ALAN conference.

October 28, 19:30-19:45 in Mendelssohn-Bartholdy-Park, Kreuzberg
October 29, 18:49-19:00 in Kaiser-Wilhelm-Platz (U3 Podbielskiallee), Dahlem

More information to come soon...

Monday, October 21, 2013

Berlin at Night - in color!

We flew over Berlin last Friday night, taking thousands of photographs in order to create a new color mosaic image of Berlin. Here is our original black and white mosaic:


One of the things that makes Berlin particularly interesting for those of us studying artificial light at night is that Berlin makes use of a wide array of lighting technologies. You can even still see the former border between East and West Berlin at many places because of a change in the color of the lamps. Here is a zoom-in of such a region imaged by the astronauts on the International Space Station:

image courtesy of the Image Science & Analysis Laboratory, NASA Johnson Space Center.

The big black area is the former Tempelhof airfield. To the right of it are two streets, one orange, one more white-ish. Here is what the area looks like in our aerial images:

click for high-res view

You can see that the aerial images have far higher resolution, allowing us to see a lot more detail and understand better what the sources of the light were.

The flight was taken during the Berlin "Festival of Lights". Here is one of the areas of the city that participates in the festival:

The Reichstag and Brandenburg Gate are at top center, Potsdammer Platz is bottom center.

Alejandro has also produced a video showing the view from the aircraft as we fly over Berlin. The video consists of multiple tracks across the city. Note that when the aircraft was flying Eastbound, the reflection of the moon is periodically visible from small lakes and the Spree river (e.g at 2:37).

Flight video by Alejandro Sanchez de Miguel


This work was done as part of the Verlust der Nacht research project, and was possible thanks to the Short Term Scientific Mission of Alejandro Sanchez de Miguel to Berlin, which is funded by the Loss of the Night Network.


New visitors: this blog is dedicated to the Loss of the Night app and citizen science project. For more information, you can read our first blog post, or even better, click the link and try out our app!

Wednesday, October 2, 2013

Preliminary results of our first Flashmob for Science

Thanks to everyone who braved the cold to come out on this crisp October night for our first ever Flashmob for Science! Alejandro Sanchez de Miguel made this video of the proceedings (more photos at the bottom):



I've glanced at the data, and have some very preliminary results: Based on the SQM measurement (18.35 mag/arcsec2) we would estimate a naked eye limiting magnitude around 4.25, but the seeing wasn't the greatest, so I'd expect something smaller. Using my (very preliminary) maximum likelihood estimation code, the average of each of the observations was 3.9, with a standard deviation of 0.7. If we include only the "highly consistent" observations, then the mean was 3.8 with a standard deviation of 0.5. This is quite promising, because we found that the standard deviation of GLOBE at Night observations from March, 2012 was 1.2 stellar magnitudes.

These preliminary numbers should be taken with a grain of salt, both because my code is a work in progress and because we didn't have a very big crowd. Now that we've gained some experience, I hope that we'll be able to hold a much bigger event either near the end of October or else when it warms up in the spring. If you live someplace warmer and would like to host your own "Flashmob for Science" event in the coming months, please contact me!

Still photos:

Citizen scientist doing fieldwork by Alejandro Sanchez de Miguel is licensed
under a Creative Commons Attribution 3.0 Unported License.

The youngest star of the night

Star observations with the Loss of the Night app by Alejandro Sanchez de Miguel is licensed
under a Creative Commons Attribution 3.0 Unported License.

Learning more about the constellations after the event

Thanks to everyone who came!

Tuesday, October 1, 2013

Flashmob für die Wissenschaft

[click here for English version]

Sehen Sie genau so viele Sterne wie Ihre besten Freunde, wenn Sie den Nachthimmel ansehen? Das ist die Frage, die wir mit dem ersten "Flashmob für die Wissenschaft" beantworten wollen. Soviele Personen wie möglich sollen die Loss of the Night app am exakt gleichen Ort zur exakt gleichen Zeit benutzen. Indem wir die Sterne, die die Flashmobber sehen können, vergleichen, können wir herausfinden, wie gut die Ergebnisse der App sind.

Der Flashmob wird in Berlin stattfinden, aber Sie können uns von überall helfen, indem Sie die Veranstaltung auf Facebook posten, darüber twittern oder Ihnen bekannten Bloggern davon mitteilen. Wenn Sie in Berlin wohnen, sagen Sie auch Ihren Freunden und Kollegen Bescheid! Sie können Ihnen den Link zu diesem Blogpost schicken.

Und falls es klar ist wo Sie wohnen, können Sie sich natürlich mit Freunden treffen und Beobachtungen aus Ihrer eigenen Stadt hinzufügen!


So funktioniert die Veranstaltung:

Flashmobber sollten die App im Voraus installieren. Android-Nutzer brauchen die  Loss of the Night app, und iOS-Nutzer können mit der Dark Sky Meter-App teilnehmen (free oder full version), die die Telefonkamera anstatt Ihrer Augen benutzt. Wenn Sie möchten, können Sie die App vorher tagsüber testen, um ein Gefühl dafür zu bekommen.

Sie sollten planen, die Mitte des Gleisdreieck-Parks in Berlin (den grünen Pfeil, nicht das "A" auf dieser Karte) gegen 20:30 Uhr zu erreichen. Sie können die App sofort starten, damit das Telefon schon im Nachtmodus ist, wenn die Messzeit beginnt. Schauen Sie die Sterne an und lassen Sie Ihre Augen an die Dunkelheit gewöhnen - Sie werden überrascht sein, wie viele Sterne man auch in der Mitte von Berlin sehen kann!

Sobald um 20:35 Uhr die astronomische Dämmerung endet und die echte Nacht beginnt, werden wir den Anwesenden mitteilen, dass die Zeit zum Sternensuchen gekommen ist.

Wenn Sie 7 Sterne gefunden haben, teilt die App mit, dass Sie aufhören können. BITTE HÖREN SIE NICHT AUF!  Mehr Sterne sind immer eine große Hilfe für uns, und werden für die Auswertung der Flashmob-Daten besonders wichtig sein. Daher wären wir sehr froh, wenn Sie mindestens 12 Sterne suchen würden. Wenn Sie die Geduld für 15-20 Sterne haben, wäre das noch toller, und wenn Sie 30 Sterne erreichen, verdienen Sie den Titel des Bürgerwissenschafts-Superhelden!

Wenn Sie mit der App fertig sind, können Sie sie einfach schließen und nach Hause gehen - Ihre Beobachtungsdaten werden beim Schließen der App automatisch an uns übertragen. Falls Sie in der Nähe Ihrer Wohnung einen guten Beobachtungsort haben (z.B. einen Park, Spielplatz oder eine Dachterrasse), dann wäre es ein super Bonus, wenn Sie dort noch eine zweite Beobachtung mit der App vornehmen würden. So könnten wir auch mehr Informationen über Berlin verteilt erhalten. Bitte nutzen Sie die App nur, wenn Sie eine zweite Person zur Sicherheit dabeihaben (die Sie zum Beispiel vorm Stolpern warnen kann, während Sie nach oben schauen!).

Bitte erzählen Sie so vielen Personen wie möglich über diese Veranstaltung, und schicken Sie ihnen den Link zu diesem Blogpost. Je mehr Personen teilnehmen, um so erfolgreicher wird dieser erste Flashmob für die Wissenschaft.

Ich freue mich darauf, morgen viele von Ihnen zu sehen!


I werde die Himmelshelligkeit mit einem Lichtmessgerät messen, und das Ergebnis mit dem der Flashmobber vergleichen.



Anmerkungen:

(1) Mehr Informationen darüber, warum wir Individuen für Beobachtungen rekrutieren, anstatt Satelliten oder andere Sensoren zu verwenden, finden Sie in unseren ersten Blogpost, oder diesem Scientific American-Artikel. Hintergründe zur Bedeutung von Forschung zur Lichtverschmutzung gibt es in den Artikeln in Die Welt, The Guardian, oder den Why Files.

(2) Falls sich direkt über dem Gleisdreieckpark eine kleine Wolke befinden sollte, die vermutlich schnell weiterzieht, werden wir die Teilnehmenden bitten, 15 Minuten mit den Messungen zu warten.

Flashmob for Science

[Deutsche Version hier]

When you look at the night sky, do you see the same number of stars as your best friend? That's the question we want to answer with our first ever "Flashmob für die Wissenschaft". We want to get as many people as possible to use the Loss of the Night app in the exact same place at the exact same time. By comparing the stars the flashmobbers can see to each other, we'll learn how consistent the results from the app are.

The event will take place in Berlin, but no matter where you live we could use your help to get the word out. Post it to Facebook, tweet or email it to bloggers you know, and if you do live in Berlin tell your friends and colleagues about it. You can pass them the link to this blog post.

And of course, as long as it's clear where you live, you can meet up with friends and do observations in your own city!



Here's how the event will work:

Flashmobbers should download the app in advance. Android users should download the Loss of the Night app, and iOS users can take part using the Dark Sky Meter app (free or full version), which uses the phone's camera instead of your eyes. If you want, you can test out the app in the daytime to get a feel for it works.

Plan to arrive in the middle of Gleisdreieck Park in Berlin starting around 20:30 (the location of the green arrow, not the "A" on this map). If you want, you can start the app as soon as you're there, so that your phone is already in night mode when the measurement time starts. Spend some time looking at the stars and letting your eyes adapt to the dark - I promise you'll be surprised how many stars are still visible from Berlin!

As soon as astronomical twilight ends and true night starts at 20:35, we'll signal the crowd that it's time to start searching for stars.

Once you've observed 7 stars, the app will tell you that you can stop if you like. PLEASE DON'T STOP! Observing more stars is always a huge help to us, and will be particularly important for getting the most out of the flashmob data. So we'd really appreciate it if you look for at least 12 stars. If you have the patience for 15-20, that would be amazing, and if you get to 30, you'll be a Citizen Science Superhero!

When you're done looking for stars, just turn off the app and head home - your data is sent to us automatically when you quit the app. If you have a good location from which to observe the app close to your home (e.g. a local park, playground, or rooftop balcony), then it would be really fantastic if you would do a 2nd observation. In this way, we'll also get a huge amount of data from around Berlin. But please only use the app if you've got a partner with you who can watch out for potential hazards (e.g. making sure you don't trip over something while you're looking up!).

Please share news about this event with everyone you know, by passing them the link to this blog post!  The more people that show up, the more successful the event will be.

I hope to see many of you tomorrow night!

I will measure the sky brightness with a light meter, and compare the result to the Flahsmobber's observations.


Notes:

(1) If you want more information about why we want people to do observations rather than satellites or other sensors, take a look at our first blog post, or this Scientific American article. For background on why light pollution is important, read this article in The Guardian, or this one from the Why Files.

(2) If there is a small cloud right above Gleisdreieck Park and it looks like it's going to move out of the way, then we'll ask everyone to delay for up to 15 minutes before starting the observations. If it is completely overcast then we will have to cancel the Flashmob and try again at the end of October.

Update: Here are the results of our first Flashmob for Science.