Tuesday, February 26, 2019
Can we get 2000 Globe at Night cloud-free observations this March?
When Globe at Night started, it was a campaign that only took place in one month out of the year: March. Over time, Globe at Night expanded to allow people to do observations at any time during the year. This was intended to make it easier for people to take part. For example, if a teacher wanted to have his students make Globe at Night observations, it might make more sense to do it at another time during the semester. And some places frequently have cloudy weather, so an amateur astronomer might be disappointed if she can't make an observation one year.
However, I believe that the change to a full-year campaign had an unintended side effect of reducing the excitement and urgency of making observations. When observations can be made at any time, there is less urgency, less social media buzz, and it is therefore in some sense harder to motivate people to take part. Perhaps as a result, the total number of Globe at Night observations has been slowly dropping over the years. The bigger problem from my point of view, however, is that the number of observations taken in March has dropped even faster:
This is a problem for me, because the reviewers of my paper might rightly ask whether it's fair to compare annual data taken during 2011-2019 to the March-only data from 2006-2010. Furthermore, can we really make strong conclusions about trends when there were thousands of March Globe at Night observations in the past, but only a few hundred in recent years?
For that reason, I'm asking amateur astronomers, light pollution activists, and citizen science promoters to help me promote Globe at Night this March. If we work together to activate our networks, can we get March participation back up to the levels it had when Globe at Night first started? Please help by sharing a link to the Globe at Night webapp in social media, posting on message boards where the members would be interested in making observations, and of course making one or more observations yourself! The webapp is available in 28 different languages, so if English is not the first language of your community, be sure to share the relevant app.
The most important days to target this year will be the weekends of March 1-3 and March 29-31. It would therefore be most helpful to spread the word within your networks on March 1 and March 29. Observations are possible throughout the periods February 26-March 7, and March 27-April 5.
I hope that together, we can get a big bump in the data in March, 2019! Thank you for your help in spreading the word!
Wednesday, March 8, 2017
Tweetstorm about light pollution and citizen science
Why we can only track global changes in skyglow using citizen science. A tweetstorm by @skyglowberlin, submitted for publication on Twitter.— Christopher Kyba (@skyglowberlin) March 8, 2017
First: what is skyglow? It's the artificial brightening of the night sky, due to artificial light. (Image from: https://t.co/6Yb1dzj7gv) pic.twitter.com/Lgsd2YWbbr
— Christopher Kyba (@skyglowberlin) March 8, 2017
On clear nights the scatter is from aerosols (dust, smoke, haze) and molecules (N2, O2). So more haze often means more skyglow.
— Christopher Kyba (@skyglowberlin) March 8, 2017
Because of this, the cloudy night sky can be hundreds of times brighter than a starlit sky far from cities. https://t.co/zl7LIIh1yT
— Christopher Kyba (@skyglowberlin) March 8, 2017
Before we had artificial light, clouds made the sky darker, just like they do in daytime.
— Christopher Kyba (@skyglowberlin) March 8, 2017
The amount of light on an overcast night is astounding. In my smallish German town that's not brightly lit, I can read books by it.
— Christopher Kyba (@skyglowberlin) March 8, 2017
Predators can use the extra light to hunt, prey are way more exposed when trying to forage or mate.
— Christopher Kyba (@skyglowberlin) March 8, 2017
IF skyglow has an ecological effect it will be most dramatic on overcast nights. https://t.co/1kE5Or5JE8
— Christopher Kyba (@skyglowberlin) March 8, 2017
Why "IF"? We don't know?
For example, we know that there are all kinds of behavioral changes near lights. But do these result in ecological changes?
— Christopher Kyba (@skyglowberlin) March 8, 2017
Even that's hard, because you must track individuals over several years. Thankfully, there are some experiments now: https://t.co/GtrlryQ269
— Christopher Kyba (@skyglowberlin) March 8, 2017
We are currently performing the first-ever controlled experiment on ecological impact of skyglow: https://t.co/6U0K2yG3bc pic.twitter.com/oCJWEeedAb
— Christopher Kyba (@skyglowberlin) March 8, 2017
@skyglowberlin Incidentally, phys/eng @AndreasJechow designed and led the implementation of the system, you probably want to follow him.
— Christopher Kyba (@skyglowberlin) March 8, 2017
We've documented how a large fraction of the Earth's land surface is affected by skyglow on clear nights: https://t.co/Ta0Rqb4MeC
— Christopher Kyba (@skyglowberlin) March 8, 2017
So that's the end of the introduction. Now we come to how we measure skyglow.
— Christopher Kyba (@skyglowberlin) March 8, 2017
Pretty much everyone should be familiar with the famous satellite images of Earth at night. pic.twitter.com/l0Yasi7chg
— Christopher Kyba (@skyglowberlin) March 8, 2017
First: the satellite sees light heading up into space, not down to the ground. That's kind of an important difference...
— Christopher Kyba (@skyglowberlin) March 8, 2017
This is because the distance to the top of the atmosphere is way larger if you travel horizontally than if you head straight upward.
— Christopher Kyba (@skyglowberlin) March 8, 2017
This is huge, because a change in lamp design (for example to LED) can nearly completely eliminate horizontal light.
— Christopher Kyba (@skyglowberlin) March 8, 2017
But ONLY if you buy good LEDs & install correctly. There are plenty of crappy LEDs that still direct light upwards, and many are glaring. pic.twitter.com/vqt37z0msA
— Christopher Kyba (@skyglowberlin) March 8, 2017
The only satellite that observes night light globally (@NASANPP ) is COMPLETELY BLIND to blue light (<500 nm).
— Christopher Kyba (@skyglowberlin) March 8, 2017
That's a disaster for two reasons:
— Christopher Kyba (@skyglowberlin) March 8, 2017
1) "White" LEDs have a lot of blue
2) The clear sky scatters blue light the best (i.e. the sky is blue) pic.twitter.com/8yQH019Mu1
So we need to measure skyglow from the ground. Lots of scientists are doing this. The most common device is the "Sky Quality Meter" pic.twitter.com/irDoaag8UJ
— Christopher Kyba (@skyglowberlin) March 8, 2017
The SQM has spectral problems as well, particularly for LED switch as recently detailed by @pmisson et al.: https://t.co/0luP5fRQWV
— Christopher Kyba (@skyglowberlin) March 8, 2017
One problem is the color switch with LEDs, but let's leave that aside (eventually color stabilizes, and you can track changes again).
— Christopher Kyba (@skyglowberlin) March 8, 2017
Imagine if every single lamp in Berlin were changed (or turned off). I'd notice almost no difference in nearby Potsdam (~20 km distant)...
— Christopher Kyba (@skyglowberlin) March 8, 2017
So while records from professionally maintained stations are great, they only tell us about changes in a handful of places (say ~200).
— Christopher Kyba (@skyglowberlin) March 8, 2017
If we want to understand how skyglow is changing GLOBALLY, we need globally distributed observations. Here's where #citizenscience comes in.
— Christopher Kyba (@skyglowberlin) March 8, 2017
You don't need expensive instruments to take part, you just need eyes and an Internet connection to take part in @GLOBEatNight.
— Christopher Kyba (@skyglowberlin) March 8, 2017
.@GLOBEatNight works by getting people to say how many stars they can see, compared to several star charts. pic.twitter.com/st34VYvZzY
— Christopher Kyba (@skyglowberlin) March 8, 2017
Tens of thousands of people have taken part, but unfortunately participation is dropping right as we are switching globally to LEDs! pic.twitter.com/ffGe8dG2kP
— Christopher Kyba (@skyglowberlin) March 8, 2017
Each given individual @GLOBEatNight observation isn't very accurate. But the data are highly accurate in aggregate: https://t.co/g7ge6h9pAo pic.twitter.com/Knk2hRT2RD
— Christopher Kyba (@skyglowberlin) March 8, 2017
1) Make cities track #lightpollution as part of environmental monitoring.
— Christopher Kyba (@skyglowberlin) March 8, 2017
2) Massive global monitoring by citizen scientists.
It's also possible to improve accuracy of visual observations by using the Loss of the Night app, but only in cities https://t.co/kt14p5r0sf pic.twitter.com/QI0OjXP2Ap
— Christopher Kyba (@skyglowberlin) March 8, 2017
Thank you editors of Twitter for reading my submission. I hope it will be accepted for publication
— Christopher Kyba (@skyglowberlin) March 8, 2017
(RT #FirstTweet https://t.co/hnEcFSCJHg)
Thursday, May 8, 2014
Possible meteor shower on May 24
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.
Wednesday, September 4, 2013
GLOBE at Night announces dates for 2014 campaign!
This is the first year that the campaign will run all year long, so (depending on your latitude) you might be able to help out scientists like me with some summer stargazing! GLOBE at Night has been building a very useful time series of observations since 2006, and it's essential that it continue into the future. This spring, we published results showing that "citizen science provides valuable data for monitoring global night sky luminance". So please plan to take part in 2014!
For both the Loss of the Night app and GLOBE at Night, it's important the moon is set, and that's why the campaign only runs about 10 days per month. The GLOBE at Night dates are a bit conservative, but are a good guide for when the app will work. For example, in Berlin, we will have moon-free periods of astronomical darkness on January 17 (for 10 minutes), January 18 (1:14), and January 19 (2:19). With the app, you can try to make a measurement at any time. If the moon is out or twilight isn't over, then the app will warn you that it's "not dark enough".
The plan is that next year the Loss of the Night app data will be an official part of the GLOBE at Night campaign, so you should be able to see your observations on the GLOBE at Night interactive map. We're still sorting out the details, but I hope we'll have this ready in time for the campaign's start!

