Tuesday, February 26, 2019

Can we get 2000 Globe at Night cloud-free observations this March?

I am currently preparing an analysis of the Globe at Night sky brightness data taken from 2006 up until today. It's really important that we do this, because the world is switching to LED lighting, and visual observations are the only way to really know if the sky is getting brighter or darker. The work is going well, but there is a problem - a problem I need your help with.

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:

Annual number of Globe at Night observations. Observations in March are shown with a dashed line.
For the purposes of this plot, multiple observations from a single location in a single month are counted only once, and only cloud-free data is included.

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!

9 comments:

  1. I'll dust off my SQM meter then and get out measuring. My eyeballs say the sky is brighter now with the LEDs than before, certainly in my town. They're just so bright and although they point down, so much light is reflected of the ground back upwards. I'd dim then all by 50%. Be interesting to get some SQM comparison to those measurements I made well before the LEDs.

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    1. Thanks BigDaz! You could let your city know that the US Department of Energy expects that for a "typical street light conversion" the town should also dim the total light output by 50%, as you suggest! Here is the DOE report about skyglow: https://www.energy.gov/sites/prod/files/2017/05/f34/2017_led-impact-sky-glow.pdf

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    2. I'm in the UK, but I'll look into this. Thanks.

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  2. I will try to participate the coming weekend. ^_^ Just an idea for the mobile app: Could you implement an option to automatically enter a series of calendar entries for times when we have new moon? Currently, there is only the ability to add one reminder for the next night with good conditions and I always forget to measure because of not being reminded automatically. Another option would be to let the app run in the background and remind the user with a notification at good conditions (no more often when once a month or so...)

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    1. Hi Uwe, thanks for your comment. We had not anticipated that someone would want to put such a long series of dates onto their calendar. I will add it to the list of requests (although we don't have funding to make changes right now). For the meantime, you can generally assume that you can observe for about two weeks after the date that it tells you - then the moon comes back :-)

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  3. What I am contending with is that winters are changing in Canada. 10 years ago we had about one storm per week with 3 or 4 clear days between. Now we are getting 2 storms with mere hours of clear skies in between. People are also burning more wood pellets so on clear cold nights the skies are very smoky in the last 3 years.

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  4. Hello! I will do this for the rest of the month. WIll this be going on for just March?

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  5. Will this be going on all year?

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    1. Hi Spacer,

      Globe at night runs all year. You can see the dates here: https://www.globeatnight.org/5-steps.php

      Thanks for taking part!

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