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Bortle Scale Survey for Stellarium Based Project

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11 years 7 months ago #94395 by pdempsey
I'm currently working on a small project in Stellarium , and am looking for Bortle scale estimates from around Ireland (or anywhere you're visting :-) ). I'm hosting a survey on www.dasurvey.com/n/irishlightpollutionsurvey/ and would appreciate continuous submission of data.

This will be a long term project, requiring regular inputs throughout the year, but depending on the responses I hope to post updates here every 6 months in the form of a map.

Please feel free to provide feedback on the survey format, and consider sending the link on to anyone who would be interested or could help.

Thanks
Paul :)

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11 years 7 months ago - 11 years 7 months ago #94396 by dave_lillis
Hi,
that looks quiet interesting, worth caring out !
would it be ok with you if i put up a link to your site on our club website?

Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)

Carrying around my 20" obsession is going to kill me,
but what a way to go. :)
+ 12"LX200, MK67, Meade2045, 4"refractor
Last edit: 11 years 7 months ago by dave_lillis.

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11 years 7 months ago - 11 years 7 months ago #94398 by pdempsey
Hi Dave,
It's purely naked eye based estimates. The astronomical objects that are used in this test are M31 (the Andromeda Galaxy), M33 (the Triangulum Galaxy), M4 (a globular cluster in Scorpius), M5 (a globular cluster in Serpens), M15 (a globular cluster in Pegasus), and M22 (a globular cluster in Sagittarius). The Bortle Scale can be estimated on a clear night as follows:
ScaleRequired Observations
1M33 seen with direct vision. Saggittarius & Scorpius regions of Milky Way cast a shadow.
2M33 easily seen and Milky Way has detailed structure.
3M4, M5, M15 or M22 and be seen distinctly.
4M33 can barely be seen, with averted vision.
5Zodiacal light can be seen on the very best nights in spring/autumn.
6The Milky Way can be seen overhead.
7Can see all seven main stars of Ursa Minor.
8Can barely see M31.
9Can't even see M31.

The more estimates by different people in different locations will allow me build up a decent map. More details are available here: www.novac.com/lp/def.php and en.wikipedia.org/wiki/Bortle_Dark-Sky_Scale . Most dark sky preseves have a bortel index of 2 ( en.wikipedia.org/wiki/Dark-sky_preserve ).

Observations can be taken from anywhere from city centres to isolated mountain tops, or even on a ship!
Last edit: 11 years 7 months ago by pdempsey.

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11 years 7 months ago - 11 years 7 months ago #94399 by pdempsey
Feel free to link to it from anywhere. Initially hoping to cover Ireland well, but if anyone in any other region is interested it's easy to setup different surveys.

If linking please passing on link please use www.dasurvey.com/n/irishlightpollutionsurvey/ , or bit.ly/MCPCcA for tweets etc., and not the address that appears in your browser, as that page is a unique instance of the questionnaire for each submission.
Last edit: 11 years 7 months ago by pdempsey.

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11 years 7 months ago #94401 by albertw
Hi Paul,

You might also want to check out mydarksky.com/home.aspx who have a database of light pollution readings. Ireland is pretty sparse at the moment apart from one survey in Kerry but we'll be updating more data there in the autumn.

The globe at night project also should have similar estimations to what you are looking for for Ireland.

A couple of points about the questionnaire from having looked at results from these before.
- Get people to specify an exact date. Otherwise they will need to state the sun's altitude (to verify its after astronomical twilight) and moon altitude, and phase.
- Specify whether they should use Summer time or UTC. At least give an option to specify which.
The above two points are necessary to be able to factor in the influence of the twilight and moon, otherwise the readings can be useless.
- Weather. This can be very subjective, but some indication of mist and cloud would is useful.
- Seeing - again subjective, especially for non amateur astronomer.
You could hope to eliminate some of those issues statistically, but even the most well publicised surveys like this rarely get sufficient data to get more than a broad idea of light pollution and dark skies.

Finally, it would be great if you could share your results with us and particular Dr. Brian Espey in TCD who co-ordinates light pollution/dark sky measurement.

Cheers,
~Albert
International Dark SKy Association - Ireland

Albert White MSc FRAS
Chairperson, International Dark Sky Association - Irish Section
www.darksky.ie/
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11 years 7 months ago #94404 by pdempsey
Thanks Albert,

I've edited the time and date fields as suggested, and added optional weather and seeing fields. I was going to take a statistical approach, but that'll depend on the amount of data. I'm hoping the fact it's a structured naked eye test will improve responses. The Bortel scale is built into Stellarium, which is the reason for that choice. My focus is on the areas around historical observatories in Ireland, but I'll shared data with any interested parties, minus names and email addresses, but moderate noise will be added to GPS coordinates to protect anyone who may have reported from their homes (like me!!).

Cheers,
Paul

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