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notaclue

Light pollution Yorkshire. (Ad hoc survey)

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As we all know the light pollution (LP for short) is a concern for astronomers. I would like members to do a quick survery when they have time and see using a chart, which stars have become less visible over the last few years. I am asking ffor this to put to the local council the dimming of the stars by LP is more widespread than they think.

The reason I am asking is to get a sort of condition of the sky in relation to the dimming of stars in constellations that you know can no longer be seen. For instance, with my eyes without glasses worn I can not see the bow of Orion. Most of the stars are either Magnitude 2-3 and can be barely seen from my location in Wakefield. Where I grew up I could see not only see all the stars of Orion (of which I still can see) but I can not see the bow, nor many of the Mag. 2-3 clearly.

So lets have a sky survey over Yorkshire. Principally West Yorkshire but other areas like Sheffield, York, Hull and other places can join in and give a blanket idea of how bad this is so as a collective we can put forward the ideas of hooding lights away from town centres and in suburban areas have lower light levels but still manage the safety of people walking about at night.

So at the moment the mag. 2-3 can be brighter if we get these lights hooded and maybe over the north we could enjoy this hobby more. Just to prove how much light there is, here is a picture showing the light level as seen from space. Picture from the ESA website.

6890185644_84c35b078a_o.jpg

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The Council for the Protection of Rural England is interested in light pollution and does an annual survey.

The following link takes you to this year's survey.

http://www.cpre.org.uk/what-we-do/countryside/dark-skies/update/item/2666-star-count-2012

I think that that the counting of the stars in the "Orion Square" looks to be a fairly good way of assessing light pollution.

From my observing location, approx. midway twixt Leeds and Huddersfield, I could count only 12 stars

I found that I needed to put up portable screens to cut out a street light and nearby security lights to make observing a more enjoyable experience.

Good luck with your project!!

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Now that I do find interesting. If we can get the councils to even go part way into hooding part of the lights in an area it will give our hobby a better chance. That and the wildlife chirping at 2am thinking it is daytime.

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If you're interested in surveying then the mydarksky website is available to host any results you may have. We use it at our astronomy club as somewhere for our GCSE students to put their own survey results.

There should be a link in my signature if you're interested.

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Light pollution around Northallerton is a fraction of what Teesside and the M62 corridor has to put up with, so I feel for your orange-hued skies. For most of the year, clear skies permitting, I can see the MIlky Way if its really dark with no Moon, M31 is visible at times also.

The only real impact over the last 5-7 years has been some factory sized buildings being placed near the industrial estate which is about 1 mile from where I live, some of which use those fantastically large orange 'security' lights, after all whats more secure than displaying your goods, windows, entry and exit locations and doorways to potential theives in almost daylight conditions during the night!

Alongside this, there is constant development either in town or nearby which always introduces new lighting. It seems that although the lighting designs change with the decades the main style is what I would call a 'nobbly shoe-box' whereby there is a rectangular metal box with the glass lamp on the underneath and a light detector on the top (if you shine a >10Mw green laser pointer at them they go out, apprently). I'm sure there's a design name for this 'shoe-box' style but as I don't know it I'll simply call it Barry. In my opinion Barry is the worst idea for residential areas, besides those security lights, because although the lights do point downwards the amount of light escaping upwards (as they're not covered on the sides) is about 40%, its the same with motorway lighting also. In my opinion its Barry and his counterpart road buddies who are the main reason for our orange skies.

I did a quick survey using some photographs and Google SketchUp a few years back and found that by simply putting a metal hood/shield over Barry, which covers the side of the glass lamp down to its base, then that 40% can be reflected downwards and in doing so the power input can be reduced to keep the same level of light with the additional 40% being reflected downwards, thus saving the council money on electricity bills. Saying this I did write to my council a few years ago demostrating this and to their credit (although they didn't fix the problem completely) they did reply to me and actually sent out a man in a van that day to fix a 1 sided shield to the back of our closest street light.

The result, it must be said was amazing, the orange presence on our front lawn was instantly gone, the birds could sleep at night, there was peace in the middle east, the sound of new born lambs bleating could be heard for 1000 miles, George Bush was never president and Andy Murray made a comment on somebody other than himself...with a smile!

Think, if they'd covered the whole of the streetlight then what might of happened.

Anyway 'notaclue', I'd like to help you with your LP survey, although I think you actually fail to specify what you'd like us to look for, ideas?

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If you pick a constellation and count how many stars you can see (for instance Urse Major would be good) withing the area using a star atlas then you can guage how many stars in that area you can not see. As Ursa Major is circumpolar then it stands a good chance of being recognised by all at any time of the year.

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Hmm.

Lets say Ursa Major but use the defining lines as outlines by Stellarium, which has 18 stars by my counting.

With vieing times of around

00:00 for Summertime

and

19:00 Wintertime

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I can just about see Megrez in Ursa Major at 01.00am (isn't that about 3.2 - 3.3 visible mag?). Certainly nothing feinter at this time of year. My location is very LP prone though - lots of street lights, plus bigger flood lights for a tramstop and carpark opposite my house.

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