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DaveS

What's your Bortle number?

  

69 members have voted

  1. 1. What's your Bortle number?

    • 1
      0
    • 2
      1
    • 3
      5
    • 4
      16
    • 5
      11
    • 6
      20
    • 7
      6
    • 8
      10
    • 9
      0


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i reckon around 5 it would be nice to be a lot lower though, im sure we all agree on that

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Using Wikidpedia as a guide I would say about 5 from where I observe from.

The dark sight we meet at is about 3 max.

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Home is Bortle 5 but my observing sites are Bortle 3 to 4 depending on what site I use.

Bortle 1 and 2 are dream observing sites and there aren't many of those in the world! 

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I'm in the black triangle between 44 and 45 deg N in this map http://www.iota-es.de/light_pollution/France.gif not sure whether that means I'm a 1 or not but it's pretty dark round here (especially at night :laugh: )

At first I was depressed looking at that map with my poor Bristolian skies. There again my family have a second home  in the south west Ireland where I can say any time for free most of the year,  right where I put the red dot. Pretty pristine there when it doesn't rain, which is not very often I might add, not the steadiest skies either but should be DSO heaven. :smiley: now I feel a bit better.

post-30537-0-79366800-1390770612_thumb.p

Edited by AlexB67

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I have some slight hope that when Ealing council finish putting in new LED street lights it may (Just *may* mind you) push the Bortle number down a notch or two.

Oh, was that a flock of pigs I just saw flying by?

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... and read your eyepiece labels and see what you are doing  when changing them :smiley:  

  • Like 1

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I should only be a 1-3 zone but my 5-6 is probable because of the local LEDs lights to me of which there are many (and many more than the old lamps they were supposed to replace).

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And yet, dealing with LP isn't expensive really, and has so many benefits, not just for us.

For instance, I was looking at a block of flats the other day on my way home from the station, and all the walkways had those round bulkhead lights, whose only function that I could work out was to light up the neighbourhood, whilst doing little to illuminate the walkway. Putting in LED downlights would not only improve the local illumination, it would stop the associated LP, pretty much entirely.

Banning architectural lighting in all its forms would be a big help.

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I doubt there's bottle 1 skies in the uk anywhere is there ? Reading the criteria .

Scottish highlands ?

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Is the wiki link that Moonshane gave (http://en.wikipedia.org/wiki/Bortle_scale) the definitive Bortle that we are working to ?
If so I find it quite contradictory **
For example, on a good night :-

"the summer Milky Way is highly structured
many Messier objects and globular clusters are naked-eye objects" YES (well they were in my youth when my eyes were brighter!)
"near surroundings are not easily visible"
 (need to get down on hands&knees to silhouette my tripod and camera against the milkyway to find it again without risking a torch !!
=Bortle2, but no zodiacal light

"the summer Milky Way still appears complex" YES, even now with my old eyes,

M31, M13, Perseus double cluster etc. NE
=Bortle3 at least, (but still no zodiacl light !)

"light pollution is visible in most, if not all, directions
clouds are noticeably brighter than the sky
the Milky Way is very weak or invisible near the horizon, and looks washed out overhead"
NO !!
So I am deffo not suburban ( my nearest street light is more than  mile away, even further after 1am when most of the village/town lights far to the south are switched off!)
=better than Bortle5

BUT my NELM is only just better than 5.5 which according to him puts me in suburbia at Bortle5
rubbish! But I suppose it gives us something to talk about when it is raining

"Surburban - -only hints of zodiacal light are seen on the best nights in autumn and spring"

Surburban hints ! He must be pulling a leg ?

** Nay, silly, or to be charitable, probably more useful in a dry Mojave desert region ?!
Didnt vote ;-)

Edited by Ptarmigan

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Is the wiki link that Moonshane gave (http://en.wikipedia.org/wiki/Bortle_scale) the definitive Bortle that we are working to ?

If so I find it quite contradictory **

For example, on a good night :-

"the summer Milky Way is highly structured

many Messier objects and globular clusters are naked-eye objects" YES (well they were in my youth when my eyes were brighter!)

"near surroundings are not easily visible"

 (need to get down on hands&knees to silhouette my tripod and camera against the milkyway to find it again without risking a torch !!

=Bortle2, but no zodiacal light

"the summer Milky Way still appears complex" YES, even now with my old eyes,

M31, M13, Perseus double cluster etc. NE

=Bortle3 at least, (but still no zodiacl light !)

"light pollution is visible in most, if not all, directions

clouds are noticeably brighter than the sky

the Milky Way is very weak or invisible near the horizon, and looks washed out overhead"NO !!

So I am deffo not suburban ( my nearest street light is more than  mile away, even further after 1am when most of the village/town lights far to the south are switched off!)

=better than Bortle5

BUT my NELM is only just better than 5.5 which according to him puts me in suburbia at Bortle5

rubbish! But I suppose it gives us something to talk about when it is raining

"Surburban - -only hints of zodiacal light are seen on the best nights in autumn and spring"

Surburban hints ! He must be pulling a leg ?

** Nay, silly, or to be charitable, probably more useful in a dry Mojave desert region ?!

Didnt vote ;-)

I just went by the limiting magnitude I could see. As I can very rarely see any stars in Ursa Minor other than the three brightest that put my skies no better than 8. If I'd gone by the description titles I might have said 7. It was disappointing either way.

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I am lucky, when I decided to move the skies were a factor on where we lived.

I reckon that on that scale I'm a 4. Occasionally like last night I reckon it might have dropped into the mid 3's, but that's only a maybe.

Ant

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I went for 3 based on my estimation of NELM.  Going by the Wikipedia article I could probably partially qualify for 2, 3 or 4, but I think 3 is the "best fit".

James

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I'm a 7 unfortunately ... Useful when I drop any equipment though ;-)

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I'm a 7 unfortunately ... Useful when I drop any equipment though ;-)

In truth, even here the only time it is really pitch black is when there's total cloud cover.  Having a dark sky doesn't actually mean the environment is really that dark.  I need a torch for detail, but there's often enough ambient light to walk around fairly safely and when the Moon is out on a clear night it's bright enough to cast very clear shadows.

James

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I reckon I'm a 4 - visitors always complain about how dark it is and the nearest streetl ight is about 2  miles away.

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It's a bit subjective for me!

I live in quite a rural area, but would chose elements from several categories including down to No. 7!  :grin:

Cheers

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rarely see any stars in Ursa Minor other than the three brightest

Ah, similar minds at work :) that is one of my standard tests as well, easy to remember !

Just now I had all in the 'box' and in the tail NE, rain showers on and off all evening seems to have washed the sky clear and just now I got down to n UMn (m4.95 -Stellarium) which is most unusual for my sky these days.

Now a haze in that area means only Polaris plus beta and gamma :(

,,, back outside to calibrating my 10x50 binos ready for the SN brightening a bit , , , :)

Edited by Ptarmigan

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