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Moonshane

Tell us your sky quality

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9 hours ago, vlaiv said:

when southern wind blows it can lift Sahara sands and carry them all the way across Mediterranean Sea. More than once we had "muddy" rain because of this in past few years.

Believe it or not these occasionally reach the UK, once every few years, leaving  film of dust on cars!

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9 hours ago, vlaiv said:

This is why it is useful to check out aerosol optical depth forecast (finally managed to find the page, they kept changing it lately):

https://atmosphere.copernicus.eu/charts/cams/aerosol-forecasts?facets=undefined&time=2019010200,3,2019010203&projection=classical_europe&layer_name=composition_aod550

Thank you, that is useful information. Unsurprisingly, we get "muddy rain" a few times a year in southern Spain. While rain is generally welcome (some years we get a total of 200mm) this effect seems to mix the greatest amount of red dust with the least amount of water. The result is no significant rainfall but the need to wash the car!

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14 minutes ago, Stub Mandrel said:

these occasionally reach the UK

16 October 2017 we had this and it was a very eerie effect

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1 hour ago, Moonshane said:

Whilst it's never going to be as accurate as single or multiple SQM readings at specific times I actually think it's a fairly usable estimate as for most it seems to reflect average conditions or be just a little off. If you live in say a Bortle 7 zone and want to use it to try and find somewhere accessible and darker than where you are, I doubt a small difference in readings will matter. If you want to get serious about levels then I agree a meter reader would be a useful investment but as this is free and you can get a rough idea of 'the world's' light pollution from the comfort of your armchair I think it does pretty much what it says on the tin.

It does concern me that I will venture to a place that according to the map has a reading of 21.8, when the actual measurement is quite off at least during an average circumstance. I do agree that the map could be of assistance as a rough guide if looking for somewhere potentially darker and that a Sky Quality Meter becomes more applicable for those that travel between different locations enabling comparisons to be made. 

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1 hour ago, Demonperformer said:

16 October 2017 we had this and it was a very eerie effect

Indeed, you remind me I got some eerie photos of the sun, no solar film required!

DSCN9346.thumb.JPG.78bd6c22cfc0b88490697ee300ed27d0.JPG

DSCN9337.thumb.JPG.730e4c6ad18ff6d9ac1fad2390322f05.JPG

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1 hour ago, scarp15 said:

It does concern me that I will venture to a place that according to the map has a reading of 21.8, when the actual measurement is quite off at least during an average circumstance. I do agree that the map could be of assistance as a rough guide if looking for somewhere potentially darker and that a Sky Quality Meter becomes more applicable for those that travel between different locations enabling comparisons to be made. 

I don't disagree Iain but at least this gives a decent idea of which places are worth traveling to and test with a SQM for future use? Otherwise you might end up wasting a lot more time. I may be wrong but do these stated measurements not generally reflect the best case scenario and in general the prevailing conditions won't be such so readings will naturally be lower on average than in optimum conditions? 

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15 minutes ago, Stub Mandrel said:

Indeed, you remind me I got some eerie photos of the sun, no solar film required!

DSCN9346.thumb.JPG.78bd6c22cfc0b88490697ee300ed27d0.JPG

DSCN9337.thumb.JPG.730e4c6ad18ff6d9ac1fad2390322f05.JPG

Better than the ones I got on my phone.

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Posted (edited)
2 hours ago, Moonshane said:

I don't disagree Iain but at least this gives a decent idea of which places are worth traveling to and test with a SQM for future use? Otherwise you might end up wasting a lot more time. I may be wrong but do these stated measurements not generally reflect the best case scenario and in general the prevailing conditions won't be such so readings will naturally be lower on average than in optimum conditions? 

Possibly Shane but I do not think that even the optimum conditions will necessarily accomplish matching some of the stated map readings in certain locations. It could as you say, convey a decent idea though, as to where is worth while travelling in which case if intent on repeated journeys, a SQM and monitoring readings becomes quite integral to the activity. I do feel that Sky Quality Meters get quite overlooked as a non requirement, and yet compared to say eyepieces for example, offer good value and taking a frequency of readings is purposeful to the experience of your session. I feel that gathering data in this way - as individuals, collectively gathering a pool of statistic monitoring, with coordinates (perhaps starting as a new link on SGL), could be useful perhaps assisting with preservation of supposive dark sky parks which of course are under continued and increased threat from development.

Edited by scarp15
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16 minutes ago, scarp15 said:

Possibly Shane but I do not think that even the optimum conditions will necessarily accomplish matching some of the stated map readings in certain locations. It could as you say, convey a decent idea though, as to where is worth while travelling in which case if intent on repeated journeys, a SQM and monitoring readings becomes quite integral to the activity. I do feel that Sky Quality Meters get quite overlooked as a non requirement, and yet compared to say eyepieces for example, offer good value and taking a frequency of readings is purposeful to the experience of your session. I feel that gathering data in this way - as individuals, collectively gathering a pool of statistic monitoring (perhaps starting as a new link on SGL), could be useful perhaps assisting with preservation of supposive dark sky parks which of course are under continued and increased threat from development.

I totally agree Iain. In fact it was a close choice between a new observing stool or a SQM-L for crimbo. I went for the former as observing mainly at home I'll get more use out of it. That said, it's my birthday next month ?. I am planning an obs and inside there, protected from ambient and neighbour lights, I'll definitely get better readings and my eyes will also adapt more. I am also going to make a more determined effort to get out this year to a darker site each month around new moon so this will also allow more remote readings too.

Coming from a background of insect recording (acting as a County Moth Recorder for Cheshire for many years) I completely agree about the power of collated data and also urge people to submit their own data when possible and considered accurate.

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14 minutes ago, Moonshane said:

urge people to submit their own data when possible and considered accurate.

To where should it be submitted?

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2 minutes ago, Demonperformer said:

To where should it be submitted?

There are couple of places (you can find them in links section on SQM-L/Unihedron website - check "Light pollution maps / databases" section).

You can also submit your reading to lightpollutionmap.info :D

image.png.72b2c132d9353b2f5bf12b5d5f3534b5.png

You can also view submitted readings with additional info by selecting appropriate layer (color dots used as markers for location - click on one to get info on readings):

image.png.b18b3e4544f243fd44a5be356b771cce.png

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Oh my!! My LP is higher than I expected... 

Apart from the hue towards Manchester to the West, all other directions are dark. 

 

562502004_ScreenShot2019-01-03at14_08_14.png.d6ba21f8b9a5560f3ef4acb1eab23f3c.png

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I just discovered these:

image.png.5a387a0e8bae8f44b142154979f064b6.png

image.png.461a0f1427558e3c0b40c93d618f25df.png

I've been thinking about doing something similar with planetary/guider cams - it looks like there is software to generate these maps.

Simple photo tripod with 1/4 thread can be used to mount most planetary cams. Simple CS wide lens can be used - like those used to capture meteors. This gives much better info on sky lp - especially for imagers as it provides direction information - useful for selecting targets. One can even do sequence of images over the course of the night to do idea of changing levels of light pollution (lights going on and off).

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I think the weakness of all such maps is that they inevitably give readings based on the zenith, yet we rarely observe or image at straight up.

On a good night I can see the Milky Way straight up at home, but unless it is exceptionally transparent anything to the north east or low down in the south west is a waste of time.

My experience of  dark sites is that good sky getting closer to the horizon is at least as dramatic as improvements in the straight up view.

A good use of these maps is to identify the light domes that are likely to affect a particular location.

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6 minutes ago, Stub Mandrel said:

A good use of these maps is to identify the light domes that are likely to affect a particular location.

That makes alot of sense Neil, and is certainly how I use them. It is quite easy to see how close even the dark sites are to big sources of pollution. I try to avoid being north of towns or alongside motorways/main roads etc. At the end of the day, it is just a guide though, actually checking the site out is the way to really tell, but it should give good pointers as to where to look.

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56 minutes ago, Stu said:

That makes alot of sense Neil, and is certainly how I use them. It is quite easy to see how close even the dark sites are to big sources of pollution. I try to avoid being north of towns or alongside motorways/main roads etc. At the end of the day, it is just a guide though, actually checking the site out is the way to really tell, but it should give good pointers as to where to look.

Certainly. What I initially found confusing and, perhaps, frustrating is that my current house location has higher LP (class 5) than my previous house (class 4). I could swear the sky looks almost identical in both locations. I struggle to see objects like M56 here in Glossop, but...that's because, obviously, I use an 8-incher whereas in my previous town I had a 12-incher. As Neil says, LP is probably measured based on the nearest city. I have Manchester about 20 miles to the North West and, I couldn't be bothered even pointing the scope lower than 50-deg in that direction. All other directions are dark. Then, of course, the house, as Sod's law has it, is right there blocking much of the darkest spot towards the East. 

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You think that's bad, I can see the actual M56 (and the M67, M60 and if I try the M66 and M62) from where I live!

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Posted (edited)
3 minutes ago, Moonshane said:

You think that's bad, I can see the actual M56 (and the M67, M60 and if I try the M66 and M62) from where I live!

Yep, that's why I find the 8-incher, although very nice, a bit frustrating. It's just...well...not quite there. As far as I remember, you use 12 and 16 inch Dobs, right?

Edited by emadmoussa

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I was referring to Motorways LOL

I have a 16" dob but mainly use my 12" and 120mm Equinox.

Once I have my obs I'll be using the 16" more regularly.

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5 minutes ago, Moonshane said:

I was referring to Motorways LOL

I have a 16" dob but mainly use my 12" and 120mm Equinox.

Once I have my obs I'll be using the 16" more regularly.

Haha... I don't drive, ergo a motorway ignoramus. Lol

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Posted (edited)

I can see the M25 out my bedroom window but curiously it's also the darkest direction so I guess the modern LED lighting is working well.

Dave

Edited by Davey-T

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3 hours ago, Davey-T said:

I can see the M25 out my bedroom window but curiously it's also the darkest direction so I guess the modern LED lighting is working well.

Dave

Even photons get stuck for hours on the M25...

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Pretty happy with my results...  Shame it doesn't take into account the wet weather though.

20190208_200107.png

Edited by bobmoss
Added more text
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1 minute ago, bobmoss said:

Pretty happy with my results... 

20190208_200107.png

AWESOME!!! I managed 21.75 in Mid Wales a few nights ago....your 21.9 is nothing short of breathtaking!  :)

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23 minutes ago, Beulah said:

AWESOME!!! I managed 21.75 in Mid Wales a few nights ago....your 21.9 is nothing short of breathtaking!  :)

Would love the get hold of a proper SQM to see how accurate the website is. It is pretty dark here though, must get around to trying to properly estimating how dark it actually is.

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