light pollution map of places that arent well known

[gurey]

Berbera is a small town, with a population of around 50,000. There are little to no street lights, the only lights come from houses or shops. The days are extremely hot and almost always very clear. For it to be assigned orange on the light pollution map at lightpollutionmap.info is strange. The milky way is visible, although not as clear as in pictures, not sure if that is how it is supposed to be, because it was here I first viewed it.

Sheekh is another small town, population approx. 15-20,000. Elevation approx. 5000feet. It is very windy and can get quite cold at night. Again no street lights and a torch is needed to get around at night. Milky way is visible here too. The only lights visible are at a nearby boarding school.

[xtreemchaos]

where in the world are we talking about?. the milkyway is never as good as pics mate if only we could stax our eyes it would be cool.  clear skys.  charl.

[Mrbloke]

Somalia?

[hjw]

Hi Gurey,

a 50000 people town will generate light pollution even in Somalia. If you have ever seen a really dark sky you will know the difference. I live in a "darkish" place and I know I have a clear night when I can see the dark clouds in the milky way with unaided eyes. But if I go to the country side there is a whole new level to it.

If you have a chance to travel 50 odd km outside of town you will see what I am talking about.

Cheers

HJ

[laudropb]

Which country are we talking about?

[ronin]

I think that you will find that the light pollution maps are not specifically based on the amount of actual produced light. They are it seems based on the population of the place and the predicted amount of light which it is then expected to produce. It is more statistical then actual.

There is on the A507 a small/medium village that is marked on the LP maps, however like the one you describe there are no street lights, and very few houses have external lights, they are sort of old style cottages and that charactor is maintained and there are no indistrial or company areas. The place is DARK very DARK.

It is designated as Yellow, but it is the sort of place that even when walking on the pavements at night you really need a torch, driving a car is a full beam eposode for fear of not quite seeing something. The cricket pitch would I suspect make a great imaging location. :grin:

[acey]

All light pollution maps need to be taken with a pinch of salt. It's important to read the fine print (if you can find it), to see what data has been used, how old the data is, how it's been processed, and what the colour coding means.

The map says that within 1 mile of Berbera town centre the radiance is about 6 x 10^(-9) W/(cm^2.sr). This is apparently equivalent to about 20 mag/arcsec^2 judging by the map's comparative SQM colour coding.

The data source is stated as being the VIIRS satellite. That data gives light shining up into space. It doesn't say how bright the sky looks, seen from ground level. That has to be inferred using a mathematical model. I don't know what model has been used for the map. Evidently, like all models, it has limitations. If you were standing in a desert next to a spotlight shining an intense beam straight up, a satellite would see a bright light at your location, but if your eye was shielded from the spotlight and the air was clear you wouldn't see it affecting your sky at all. Equally, if you were 30 miles away from a major city and the air was very moist, you'd see a bright light dome over the horizon.

It's a pretty safe bet that if you walk away from direct light sources in Berbera you'll have a clear view of the Milky Way. I wouldn't want to do it - Somalia is not the safest of places. Though I assume the OP has been there?

[gurey]

All light pollution maps need to be taken with a pinch of salt. It's important to read the fine print (if you can find it), to see what data has been used, how old the data is, how it's been processed, and what the colour coding means.

The map says that within 1 mile of Berbera town centre the radiance is about 6 x 10^(-9) W/(cm^2.sr). This is apparently equivalent to about 20 mag/arcsec^2 judging by the map's comparative SQM colour coding.

The data source is stated as being the VIIRS satellite. That data gives light shining up into space. It doesn't say how bright the sky looks, seen from ground level. That has to be inferred using a mathematical model. I don't know what model has been used for the map. Evidently, like all models, it has limitations. If you were standing in a desert next to a spotlight shining an intense beam straight up, a satellite would see a bright light at your location, but if your eye was shielded from the spotlight and the air was clear you wouldn't see it affecting your sky at all. Equally, if you were 30 miles away from a major city and the air was very moist, you'd see a bright light dome over the horizon.

It's a pretty safe bet that if you walk away from direct light sources in Berbera you'll have a clear view of the Milky Way. I wouldn't want to do it - Somalia is not the safest of places. Though I assume the OP has been there?

Thanks for the info. It's pretty safe in the northern areas, if you dont mind the hyenas, snakes, lizards etc

[toxic]

get yourself to a good dark site no astrophoto can compare to what you see with your own eyes (galaxy arm) that is what started all this for me it is simply gobsmaking.

[pete_l]

It's always worth bearing in mind that LP (or lack of) is only one factor of many in finding a good observing spot. It's probably not even the most important.

Atmospheric dust, cloud-cover, turbulence, sky obscuration (whether by trees, buildings, mountains etc) are others. As is physical access (is it fenced-off, private property), quality of the ground - is it too rocky, too marshy, at sea , uneven, no roads, in North Korea.

Just because we can measure the LP of a site (or guess-timate it from websites) doesn't mean it works out,when you actually get there, unfortunately.