Clear Outside / Light Pollution Update

[FLO]

We've added a new feature into Clear Outside today - an estimate of light pollution

The data is coming from the excellent website: https://www.lightpollutionmap.info/ and utilises the ATLAS 2015 dataset. As you can see, the middle of Exeter is not great for light pollution.

Luckily, Lucksall fares better!

This has been added to the website and the mobile apps to.

We hope you find this interesting and useful - we have other updates planned for this year including the much demanded unit of measure preference options

[Demonperformer]

Interesting. Just wish I could get anything like 19.33!

[Beulah]

Awesome!

[ChrisEll]

Nice to see this addition... I use Clear Outside a lot.

[Alan White]

An interesting addition, thank you FLO.

[alanjgreen]

Now that is useful

Here is what my Cumbria sky has to offer...

[Stu]

Seems pretty good. Says mag 19.4 locally, at best we have measured 19.3 at our site near home. Also says 21.23 for Bignor and we measured 21.3 there. Great stuff!

[scarp15]

Interesting, I have encountered this else where, perhaps a useful reference, but it is still best to take your own sky quality meter readings, as in my opinion the map readings are somewhat exaggerated, maybe nudging a little closer on a perfect dry transparent night / early morning. For example, I have on occasion used the Northumberland National Park car park, just to the west of Ingram in the Breamish Valley. My SQM-L  readings had been typically 21.05 - 21.3 so far at least and I'm sure this could be bettered on a superb night or by venturing deeper into the valley. However the map reference is 21.84. Well no this is not really accurate. As I am aware, the top reading taken within Northumberland has been 21.7 at a N/W point of Kielder. Some areas would reach 21.6, but not I doubt 21.84 (perhaps under exceptional circumstances which are extremely rare and even then)?

Use the map as a broad overview reference, best to invest in a Unihedron Sky Quality Meter L, obtainable such as through FLO, understand how to use it correctly and in what circumstance, take your own readings and work on the average, each time you are out at a specific location. Take regard to the conditions on the night. In my opinion they are a good invest if you celebrate accessing dark sky locations.

[DaveS]

Thanks.

I have been using the light pollution map a lot lately thinking about somewhere to retire to.

Only thing is, it says Bortle 7 here, which I think is a little optimistic.

[DaveS]

That's interesting.....

CO says 18 62 and Bortle 8, lp map says 18.70 and Bortle 8. TBH I think CO is right .

 

Edit, that should be lp map saying Bortle 7

[souls33k3r]

Hahaha bortle 8 skies. That's it, time for a new hobby ?

[mcrowle]

Ah, interesting - thanks, FLO! Not too bad here in Cornwall:
 

[Mr Spock]

A trifle optimistic I would say...

[happy-kat]

And a yellow one. It's about right, though it can't see my 6 street lights that prevent me seeing my reasonable sky :-)

 

[wookie1965]

So mine says 19.04 magnitude class 6 bortle can someone explain this please. 

[AKB]

18 minutes ago, wookie1965 said:

So mine says 19.04 magnitude class 6 bortle can someone explain this please. 

I found this helpful: https://en.wikipedia.org/wiki/Bortle_scale

[Moonshane]

I have moved from a house at 19.17 with security lights to 19.31 without security lights. A slight improvement at least !

[Beulah]

29 minutes ago, wookie1965 said:

So mine says 19.04 magnitude class 6 bortle can someone explain this please. 

You can run that through a conversion calculator to get Naked Eye Limiting Magnitude (MPSAS to NELM ) : http://unihedron.com/projects/darksky/NELM2BCalc.html

19.04 MPSAS gives you 4.80 NELM. NELM being the faintest object the human eye can see.

 

 

[wookie1965]

Does this mean I can only see 4.80 mag stars or brighter.? 

[Stu]

2 minutes ago, wookie1965 said:

Does this mean I can only see 4.80 mag stars or brighter.? 

That's what this suggests. What does your experience say?

[Mark at Beaufort]

I saw this new feature tonight by accident - and thought this was new. My home reading is 20.55 which gives me a NELM of 5.8 which is close to Lucksall at 21.27. Nice feature - thanks FLO.

[wookie1965]

48 minutes ago, Stu said:

That's what this suggests. What does your experience say?

To be truthfull I'm not sure,  I can see polaris but cannot see kochab or any of the other stars in Ursa minor. Cannot see M33 even in the 8". 

[Stu]

1 hour ago, wookie1965 said:

To be truthfull I'm not sure,  I can see polaris but cannot see kochab or any of the other stars in Ursa minor. Cannot see M33 even in the 8". 

That implies Mag 2 NELM which is pretty awful  I assume the figures are for best local conditions, aware from glare and I know you have some pretty trying conditions to contend with Paul.

[Demonperformer]

15 hours ago, Demonperformer said:

Interesting. Just wish I could get anything like 19.33!

 

My previous comment was based on the 'old' figure that I used to get under the Na streetlights, which seems to be burned into my brain, which was 16.8-16.9. I have checked with my SQM this morning and got figures between 18.5 to 18.6, which would suggest about 3/4 of a magnitude's worth of 'optimism'.

[Stu]

4 hours ago, Demonperformer said:

 

My previous comment was based on the 'old' figure that I used to get under the Na streetlights, which seems to be burned into my brain, which was 16.8-16.9. I have checked with my SQM this morning and got figures between 18.5 to 18.6, which would suggest about 3/4 of a magnitude's worth of 'optimism'.

That is a very nice improvement with the new lights! Worth checking on other nights too, you perhaps might get better readings on more transparent nights. Was the moon around when you took the reading? It was quite full last night, and would have been having an impact this morning I should think?