London SQM historic data??

[PeterW]

Long shot, but does anyone have any SQM data for places in London over a period of many years? I am seeing if we have any historic time series “ground truth” light pollution data for places in London. There have been plenty of changes in light fittings and some reports of “10% rises in light pollution” floating about. Looking at VIIRS data it seems some area may have seen reduction and others increases in light pollution, so anyone witH SQM data could be helpful to see if things might correlate. A recent paper noted that streetlights (at least in the city in the US studied) contributed potentially less than 10% to the overall night light levels seen from space…. 

 

Thanks

 

Peter

[vlaiv]

37 minutes ago, PeterW said:

A recent paper noted that streetlights (at least in the city in the US studied) contributed potentially less than 10% to the overall night light levels seen from space…. 

This might well be true.

I've seen significant drop in LP after say about midnight or 1am when most human activity drops significantly. Less traffic, less lights from houses.

[DaveS]

Only anecdotally, but as late as 1988 I could, on a good night from west London see all the main stars off UMi, and a faint trail of the milky way.

[PeterW]

My SQM now reads about half a magnitude higher (darker) since full cut off LED locally (potential for some spectral systematic issues though). I can sometimes see all of UMi , but never the milkyway.

 

peter

[lunator]

Peter, like DaveS I can provide provide some anecdotal evidence.

In the early to mid-80's. M31 was clearly visible naked eye. 

My Garden was in SW London it overlooked Fulwell Golf cours so may have been darker than expected.for the location.

Cheers

Ian

[PeterW]

I’m not far from your previous location Ian, sadly M31 is not naked eye anymore.

Peter