Guys,
Please allow my single digit IQ brain to analyse this logically. I indicated earlier that 22.0 was the theoretical maximum and I felt 21.9 was the "practical" maximum because of skyglow and starlight. I did forget to adjust this for the fact there are bugger all stars visible in the Northern hemisphere to create starlite glow
I did neglect to allow for the tolerance error of the unit which is stated at + or -10%, or .1 mag. Lets also assume some units could be a "touch" out of calibration, or have a slightly greater tolerance error, so lets allow a tolerance of .2 mag. This takes the practical maximum to 22.1.
Attached is a PDF file extracted from the Unihedron database on their website of all readings > 22.1. There are 8 of them. What I find truly amazing is that the highest 5 readings come from 4 different dark sites in CONUS. ONE OF THE MOST LIGHT POLLUTED CONTINENTS ON THE PLANET. It would be a tie between North eastern CONUS and Western Europe as to which area is the most light polluted area on the planet. Here is a link to the world light pollution map
http://www.lightpollution.it/downloa...idotto0p25.gif
The top 2 readings come from Potter County Pennsylvania which just so happens to be smack bang right in the middle of that really big patch of light pollution in the middle of North East CONUS. I have no doubt the skies there are reasonable (they hold a Star Party there), but darker than anywhere else in the world where people have taken readings from over the past 5 or more years? It's also worth noting that these eight readings >22.1 are all taken in 2005, 2006 and 2007 which in all likelihood would indicate they were taken with one of the older units.
I note the highest reading from Australia is 22.07 from outside Mullawa in WA, which is about 100km West of Geraldton and 500km North of Perth. I have no doubt it's right. There are 3 men and a dog per 1,000 square km out there. But not close to the equal of several readings in CONUS? I note the highest reading from New Zealand is 22.02 from Benmore Peak Observatory. Again I have no doubt it's correct as indicated in one of my earlier posts. But again not close to the equal of several readings in CONUS? I suggest some of you revisit that light pollution map.
You guys believe and think what you wish, that's your choice. But, if you don't believe me, please email Anthony and ask him to include that 23.45 reading of Andrew Murrell's taken at about 11:45pm on 12/10/2007 at Coonababran NSW
Cheers,
John B