Quote:
Originally Posted by ArcturusMDS
Can't work out if you're being serious or not.
Can't wait to see these readings enetered onto the system. They're getting better eachtime. With a bit of luck you might beat the 22.02 from NZ. Although John B will want your reading disqualified if you do  |
Hi Darren,
I couldn't be more serious. The theoretical maximum reading is 22.0. With Sky Glow and the light output from the stars themselves this brings the practical maximum to about 21.9!
How I learned about this? One evening at Coonabarabran in October, 2007 I was observing under "stunning" observing conditions with some friends. My observing partners were Andrew Murrell (another 3RF Volunteer), Gary Kopff from Wildcard Innovations, Dave Kriege from Obsession Telescopes and Monte Wilson from AS of NSW. We were discussing how good the observing conditions were. M33 was visible naked eye, notwithstanding it was only about 20 degrees above the horizon. Dave Kriege has observed all over the world from some very dark skies, including, the Atacama Destert in Chile, Lake Titicaca in Bolivia, and Mauna Kea in Hawaii. Dave commented that these were the best observing conditions he had experienced anywhere in the world apart from one solitary night at high elevation on Mauna Kea. There were also 5 other US visitors with us including Scott Tannehill and Don Wyman.
We decided to put the sky conditions to the test with the SQM. Andrew Murrell pulled out his Unihedron SQM and got a reading of 23.45. I commented, "Andrew that can't be right, 22.0 is the maximum". I then used my own identical meter aimed at the same area of sky and got a reading of 21.88. Gary Kopff, who knows a little bit about electronic devices, suggested to Andrew that he should put fresh batteries in his unit, as they may be depleted. Andrew put a fresh battery in his unit and got a reading of 21.85, aimed at the same patch of sky. It was then very obvious that the partially depleted batteries had given an incorrect "false" high reading. On a number of subsequent occasions I have received readings over 22. I have immediately put in a new battery and got an accurate reading of between 21.4 and 21.7.
I believe you should eliminate any reading over 21.9 from your database because IMO it's not an accurate reading.
However, if you don't believe me you had better record an entry of 23.45 on
12/10/2007 for Coonababran NSW taken by Andrew Murrell.
Cheers,
John B