In my last post, I mentioned the imminent release of a new model of Sky Quality Meter. Unihedron released the new product on time and it is shipping now.
Since that post I've had some time to use the meter with SQM-LE Reader software. One of the first questions a friend asked was 'what does the reading really mean?' He was looking for a way to relate the reading in magnitudes per square arcsecond to something more familiar - like visual limiting magnitude. Fortunately, the Unihedron website has a link to such a computation.
It became apparent quickly that SQM-LE Reader should include this computation along with other reading data. Furthermore, the ability to write readings to a comma separated value file was needed; whence, SQM-LE Reader v1.1. The CSV file format is easily imported into a spreadsheet for further analysis, or browsed with a text file utility such as notepad. These capabilities will appear in a future release of Deep-Sky Planner, but in the meantime they are available for free in SQM-LE Reader.
With these tools in hand, I hope to quantify the darkness of observing sites over the span of an evening, and over the span of seasons. I'd also like to determine whether the visual limiting magnitude computation is accurate (at least for my eyes.) I look forward to collecting and analyzing data over the coming months.
Finally, I've compared readings from the new model with those taken simultaneously with an SQM-L model device. The readings are consistently within .01 of each other, well within the stated accuracy of the device. How about that - delivered on time and functioning to specification!