SQM-L measurements

SQM-L sky brightness measurements

Since November 2010 we have performed sky brightness measurements with a SQM-L during our comet observing sessions.
Usually a first series was done near the start of a session, and another one near the end.
The results are given in the table below. Each number is the average of at least 3 measurements, rounded to 1 decimal place.
Measurements were made near the zenith, but when denser parts of the Milky Way were overhead the SQM-L was pointed
slightly lower, but never below 70° altitude.
Factors that might have affected the sky quality are mentioned in the notes. Otherwise it can be assumed that measurements
were made when skies were clear without interfering clouds, moonlight or twilight.

Date (yyyy-mm-dd.dd) Magnitude Site Notes

2012-05-12.951 21.4 Burlage -

2012-04-26.915 20.9 Sint Annen 5.6d Moon low in west

2012-04-24.931 21.0 Sint Annen -

2012-04-16.002 21.6 Burlage -

2012-04-15.877 21.3 Burlage -

2012-04-13.904 21.0 Sint Annen -

2012-04-12.905 21.1 Sint Annen -

2012-03-26.947 21.0 Sint Annen -

2012-03-22.990 21.4 Burlage -

2012-03-22.875 21.0 Burlage -

2012-03-19.938 21.2 Burlage -

2012-02-24.885 20.9 Sint Annen -

2011-11-27.98 20.9 Burlage -

2011-11-27.851 20.8 Burlage -

2011-10-29.743 20.7 Sint Annen Sun 15.5° below horizon.

2011-10-24.104 21.1 Burlage -

2011-10-23.840 20.9 Burlage -

2011-10-22.854 21.0 Burlage -

2011-10-09.166 20.8 Sint Annen -

2011-10-01.835 21.0 Burlage -

2011-09-30.121 21.3 Burlage -

2011-09-29.924 21.2 Burlage -

2011-09-18.824 20.8 Sint Annen close to moonrise.

2011-09-03.878 21.1 Burlage -

2011-09-01.879 20.9 Sint Annen -

2011-08-31.865 20.9 Sint Annen -

2011-07-06.983 20.6 Sint Annen grey night; Sun 14.1° below horizon.

2011-06-02.996 20.9 Burlage grey night; Sun 14.5° below horizon.

2011-05-02.00 21.7 Burlage -

2011-05-01.92 21.6 Burlage -

2011-04-02.12 21.1 Sint Annen haze near horizon.

2011-03-08.02 21.6 Burlage -

2011-03-07.91 21.4 Burlage -

2011-03-07.84 21.1 Burlage 3.0d Moon 4° over W. horizon.

2011-01-29.02 21.4 Burlage -

2011-01-28.93 21.3 Burlage -

2011-01-09.98 21.2 Burlage -

2011-01-09.92 21.2 Burlage -

2011-01-03.02 21.1 Burlage ground covered in snow.

2011-01-02.98 21.2 Burlage ground covered in snow.

2010-12-13.00 21.0 Burlage -

2010-12-12.95 20.9 Burlage -

2010-11-07.90 20.9 Burlage -

2010-11-07.79 20.9 Burlage -

Date (yyyy-mm-dd.dd)	Magnitude	Site	Notes
2012-05-12.951	21.4	Burlage	-
2012-04-26.915	20.9	Sint Annen	5.6d Moon low in west
2012-04-24.931	21.0	Sint Annen	-
2012-04-16.002	21.6	Burlage	-
2012-04-15.877	21.3	Burlage	-
2012-04-13.904	21.0	Sint Annen	-
2012-04-12.905	21.1	Sint Annen	-
2012-03-26.947	21.0	Sint Annen	-
2012-03-22.990	21.4	Burlage	-
2012-03-22.875	21.0	Burlage	-
2012-03-19.938	21.2	Burlage	-
2012-02-24.885	20.9	Sint Annen	-
2011-11-27.98	20.9	Burlage	-
2011-11-27.851	20.8	Burlage	-
2011-10-29.743	20.7	Sint Annen	Sun 15.5° below horizon.
2011-10-24.104	21.1	Burlage	-
2011-10-23.840	20.9	Burlage	-
2011-10-22.854	21.0	Burlage	-
2011-10-09.166	20.8	Sint Annen	-
2011-10-01.835	21.0	Burlage	-
2011-09-30.121	21.3	Burlage	-
2011-09-29.924	21.2	Burlage	-
2011-09-18.824	20.8	Sint Annen	close to moonrise.
2011-09-03.878	21.1	Burlage	-
2011-09-01.879	20.9	Sint Annen	-
2011-08-31.865	20.9	Sint Annen	-
2011-07-06.983	20.6	Sint Annen	grey night; Sun 14.1° below horizon.
2011-06-02.996	20.9	Burlage	grey night; Sun 14.5° below horizon.
2011-05-02.00	21.7	Burlage	-
2011-05-01.92	21.6	Burlage	-
2011-04-02.12	21.1	Sint Annen	haze near horizon.
2011-03-08.02	21.6	Burlage	-
2011-03-07.91	21.4	Burlage	-
2011-03-07.84	21.1	Burlage	3.0d Moon 4° over W. horizon.
2011-01-29.02	21.4	Burlage	-
2011-01-28.93	21.3	Burlage	-
2011-01-09.98	21.2	Burlage	-
2011-01-09.92	21.2	Burlage	-
2011-01-03.02	21.1	Burlage	ground covered in snow.
2011-01-02.98	21.2	Burlage	ground covered in snow.
2010-12-13.00	21.0	Burlage	-
2010-12-12.95	20.9	Burlage	-
2010-11-07.90	20.9	Burlage	-
2010-11-07.79	20.9	Burlage	-