The sky, as measured.

SQM values are in mag/arcsec². One magnitude higher means about 2.512 times less background light. SQM does not measure transparency, seeing or lighting compliance.

The default selection uses lensed SQM meters pointed overhead, observer-reported cloud-free conditions, at least three retained readings and a spread no larger than 0.10 mag. Stored astronomical context must show the Sun at or below −18° and the Moon at or below −2°. The Moon margin helps avoid uncertain horizon conditions.

Switch to all reviewed readings to see other conditions or observations awaiting astronomical context. Missing context is not assumed to be moonless or dark. Passing these rules does not remove instrument offsets, haze, airglow or Milky Way effects.

Summary locations are coordinate cells rounded to 0.01° (roughly a kilometre), separated by instrument model. They are approximate groups, not surveyed observing stations. Within each group, submissions are first combined into one median per UAE observing night, from noon to the next noon. The displayed result is the median of those nightly medians.

The range describes the lowest and highest nightly medians in your selection, not a confidence interval. One night is labelled preliminary. Even several nights can be seasonally biased. No smoothing or interpolation fills places without measurements.

Open a summary to inspect its dated nightly history. The original submitted values remain available as individual observations.