Table 1. Overview of spectral measurements and metadata.

Location	Start/end time		Twilight sequence [E = evening, M = morning]	Solar elevation [°] Min./max.	Lunar elevation [°] Min./max.	Fraction of the Moon Illuminated Min./max.	n
Rural	30-Jun-2014 18:52:55	01-Jul-2014 01:04:39	E	−26.94–16.73	−27.17–38.55	0.12–0.13	371
	01-Jul-2014 01:05:39	01-Jul-2014 08:08:23	M	−26.94–26.45	−41.19–−16.94	0.13–0.16	404
	01-Jul-2014 17:29:18	02-Jul-2014 04:04:24	E	−27.01–32.46	−43.87–53.96	0.18–0.21	451
	02-Jul-2014 19:38:19	03-Jul-2014 01:04:48	E	−27.09–8.52	−19.06–39.73	0.27–0.28	319
	03-Jul-2014 01:05:48	03-Jul-2014 06:07:19	M	−27.09–4.28	−48.64–−19.24	0.28–0.31	299
	12-Jul-2014 19:09:09	12-Jul-2014 23:50:01	E	−25.69–13.34	−15.30–28.01	0.99–0.99	279
	14-Jul-2014 12:35:07	14-Jul-2014 21:51:36	E	−13.53–70.54	−59.59–−1.93	0.90–0.93	249
	18-Jul-2014 14:41:32	19-Jul-2014 01:05:16	E	−29.19–62.29	−41.35–7.16	0.48–0.54	489
	19-Jul-2014 01:06:16	19-Jul-2014 05:58:09	M	−29.19–0.92	7.35–56.83	0.47–0.48	292
	19-Jul-2014 18:08:44	19-Jul-2014 18:48:58	E	16.49–24.07	−36.88–−34.56	0.41–0.42	39
City	05-Jul-2014 19:30:28	06-Jul-2014 01:05:35	E	−27.36–9.84	−2.66–41.20	0.55–0.57	299
	06-Jul-2014 01:06:35	06-Jul-2014 09:33:28	M	−27.36–42.29	−60.39–−2.84	0.57–0.61	487
	06-Jul-2014 19:26:43	07-Jul-2014 06:52:57	E	−27.46–11.95	−56.98–37.62	0.65–0.70	566
	10-Jul-2014 19:23:45	10-Jul-2014 23:44:06	E	−25.04–10.82	6.04–30.31	0.97–0.97	255
	11-Jul-2014 19:49:55	11-Jul-2014 20:41:57	E	−2.72–6.10	1.08–9.43	1.00–1.00	53
	16-Jul-2014 19:13:22	17-Jul-2014 01:05:37	E	−28.84–12.26	−40.82–20.41	0.70–0.73	351
	17-Jul-2014 01:06:37	17-Jul-2014 10:16:50	M	−28.84–49.33	17.14–52.33	0.67–0.70	536
	17-Jul-2014 19:02:59	18-Jul-2014 01:05:03	E	−29.02–14.08	−42.89–13.91	0.59–0.62	333
	18-Jul-2014 01:06:03	18-Jul-2014 06:33:32	M	−29.01–7.23	14.09–56.88	0.57–0.59	319