Table 1: Log of the observations.

Date UT	Filter	Exp. time (s)	Air mass
1999 Jun. 1 06:46:24	V	180	1.232
1999 Jun. 1 06:51:08	V	180	1.246
1999 Jun. 1 06:55:52	V	180	1.261
1999 Jun. 1 07:00:36	V	180	1.277
1999 Jun. 16 02:27:00	R	180	1.163
1999 Jun. 16 02:31:45	R	180	1.154
1999 Jun. 16 02:36:29	R	180	1.146
1999 Jun. 16 02:41:13	R	180	1.138
1999 Jun. 16 02:46:07	V	180	1.131
1999 Jun. 16 02:50:51	V	180	1.124
1999 Jun. 16 02:55:35	V	180	1.118
1999 Jun. 16 03:00:19	V	180	1.112
1999 Jun. 16 03:05:13	R	180	1.107
1999 Jun. 16 03:09:57	R	180	1.103
1999 Jun. 16 03:14:41	R	180	1.099
1999 Jun. 16 03:19:25	R	180	1.095
1999 Jun. 16 04:06:32	V	180	1.086
1999 Jun. 16 04:11:17	V	180	1.087
1999 Jun. 16 04:16:01	V	180	1.089
1999 Jun. 16 04:20:45	V	180	1.092