Cataclismic variable stars

Example observations of cataclismic variable stars.

U Gem is a bright dwarf nova which has an outburst in progress. The nova has a period of variability 105^d.2. Equatorial coordinates of the star (AAVSO): α(2000): 7^h 55^m05.20^s, δ(2000): +22° 08′ 01″

"Pi of the Sky" images 100x100 arcmin (click at the picture to enlarge):

Light curve (click at the picture to enlarge) and some of our data points (there are averages of 20 frames):

Some of our data:

HJD Date UT Time UT magnitude

2454237.522 2007.05.17   0:35 11.14

2454237.537 2007.05.17   0:58 11.19

2454237.553 2007.05.17   1:20 11.04

2454238.487 2007.04.17 23:46 10.08

2454238.502 2007.05.18   0:07 10.00

2454238.517 2007.05.18   0:28 9.97

2454239.461 2007.05.18 23:08 10.16

2454239.477 2007.05.18 23:31 10.19

2454239.511 2007.05.19   0:21 10.20

2454240.459 2007.05.19 23:06 10.41

2454240.472 2007.04.19 23:24 10.38

2454243.459 2007.05.22 23:05 10.96

2454243.465 2007.05.22 23:15 11.01

2454243.472 2007.05.22 23:24 11.07

2454244.457 2007.05.23 23:03 11.52

2454244.463 2007.05.23 23:12 11.61

2454244.470 2007.05.23 23:21 11.62

Some of our data:
HJD	Date UT	Time UT	magnitude
2454237.522	2007.05.17	0:35	11.14
2454237.537	2007.05.17	0:58	11.19
2454237.553	2007.05.17	1:20	11.04
2454238.487	2007.04.17	23:46	10.08
2454238.502	2007.05.18	0:07	10.00
2454238.517	2007.05.18	0:28	9.97
2454239.461	2007.05.18	23:08	10.16
2454239.477	2007.05.18	23:31	10.19
2454239.511	2007.05.19	0:21	10.20
2454240.459	2007.05.19	23:06	10.41
2454240.472	2007.04.19	23:24	10.38
2454243.459	2007.05.22	23:05	10.96
2454243.465	2007.05.22	23:15	11.01
2454243.472	2007.05.22	23:24	11.07
2454244.457	2007.05.23	23:03	11.52
2454244.463	2007.05.23	23:12	11.61
2454244.470	2007.05.23	23:21	11.62