We report on observations of transit events of the transiting planets XO-1b
and TrES-1 with the AIU Jena telescope in Grossschwabhausen. Based on our IR
photometry (in March 2007) and available transit timings (SuperWASP, XO and
TLC-project-data) we improved the orbital period of XO-1b (P =
3.941497±0.000006) and TrES-1 (P = 3.0300737±0.000006), respectively.
The new ephemeris for the both systems are presented.Comment: 4 pages, 2 figure