Abstract
Four transits of the exoplanet HAT-P-23b were recently observed with the 0.36 m telescope at the Universidad de Monterrey Observatory. The four light curves were successfully combined to obtain a resulting one with reduced scattering per bin. This curve was modeled using a Monte Carlo method to obtain the essential parameters that characterize the system. Assuming orbital parameters such as eccentricity e and longitude of periastron ω from the discovery paper, we found values of Rp/R_⋆=0.1105^+0.0015_-0.0013 for the planet-to-star radius ratio, a/R_⋆=4.23^+0.06_-0.12 for the scaled semimajor axis, and an orbital inclination of the system of i=87.9°^+1.5_-2.2. We also derive an improved orbital period of 1.2128868±0.0000004 (T_o=2,454,852.26542±0.00018 BJD_TDB) for the system.