HAT-P-21b was clearly observed at Taurus Hill Observatory 6./7.3.2011. This so called Hot Jupiter orbits once in 4.12 days a G3 type of star that is same size than our Sun. The distnce of the object form the Earth is about 830 light years. The duration of the transit was 250.6 minutes and the depth of dimmening 10.8 mmag. (CREDIT TRESCA: http://var2.astro.cz/EN/tresca/transit-detail.php?id=1299481034 ).