Astronomy is one of the oldest sciences and also one of the youngest sciences. Today it is a field at the forefront with exciting discoveries like planets around other stars. There are new ideas like dark energy and black holes. We have large, ambitious, and complex international projects like the Laser Interferometric Gravitational wave observatory (LIGO) and Square Kilometer Array (SKA) which keep appearing in the headlines, and in which India too has a share. These use all wavelengths of electromagnetic radiation, and other messengers like cosmic rays, neutrinos, and gravitational waves. An introductory astronomy course at the undergraduate level brings several areas of physics together in with exciting applications, keeping the principles accessible. One starts with things students are familiar with but also curious about like planets, stars and galaxies, and this is taken right up to current developments. Astronomy is largely an observational science and this course will emphasize how we know as much as what we know. The treatment is quantitative but not detailed, so what is really needed is sound grasp of twelfth standard physics and mathematics and willingness to recollect use, and add to these.