Deimos and Phobos are the two moons of our neighbouring planet Mars. Asaph Hall, the man who discovered both these satellites, had a rich haul in one particular week, for he spotted both these moons within seven days of each other – Deimos on August 11, 1877 and Phobos on August 17. A.S.Ganesh takes a look at the moons and the man who discovered them...