Blue Moon versus Super moon
Blue moon does not mean blue coloured moon. It is just second full moon of any calendar month. A blue moon happens, on average, once every 2.7 years
A super moon is a full moon which occurs when the Moon is closest to the Earth, making it appear bigger and brighter. During every 27-day orbit around earth, the moon reaches both its apogee (farthest point from earth) and perigee (closest point from earth0. Full moons can occur at any point along the moon’s elliptical path, but when a full moon occurs at or near the perigee, it looks slightly larger and brighter than a typical full moon. This is called a supermoon.
On Super moon day, moon appears 14% larger and 40% brighter. In the year 2018, Blue moon on January 31 was very rare because the Super moon, blue moon and total lunar eclipse occurred simultaneously. That had happened after 174 years.