Image of the Month - March 2018
After a terrible start to 2018 due to the weather on La Palma, we're now back up and running and have been busy catching up on the backlog of observations. Spring is a wonderful time of year for observing galaxies in the northern hemisphere, with a large range of objects to choose from. This month's Image of the Month is one of our personal favourites - Messier (M) 51 or the Whirlpool Galaxy. This is a pair of interacting galaxies, the dominant large spiral system to the south of the image and a dwarf galaxy to the north. By combining the 3 images taken by our observer, in 3 different filters - which let through different colours (or wavelengths) of light - we can clearly see the difference between the blue-coloured large galaxy, full of young stars, and the older, redder dwarf galaxy. The colours give us an indication of the age of the stars in the galaxies, young stars emit much more blue light (high temperature) and older stars are cooler emitting predominantly in the red. This galaxy barely fits in the field of view of the camera with a diameter of around 50,000 light years, and sitting only 30 million light years from Earth!