March / April (usually visible from southern latitudes)
Collinder 240 is an extensive open cluster set against the clouds extending eastward from the Eta Carinae Nebula. The broad span of this region of the sky contains areas of more concentrated stars, and these are designated as further clusters in their own right: Collinder 239 to the northwest, and Trumpler 18 to the south. The brightstar dominating the cluster - seen here to the east (left) of centre - is its most luminous member, the supergianty Carinae. Imagery provided by Aladin sky atlas