M7 20th June 2015
The second attempt at M7, this time using the RC6
M7 30 May 2015
Ptolemy’s Cluster (NGC6475), located in Scorpius.
Open Cluster
An open, or galactic, cluster is a grouping of up to several 1000’s of stars which have formed from the same giant molecular cloud, therefore have approximately similar ages.
In contrst to globular clustrs, open vlusters are located within the galactic disc and are only loosely bound together by gravimetric attraction therefore have a more irregular shape and cluster members can be lost through iinterstellar interactons leading to ejection.
Young open clusters will still be contained within the molecular cloud from which they formed providing the energy to convert them to H11 emission nebula. This will only last until the pressure of the stellar winds is sufficient to disperse the molecular cloud – typically when approximately 10% of the cloud has coallesced into stars.