Wednesday, 4 July 2018

NGC6507: My cup of tea

A few days ago I showed you brilliant M23, an open star cluster in Sagittarius that's a real treat for binoculars and small telescopes. In a large telescope you'll have a hard time trying to fit everything in the telescope's eyepiece and therefore the view will become somewhat less pleasing. Now onto a small cluster in M23's vicinity: NGC6507. There's surprisingly little information to be found about it and that's a real shame because this is the sort of object I (personally) go nuts about. Being over 3,900 light-years away it lies almost twice as far from us as M23 and if it doesn't nearly appear as impressive it's mostly due to its much greater distance. Observe it with a sufficiently large telescope and you'll be surprised about the number of tiny little stars that appear in between the brighter ones. Well... brighter ones... even those are of mag. 11-12. 

Now try to focus on what this cluster's telling you. Look at how its stars are no longer contained in a more or less spherical shape but how they seem to be smeared out somewhat. Clearly, this cluster's already a bit older than M23 (400-450 million years) and the effect of our galaxy's gravity is taking its toll. Its stars are being pulled into a streak along our galaxy's plane and will then disperse to lead their adult lives in solitude. 

Again, the brightest star, towards the bottom-right, lies much closer to us and therefore doesn't belong to the cluster at all. 


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