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Double Cluster

Last night, I photographed the Double Cluster in the constellation of Perseus.

As the name implies these are two closely positioned star clusters, known for their bright stars and dense arrangement. The clusters, NGC 869 and NGC 884, are young, at about 12-13 million years old. They are approximately 7,500 light-years away and each cluster contains several hundred stars, including many supergiants and blue-white stars. The reddish stars are cooler and have already spent much of their hydrogen and have moved onto other sources of fuel such as helium. The bluish stars are much hotter, and spending their hydrogen at a furious rate. Here's a closer look at the colourful mix of stars.

I didn't want to blow out the details and colours of the brighter stars. I was using an ASI1600MM Pro monochrome camera, so I captured very short 10 second frames: 25 x red, 25 x green and 25 x blue. Then I worked to capture the fainter stars with much longer 9 x 5 minute frames, consisting of 3 x red, 3 x green and 3 x blue. Overall it only took a bit over an hour for the total exposure- very short in astrophotography terms. All the stacking and correction was shared between Pixinsight and Photoshop.


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