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Double Cluster in Perseus



NGC 869 and 884: Double Cluster in Perseus

RA: 2 hrs 20 min; Dec 57 deg 8 min

Date & Site:

9/26/14; Palomar Mountain

Clear; very good seeing; little or no wind; temps in the low 50's


Telescope: FSQ 106 (540mm fl f5)

Mount: AP1100
Camera: ST-10XME; CFW10 with Astrodon Gen II RGB filters;

Internal Autoguiding


Exposures and filters: 20 min each (5 min subexposures) for RGB for a total exposure of 60 minutes

FOV =96 x 65 arc minutes

NGC 869 and NGC 884 both lie at a distance of 7500 light years. NGC 869 has a mass of 3700 solar masses and NGC 884 weighs in at 2800 solar masses; however, later research has shown both clusters are surrounded with a very extensive halo of stars, with a total mass for the complex of at least 20,000 solar masses. Based on their individual stars, the clusters are relatively young, both 12.8 million years old

Distance: ~7,500 light years

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