Star Clusters / Double Cluster
Double Cluster
View 33% sized image View 50% sized image View 67% sized image View 100% sized image

Double Cluster with Spikes
Version With Star Spikes
View 33% sized image View 50% sized image View 67% sized image View 100% sized image

The "Double Cluster" in Perseus

Object Description:
NGC 884 (chi Persei) and NGC 869 (h Persei) together are more popularly known as the “Double Cluster”.  Located in the constellation, Perseus, they are each 7,600 and 6,800 light-years away, and are situated close to one another as well.  These open clusters are easily visible to the naked eye from a dark sky sight and were cataloged in 130 BC by the Greek astronomer, Hipparchus.

These clusters are quite young; NGC 884 thought to be 5.6 million years old, and NGC 869 at 3.2 million years in age.  They contain hot main sequence stars of spectra O and B0.  Additionally, they are somewhat blue-shifted, with NGC 869 approaching Earth at a speed of 22 km/s and NGC 884 approaching at a similar speed of 21 km/s.

Date Taken:
 - November 19, 2009

Equipment Used:
 - TAK FSQ-106NSV
 - EM-200
 - STL-6303
 - Astrodon Gen II RGB filters

Exposures:
 - Red:  22x1 minute
 - Green:  18x1 minute
 - Blue: 23x1 minute
Totaling 63 minutes

Processing:
CCDStack:
 - Calibration, registration, normalization, data rejection, master channel combines
 - Initial color combine
 - Color calibration via Bernhard’s B-V/Aladin technique
 - DDP

Photoshop:
 - Gradient control
 - Noise reduction (NeatImage)
 - Noel Carboni's Photoshop action for “Increase Star Color”
 - “Spiked” version of this image produced with Noel Carboni’s “StarSpikePro” plug-in for Photoshop