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.
- November 19, 2009
- TAK FSQ-106NSV
- Astrodon Gen II RGB filters
- Red: 22x1 minute
- Green: 18x1 minute
- Blue: 23x1 minute
Totaling 63 minutes
- Calibration, registration, normalization, data rejection, master channel combines
- Initial color combine
- Color calibration via Bernhard’s B-V/Aladin technique
- 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