Open Clusters H & Chi Persei
The Double Cluster is the common name for the naked-eye open clusters NGC 884 and NGC 869, which are close together in the constellation Perseus. NGC 884 and NGC 869 are at distances of 7600 and 6800 light-years away, respectively, so they are close to one another in space as well.
They are relatively young clusters, with NGC 869 5.6 million years and NGC 884 at 3.2 million years according to the 2000 Sky Catalogue. In comparison, the Pleiades have an estimated age ranging from 75 million years to 150 million years.
They are also 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.
You can also see another version taken outside of the city but in relatively good seeing condition
Clik here for this version
Photo Details
Telescope: FSQ106EDX (530 mm) Takahashi
Camera: Sbig ST-8300M, Filter wheel, Baader 1.25" LRGB filtes
Mount: NJP Takahashi
Guiding: OrionST80, Orion SS Autoguider
Exposure: LRGB L 15x300sek, R 8x300sek, G 8x300sek, B 8x300sek
When: October 2011
Other information: good transparency, terrible seeing, partially setting Moon > 0.7
Older "quick session" version
Photo Details
Telescope: FSQ106EDX (530 mm) Takahashi
Camera: Sbig ST-2000XM, Filter wheel, Baader 1.25" LRGB filtes
Mount: NJP Takahashi
Guiding: Self-guided
Exposure: LRGB L 1x300sek, R 1x300sek, G 1x300sek, B 1x300sek
When: October 2010
Other information: very good transparency, bad seeing, full moon (0.98)