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NGC 4725: One-Armed Spiral Galaxy type SBb/Sb and NGC 4712 in Coma Berenices

LRGB combination - spikes added (Click for a larger view 1200 x 1200 px)

 

 

Inverted B/W version

Details

NGC 4725: One-Armed Spiral Galaxy type SBb/Sb and NGC 4712 in Coma Berenices

Discovered by William Herschel in 1785.

While most spiral galaxies, including our own Milky Way, have two or more spiral arms, NGC 4725 seems to have only one. The spiral arm is separated from the central nucleus by a bar structure. The galaxy has obscuring dust lanes, a prominent ring, and a yellowish central bar structure composed of an older population of stars. NGC 4725 is over 100 thousand light-years across and lies 41 million light-years away in the constellation Coma Berenices. NGC 4725 is a Seyfert Galaxy, suggesting an active galactic nucleus containing a supermassive black hole.

NGC 4712 can be seen on the right of the image.

Right Ascension 12 : 50.4 (h:m)
Declination +25 : 30 (deg:m)
Distance 41 000 (kly)
Visual Brightness 9.2 (mag)
Apparent Dimension 11 (arc min)

Seeing: Pickering 7 rating - Good
Optic(s): Celestron 11" Schmidt Cassegrain + TSSCKorr2" flattener @ f/8
Mount: ASA DDM85 Premium
Camera: ATIK 4000 - monochrome CCD – 2048 x 2048 px ; 16x16 mm; 7.4 µm x 7.4 µm
Filters: Astronomics L, R, G, B set, SupaSlim TrueTechnology Computerized Filter Wheel
Dates/Times: 2012-04-29
Location: Rozhen Observatory, BG, longitude: E 24 44' 18", latitude: N 41 41' 42"
Exposure Details:

L = 60 min, R = 30 min, G = 30 min, B = 30 min, (Bin 1), Subexposures = 10 min, Total Exposure Time - 150 min

More details: Dark and flat frames reduction
Guiding: All subexposures are unguided thanks to ASA DDM85 Premium mount
Processing:

PixInsight / PS

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All Contents copyright Velimir Popov unless otherwise noted.