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M 31 Andromeda Galaxy



 

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Common Name Andromeda Galaxy
Formal Name M 31 / NGC 224
Date 9/21-9/1/2017
Constellation Andromeda
Location BrewSky Observatory, Casa Grande, AZ
Equipment Takahashi FSQ106ED on Paramount MX, SBig STF8300M Camera/Filter Wheel/STi guider
Temperature -5°C
Exposures
# Exp (sec) Filter Bin Net Time (hr)
20 900 Red 1x1 5.0
14 900 Green 1x1 3.5
14 900 Blue 1x1 3.5
19 900 HAlpha 1x1 3.75
Total 15.75 hrs
Processing Calibrated in Maxim, Aligned/Stacked/Processed in PixInsight. Images were done in 1x1 bin, then drizzled in PI. Synthetic Lum by integrating RGB.
Notes The Andromeda Galaxy, also known as Messier 31, M31, or NGC 224, is a spiral galaxy approximately 780 kiloparsecs (2.5 million light-years) from Earth. It is the nearest major galaxy to the Milky Way and was often referred to as the Great Andromeda Nebula in older texts. It received its name from the area of the sky in which it appears, the constellation of Andromeda, which was named after the mythological princess Andromeda.

Andromeda is approximately 220,000 light years across, and it is the largest galaxy of the Local Group, which also contains the Milky Way, the Triangulum Galaxy, and other smaller galaxies. Despite earlier findings that suggested that the Milky Way contains more dark matter and could be the largest in the grouping, the 2006 observations by the Spitzer Space Telescope revealed that Andromeda contains one trillion (1012) stars: at least twice the number of stars in the Milky Way, which is estimated to be 200–400 billion. The mass of the Andromeda Galaxy is estimated to be 1.5×1012 solar masses, while the Milky Way is estimated to be 8.5×1011 solar masses.

The Milky Way and Andromeda galaxies are expected to collide in 4.5 billion years, eventually merging to form a giant elliptical galaxy or perhaps a large disc galaxy. The apparent magnitude of the Andromeda Galaxy, at 3.4, is among the brightest of the Messier objects, making it visible to the naked eye on moonless nights, even when viewed from areas with moderate light pollution.