230411 - M51 "Whirlpool" galaxy
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click image to enlarge
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ASTRO:
type=Spiral galaxy const=Canes Venatici mag=8.4 dist=31 M ly size=76k ly IMAGE: location=EB Driveway BrtlCls=4 moon=70% WnGb exposure=CMOS OSC (avg.): 85x207s (4.9h), Gain159 EQUIPMENT: camera=ZWO ASI2600MC-Pro optics=ES102 w1.0x fltnr, F=714mm, f/7.0 filter=Optolong L-Pro LPS - 69x180s Radian Triad Ultra Quad NB - 16x300s mount=Celestron AVX EQ guiding=Orion 60x240mm, ZWO ASi224MC SOFTWARE: acquisition=Stellarium, APT, PHD2, processing=DSS, PhotoshopCC, APF-R, GraXpert, RCAstro, StarNet++, LrC |
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The Whirlpool Galaxy, also known as Messier 51, or M51, and NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus. It lies in the constellation Canes Venatici, and was the first galaxy to be classified as a spiral galaxy. Its distance is appx 31 M light-years away from Earth.
The Whirlpool and its companion, NGC 5195, are easily observed by amateur astronomers, and the two galaxies may be seen with binoculars. It has been extensively observed by professional astronomers, who study it to understand galaxy structure (particularly that associated with spiral arms) and galaxy interactions.
What later became known as the Whirlpool Galaxy was discovered in 1773 by Charles Messier while hunting for objects that could confuse comet hunters, and was designated in his published catalogue as M51. Its companion galaxy, NGC 5195, was discovered in 1781 by Pierre Méchain, although it was not known whether it was interacting or merely another galaxy passing at a distance. In 1845, William Parsons, 3rd Earl of Rosse, employing a 72-inch (1.8 m) reflecting telescope at Birr Castle, Ireland, found that the Whirlpool possessed a spiral structure, the first "nebula" to be known to have one. These "spiral nebulae" were not recognized as galaxies until appx 1936 when Edwin Hubble was able to observe Cepheid variable stars inside some of these spiral nebulae, which provided evidence that they were extra far distances away, and led him to be the first to theorize they must lie outside the Milky Way, and be entirely separate galaxies.
20 years later, in appx 1956, the advent of radio astronomy and subsequent radio images of M51 unequivocally demonstrated that the Whirlpool is indeed outside the Milky Way; and, it together with its companion galaxy are indeed interacting.
The Whirlpool and its companion, NGC 5195, are easily observed by amateur astronomers, and the two galaxies may be seen with binoculars. It has been extensively observed by professional astronomers, who study it to understand galaxy structure (particularly that associated with spiral arms) and galaxy interactions.
What later became known as the Whirlpool Galaxy was discovered in 1773 by Charles Messier while hunting for objects that could confuse comet hunters, and was designated in his published catalogue as M51. Its companion galaxy, NGC 5195, was discovered in 1781 by Pierre Méchain, although it was not known whether it was interacting or merely another galaxy passing at a distance. In 1845, William Parsons, 3rd Earl of Rosse, employing a 72-inch (1.8 m) reflecting telescope at Birr Castle, Ireland, found that the Whirlpool possessed a spiral structure, the first "nebula" to be known to have one. These "spiral nebulae" were not recognized as galaxies until appx 1936 when Edwin Hubble was able to observe Cepheid variable stars inside some of these spiral nebulae, which provided evidence that they were extra far distances away, and led him to be the first to theorize they must lie outside the Milky Way, and be entirely separate galaxies.
20 years later, in appx 1956, the advent of radio astronomy and subsequent radio images of M51 unequivocally demonstrated that the Whirlpool is indeed outside the Milky Way; and, it together with its companion galaxy are indeed interacting.