Cassiopeia the Queen Constellation Is True Arrow to Andromeda Galaxy

Summary: Cassiopeia the Queen is a northern sky constellation that points directly to the Andromeda Galaxy, the Milky Way’s closest spiral galaxy.

Constellation Cassiopeia's distinctive M/W asterism points to the Adromeda Galaxy, the Milky Way's closest spiral galaxy: EarthSky @earthskyscience via Twitter Aug. 22, 2016

The constellation of Cassiopeia the Queen of ancient Ethiopia distinctively plies Northern Hemisphere skies north of 35 degrees north latitude year-round as a circumpolar constellation. Sited on the opposite side of the North Star, Polaris, from the Great Bear's Big Dipper asterism, Cassiopeia points to the Milky Way’s closest spiral galaxy, the Andromeda Galaxy, with the constellation's M/W asterism, or distinctive pattern of stars.

Following the deeply notched V portion of the W shape leads to the Andromeda galaxy. Known officially as Messier 31, M31 or NGC 224, the Andromeda Galaxy is located about 2.5 million light years from Earth. With a diameter of 220,000 light years, the Andromeda Galaxy is double the Milky Way's diameter of 100,000 light years. The spiral galaxy has an estimated inclination of 77 degrees relative to Earth.

The Andromeda Galaxy appears to unaided eyes as a fuzzy star or a smudgy patch around a central core of light. To unaided eyes, the galaxy has the width of a full moon. The Andromeda Galaxy is the most distant object that is visible to unaided eyes.

Andromeda Galaxy, March 2, 2014: Brad Sutton/National Park Service, Public Domain, via Joshua Tree National Park @ Flickr

The distinctive M or W shape traced by the constellation’s five brightest stars qualify Cassiopeia the Seated Queen as one of the nighttime’s most easily recognizable constellations. Placement relative to Polaris determines the appearance of the five-star asterism as an M or as a W. The asterism appears as an M when above the North Star and as a W when below Polaris.

The old-fashioned name of Cassiopeia’s Chair recognizes the importance of the asterism for easy discernment of the constellation. The International Astronomical Union agreed upon Cassiopeia as the constellation’s official name for the list of 88 constellations approved by the association’s inaugural General Assembly in May 1922 in Rome, Italy. Nevertheless, the asterism’s old-fashioned name continues to provide successful guidance for succeeding generations to the chair’s exact placement in the night sky.

Of Cassiopeia’s five main telltale stars, Alpha Cassiopeiae (α Cassiopeiae; Alpha Cas, α Cas) is the brightest. The 2.24-magnitude star is sited about 230 light years away. The orange giant’s traditional name is Schedar (Arabic: şadr, “breast). As the deeply notched point in the M or W shape, Alpha Cassiopeiae serves as the true arrow that points to the Andromeda galaxy.

Of Cassiopeia’s total of 53 stars, the second brightest is Beta Cassiopeiae (ß Cassiopeiae; Beta Cas, ß Cas). Beta Cassiopeiae’s traditional names include Caph (Arabic: kaf, “palm”) and al-Sanam al-Nakah (“the camel’s hump”). White-yellow giant Caph is located about 55 light years away. Its magnitude is 2.28.

Gamma Cassiopeiae (γ Cassiopeiae; Gamma Cas, γ Cas) holds third place as a 2.47-magnitude star. Gamma Cassiopeiae is around 550 light years away. As the dip between the asterism’s two peaks, the variable blue star lies at the center of the Seated Queen’s chair.

On the Apollo 10 Flown CSM (Command and Service Module) Star Chart of Pilot John Young, Gamma Cassiopeiae is designated as Navi, in honor of Virgil Ivan “Gus” Grissom (April 3, 1926-Jan. 27, 1967). U.S. Air Force test pilot and NASA astronaut Grissom perished, along with astronauts Roger Bruce Chaffee (Feb. 15, 1935-Jan. 27, 1967) and Edward Higgins "Ed" White (Nov. 14, 1930-Jan. 27, 1967), in a fire in the Command Module interior during a pre-launch test for the Apollo 1 program.

The Seated Queen’s fourth brightest star is Delta Cassiopeia (δ Cassiopeiae; Delta Cas, δ Cas). The 2.68-magnitude star is actually an eclipsing binary star system. The larger of the starry pair is a white subgiant. Delta Cassiopeia lies about 100 light years from Earth. Its traditional name is Ruchbah (Arabic: rukbah, “knee”).

With a magnitude of 3.37, Epsilon Cassiopeiae (ε Cassiopeiae; Epsilon Cas, ε Cas) is the asterism’s and the constellation’s fifth brightest star. The blue giant is located around 400 light years away.

The asterism in Cassiopeia's constellation that points like a true arrow to Andromeda Galaxy brightens night skies with easy familiarity and visibility. The arrow's path traverses fantastic distances across time to Andromeda Galaxy's recognizable hazy patch. Each night's light from Andromeda Galaxy began the journey of visibility to Earthlings 2.5 million years ago.

Andromeda Galaxy is visible Oct. 21, 2013, to left of the fourth Unit Telescope (UT) in the European Southern Observatory's Very Large Telescope (VLT), Cerro Paranal, northern Chile; the fourth UT is known as Yepun (Mapuche: yeln, "to carry" + pun, "night": i.e., the evening star, Venus): Babak Tafreshi/European Southern Observatory, CC BY 2.0, via Flickr

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Constellation Cassiopeia's distinctive M/W asterism points to the Adromeda Galaxy, the Milky Way's closest spiral galaxy: EarthSky (@earthskyscience) via Twitter Aug. 22, 2016, @ https://twitter.com/earthskyscience/status/767740393471565824

Andromeda Galaxy, March 2, 2014: Brad Sutton/National Park Service, Public Domain, via Joshua Tree National Park @ Flickr @ https://www.flickr.com/photos/joshuatreenp/20703855582

Andromeda Galaxy, in Chilean skies, Oct. 21, 2013: Babak Tafreshi/European Southern Observatory, CC BY 2.0, via Flickr @ https://commons.wikimedia.org/wiki/File:Two_naked-eye_galaxies_above_the_VLT_(wallpaper).jpg?uselang=fr

For further information:

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Available @ https://historical.ha.com/itm/transportation/space-exploration/apollo-10-flown-csm-star-chart-directly-from-the-personal-collection-of-mission-command-module-pilot-john-young-signed-and-ce/a/6037-41082.s?ts=off#Photo

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Available @ https://twitter.com/earthskyscience/status/767740393471565824

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