Globe at Night 2018 Bootes and Crux Campaigns Happen in May

Summary: The Globe at Night Bootes and Crux campaigns happen in May in the Northern Hemisphere and the Southern Hemisphere, respectively.

Arcing to Arcturus traces a path from the Big Dipper asterism’s handle to the brightest star in Bootes the Herdsman, or Plowman, constellation: Learn to Skywatch @Learntoskywatch, via Twitter April 30, 2016

The Globe at Night 2018 Bootes and Crux campaigns happen in May, with dates of Saturday, May 5, to Monday, May 14, for Bootes in the Northern Hemisphere and for Crux in the Southern Hemisphere.

The May campaign is the only campaign concerning Bootes the Herdsman, or Plowman, constellation. Six stars in a large kite-shaped asterism, or star pattern, are responsible for easy recognizability of Bootes. Alpha Boötis (Alpha Boo, α Boötis, α Boo), the constellation’s brightest star, anchors the base of the kite, where the kite tail would begin. The red giant’s traditional name is Arcturus (Ancient Greek: Ἀρκτοῦρος, Arktouros, “Guardian of the Bear”).

The Globe at Night international citizen-science campaign’s website suggests finding Bootes by way of the Big Dipper asterism in constellation Ursa Major (“Great Bear”). Three stars form the Big Dipper’s handle.

Epsilon Ursae Majoris (Epsilon UMa, ε Ursae Majoris, ε UMa) is the closest of the handle’s trio to the asterism’s bowl. Epsilon Ursae Majoris rates as the handle’s brightest star and also as the constellation’s brightest star. Its traditional name is Alioth (Arabic: alyat, “fat tail of a sheep”).

Zeta Ursae Majoris (Zeta UMa, ζ Ursae Majoris, ζ UMa) shapes the handle’s curve. Its traditional name is Mizar (Arabic: mi’zar, “apron, cover”).

Eta Ursae Majoris (Eta UMa, η Ursae Majoris, η UMa) marks the end of the dipper’s handle. Eta Ursae Majoris shines as the handle’s second brightest star and as the constellation’s third brightest star. Its traditional names of Alkaid and Benetnash derive from an Arabic phase meaning “the leader of the daughters of the bier” (Arabic: qa’id binat na’sh). Arab astronomy views the Big Dipper’s handle as three mourning maidens and the asterism’s bowl of four stars as a bier.

Stargazers arc to Arcturus by following the arc of the Big Dipper’s handle to Arcturus’s orange brightness. In terms of constellation Bootes, Arcturus marks the Herdsman’s waist.

Globe at Night’s Northern Hemisphere 2018 Bootes campaign runs simultaneously with the light pollution awareness program’s Southern Hemisphere 2018 Crux campaign. The May 2018 Crux campaign is the second of three 2018 Crux campaigns. The Southern Hemisphere’s first 2018 Crux campaign ran from Friday, April 6, to Sunday, April 15. The third 2018 Crux campaign will be conducted from Monday, June 4, to Wednesday, June 13.

Crux (Latin: “cross”) is easily recognizable as both an asterism and a constellation. Its four main stars shape a cross-shaped asterism known as the Southern Cross.

Gamma Crucis (Gamma Cru, γ Crucis, γ Cru) perches at the top of the cross. Gamma Crucis shines as Crux the Cross constellation’s third brightest star and rates as the red giant star that is nearest to the solar system’s sun. The red giant’s historical name of Gacrux, attributed to American astronomer Elijah Hinsdale Burritt (April 20, 1794-Jan. 3, 1838), was approved as the star’s proper name July 20, 2016, by the International Astronomical Union’s (IAU) Working Group on Star Names (WGSN).

Opposite Gamma Crucis, at the bottom of the cross, Alpha Crucis (Alpha Cru, α Crucis, α Cru) shines as the constellation’s brightest and most southerly star. The IAU’s Working Group on Star Names approved the 19th century historical name of Acrux as the proper name for the bluish-white multiple star system on July 20, 2016.

Beta Crucis (Beta Cru, β Crucis, β Cru) rests at the east end of crossbar. Beta Crucis shines as the Crux the Cross constellation’s second brightest star. The binary star system’s traditional name is Mimosa (Latin: “actor”).

Delta Crucis (δ Cru, δ Crucis) marks the crossbar’s west end. Delta Crucis shines the faintest of the Southern Cross asterism’s four stars. Unlike the asterism’s three other stars, Delta Crucis lacks a proper name.

Epsilon Crucis (Eps Cru, ε Crucis, ε Cru) does not participate in the four-star Southern Cross asterism. The orange-hued star lies in Crux the Cross constellation, southeast of the western crossbar’s Delta Crucis. Epsilon Crucis claims the traditional name of Ginan, from the Wardaman people of Australia’s Northern Territory.

Globe at Night’s Crux campaign cautions stargazers to distinguish between Crux the Cross constellation’s Southern Cross asterism and the nearby False Cross asterism. The diamond-shaped False Cross asterism lies west-northwest of the Southern Cross asterism. The False Cross asterism gathers two stars apiece from two nearby constellations, Carina the Keel and Vela the Sails. The False Cross is larger, but generally dimmer, than the Southern Cross.

Crux the Cross constellation’s fifth main star, Epsilon Crucis, helps distinguish the Southern Cross from the False Cross. Also, Centaurus the Centaur constellation’s two brightest stars lie to the east of the Southern Cross’s crossbar. Known as the Southern Pointers, the triple star systems of Alpha Centauri (Alf Cen, α Centauri, α Cen) and Beta Centauri (Beta Cen, β Centauri, β Cen) point toward the Southern Cross. The False Cross lacks both a fifth star and neighboring pointer stars.

Citizen scientist participants in constellation campaigns supply details that inform the Globe at Night international scientific research program about light pollution in the night sky in the Southern and Northern Hemispheres. Participants refer to Globe at Night’s seven magnitude charts for identifying the magnitude of the faintest stars. Magnitudes range from zero for cloudy sky to seven for star-filled.

The takeaway for the Globe at Night 2018 Bootes and Crux campaigns, which begin Saturday, May 5, is that the Northern Hemisphere’s Bootes campaign only runs in May, while the Southern Hemisphere’s Crux campaign in May occurs as the second of three monthly Crux campaigns in 2018.

Contact details for Globe at Night:

email: globeatnight@noao.edu
website: https://www.darksky.org

Crux the Cross constellation’s Southern Cross asterism (below Eta Carinae) is smaller and brighter than the larger, generally dimmer False Cross asterism (above Eta Carinae), which comprises two stars apiece from two constellations, Carina the Keel and Vela the Sails: Duncan Waldron @ozalba, via Twitter Dec. 27, 2017

Acknowledgment

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

Image credits:

Arcing to Arcturus traces a path from the Big Dipper asterism’s handle to the brightest star in Bootes the Herdsman, or Plowman, constellation: Learn to Skywatch @Learntoskywatch, via Twitter April 30, 2016, @ https://twitter.com/Learntoskywatch/status/726471367701499904

Crux the Cross constellation’s Southern Cross asterism (below Eta Carinae) is smaller and brighter than the larger, generally dimmer False Cross asterism (above Eta Carinae), which comprises two stars apiece from two constellations, Carina the Keel and Vela the Sails: Duncan Waldron @ozalba, via Twitter Dec. 27, 2017, @ https://twitter.com/ozalba/status/946228839629275136

For further information:

“Can You Find Bootes?” Globe at Night > Finding Constellations.
Available @ https://www.globeatnight.org/finding/bootes

“Can You Find Crux?” Globe at Night > Finding Constellations.
Available @ https://www.globeatnight.org/finding/crux

Duncan Waldron ‏@ozalba. "Eta Carinae, currently around magnitude 4.5, is in the magenta circle in this image, which also shows the Southern Cross and pointers, nova Centauri 2013 and the 'false cross.'" Twitter. Dec. 27, 2017.
Available @ https://twitter.com/ozalba/status/946228839629275136

Fazekas, Andrew. “GLOBE at Night -- Helping to Save the Night Sky.” National Geographic Blog > Changing Planet. Jan. 20, 2012.
Available @ https://blog.nationalgeographic.org/2012/01/20/globe-at-night-helping-to-save-the-night-sky/

Learn to Skywatch ‏@Learntoskywatch. "Tonight's Target: Follow the Arc to 'Arcturus' and Speed on to 'Spica.'" Twitter. April 30, 2016.
Available @ https://twitter.com/Learntoskywatch/status/726471367701499904

Marriner, Derdriu. “Globe at Night 2018 Leo Campaign Begins April 6 for Northern Latitudes.” Earth and Space News. Wednesday, April 4, 2018.
Available @ https://earth-and-space-news.blogspot.com/2018/04/globe-at-night-2018-leo-campaign-begins.html