Summary: Globular cluster NGC 5634 lies midway between Iota Virginis and Mu Virginis in southeastern Virgo the Virgin constellation.
Globular cluster NGC 5634 lies midway between Iota Virginis and Mu Virginis, stars with naked eye visibility in southeastern Virgo the Virgin constellation, near Virgo’s border with northwestern Libra the Scales constellation.
Fourth magnitude stars Iota Virginis and Mu Virginis star hop binocular and telescopic observers to globular cluster NGC 5634. Lying east of yellowish Iota Virginis, bluish-white Mu Virginis hovers near the southeastern Virgo-northwestern Libra border.
Celestial coordinates for Iota Virginis are right ascension (RA; similar to geographic longitude) at 14 hours 16 minutes 00.866 seconds and declination (DEC; similar to geographic latitude) at minus 6 degrees 00 minutes 02.01 seconds, according to Hubble Legacy Archive (HLA). HLA celestial coordinates for Mu Virginis are right ascension at 14 hours 43 minutes 03.618 seconds and declination at minus 5 degrees 39 minutes 29.59 seconds. NGC 5634’s right ascension is 14 degrees 29 minutes 37.279 seconds, with declination at minus 5 degrees 58 minutes 35.15 seconds, according to Hubble Legacy Archive.
Both stars participate in the recently discovered February mu Virginid (FMV) meteor shower as radiants. Mu Virginis is the shower’s namesake. Radiant drift accounts for February mu Virginid members appearing to trace back to a point five degrees east of Iota Virginis just before the onset of the shower’s annual activity dates of mid-February to early March. The February mu Virginid shower’s radiant drift also takes in Libra the Scales and Ophiuchus the Snake Bearer constellations.
The discovery of the February mu Virginid shower was announced in the June 2013 issue of WGN, the Journal of the International Meteor Organization (IMO). Damir Šegon and five other members of the Croatian Meteor Network are credited with detecting eight new
showers, including the February mu Virginids, via the Croatian Meteor Network’s 2007 to 2010 catalogues and Japan’s SonotaCo Network’s 2007 to 2011 catalogues.
Astronomer and Sky & Telescope magazine editor James Mullaney suggests another star hopping strategy for locating NGC 5634. Mullaney specifies NGC 5634’s celestial placement at three degrees west of Mu Virginis and 30 minutes east of sixth magnitude star 104 Virginis. The blue subgiant is visible to the naked eye. HLA celestial coordinates for 104 Virginis are right ascension at 14
hours 27 minutes 24.387 seconds and declination at minus 6 degrees 7 minutes 13.21 seconds. Mullaney notes the location of 104 Virginis in “the same wide eyepiece field.”
Hartmut Frommert of the University of Konstanz’s Physics Department in southwestern Germany locates NGC 5634 at a distance of 82.2
kilo-light years. Southeastern Virgo’s globular cluster lies 69.1 kilo-light years from the Milky Way’s Galactic Center. One kilo-light year approximates 63,240,000 astronomical units (AU); 9,460,528,405,000,000 kilometers; 5,878,499,814,210,000 miles.
German-British astronomer and composer Sir Frederick William Herschel (Nov. 15, 1738-Aug. 25, 1822) is credited as NGC 5634’s discoverer. He discerned southeastern Virgo’s globular cluster March 5, 1785, almost four years after his discovery of the planet Uranus. Sir Herschel’s discovery of the solar system’s seventh planet happened March 13, 1781.
NGC 5634 appears as number 70 in “I. First Class. Bright Nebulae” in Sir William’s Catalogue of One Thousand New Nebulae and Clusters of Stars (1786). In his system of abbreviated descriptions, Sir William summarized Virgo’s globular cluster (page 472): “vB. cL. iF. vgbM.” His description translates as: “very bright. considerably round. irregularly faint. very gradually brighter in the middle.”
Sir William identified 106 Virginis as the star referenced for NGC 5634’s placement. His details revealed “that the nebula is . . . following the star” by a sidereal time of 1 minute 2 seconds and at 0 degrees 54 minutes north of the “determining star.”
With an apparent magnitude of 5.42, the fifth magnitude star comes in close to sixth magnitude. HLA celestial coordinates for 106 Virginis are right ascension of 14 hours 28 minutes 41.721 seconds and declination of minus 6 degrees 54 minutes 01.89 seconds.
Sir William’s son, English astronomer and polymath Sir John Frederick William Herschel, 1st Baronet (March 7, 1792-May 11, 1871), also catalogued astronomical observations. In his 1833 catalogue, Sir John noted his observations of southeastern Virgo’s globular cluster, under entry 1813 (page 451): “A fine small compressed globular cluster. I can barely discern the stars; they are 19 m 80” diam; has a * 7.8 m 90” dist, pos 30° s f, and another 10 m, n p.”
Sir William’s catalogue entry I.70 equates to number 3900 in Sir John’s 1864 catalogue. Sir John sought to combine his and his father’s observations in an abbreviated description (page 116): “⊕; vB; cL; R; gbM; rrr; st 19; *17 sf.” His abbreviations
translate as: “globular cluster of stars; very bright; considerably large; round; gradually brighter in the middle; well resolved -- clearly seen to consist of stars; stars of the 19th magnitude; star of 17th magnitude south following.”
The prefix NGC for Virgo’s lone globular cluster abbreviates New General Catalogue, a list of deep-sky objects compiled by Danish-Irish astronomer John Louis Emil Dreyer (Feb. 13, 1852-Sept. 14, 1926). Published in 1888 in the Memoirs of the Royal Astronomical Society, Dreyer’s catalogue comprises observations by Sir William; his son, Sir John; his sister, Caroline Herschel (March 16, 1750-Jan. 9, 1848); Scottish Southern Hemisphere astronomer James Dunlop (Oct. 31, 1793-Sept. 22, 1848); and other sources.
The takeaways for globular cluster NGC 5634, which lies midway between Iota and Mu Virginis in southeastern Virgo the Virgin constellation, are that its discovery is credited to German-British astronomer Sir William Herschel, the discoverer of Uranus, that naked eye stars 104, Iota and Mu Virginis star hop deep-sky observers to its location and that Virgo claims NGC 5634 as the constellation’s only globular cluster.
Acknowledgment
My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.
Image credits:
Image credits:
Sir William Herschel’s 1785 discovery of Virgo’s only globular cluster, NGC 5634, occurred almost four years after his 1781 discovery of Uranus; 2.2 arcmin wide image of NGC 5634’s northwestern part: Hubble Legacy Archive, Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:NGC_5634_Hubble_WikiSky.jpg
Located in southeastern Virgo the Virgin, NGC 5634 rates as the constellation's only globular cluster: HST (Hubble Space Telescope) Phase 2 GSC2 (Guide Star Catalog 2)/NASA and STScI (Space Telescope Science Institute), Public Domain, via STScI MAST (Barbara A. Mikulski Archive for Space Telescopes) @ http://archive.stsci.edu/cgi-bin/dss_search?v=poss2ukstu_red&r=14+29+37.28&d=-05+58+35.1&e=J2000&h=15.0&w=15.0&f=gif&c=none&fov=NONE&v3=
For further information:
For further information:
“00516 FMV February mu Virginids.” IAU (International Astronomical Union) Meteor Data Center > List of All Meteor Showers.
Available @ https://www.ta3.sk/IAUC22DB/MDC2007/Roje/pojedynczy_obiekt.php?kodstrumienia=00516&colecimy=0&kodmin=00001&kodmax=01032&sortowanie=0
Available @ https://www.ta3.sk/IAUC22DB/MDC2007/Roje/pojedynczy_obiekt.php?kodstrumienia=00516&colecimy=0&kodmin=00001&kodmax=01032&sortowanie=0
Baade, W. (Walter). “The Globular Clusters NGC 5634 and NGC 6229.” The Astrophysical Journal, vol. 102 (July 1945): 17-25.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://articles.adsabs.harvard.edu/full/1945ApJ...102...17B
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://articles.adsabs.harvard.edu/full/1945ApJ...102...17B
Bellazzini, Michele; Francesco R. Ferraro; Rodrigo Ibata. “The Stellar Population of NGC 5634: A Globular Cluster in the Sagittarius dSph Stream?” The Astronomical Journal, vol. 124, issue 2 (August 2002): 915-923.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://articles.adsabs.harvard.edu/full/1945ApJ...102...17B
Available via IOPscience @ http://iopscience.iop.org/article/10.1086/341755/fulltext/
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://articles.adsabs.harvard.edu/full/1945ApJ...102...17B
Available via IOPscience @ http://iopscience.iop.org/article/10.1086/341755/fulltext/
Dibon-Smith, Richard. “α Virginis.” The Constellations.
Available @ http://www.dibonsmith.com/vir_a.htm
Available @ http://www.dibonsmith.com/vir_a.htm
Dreyer, J.L.E. (John Louis Emil). “A New General Catalogue of Nebulae and Clusters of Stars, Being the Catalogue of the Late Sir John F.W. Herschel, Bart., Revised, Corrected, and Enlarged.” Memoirs of the Royal Astronomical Society, vol. XLIX, part I. London, England: Royal Astronomical Society, 1888.
Available @ https://ia800501.us.archive.org/14/items/newgeneralcatalo00dreyrich/newgeneralcatalo00dreyrich.pdf
Available via HathiTrust @ https://hdl.handle.net/2027/osu.32435078053089
Available @ https://ia800501.us.archive.org/14/items/newgeneralcatalo00dreyrich/newgeneralcatalo00dreyrich.pdf
Available via HathiTrust @ https://hdl.handle.net/2027/osu.32435078053089
Dreyer, J.L.E. (John Louis Emil). “A Supplement to Sir John Herschel’s ‘General Catalogue of Nebulae and Clusters of Stars.’ (Read February 26, 1877.).” The Transactions of the Royal Irish Academy, vol. XXVI (March 1878). Dublin, Ireland: Royal Irish Academy, 1878.
Available via Internet Archive @ https://archive.org/details/supplementtosirj00dreyrich/
Available via Internet Archive @ https://archive.org/details/supplementtosirj00dreyrich/
Frommert, Hartmut. “NGC 5634.” Spider SEDS (Students for the Exploration and Development of Space).
Available @ http://spider.seds.org/spider/MWGC/n5634.html
Available @ http://spider.seds.org/spider/MWGC/n5634.html
Heckman, Kurt. “Kilo-Light Year.” vCalc.
Available @ https://www.vcalc.com/wiki/vCalc/Kilo-Light+Year
Available @ https://www.vcalc.com/wiki/vCalc/Kilo-Light+Year
Herschel, Sir John Frederick William. “Catalogue of Nebulae and Clusters of Stars. Received October 16, -- Read November 19, 1863.” Philosophical Transactions of the Royal Society of London. For the Year MDCCCLXIV [1864]. Vol. 154: 1-137. London, England: Taylor and Francis, MDCCCLXV (1865).
Available via Biodiversity Heritage Library (Natural History Museum Library, London) @ https://biodiversitylibrary.org/page/54093164
Available via JSTOR @ https://www.jstor.org/stable/108864
Available via Biodiversity Heritage Library (Natural History Museum Library, London) @ https://biodiversitylibrary.org/page/54093164
Available via JSTOR @ https://www.jstor.org/stable/108864
Herschel, Sir John Frederick William. “No. 3900.” In: “Catalogue of Nebulae and Clusters of Stars. Received October 16, -- Read November 19, 1863.” Philosophical Transactions of the Royal Society of London. For the Year MDCCCLXIV [1864]. Vol. 154: 116. London, England: Taylor and Francis, MDCCCLXV (1865).
Available via Biodiversity Heritage Library (Natural History Museum Library, London) @ https://biodiversitylibrary.org/page/54093279
Available via JSTOR @ https://www.jstor.org/stable/108864?seq=116#metadata_info_tab_contents
Available via Biodiversity Heritage Library (Natural History Museum Library, London) @ https://biodiversitylibrary.org/page/54093279
Available via JSTOR @ https://www.jstor.org/stable/108864?seq=116#metadata_info_tab_contents
Herschel, Sir John Frederick William. “No. of Catalogue: 1813.” In: “Observations of Nebulae and Clusters of Stars, Made at Slough, With a Twenty-Feet Reflector, Between the Years 1825 and 1833. Received July 1, -- Read November 21, 1833.” Philosophical Transactions of the Royal Society of London, vol. 123 (1833): 451.
Available via JSTOR @ https://www.jstor.org/stable/108003?seq=93#metadata_info_tab_contents
Available via JSTOR @ https://www.jstor.org/stable/108003?seq=93#metadata_info_tab_contents
Herschel, Sir John Frederick William. “Observations of Nebulae and Clusters of Stars, Made at Slough, With a Twenty-Feet Reflector, Between the Years 1825 and 1833. Received July 1, -- Read November 21, 1833.” Philosophical Transactions of the Royal Society of London, vol. 123 (1833): 359-505.
Available via JSTOR @ https://www.jstor.org/stable/108003
Available via JSTOR @ https://www.jstor.org/stable/108003
Herschel, William. “Catalogue of 500 New Nebulae, Nebulous Stars, Planetary Nebulae, and Clusters of Stars; With Remarks on the Construction of the Heavens. Read July 1, 1802.” Philosophical Transactions of the Royal Society of London. For the Year MDCCCII [1802] [vol. 92], part II: 477-528. London, England: W. Bulmer and Co., MDCCCII.
Available via Biodiversity Heritage Library (Smithsonian Libraries) @ https://biodiversitylibrary.org/page/49130796
Available via Biodiversity Heritage Library (University of Toronto -- Robarts Library) @ https://biodiversitylibrary.org/page/22894665
Available via JSTOR @ https://www.jstor.org/stable/107131
Available via Biodiversity Heritage Library (Smithsonian Libraries) @ https://biodiversitylibrary.org/page/49130796
Available via Biodiversity Heritage Library (University of Toronto -- Robarts Library) @ https://biodiversitylibrary.org/page/22894665
Available via JSTOR @ https://www.jstor.org/stable/107131
Herschel, William. “Catalogue of One Thousand New Nebulae and Clusters of Stars. Read April 27, 1786.” Philosophical Transactions of the Royal Society of London, vol. LXXVI, part II (1786): 457-499. London, England: Lockyer Davis and Peter Elmsly, Printers to The Royal Society, MDCCLXXXVI.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/48283813
Available via JSTOR @ https://www.jstor.org/stable/106639
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/48283813
Available via JSTOR @ https://www.jstor.org/stable/106639
Herschel, William. “Catalogue of a Second Thousand of New Nebulae and Clusters of Stars; With a Few Introductory Remarks on the Construction of the Heavens. Read June 11, 1789.” Philosophical Transactions of the Royal Society of London, vol. LXXIX, part II (1789): 212-255. London, England: Lockyer Davis and Peter Elmsly, Printers to The Royal Society, MDCCLXXXIX.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/51828742
Available via JSTOR @ https://www.jstor.org/stable/106695
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/51828742
Available via JSTOR @ https://www.jstor.org/stable/106695
Jenniskens, P. (Peter). “New Meteor Showers Recognized.” CBET (Central Bureau for Electronic Telegrams), no. 3707. Nov. 12, 2013. Edited by Daniel W.E. Green.
Available via Harvard University’s Central Bureau for Astronomical Telegrams @ http://www.cbat.eps.harvard.edu/cbet/003700to003800.txt
Available via Harvard University’s Central Bureau for Astronomical Telegrams @ http://www.cbat.eps.harvard.edu/cbet/003700to003800.txt
Marriner, Derdriu. “February Mu Virginids Shower Earth’s Skies February to Early March.” Earth and Space News. Wednesday, Feb. 20, 2019.
Available @ https://earth-and-space-news.blogspot.com/2019/02/february-mu-virginids-shower-earths.html
Available @ https://earth-and-space-news.blogspot.com/2019/02/february-mu-virginids-shower-earths.html
Marriner, Derdriu. “Uranus the Blue Green Ice Giant: Sideways Seventh Planet From the Sun.” Earth and Space News. Friday, March 13, 2015.
Available @ https://earth-and-space-news.blogspot.com/2015/03/uranus-blue-green-ice-giant-sideways.html
Available @ https://earth-and-space-news.blogspot.com/2015/03/uranus-blue-green-ice-giant-sideways.html
Marriner, Derdriu. “Uranus Discovery 234 Years Ago on March 13, 1781, by Sir William Herschel.” Earth and Space News. Friday, March 13, 2015.
Available @ https://earth-and-space-news.blogspot.com/2015/03/uranus-discovery-234-years-ago-on-march.html
Available @ https://earth-and-space-news.blogspot.com/2015/03/uranus-discovery-234-years-ago-on-march.html
Mullaney, James. The Herschel Objects and How to Observe Them. AST Astronomers’ Observing Guides. New York NY: Springer Science+Business Media LLC, 2007.
Mullaney, James; Wil Tirion. The Cambridge Atlas of Herschel Objects. Cambridge, England; New York NY; Melbourne, Australia; Madrid, Spain; Cape Town, South Africa; Singapore; São Paulo, Brazil; Delhi, India; Dubai, United Arab Emirates; Tokyo, Japan; Mexico City: Mexico: Cambridge University Press, 2011.
O’Meara, Steve. Herschel 400 Observing Guide: How to Find and Explore 400 Star Clusters, Nebulae, and Galaxies Discovered by William and Caroline Herschel. Cambridge, England; New York NY; Melbourne, Australia; Madrid, Spain; Cape Town, South Africa; Singapore; São Paulo, Brazil: Cambridge University Press, 2007.
Seligman, Courtney. “NGC 5634 (= GCL 28).” Courtney Seligmen Website > Online Astronomy Text > Sky Atlas > NGC Objects > NGC 5600-5649.
Available @ http://cseligman.com/text/atlas/ngc56.htm#5610
Available @ http://cseligman.com/text/atlas/ngc56.htm#5610
Šegon, Damir; Željko Andreić; Korado Korlević; Filip Novoselnik; Denis Vida; Ivica Skokić. “8 New Showers From Croatian Meteor Network Data.” WGN, vol. 41, no. 3 (June 2013): 70-74.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://articles.adsabs.harvard.edu/full/2013JIMO...41...70S
Available via IMO @ https://www.imo.net/publications/wgn/
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://articles.adsabs.harvard.edu/full/2013JIMO...41...70S
Available via IMO @ https://www.imo.net/publications/wgn/