William Herschel Discovered Lenticular Galaxy NGC 7302 Oct. 3, 1785

Summary: Uranus discoverer William Herschel discovered NGC 7302, Oct. 3, 1785, four years six-plus months after discovering Uranus March 13, 1781.

On Oct. 3, 1785, Uranus discoverer William Herschel discovered a lenticular galaxy, entered in his catalogue as IV-31 and now known as NGC 7302, in Aquarius the Water Bearer constellation; "Atlas Image courtesy of 2MASS/UMass/IPAC-Caltech/NASA/NSF": 2MASS (Two Micron All Sky Survey), Public Domain, via NASA/JPL-Caltech IPAC (Infrared Processing and Analysis Center)

Uranus discoverer William Herschel discovered NGC 7302 Oct. 3, 1785, four years six-plus months after his March 13, 1781, discovery of the solar system’s dark ringed, blue-green planet, Uranus.

German-British astronomer and composer Sir Frederick William Herschel (Nov. 15, 1738-Aug. 25, 1822) discovered NGC 6818 at his residence, Clay Hall, in Old Windsor, Royal Borough of Windsor and Maidenhead, Royal County of Berkshire, South East England. Herschel and his sister Caroline (March 16, 1750-Jan. 9, 1848) lived and astronomized at Clay Hall from June 1785 until their move April 3, 1786, to Herschel’s final residence, Observatory House, in Slough.

Sir William’s discovery of NGC 7302 was made with his 20-foot reflector telescope. The long-focus Newtonian had an 18.7 inch-aperture.

Sir William’s discovery Oct. 3, 1785, appeared as number 31 under “IV. Fourth claſs. Planetary nebulae” in his Catalogue of a Second Thousand of New Nebulae and Clusters of Stars, published in 1789. A subtitle described the classification: “Stars with burs, with milky chevelure, with ſhort rays, remarkable ſhapes, &c.”

Sir William systematized his discoveries of new nebulae and star clusters into eight classes. His classifications were labeled as: “I. First claſs. Bright nebulae”; “II. Second claſs. Faint nebulae”; “III. Third claſs. Very faint nebulae”; “IV. Fourth claſs. Planetary nebulae”; “V. Fifth claſs. Very large nebulae”; “VI. Sixth claſs. Very compreſſed and rich cluſters of ſtars”; “VII. Seventh claſs. Pretty much compreſſed cluſters of large or ſmall ſtars”; “VIII. Eighth claſs. Coarſely ſcattered cluſters of ſtars.”

Sir William identified “50 Aquarii” as the star determining the placement of IV-31. Sir William’s calculations determined that IV-31 followed 50 Aquarii (50 Aqr) by a sidereal time of 7 minutes 55 seconds. The sixth magnitude star and IV-31 are separated by 0 degrees 37 minutes.

Sir William's solitary observation yielded a description of “F. S. ſtellar. with pL. chev.” Sir William’s abbreviated description translates as: “Faint. Small. Stellar. With pretty large chevelure.”

Sir William’s IV-31 entry appears as NGC 7302 in A New General Catalogue by Danish-Irish astronomer John Louis Emil Dreyer (Feb. 13, 1852-Sept. 14, 1926). Dreyer’s catalogue compiles discoveries and observations by Sir William; his son, Sir John Frederick William Herschel, 1st Baronet (March 7, 1792-May 11, 1871); his sister Caroline; and other observational astronomers. The catalogue assigns NGC (New General Catalogue) numbers to its entries, which are arranged in order of right ascension (celestial equivalent of terrestrial longitude).

NGC 7302 is located in Aquarius the Water Bearer, a celestial equatorial constellation largely lying in the Southern Celestial Hemisphere. The NASA/IPAC Extragalactic Database (NED) indicates that NGC 7302 has a galaxy morphology of SA0^-(s), denoting a ringless, unbarred lenticular galaxy. An extended, disk-like, non-spiral structure that surrounds a central bulge characterizes a lenticular galaxy.

The 12th-magnitude lenticular galaxy’s equatorial coordinates are right ascension of 22 hours 32 minutes 23.80 seconds, declination of minus 14 degrees 07 minutes 13.9 seconds, according to the NED Database. The equatorial coordinates for 50 Aquarii, Sir William’s “determining star” for NGC 7302, are right ascension of 22:24:27.113, declination of minus 13:31:45.51, according to Hubble Legacy Archive (HLA), an online project of Hubble products jointly administered by the Space Telescope Science Institute (STScI), the Space Telescope European Coordinating Facility (ST-ECF) and the Canadian Astronomy Data Centre (CADC).

The major axis diameter for NGC 7302 is 1.8 arcminutes, according to the NED Database. The lenticular galaxy’s minor axis diameter is 1.1 arcminutes. The major axis references the galaxy’s longest diameter. The minor axis represents the shortest distance as measured by an imaginary line with perpendicular placement at the center of the major axis.

An arcminute (abbreviated as arcmin) is a unit of angular measurement. One arcminute equals one-sixtieth of one degree. One degree is expressed as one-three hundred sixtieth of a complete rotation. One arcminute represents one-twenty-one thousand six hundredth (1/21,600) of one complete rotation.

The takeaway for Uranus discoverer William Herschel’s discovery of NGC 7302 Oct. 3, 1785, is that the lenticular galaxy lies in Aquarius the Water Bearer constellation.

portrait of German-British astronomer William Herschel in the year in which he discovered NGC 7302: 1785 oil on canvas by English portrait painter Lemuel Abbott (ca. 1760/1761-Dec. 5, 1802); National Portrait Gallery, London, United Kingdom: Public Domain, via Wikimedia Commons

Acknowledgment

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

Image credits:

On Oct. 3, 1785, Uranus discoverer William Herschel discovered a lenticular galaxy, entered in his catalogue as IV-31 and now known as NGC 7302, in Aquarius the Water Bearer constellation; "Atlas Image [or Atlas Image mosaic] obtained as part of the Two Micron All Sky Survey (2MASS), a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation.": Public Domain, via NASA/JPL-Caltech IPAC (Infrared Processing and Analysis Center) @ https://irsa.ipac.caltech.edu/cgi-bin/2MASS/PubGalPS/nph-galps?objstr=2MASXJ22322379-1407137

portrait of German-British astronomer William Herschel in the year in which he discovered NGC 7302: 1785 oil on canvas by English portrait painter Lemuel Abbott (ca. 1760/1761-Dec. 5, 1802); National Portrait Gallery, London, England: Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:William_Herschel01.jpg

For further information:

Bratton, Mark. The Complete Guide to the Herschel Objects: Sir William Herschel’s Star Clusters, Nebulae and Galaxies. Cambridge, UK; New York NY; Melbourne, Australia; Madrid, Spain; Cape Town, South Africa; Singapore; São Paulo, Brazil; Delhi, India; Tokyo, Japan; Mexico City, Mexico: Cambridge University Press, 2011.

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

Dreyer, J.L.E. (John Louis Emil). “No. 7302.” In: “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: 198. 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?urlappend=%3Bseq=204

Dreyer, J.L.E. (John Louis Emil). The Scientific Papers of Sir William Herschel. Volume I. London, England: The Royal Society and The Royal Astronomical Society, 1912.
Available via Internet Archive @ https://archive.org/details/scientificpapers032804mbp/

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/

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

Herschel, Sir John Frederick William. “No. 2165.” 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): 473.
Available via JSTOR @ https://www.jstor.org/stable/108003?seq=115#metadata_info_tab_contents

Herschel, Sir John Frederick William. “No. of Catalogue: 4802.” 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: 132. London, England: Taylor and Francis, MDCCCLXV (1865).
Available via Biodiversity Heritage Library (Natural History Museum Library, London) @ https://biodiversitylibrary.org/page/54093295 Available via JSTOR @ https://www.jstor.org/stable/108864?seq=132#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

Herschel, William. “IV. 31.” In: “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): 246. London, England: Lockyer Davis and Peter Elmsly, Printers to The Royal Society, MDCCLXXXIX.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/51828776
Available via JSTOR @https://www.jstor.org/stable/106695

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

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

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 JSTOR @ https://www.jstor.org/stable/106639

Holden, Edward S. (Singleton). Sir William Herschel, His Life and Works. New York NY: Charles Scribner’s Sons, 1881.
Available via Internet Archive @ https://archive.org/details/sirwilliamhersch00holduoft/

Jet Propulsion Laboratory, California Institute of Technology. “Index for NGC 7302.” NASA/IPAC Extragalactic Database (NED).
Available @ http://ned.ipac.caltech.edu/cgi-bin/objsearch?search_type=Obj_id&objid=51979

Jet Propulsion Laboratory, California Institute of Technology. “Index for NGC 7302 Group.” NASA/IPAC Extragalactic Database (NED).
Available @ http://ned.ipac.caltech.edu/cgi-bin/objsearch?search_type=Obj_id&objid=175191681

Marriner, Derdriu. "John Herschel Made Four Observations of Lenticular Galaxy NGC 7302." Earth and Space News. Wednesday, July 25, 2012.
Available @ https://earth-and-space-news.blogspot.com/2012/07/john-herschel-made-four-observations-of.html

Marriner, Derdriu. "Lunar Crater Herschel Honors German-British Astronomer William Herschel." Earth and Space News. Wednesday, Aug. 24, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/08/lunar-crater-herschel-honors-german.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.

Sadler, Herbert. “The Face of the Sky for July.” Knowledge, vol. XVII, new series, vol. IX (July 2, 1894): 166-167. London, England: Witherby & Co., 1894.
Available via HathiTrust @ https://hdl.handle.net/2027/uc1.c2834645?urlappend=%3Bseq=240

Schaffer, Simon. “Uranus and the Establishment of Herschel’s Astronomy.” Journal for the History of Astronomy, vo. XII (1981): 11-26.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://adsabs.harvard.edu/full/1981JHA....12...11S

Seligman, Courtney. “NGC 7302 (= IC 5228 = PGC 69094).” Courtney Seligmen Website > Online Astronomy Text > Sky Atlas > NGC Objects > NGC 7300-7349.
Available @ http://cseligman.com/text/atlas/ngc73.htm

Space Telescope Science Institute (STScI); Space Telescope European Coordinating Facility (ST-ECF); Canadian Astronomy Data Centre (CADC). “HIP 110602.” Hubble Legacy Archive.
Available @ https://hla.stsci.edu/hlaview.html#Inventory|filterText%3D|query_string=HIP%20110602

Space Telescope Science Institute (STScI); Space Telescope European Coordinating Facility (ST-ECF); Canadian Astronomy Data Centre (CADC). “NGC 7302.” Hubble Legacy Archive.