Earth and Space News: Pegasus barred spiral galaxy

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Wednesday, October 16, 2019

William Herschel Discovered Barred Spiral Galaxy NGC 7479 Oct. 19, 1784

Summary: William Herschel discovered barred spiral galaxy NGC 7479 Oct. 19, 1784, three years seven-plus months after his March 13, 1781, discovery of Uranus.

Uranus discoverer Sir William Herschel discovered barred spiral galaxy NGC 7479 in constellation Pegasus Oct. 19, 1784; image of NGC 7479 “created from observations at visible and near-infrared wavelengths”; three brightest stars are “foreground stars -- caught on camera because they lie between the galaxy and Hubble”; NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys’ Wide Field Channel; image ID potw1125a; image release date 20 June 2011, 10:00; image credit ESA/Hubble & NASA: CC BY 4.0 International, via NASA ESA Hubble

Sir William Herschel discovered barred spiral galaxy NGC 7479 Oct. 19, 1784, three years seven-plus months after his March 13, 1781, discovery of the solar system’s seventh planet, Uranus.

Sir William (Nov. 15, 1738-Aug. 25, 1822) made his discovery of the barred spiral galaxy now known as NGC 7479 at his residence in Datchet, Royal County of Berkshire, South East England. He and his astronomer sister Caroline (March 16, 1750-Jan. 9, 1848) lived in the village from Aug. 1, 1782, until their move to Clay Hall, in Old Windsor, in June 1785.

The telescope that Sir William used was his 20-foot reflector. The long-focus Newtonian-styled model had an 18.7 inch-aperture.

Sir William’s Oct. 19, 1784, galactic discovery appears in his Catalogue of One Thousand New Nebulae and Clusters of Stars, published in 1786. He entered his discovery as number 55 under the category of “Firſt claſs. Bright nebulae.”

Sir William identified “66 Pegaſi” as “the ſtar, or other object, by which the place has been determined.” He determined that I-55 precedes 66 Pegasi by a sidereal time of 17 minutes 59 seconds. The galaxy lies 0 degrees 2 minutes to the north of 66 Pegasi.

Sir William made three observations of I-55. He described his discovery as: “cB. mE. Mer. gbM. 4’l. 2’b.” His abbreviated description translates as: “Considerably bright. Much extended in the direction of the meridian of the nebula. Gradually brighter in the middle. 4 minutes long. 2 minutes broad.”

Object I-55 appears as NGC 7479 in the New General Catalogue, published in 1888 by Danish-Irish astronomer John Louis Emil Dreyer (Feb. 13, 1852-Sept. 14, 1926). Dreyer’s catalogue organizes the discoveries and observations of the Herschels (Sir William; his astronomer sister Caroline; his son John) and other observational astronomers into a system ordered by right ascension (celestial equivalent of terrestrial longitude), with assigned NGC (New General Catalogue) numbers.

NGC 7479 is located in Pegasus the Winged Horse, a constellation in the Northern Celestial Hemisphere. The Winged Horse’s southern borders lie about two degrees from the celestial equator. The galaxy’s equatorial coordinates are right ascension 23 hours 04 minutes 49.61 seconds, declination plus 12 degrees 20 minutes 37.3 seconds (epoch J2000.0), according to NASA/IPAC Extragalactic Database (NED).

NGC 7479 classifies as having a galaxy morphology of SB(s)c, according to SIMBAD (Set of Identifications, Measurements and Bibliography for Astronomical Data), an astronomical database of extrasolar objects maintained by France’s Centre de Données Astronomiques de Strasbourg (CDS; Strasbourg Astronomical Data Center). The classification denotes a barred spiral galaxy (SB), without rings (s) and with very loosely wound arms (c). NGC 7479 is an 11th magnitude galaxy, according to Seppo Laine, research scientist at Spitzer Science Center, and Courtney Seligman, Professor Emeritus of Astronomy at California’s Long Beach City College.

The Hipparcos designation for 66 Pegasi (66 Peg), Sir William’s “determining star” for I-55, is HIP 115444. Released in June 1997, the Hipparcos Catalogue provides precise astrometric data for 118,218 stars. The catalogue’s data originates from Hipparcos (High Precision Parallax Collecting Satellite), a scientific satellite launched Aug. 8, 1989, by the European Space Agency (ESA) and deactivated Aug. 15, 1993.

The equatorial coordinates for HIP 115444 are right ascension 23 hours 23 minutes 04.567 seconds and declination plus 12 degrees 18 minutes 50.07 seconds (epoch J2000), according to Hubble Legacy Archive (HLA). Hubble Legacy Archive is 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).

Fifth magnitude binary star 66 Pegasi and barred spiral galaxy NGC 7479 lie south of Pegasus the Winged Horse constellation’s Great Square of Pegasus asterism, or recognizable pattern of stars. NGC 7479 lies 2.9 degrees south of Alpha Pegasi, according to Astronomy magazine senior editor Michael E. Bakich.

Alpha Pegasi (α Pegasi; Alpha Peg; α Peg) belongs to the starry quartet forming the Winged Horse’s Great Square asterism. Alpha Pegasi shines as the third brightest star in constellation Pegasus. Its IAU (International Astronomical Union) approved traditional name is Markab, either derived from Arabic for “saddle of the horse" or mistranscribed from Arabic for "shoulder of the horse."

The takeaway for Uranus discoverer Sir William Herschel’s discovery of barred spiral galaxy NGC 7479 Oct. 19, 1784, is that Sir William’s celestial object I-55 lies strategically south of Pegasus the Winged Horse constellation’s distinctive Great Square of Pegasus asterism.

Acknowledgment

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

Image credits:

Hubble Space Telescope Wide Field Camera image of NGC 7479; RA 23:04:54.69, DEC 12:19:43.6; Monday, Oct. 25, 2010; image NGC7479 hst_11575_53 ACS/WFD (color) SN2009JF f814w/f555w: HLA (Hubble Legacy Archive), via HLA-STScI (Space Telescope Science Institute) @ http://hla.stsci.edu/hlaview.html#Inventory|filterText%3D%24filterTypes%3D|query_string=ngc%207479

For further information:

Bakich, Michael E. “Spend a Night in Pegasus.” Astronomy > The Magazine. Sept. 26, 2018 (October 2018 issue).
Available @ http://www.astronomy.com/magazine/2018/09/spend-a-night-in-pegasus

Blanc, Guillermo A.; Tim Weinzirl; Mimi Song; Amanda Heiderman; Karl Gebhardt; Shardha Jogee; Neal J. Evans II; Remco C.E. van den Bosch; Rongxin Luo; Niv Drory; Maximilian Fabricius; David Fisher; Lei Hao; Kyle Kaplan; Irina Marinova; Nalin Vutisalchavakul; and Peter Yoachim. “The VIRUS-P Exploration of Nearby Galaxies (VENGA): Survey Design, Data Processing, and the Spectral Analysis Methods.” The Astronomical Journal, vol. 145 (May 2013): 138-165.
Available via IOPscience @ http://iopscience.iop.org/article/10.1088/0004-6256/145/5/138/pdf

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.

Buta, Ronald. “Galaxy Morphology and Classification.” Pages 29-47. In: Harold G. Corwin, Jr., and Lucette Bottinelli, eds. The World of Galaxies: Proceedings of the Conference “Le Monde des Galaxies” Held 12-14 April 1988 at the Institute d’Astrophysique de Paris in Honor of Gérard and Antoinette de Vaucouleurs on the Occasion of His 70th Birthday. New York NY: Springer-Verlag, 1989. Available via NASA/IPAC Extragalactic Database (NED) @ https://ned.ipac.caltech.edu/level5/March01/Buta/frames.html

Dreyer, J.L.E. (John Louis Emil). “No. 7479.” 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: 202. 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=208

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). “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. 2205.” 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): 475.
Available via Internet Archive @ https://archive.org/details/philtrans06301558/page/n116
Available via JSTOR @ https://www.jstor.org/stable/108003?seq=117#metadata_info_tab_contents

Herschel, Sir John Frederick William. “No. of Catalogue: 4892.” 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: 134. London, England: Taylor and Francis, MDCCCLXV (1865).
Available via Biodiversity Heritage Library (Natural History Museum Library, London) @ https://biodiversitylibrary.org/page/54093297
Available via JSTOR @ https://www.jstor.org/stable/108864?seq=134#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, Sir John F.W. (Frederick William). Results of Astronomical Observations Made During the Years 1834, 5, 6, 7, 8, at the Cape of Good Hope: Being the Completion of a Telescopic Survey of the Whole Surface of the Visible Heavens, Commenced in 1825. London, England: Smith, Elder and Co., 1847.
Available via Internet Archive @ https://archive.org/details/resultsofastrono00hers/

Herschel, Sir John F.W. (Frederick William). “Synoptic Table of the Dates of the Sweeps.” In: Results of Astronomical Observations Made During the Years 1834, 5, 6, 7, 8, at the Cape of Good Hope: Being the Completion of a Telescopic Survey of the Whole Surface of the Visible Heavens, Commenced in 1825: 130-131. London, England: Smith, Elder and Co., 1847.
Available via Internet Archive @ https://archive.org/details/resultsofastrono00hers/page/130

Herschel, William. “I-55.” In: “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): 472. London, England: Lockyer Davis and Peter Elmsly, Printers to The Royal Society, MDCCLXXXVI.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/48283828
Available via JSTOR @ https://www.jstor.org/stable/106639?seq=16#metadata_info_tab_contents

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 Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/48283813
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 7479:[HK83]66.” NASA/IPAC Extragalactic Database (NED).
Available @ http://ned.ipac.caltech.edu/cgi-bin/objsearch?search_type=Obj_id&objid=7363072

Laine, Seppo. “NGC 7479.” IPAC Caltech Spider.
Available @ http://spider.ipac.caltech.edu/staff/seppo/ngc7479.html

Marriner, Derdriu. “Alpheratz Links Andromeda the Chained Princess With Pegasus the Winged Horse.” Earth and Space News. Wednesday, Nov. 1, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/11/alpheratz-links-andromeda-chained.html

Marriner, Derdriu. “Five Star Circlet of Pisces Asterism Is Below Great Square of Pegasus.” Earth and Space News. Wednesday, Oct. 11, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/10/five-star-circlet-of-pisces-asterism-is.html

Marriner, Derdriu. “Globular Cluster NGC 5634 Lies Midway Between Iota and Mu Virginis.” Earth and Space News. Wednesday, Feb. 27, 2019.
Available @ https://earth-and-space-news.blogspot.com/2016/08/cassiopeia-queen-constellation-true.html

Marriner, Derdriu. “Great Square of Pegasus Asterism Has Four Second Magnitude Stars.” Earth and Space News. Wednesday, Oct. 4, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/10/great-square-of-pegasus-asterism-has.html

Marriner, Derdriu. "Herschel Crater Hosts Eight Satellites in South Central Lunar Near Side." Earth and Space News. Wednesday, Aug. 31, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/08/herschel-crater-hosts-eight-satellites.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

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

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

Marriner, Derdriu. “William Herschel Discovered Lenticular Galaxy NGC 665 Sept. 4, 1786.” Earth and Space News. Wednesday, Aug. 28, 2019.
Available @ https://earth-and-space-news.blogspot.com/2019/08/william-herschel-discovered-lenticular.html

Marriner, Derdriu. “William Herschel Discovered NGC 6818, Little Gem Nebula, Aug. 8, 1787.” Earth and Space News. Wednesday, Aug. 7, 2019.
Available @ https://earth-and-space-news.blogspot.com/2019/08/william-herschel-discovered-ngc-6818.html

Marriner, Derdriu. “William Herschel Discovered Spiral Galaxy NGC 673 Sept. 4, 1786.” Earth and Space News. Wednesday, Sept. 4, 2019.
Available @ https://earth-and-space-news.blogspot.com/2016/09/north-star-pointer-constellation.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 7479 (= PGC 70419).” Courtney Seligman Website > Online Astronomy Text > Sky Atlas > NGC Objects > NGC 7450-7499.
Available @ http://cseligman.com/text/atlas/ngc74a.htm

Sloan Digital Sky Survey Eighth Data Release (SDSS DR8). “Spiral Galaxies.” Sloan Digital Sky Survey SkyServer > Education > DR8 Projects > Basic > Galaxies.
Available @ http://skyserver.sdss.org/dr8/en/proj/basic/galaxies/spirals.asp

Space Telescope Science Institute (STScI); Space Telescope European Coordinating Facility (ST-ECF); Canadian Astronomy Data Centre (CADC). “HIP 115444.” Hubble Legacy Archive.
Available @ https://hla.stsci.edu/hlaview.html#Inventory|filterText%3D%24filterTypes%3D|query_string=HIP%20115444

Steinicke, Wolfgang. “'Historic WH' Columns.” Astronomie-Homepage von Wolfgang Steinicke > Current Matters: Historic WH > Discovery and Cataloguing of Nebulae and Star Clusters > 2. Historical Catalogues: W. Herschel: Historic WH > “Historic WH” -- Explanation. Jan. 14, 2018.
Available @ http://www.klima-luft.de/steinicke/ngcic/Expl_Hist_WH.htm

Steinicke, Wolfgang. Revised New General Catalogue and Index Catalogue. Jan. 14, 2018.
Available @ http://www.klima-luft.de/steinicke/ngcic/rev2000/Explan.htm#3.2

Université de Strasbourg/CNRS. “NGC 7479.” SIMBAD Astronomical Database -- CDS (Strasbourg).
Available @ http://simbad.u-strasbg.fr/simbad/sim-id?protocol=html&Ident=NGC+7479

Whitworth, N. John. “66 Pegasi, HD220363, HIP115444, HR8893.” Universe Guide > Aliens, Earth and Space Facts > Star > What Is Star Luminosity.
Available @ https://www.universeguide.com/star/66pegasi

Wednesday, October 9, 2019

Sir John Herschel Observed NGC 7479 in October 1823 and October 1830

Summary: Sir John Herschel observed NGC 7479 in October 1823 and October 1830, over four decades after his father’s Oct. 19, 1784, discovery of the galaxy.

NGC 7479, imaged with SBIG STL11000 CCD Camera, 24-inch RC Optical Systems Telescope, Mount Lemmon SkyCenter, Santa Catalina Mountains, Coronado National Forest, southeastern Arizona; September 2010: Adam Block/Mount Lemmon SkyCenter/University of Arizona, CC BY SA 3.0 United States, via Wikimedia Common

Sir John Herschel observed NGC 7479 in October 1823 and October 1830, over four decades after his father’s Oct. 19, 1784, discovery of the barred spiral galaxy in constellation Pegasus.

German-British astronomer and composer Sir Frederick William Herschel (Nov. 15, 1738-Aug. 25, 1822) discovered NGC 7479 three years seven-plus months after his March 13, 1781, discovery of solar system planet number seven, Uranus. Sir William recorded his discovery of NGC 7479 in his Catalogue of One Thousand New Nebulae and Clusters of Stars, published in 1786. The discovery appears as number 55 in the category of “Firſt claſs. Bright nebulae.”

John Frederick William Herschel, 1st Baronet (March 7, 1792-May 11, 1871), shared his father’s interest in astronomy. Sir William’s only child also kept written records of his own discoveries and observations.

Observations of his father’s Pegasid barred spiral galactic discovery appear in two of Sir John’s astronomical catalogues in which he collated his discoveries and observations with those of his father. In 1833, he published Observations of Nebulae and Clusters of Stars, Made at Slough, With a Twenty-Feet Reflector, Between the Years 1825 and 1833. In 1864, Sir John published Catalogue of Nebulae and Clusters of Stars. Both catalogues appeared in the Philosophical Transactions of the Royal Society of London.

Entry number 2205 in Observations of Nebulae and Clusters of Stars (1833) is synonymized with “I.55,” known now as NGC 7479. Sir John details four observations that he made during four astronomical “sweeps,” or surveys. Sweeps 13 and 14 took place Oct. 12 and Oct. 13, respectively, in 1823. Sweeps 304 and 305 were conducted Oct. 9 and Oct. 10, respectively, in 1830.

Sir John arranged his entries in order of right ascension (the celestial equivalent of terrestrial longitude). Accordingly, the observation from Sweep 14 (Oct. 13, 1825) appears first. The right ascension is calculated at 22 hours 56 minutes 24.0 seconds, and the declination is 78 degrees 35 minutes 19 seconds (epoch J1830.0). He described “I.55” as: “p B; irreg R; r; I see 2 or 3 stars in it; E between 2 stars. (See fig 63.).” His description translates as: “Pretty Bright; irregularly round; resolvable; I see two or three stars in it; extended between two stars.”

Sir John’s observations during Sweep 304 (Oct. 9, 1830) appear next. Right ascension is 22 hours 56 minutes 26.0 seconds, and the declination is 78 degrees 35 minutes 30 seconds. Sir John remarked: “B; m E; pos by micr = 192°.0; p g m b M; has a * 12 m n p; a large * s, and one or two 15.16 m in or near the middle.” His description translates as: “Bright; much extended; angle of position measured 192°.0 by the micrometer; pretty gradually much brighter in the middle; has a star of the 12th magnitude north preceding; a large star south, and one or two 15.16 magnitude in or near the middle.”

The observation of NGC 7479 during Sweep 305 (Oct. 10, 1830) gives right ascension of 22 hours 56 minutes 26.9 seconds and declination of 78 degrees 35 minutes 35 seconds. The description notes: “p B; m E, pos by micr = 11°.8 (= 191.8); 2’ l, 30” br; between 2 small stars. Has two v S stars in it.” The description transcribes as: “Pretty bright; much extended; angle of position measured 11°.8 (= 191.8) by micrometer; 2 minutes long, 30 seconds broad; between two small stars. Has two very small stars in it.”

The last observation under Sir John’s entry number 2205 comes from Sweep 13, chronologically the first observation with a date of Oct. 12, 1823. Right ascension measures 22 hours 56 minutes 28.8 seconds, and declination is figured at 78 degrees 35 minutes 50 seconds. The description states: “p F; b M; E in merid between 2 stars; 90” l, 40” br.” The expanded description reads: “Pretty faint; bright in the middle; extended in the meridian between two stars; 90 seconds long, 40 seconds broad.”

Sir John detailed NGC 7479 as entry number 4892 in his Catalogue of Nebulae and Clusters of Stars (1864). He synonymized 4892 with his previous catalogue’s entry number 2205 and with his father’s entry as “I.55.” His compressed description observes: “pB; cL; mE 11°9; bet 2 st.” The observation expands as: “Pretty bright; considerably large; much extended, 11°9; between two stars.”

The designation of Sir William’s barred spiral galaxy in Pegasus the Winged Horse constellation as NGC 7479 reflects the entry number for I-55 in the New General Catalogue by Danish-Irish astronomer John Louis Emil Dreyer (Feb. 13, 1852-Sept. 14, 1926). Published in 1888, Dreyer’s catalogue is a compilation of the discoveries and observations of the Herschels (Sir William; his astronomer sister Caroline; his son John) and other observational astronomers.

The takeaway for Sir John Herschel’s observations of NGC 7479 in October 1823 and in October 1830 is that, over four decades after Uranus discoverer William Herschel’s Oct. 19, 1784, discovery of the barred spiral galaxy in Pegasus, his son added four detailed observations to NGC 7479’s observational history.

Acknowledgment

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

Image credits:

Hubble Space Telescope Wide Field Planetary Camera image of NGC 7479; RA 23:04:56.08, DEC 12:19:20.9; Oct. 16, 1995; image NGC 7479 hst_06266_01_wfpc2_total_pc: HLA (Hubble Legacy Archive), via HLA-STScI (Space Telescope Science Institute) @ http://hla.stsci.edu/hlaview.html#Inventory|filterText%3D%24filterTypes%3D|query_string=ngc%207479

For further information:

Buta, Ronald. “Galaxy Morphology and Classification.” Pages 29-47. In: Harold G. Corwin, Jr., and Lucette Bottinelli, eds. The World of Galaxies: Prcoeedings of the Conference “Le Monde des Galaxies” Held 12-14 April 1988 at the Institute d’Astrophysique de Paris in Honor of Gérard and Antoinette de Vaucouleurs on the Occasion of His 70th Birthday. New York NY: Springer-Verlag, 1989.
Available via NASA/IPAC Extragalactic Database (NED) @ https://ned.ipac.caltech.edu/level5/March01/Buta/frames.html

Herschel, Sir John Frederick William. “No. 2205.” 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): 475.
Available via JSTOR @ https://www.jstor.org/stable/108003?seq=117#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, for the Year MDCCCXXXIII. Vol. 123 (1833), Part II: 359-505.
Available via JSTOR @ https://www.jstor.org/stable/108003

Hubble Legacy Archive. "NGC 7479 Inventory: Dataset hst_11575_53_acs_wfc_total." Hubble Legacy Archive -- Space Telescope Science Institute (HLA-STScI). Oct. 25, 2010 (Release Date: Oct. 25, 2010).
Available via HLA-STScI (Hubble Legacy Archive -- Space Telescope Science Institute) @ http://hla.stsci.edu/hlaview.html#Inventory|filterText%3D%24filterTypes%3D|query_string=ngc%207479

Mullaney, James. The Herschel Objects and How to Observe Them. AST Astronomers’ Observing Guides. New York NY: Springer Science+Business Media LLC, 2007.

Steinicke, Wolfgang. “’Historic WH’ Columns.” Astronomie-Homepage von Wolfgang Steinicke > Current Matters: Historic WH > Discovery and Cataloguing of Nebulae and Star Clusters > 2. Historical Catalogues: W. Herschel: Historic WH > “Historic WH” -- Explanation. Jan. 14, 2018.
Available @ http://www.klima-luft.de/steinicke/ngcic/Expl_Hist_WH.htm

Steinicke, Wolfgang. Revised New General Catalogue and Index Catalogue. Jan. 14, 2018.
Available @ http://www.klima-luft.de/steinicke/ngcic/rev2000/Explan.htm#3.2