Editing Sagitta (section)

===Deep-sky objects===
The band of the Milky Way and the [[Great Rift (astronomy)|Great Rift]] within it pass though Sagitta, with Alpha, Beta and Epsilon Sagittae marking the Rift's border.<ref name="crossen 2004">{{cite book|author1=Crossen, Craig |author2=Rhemann, Gerald |title=Sky Vistas: Astronomy for Binoculars and Richest-Field Telescopes|publisher=[[Springer Science+Business Media|Springer]]|location=New York|orig-date=2004 | year=2012 | page=150 | url=https://books.google.com/books?id=3vELBwAAQBAJ&pg=PA150 | isbn=978-3-709-10626-6}}</ref> Located between Beta and Gamma Sagittae is [[Messier 71]],<ref name=moore366/> a very loose [[globular cluster]] mistaken for some time for a dense [[open cluster]].<ref name=tt/> At a distance of about {{val|13000|fmt=commas|u=light-years}} from Earth,<ref name=inglis2017>{{cite book |last1=Inglis |first1=Mike |title=Astronomy of the Milky Way: The Observer's Guide to the Northern Sky |date=2017 |publisher=[[Springer Science+Business Media|Springer]] |location=New York |isbn=978-3-319-49082-3 |pages=83–89 |url=https://books.google.com/books?id=02DTDgAAQBAJ&q=Messier+71&pg=PA89}}</ref> it was first discovered by the French astronomer [[Philippe Loys de Chéseaux]] in the year 1745 or 1746.<ref name=tt>{{cite book | last1 = Thompson | first1 = Robert Bruce | last2 = Thompson | first2 = Barbara Fritchman | date = 2007 | title = Illustrated Guide to Astronomical Wonders: From Novice to Master Observer | page=394 | url=https://books.google.com/books?id=ymt9nj_uPhwC&pg=PA394 | publisher = [[O'Reilly Media]] | location = North Sebastopol, California | isbn = 978-0-596-52685-6  }}</ref> The loose globular cluster has a mass of around {{solar mass|53,000|link=yes}} and a [[Luminosity#In astronomy|luminosity]] of approximately 19,000 {{lo|link=yes}}.<ref name="Dalgleish">{{cite journal |last1=Dalgleish |first1=H. |last2=Kamann |first2=S. |last3=Usher |first3=C. |last4=Baumgardt |first4=H. |last5=Bastian |first5=N. |last6=Veitch-Michaelis |first6=J. |last7=Bellini |first7=A. |last8=Martocchia |first8=S. |last9=Da Costa |first9=G. S. |last10=Mackey |first10=D. |last11=Bellstedt |first11=S. |last12=Pastorello |first12=N. |last13=Cerulo |first13=P. |title=The WAGGS project-III. Discrepant mass-to-light ratios of Galactic globular clusters at high metallicity |journal=Monthly Notices of the Royal Astronomical Society |date=March 2020 |volume=492 |issue=3 |pages=3859–3871 |doi=10.1093/mnras/staa091 |arxiv=2001.01810 |bibcode=2020MNRAS.492.3859D |doi-access=free }}</ref>

There are two notable [[planetary nebula]]e in Sagitta: [[NGC 6886]] is composed of a hot central post-AGB star that has 55% of the Sun's mass yet {{val|2700|850|fmt=commas}} times its luminosity, with a surface temperature of {{val|142000|fmt=commas|u=K}}, and surrounding nebula estimated to have been expanding for between 1,280 and 1,600 years,<ref name=schonberner>{{Cite journal | doi=10.1051/0004-6361/201731788 | bibcode=2018A&A...609A.126S| title=Expansion patterns and parallaxes for planetary nebulae| year=2018| last1=Schönberner| first1=D.| last2=Balick| first2=B.| last3=Jacob| first3=R.| journal=[[Astronomy & Astrophysics]]| volume=609| pages=A126| doi-access=free}}</ref> The nebula was discovered by [[Ralph Copeland]] in 1884.<ref>{{cite web|last=Seligman|first=Courtney|title=NGC Objects: NGC 6850 - 6899|url=http://cseligman.com/text/atlas/ngc68a.htm|access-date=22 August 2015}}</ref> The [[Necklace Nebula]]—originally a close binary, one component of which swallowed the other as it expanded to become a giant star. The smaller star remained in orbit inside the larger, whose rotation speed increased greatly, resulting in it flinging its outer layers off into space, forming a ring with knots of bright gas formed from clumps of stellar material.<ref name=NASANN>{{cite press release |last1=Weaver |first1=Donna |first2=Ray |last2=Villard |date=11 August 2011 |title=Hubble Offers a Dazzling 'Necklace' |url=https://www.nasa.gov/mission_pages/hubble/science/necklace-nebula.html |publisher=NASA |agency=Space Telescope Science Institute |access-date=20 October 2020}}</ref> It was discovered in 2005 and is around 2 light-years wide.<ref name=STSINN>[https://web.archive.org/web/20111014231028/http://hubblesite.org/newscenter/archive/releases/2011/24/image/b/ Hubble Offers a Dazzling View of the 'Necklace' Nebula], news release STScI-2011-24 dated August 11, 2011, from [[Space Telescope Science Institute]]</ref><ref name=NASANN/> It has a size of {{Val|0.35|ul=arcminute}}.<ref name=Sabin2014>{{cite journal | display-authors=1
 | title=First release of the IPHAS catalogue of new extended planetary nebulae
 | last1=Sabin | first1=L. | last2=Parker | first2=Q. A.
 | last3=Corradi | first3=R. L. M. | last4=Guzman-Ramirez | first4=L.
 | last5=Morris | first5=R. A. H. | last6=Zijlstra | first6=A. A.
 | last7=Bojičić | first7=I. S. | last8=Frew | first8=D. J.
 | last9=Guerrero | first9=M. | last10=Stupar | first10=M.
 | last11=Barlow | first11=M. J. | last12=Cortés Mora | first12=F.
 | last13=Drew | first13=J. E. | last14=Greimel | first14=R.
 | last15=Groot | first15=P. | last16=Irwin | first16=J. M.
 | last17=Irwin | first17=M. J. | last18=Mampaso | first18=A.
 | last19=Miszalski | first19=B. | last20=Olguín | first20=L.
 | last21=Phillipps | first21=S. | last22=Santander García | first22=M.
 | last23=Viironen | first23=K. | last24=Wright | first24=N. J.
 | journal=Monthly Notices of the Royal Astronomical Society
 | volume=443 | issue=4 | pages=3388–3401 | date=October 2014
 | doi=10.1093/mnras/stu1404 | doi-access=free
 | arxiv=1407.0109
 | bibcode=2014MNRAS.443.3388S }}</ref> Both nebulae are around {{val|15000|fmt=commas|u=light-years}} from Earth.<ref name=schonberner/><ref name=NASANN/>