Editing Deimos (moon) (section)

== Discovery and etymology ==
{{Main|Moons of Mars#Discovery}}
[[File:T-asaph-hall.jpg|thumb|left|Asaph Hall III, discoverer of Deimos]]
Deimos was discovered by [[Asaph Hall]]<!--- there is an Asaph Hall, Junior, less well known ---> at the [[United States Naval Observatory]] in [[Washington, D.C.]], on 12 August 1877, at about 07:48 [[Coordinated Universal Time|UTC]].{{efn|Given in contemporary sources as "11 August 14:40" [[Washington Mean Time]], using a pre-1925 [[astronomical day|astronomical convention]] of beginning a day at noon,<ref name="Campbell "Beginning"'>{{cite journal|last=Campbell|first=W.W.|title=The Beginning of the Astronomical Day |journal=Publications of the Astronomical Society of the Pacific |volume=30 |issue=178 |page=358|bibcode=1918PASP...30..358C|year=1918|doi=10.1086/122784|doi-access=free}}</ref> so 12 hours must be added to get the actual local mean time.<ref>Hall, A.; [http://adsabs.harvard.edu//full/seri/AN.../0091//0000013.000.html ''Observations of the Satellites of Mars''], Astronomische Nachrichten, Vol. 91, No. 2161 (17 October 1877, signed 21 September 1877) pp. 11/12–13/14</ref><ref name="Morley1989">Morley, T. A.; [http://adsabs.harvard.edu//full/seri/A+AS./0077//0000220.000.html ''A Catalogue of Ground-Based Astrometric Observations of the Martian Satellites, 1877–1982''], Astronomy and Astrophysics Supplement Series, Vol. 77, No. 2 (February 1989), pp. 209–226 (Table II, p. 220: first observation of Deimos on 12 August 1877.32526)</ref><ref>[http://adsabs.harvard.edu//full/seri/Obs../0001//0000181.000.html ''Notes: The Satellites of Mars''], The Observatory, Vol. 1, No. 6 (20 September 1877), pp. 181–185</ref><ref>[http://adsabs.harvard.edu//full/seri/MNRAS/0038//0000205.000.html ''The Discovery of the Satellites of Mars''], [[Monthly Notices of the Royal Astronomical Society]], Vol. 38, No. 4, (8 February 1878), pp. 205–209</ref>}} Hall, who also discovered [[Phobos (moon)|Phobos]] shortly afterwards, had been specifically searching for Martian moons at the time.

The moon is named after [[Deimos (deity)|Deimos]], a figure representing [[fear|dread]] in [[Greek mythology]].<ref name=Blunck>{{cite book |last= Blunck |first=Jürgen |title= Solar System Moons: Discovery and Mythology |year=2009 |publisher=[[Springer Science+Business Media|Springer]] |isbn=978-3-540-68852-5 |page=5|chapter=The Satellites of Mars; Discovering and Naming the Satellites}}</ref> The name was suggested by academic [[Henry George Madan|Henry Madan]], who drew from Book XV of the ''[[Iliad]]'', where [[Ares]] (Greek counterpart of the Roman god [[Mars (mythology)|Mars]]) summons Dread (Deimos) and Fear ([[Phobos (mythology)|Phobos]]).<ref>Hall, A.; [http://adsabs.harvard.edu//full/seri/AN.../0092//0000031.000.html ''Names of the Satellites of Mars''], Astronomische Nachrichten, Vol. 92, No. 2187 (14 March 1878, signed 7 February 1878), p. 47/48</ref>

Planetary moons other than Earth's were never given symbols in the astronomical literature. Denis Moskowitz, a software engineer who designed most of the [[dwarf planet]] symbols, proposed a Greek [[delta (letter)|delta]] (the initial of Deimos) combined with Mars' spear as the symbol of Deimos ([[File:Deimos symbol (fixed width).svg|16px]]). This symbol is not widely used.<ref name=moons>{{cite web |url=https://www.unicode.org/L2/L2025/25079-phobos-and-deimos.pdf |title=Phobos and Deimos symbols |last1=Bala |first1=Gavin Jared |last2=Miller |first2=Kirk |date=7 March 2025 |website=unicode.org |publisher=The Unicode Consortium |access-date=14 March 2025 |quote=}}</ref>