Editing Hydrus (section)

==Characteristics==
Irregular in shape,<ref name="motz"/> Hydrus is bordered by [[Mensa (constellation)|Mensa]] to the southeast, [[Eridanus (constellation)|Eridanus]] to the east, [[Horologium (constellation)|Horologium]] and [[Reticulum]] to the northeast, [[Phoenix (constellation)|Phoenix]] to the north, [[Tucana]] to the northwest and west, and [[Octans]] to the south; Lacaille had shortened Hydrus' tail to make space for this last constellation he had drawn up.<ref name=ridphydrus/> Covering 243 square degrees and 0.589% of the night sky, it ranks 61st of the 88 constellations in size.<ref name=bagnall251>{{cite book |last=Bagnall |first=Philip M. |title=The Star Atlas Companion: What You Need to Know about the Constellations |publisher=Springer |location=New York City |date=2012 |isbn=978-1-4614-0830-7 |page=251|url=https://books.google.com/books?id=KcIg02TKW6QC&pg=PA251}}</ref> The three-letter abbreviation for the constellation, as adopted by the [[International Astronomical Union]] in 1922, is "Hyi".<ref name="pa30_469">{{cite journal | last=Russell | first=Henry Norris |author-link=Henry Norris Russell | title=The New International Symbols for the Constellations | journal=[[Popular Astronomy (US magazine)|Popular Astronomy]] | volume=30 | page=469 | bibcode=1922PA.....30..469R | date=1922 }}</ref> The official constellation boundaries, as set by Belgian astronomer [[Eugène Joseph Delporte|Eugène Delporte]] in 1930, are defined by a polygon of 12 segments. In the [[equatorial coordinate system]], the [[right ascension]] coordinates of these borders lie between {{RA|00|06.1}} and {{RA|04|35.1}}, while the [[declination]] coordinates are between −57.85° and −82.06°.<ref name="boundary">{{Cite journal | title=Hydrus, Constellation Boundary | journal=The Constellations | url=https://www.iau.org/public/themes/constellations/#hyi | access-date=11 September 2013}}</ref> As one of the deep southern constellations, it remains below the horizon at latitudes north of the [[30th parallel north|30th parallel]] in the [[Northern Hemisphere]], and is circumpolar at latitudes south of the [[50th parallel south|50th parallel]] in the [[Southern Hemisphere]].<ref name="motz">{{cite book|last=Motz|first=Lloyd|author2=Nathanson, Carol|title=The Constellations: An Enthusiast's Guide to the Night Sky|publisher=Aurum Press|location=London, United Kingdom|date=1991|pages=385, 391|isbn=978-1-85410-088-7}}</ref> [[Herman Melville]] mentions it and [[Argo Navis]] in ''[[Moby Dick]]'' "beneath effulgent Antarctic Skies", highlighting his knowledge of the southern constellations from whaling voyages.<ref>{{cite book|last=Zimmerman|first=Brett |title=Herman Melville: Stargazer|publisher=McGill-Queen's University Press|location=Montreal, Quebec|date=1998|pages=[https://archive.org/details/hermanmelvillest0000zimm/page/5 5]|isbn=978-0-7735-1786-8|url=https://archive.org/details/hermanmelvillest0000zimm|url-access=registration}}</ref> A line drawn between the long axis of the [[Crux|Southern Cross]] to [[Beta Hydri]] and then extended 4.5 times will mark a point due south.<ref name="Stilwell 2010">{{cite book |author=Stilwell. Alexander | title=Crisis Survival |series=SAS and Elite Forces Survival Guide | date=2010 |url=https://books.google.com/books?id=ZKRfAu1xfOMC&pg=PT201 | publisher=Amber Books |location=London, United Kingdom |isbn=978-1-908696-06-9 |page=201}}</ref> Hydrus [[culmination|culminates]] at midnight around 26 October.<ref name=hartungs/>