Editing 3C 273 (section)

== Observation ==
3C 273 is visible from March to July in both the [[Northern Hemisphere|northern]] and [[Southern Hemisphere|southern]] hemispheres. Situated in the Virgo constellation, it is bright enough to be observed by eye with a {{convert|6|inch|adj=on}} [[amateur astronomy|amateur telescope]].<ref>{{citation|work=[[Astronomy (magazine)|Astronomy]]|title=Target acquired: Observe Quasar 3C 273|first=Richard |last=Talcott | date=November 17, 2023|url=https://www.astronomy.com/observing/hunting-quasar-3c-273/}}</ref> Due in part to its radio luminosity and its discovery as the first identified quasar, 3C 273's [[right ascension]] in the [[Fifth Fundamental Catalog]] (FK5) is used to standardize the positions of 23 extragalactic radio sources used to define the [[International Celestial Reference System]] (ICRS).<ref name="def_syst">{{cite web | url=http://hpiers.obspm.fr/icrs-pc/icrs/def_syst.html | title=Definition of ICRS Axes | author=International Earth Rotation & Reference Systems Service | access-date=11 January 2012}}</ref>

Given its distance from [[Earth]] and visual magnitude, 3C 273 is the most distant celestial object average amateur astronomers are likely to see through their telescopes.