 ʻOumuamua had been discovered as it was leaving the system, and thus could only be observed for 80 days before it was out of range.Because of its closest approach occurring near traditional year-end holidays, and the capability to have extended observations, some astronomers have called 2I/Borisov a "Christmas comet".Observations using the Hubble Space Telescope began on 12 October, when the comet moved far enough from the Sun to be safely observed by the telescope.