space December 21, 2020 1:17 pm Rare ‘Christmas Star' Will Be Visible on Monday for First Time in 800 Years NASA says the planetary conjunction known as the ‘Christmas Star,’ which is only seen once every 800 years, will be visible on Monday night. US & World Videos 5:11 Lili Taylor crushed cowboy camp for ‘Outer Range' 3:25 Why Mary Bonet is scared for new season of ‘Selling Sunset' to air 5:59 James Arthur meets bride-to-be from viral concert proposal 0:48 Target to lower prices on about 5,000 basic goods 0:47 WATCH: Comet fragment lights up the sky in Portugal