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C/2022 E3 (ZTF) is a long-period comet from the Oort cloud that was discovered by the Zwicky Transient Facility in March 2022. The comet has a bright green glow around its nucleus, due to the effect of sunlight on diatomic carbon and cyanogen. Its comet nucleus is estimated to be about 1 kilometre (0.62 mi) in size, rotating every 8.5 to 8.7 hours. Its tails of dust and gas extended for millions of kilometres and, during January 2023, an anti-tail was also visible. The comet reached perihelion on 12 January 2023, at a distance of 1.11 AU (166 million km; 103 million mi), and its closest approach to Earth was on 1 February 2023, at a distance of 0.28 AU (42 million km; 26 million mi). The comet reached magnitude 5 during this approach, and was visible with the naked eye under moonless dark skies. This photograph of C/2022 E3 (ZTF), released by the Italian National Institute for Astrophysics, was taken on 27 January 2023.Photograph credit: Alessandro Bianconi