For up-to-date info on observing bodies like this, read our guide on what comets and asteroids and visible in the sky tonight<\/a>.<\/p>\n One observer who really made the most of C\/2017 O1 ASASSN\u2019s movements across the sky was comet-chaser and astrophotographer Jos\u00e9 J. Chamb\u00f3, who photographed the comet on multiple occasions over a period of months.<\/p>\n Jos\u00e9 captured the image below on 28 July 2017 from Valencia, Spain, using an Atik 383L+ camera and a GSO 8-inch telescope.<\/p>\n He said: \u201cThe comet was discovered during an abrupt increase of brightness, which continued until its present mag. +10.<\/p>\n \u201cAs seen in this image, it has developed a green gassy coma of diatomic carbon, with an apparent size of 10 arcminutes.<\/p>\n \u201cThis comet may reach a maximum brightness around mag. +7 in October (2017), when it will be observable from the northern hemisphere passing near the celestial zenith.<\/p>\n \u201cThere are some galaxies<\/a> in this field, at right NGC 1084 and at bottom-left NGC 1110 edgeways.\u201d<\/p>\n \u00a0<\/p>\n Jos\u00e9 then photographed C\/2017 ASSASSN again on 22 August 2017 (see image below).<\/p>\n He said: \u201cOne month after being discovered, the comet\u2019s brightness has increased to mag. +9 and its tail continues growing. In this image it appears to be 10 arcminutes long, although seems more long and shaped.\u201d<\/p>\n \u00a0<\/p>\n On 17 September 2017, Jos\u00e9 was able to capture an image remotely from Mayhill, New Mexico, US, showing two comets in the same field of view.<\/p>\n \u201cComet C\/2017 O1 ASASSN, down left, is observable by binoculars now while approaching perihelion, showing a greenish coma of diatomic carbon and a small ionic tail,\u201d he said.<\/p>\n \u201cAt the same time, Comet C\/2015 ER61 PANSTARRS, up right, moving away for four months now and twice as far from Earth, can be still imaged with a long and narrow tail.<\/p>\n \u201cBetween both you can see a shred of IFN (Integrated Flux Nebula) very near to the Pleiades<\/a>.<\/p>\n \u00a0<\/p>\n \u00a0<\/p>\n On 18 September 2017, Jos\u00e9 once again photographed the comet from Valencia, Spain, which can be seen below.<\/p>\n He said: \u201cComparing this image with the one I took a month ago, you can see an increase in the apparent size of its greenish coma from 7 arcminutes to 10, and the length of its ionic tail from 10 arcminutes to 20.<\/p>\n \u201cIts brightness has slightly increased at the same time from mag.+9 to +8.5 approximately. The brightest star in the field is 37 Tauri, at mag. +4.4.\u201d<\/p>\n The image below was then captured on 25 September 2017.<\/p>\n Jos\u00e9 said: \u201cComet C\/2017 O1 ASASSN is keeping its morphological shape with a coma of 8 arcminutes\u2019 diameter and tail about 15 arcminutes long.<\/p>\n \u201cIn this image it\u2019s currently located in the constellation Taurus, passing by a zone of dark clouds of dust that obscures the starry background.\u201d<\/p>\n Jos\u00e9 captured the comet once more on 21 October 2017, as seen below.<\/p>\n He said: \u201cDespite having a brightness drop of half magnitude to mag. +8.5 the comet still reveals a coma 10 arc minutes in diameter in images.<\/p>\n \u201cHowever, its external layer is very diffuse, and you can also see a faint tail 20 arcminutes long toward southwest.\u201d<\/p>\n \u00a0<\/p>\n \u00a0<\/p>\n \u00a0<\/p>\n Jos\u00e9\u2019s final image was captured on 18 November 2017.<\/p>\n He said: \u201cIts brightness has dropped clearly over the last month, now down to about mag. +10.<\/p>\n \u201cIn this image, taken when the comet is moving into the constellation Cepheus towards the celestial north pole, it displays a green-bluish coma of 7 arcminutes\u2019 diameter and a tail more faint and short, about 10 arcminutes in length.\u201d<\/p>\n \u00a0<\/p>\n Thanks to Jos\u00e9 for sending in his images of Comet C\/2017 O1 ASASSN and his reports on how the comet was changing over periods of weeks and months.<\/p>\n You can also read Jos\u00e9\u2019s report on Comet C\/2015 V2 Johnson<\/a>.<\/p>\n![\""Comet\"](\""https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2019\/02\/2017O1_170728_2400-b60a3ba.jpg?quality=90&resize=620%2C465"\" "\\"\"Comet_C-2017\\"")
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