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Great conjunction of Jupiter and Saturn, 21 December 2020

The upcoming great conjunction of Jupiter and Saturn will be on the day of the winter solstice: December 21, 2020. Jupiter-Saturn conjunctions are rare events as they happen every 20 years; the last one was in the year 2000. This time it is even more special as the angular separation between the two planets in the sky will be a mere 0.1° or 6′ – 6 minutes of arc – the closest they have been since 16 July, 1623 (nearly 400 years). However, the smallest separation then occurred during the daytime. The smallest nighttime separation occurred last time in 1226, nearly 800 years ago.

This is a simulated view of the southwestern horizon at Nainital using Stellarium showing the gradually changing separation between Jupiter and Saturn from 18-23 December, 2020. They will be closest at 13:30 Universal Time on Monday, 21 December, 2020. That’s 13:30 GMT/19:00 IST, luckily night time in India/Nainital.

We at ARIES will be keeping our telescopes ready and pointed toward the southwestern horizon to capture the great conjunction. The captured images will be used for scientific purposes and available on ARIES’ website and social media channels for public viewing. We urge you also to go out and enjoy this wonderful celestial phenomenon with amateur telescopes, binoculars and even naked eyes.

Conjunction of Jupiter and Saturn, 21 December 2020, ARIES, Nainital

Img2The coming great conjunction of Jupiter and Saturn will be on the day of the solstice: December 21, 2020. Jupiter-Saturn conjunctions happen every 20 years; the last one was in the year 2000 as one of the rare but popular astronomical event of a potential public interest and enthusiasm. It could even be seen through naked eyes towards the southwestern horizon.

On behalf of ARIES, the 1.04m, the 3.6m DOT and several ameture cameras by enthusiastic research students were used to have snap-shots using CCD cameras during 20-21 Dec 2020. These data sets taken with the telescopes could be used both for public viewing and for scientific purposes like measuring apparent sizes, the inter-distance between the two objects, brightness, relative velocities etc. with a desired accuracy using trigonometric methods, if required. The images taken from ARIES were also posted to various print aImage1nd electronic media including ARIES webpage, facebook etc.

The images taken by the 1.04m Telescope and the 3.6m Devasthal Optical Telescopes are appended below for references. It is clear from the images taken below using ARIES telescopes that both Jupitor and Saturn were closer than the diameter of the Moon itself on 20th Dec evening. On 21st evening they are expected to come even closer. The apparent angular distance between the two objects at the time of maxima on 21st Dec 2020 (around 07:00pm IST) would be around 6 minutes of arc. Further analysis of the data obtained using ARIES telescopes are ongoing.


This note is circulated for local print and electronic media for their ready references for the public awareness of this popular astronomical event. It is also possible for other science popularization groups to use these images for references.

Conjuction captured today