Gear up for Mars and Jupiter’s great coming-together

Mars and Jupiter lay within a degree on the morning of 19 March 2020. Image: David Blanchflower.

Mars and Jupiter presently lie within a binocular field-of-view, though you’ll need to rise early to catch them lying around 20° high at about 3am BST. Both planets are hosted by the bright stars of the constellation of Taurus, the Bull, which provide a suitably stunning backdrop leading up to and during close approach. 

For the conjunction Mars and Jupiter lie in Taurus, east of the Hyades. This is the view on the morning of 14 August. All AN graphics by Greg Smye–Rumsby.

Mars lies west of Jupiter, lying around 5° above orange-red Aldebaran (alpha Tauri) on the morning of 7 August. Aldebaran, marking the Bull’s right eye, dominates the familiar and bright ‘V’ shape outline of the Hyades open cluster, though its not a member of the cluster. As chance would have it, both Mars and Aldebaran shine at around magnitude +0.9, and with a similar coloration. Jupiter dazzles at magnitude – 2.2, totally dominating the morning scene.

A small telescope gives a great view of the conjunction of Mars and Jupiter. Mars and Jupiter lie around 23’ apart on the morning of 14 August. This is the view through a 80mm (~three-inch) telescope at low power. There’s a second chance to see them as close on the following night.

Over the course of the next week, Mars’ more rapid easterly motion through Taurus draws the red planet ever closer to Jupiter. The planetary pair lie within 1.3° of each other between the mornings of 12th to 17th August. Closest approach occurs on 15 August at 16:52 UT, daytime in the UK, when Mars lies 18’ north-west of Jupiter. 

Close planetary conjunctions aren’t all that common and are very exciting to see. It’s not that long ago that we witnessed the so-called ‘Christmas Star Conjunction’ of 21 December 2020, when Jupiter and Saturn hadn’t been as close in the night sky for almost 400 years. This type of event often get the attention of the mass media, like a bright comet or colourful aurora. So, it’ll be well-worth trying to observe and image the conjunction.  

From UK shores, there’s two opportunities to see Mars and Jupiter at their closest. The mornings of 13/14 and 14/15 August see Mars slides past Jupiter, when the red planet appears to lie 23’ above and 23’ to the left of Jupiter, respectively, a distance a fair bit less than the diameter of a full Moon. This is the closest that Mars and Jupiter have been since they were around 13’ apart in the pre-dawn sky on 7 January 2018.  

The respective apparent diameters of Jupiter (36.6”) and Mars (6.1”) on the morning of 14 August.