If you’re an early riser in the British Isles, let the waning crescent Moon be your guide to three naked-eye planets – Mars, Jupiter and Saturn – at dawn on 18 and 19 March 2020. This celestial conjunction occurs in the constellation of Sagittarius where you can see all four Solar System bodies within the span of a fist at arm’s length. Look for attractive binocular conjunctions too.
Mercury is poised to put on a fine evening show for Northern Hemisphere observers at dusk, attaining a greatest elongation 18.2 degrees east of the Sun on Monday, 10 February 2020. For ten evenings starting 3 February, the innermost planet and its brightest sibling, Venus, maintain an almost constant angular separation low in the west-southwest 40 minutes after UK sunset.
Innermost planet Mercury puts on its best morning display of the year for Northern Hemisphere observers from late November to early December. Skywatchers in the British Isles should find a location offering an unobstructed view of the southeast horizon about 45 minutes before sunrise to get the best views, with the Red Planet and star Spica – the brightest in Virgo – also nearby.
On Monday, 11 November 2019 just after 12:30pm GMT, suitably equipped observers in the British Isles can witness the start of a 3.7-hour spectacle that hasn’t been seen for three-and-a-half years — the silhouette of innermost planet Mercury crossing the face of the Sun. Here’s our online guide to observing this fascinating and comparatively rare event in complete safety.
On 18 June at the end of civil twilight in the UK, planets Mars and Mercury lie slightly less than one-quarter of a degree apart in the constellation of Gemini. Observing this conjunction will be a challenge from the UK as the pair will be just 5 degrees high in the west-northwest at civil dusk in bright twilight, which is about 50 minutes after sunset for London.
Mercury attains a very favourable western elongation of almost 28 degrees from the Sun on 11 April, which means that the innermost planet is a morning object in the eastern sky before sunrise. Antipodean skywatchers are in the enviable position of being able to see Mercury and Venus close together for several mornings in a dark sky before the onset of astronomical twilight.