The Night Sky in February
Venus has been blazing away in the evening twilight for a number of weeks, gradually gaining altitude after sunset as it increases its separation from the Sun. From the beginning of February, Venus will be joined by neighbouring Mercury.
Mercury appears at its brightest at the start of February, but remains reasonably bright through to the middle of the month. It reaches furthest apparent separation from the Sun on Feb 10. A relatively flat west-southwest horizon is recommended to see it.
Having a smaller orbit than Venus, Mercury’s maximum apparent separation from the Sun can never be as large. On Feb 12, Mercury sets just under two hours after the Sun, down to 1.5 hours by Feb 15 and to just 70 minutes by Feb 20. Currently, Venus remains above the horizon for four hours, increasing by 20 minutes by the end of the month. Using a telescope, it’s possible to see that both Venus and Mercury show phases. They are inferior planets, so named because their orbits are smaller than Earth’s. Using Venus as an example, when it appears close to the Sun on the far side of its orbit from Earth, a telescope shows it as a small, virtually fully illuminated disc. As it creeps around its orbit, the Earthsun-venus angle changes to give us a different view of its illuminated hemisphere. It appears to diminish in phase and grows in size as its distance from Earth decreases.
A beautiful meeting of the crescent Moon and Venus occurs from Feb 26-28. The closest separation occurs on Feb 27 when the slender 14 per cent illuminated lunar crescent sits 12 apparent Moon diameters south of Venus.
In the hours running up to midnight, it’s the stars of spring that take charge. The backward question mark arrangement of the Sickle is the strongest pattern high in the south. Formed from stars in Leo, the constellation’s brightest star, Regulus, forms the “punctuation dot” at the base of the pattern. Further west are the distinctive Castor and Pollux, representing the heads of Gemini. The midpoint of the line from the northern twin star Castor to Regulus brings you to faint misty object easily hidden by poor skies. This is the Beehive Cluster, M44. It sits at the heart of a dim upside-down, Y-shaped pattern representing Cancer. A sideways teardrop pattern lies immediately below (south) the open end of the
“Y”. This represents the head of Hydra, the largest constellation by area. Despite this accolade, there’s little to Hydra, it being devoid of bright stars save for orange-hued Alphard in the creature’s neck. The head and neck greatly resemble the classic Loch Ness Monster head silhouette image.
Hydra takes nine hours to rise above the UK’S horizon, a number of smaller constellations riding its back as it appears. Near the neck is indistinct Sextans the Sextant, containing no bright stars at all. Near the tail sit Crater the Cup and Corvus the Crow. Crater is also faint but does have a distinctive outline. Corvus is more prominent, its main pattern forming a small shape known as The Sail.
Two defunct constellations accompany Hydra across the sky. One is Noctua the Owl close to the end of Hydra’s tail. The second was Felis the Cat, a faint pattern south of Hydra’s mid-body. In 2018, the official star naming body, the International Astronomical Union, declared that although Felis was defunct, its brightest star would still carry the name Felis.