Awyr y Nos: Mawrth 2020

6^th Close approach of the Moon and M44 (figure 1). The Moon and M44 will make a close approach, passing within 1°23' of each other.

The Moon will be 12 days old, visible in the evening sky, becoming accessible around 18:28 (GMT) as the dusk sky fades, 38° above Eastern horizon. They will then reach highest point in the sky at 21:57, 57° above Southern horizon. They will continue to be observable until 04:51, when they go below 7° above Western horizon.

Too widely separated to fit within the field of view of a telescope, but will be visible through binoculars.

Figure 1: Close approach, Moon and M44.

20^thwill be the March equinox (figure 2). Marking the first day of spring in the Northern hemisphere.

On the day of the equinox, everywhere on Earth has almost exactly 12 hours of day and night, as the Sun's annual journey through the constellations of the zodiac carries it across the celestial equator.                                                                 The word equinox, derived from Latin words aequus (equal) and nox (night)

Wherever you live on Earth, on the day of the equinox the Sun will rise from the point on the horizon which lies due East and set beneath the point which lies due West.

Equinoxes occur because the axis of Earth's spin, its polar axis, is tilted at an angle of 23.5° to the plane of its orbit around the Sun.

The direction of Earth's spin axis remains fixed in space as it circles around the Sun, while the Earth's sight line to the Sun moves through the constellations of the zodiac. As a result, sometimes Earth's North pole is tilted towards the Sun (June), and sometimes it is tilted away from it (December).                                         This gives rise to Earth's seasons:

Figure 2: March Equinox.

At the intermediate points between the solstices, the Sun lies directly over the Earth's equator on approximately 21^st March and 23^rd September. In March, the Sun is travelling Northwards across the equator and in September it is travelling Southwards.

27^th Venus (figure 3 & 4) reaches highest point in the evening sky in its 2019–2020 evening apparition. It will be shining brightly. This apparition will be well placed and prominent, reaching a peak altitude of 41° above the horizon at Sunset on 27 Mar 2020.

Figure 3: Venus at highest point in sky.

Figure 4: Venus at highest point.

28^th Moon and Venus (figure 5) will share the same right ascension, with the Moon passing 6°48' to the South of Venus. The Moon will be 4 days old.

They become visible approximately 19:03 (GMT) as the dusk sky fades, 37° above Western horizon. They will sink towards the horizon, setting at 23:21.

Figure 5: Conjunction of Moon and Venus.

WARNING: Never attempt to view through binoculars, telescope or any optical aid an object near to the Sun. Also, never attempt to view the Sun unaided, doing so may result in immediate and permanent blindness. Always use astronomical approved viewing equipment.

The Stellarium software will assist greatly in locating objects in the sky.

Mark R Smith FRAS

Physicist

Nuclear Fusion Physics

Astrophysics