SkyEye

April 2017

Welcome to SkyEye, your guide to this month's celestial events.

The Calendar

Date Event
Saturday 1 Mercury at greatest elongation east
Moon occults first magnitude star Aldebaran: visible from Japan, northern Pacific (beginning around 09:30 UT).
Sunday 2
Monday 3 First Quarter Moon
Tuesday 4
Wednesday 5
Thursday 6
Friday 7 Moon occults first magnitude star Regulus: visible from Easter Island, southern South America (beginning around 04:25 UT).
Jupiter at opposition
Saturday 8
Sunday 9
Monday 10
Tuesday 11 Full Moon
Wednesday 12
Thursday 13
Friday 14 Uranus at conjunction
Saturday 15 Moon at apogee
Sunday 16
Monday 17
Tuesday 18
Wednesday 19 Last Quarter Moon
Thursday 20 Mercury at inferior conjunction
Friday 21 Moon at apogee
Saturday 22 Dark skies greet this year's arrival of the Lyrid meteor shower (theoretical maximum: 12:00 UT).
Moon occults Neptune: visible from Australia, New Zealand (beginning around 18:25 UT).
Sunday 23 This year provides optimal viewing conditions for the Pi-Puppids (theoretical maximum: 17:00 UT).
Monday 24
Tuesday 25
Wednesday 26 New Moon
Thursday 27 Moon at perigee
Friday 28 Moon occults first magnitude star Aldebaran: visible from northern Africa, eastern Europe (beginning around 18:15 UT).
Saturday 29
Sunday 30

The Solar System

The word planet is derived from the Greek word for 'wanderer'. Unlike the background stars, planets seem to move around the sky, keeping mostly to a narrow track called the ecliptic, the path of the Sun across the stars. Dwarf planets and small solar-system bodies, including comets, are not so constrained, often moving far above or below the ecliptic.

Sun PiscesAries

Mercury AriesPisces

At greatest elongation east on the first day of the month, Mercury is particularly viewable from the northern hemisphere for the following few days. It gradually disappears into the evening twilight and undergoes inferior conjunction on 20 April before reappearing in the morning sky by the end of the month. The southern hemisphere will get the best morning sky views.

Venus Pisces

Last month, the northern hemisphere had the best views of Venus. As it passed north of the Sun's disc late last month, observers from northern latitudes were able to see our nearest neighbour both in the evening and in the morning. This month it rises slowly above the horizon in the morning sky. However, southern hemisphere views of the morning star are much more favourable, with Venus climbing rapidly above the eastern horizon.

Mars AriesTaurus

Evening twilight is beginning to catch up with the red planet. Look for Mars towards the west where it sets in the early evening for southern hemisphere observers and a little later for those in the north.

Jupiter Virgo

Jupiter is at opposition on 7 April so it is up most of the night and well-placed for observing during the evening hours.

Saturn Sagitarius

The ringed planet now rises before midnight for all terrestrial observers.

Uranus Pisces

At solar conjunction on the fourteenth day of the month, this ice giant is unobservable throughout April.

Neptune Aquarius

A small telescope is necessary to view the most distant planet in the solar system. It may be far enough removed from the solar glare to be visible in the early morning hours.

The Celestial Sphere

Constellations are patterns of stars in the sky. The International Astronomical Union recognises 88 different constellations. The brightest stars as seen from the Earth are easy to spot but do you know their proper names? With a set of binoculars you can look for fainter objects such as nebulae and galaxies and star clusters or some of the closest stars to the Sun.

Descriptions of the sky for observers in both the northern and southern hemispheres are available for the following times this month. Subtract one hour from your local time if summer (daylight savings) time is in effect.

Local Time Northern Hemisphere Southern Hemisphere
1730 hours (1830 hours summer time) 45° N 30° S
1930 hours (2030 hours summer time) 45° N 30° S
2130 hours (2230 hours summer time) 45° N 30° S
2330 hours (0030 hours summer time) 45° N 30° S
0130 hours (0230 hours summer time) 45° N 30° S
0330 hours (0430 hours summer time) 45° N 30° S
0530 hours (0630 hours summer time) 45° N 30° S