July 2016

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

The Calendar

Date Event
1 Friday Moon at perigee
2 Saturday Moon occults first-magnitude star Aldebaran: daytime event
3 Sunday
4 Monday New Moon
Earth at aphelion
5 Tuesday NASA's Juno mission is scheduled for Jupiter Orbit Insertion at 02:30 UT (spacecraft time - Earth received time is 48 minutes later). It was launched on 5 August 2011 to study the origin and evolution of the planet Jupiter. The mission is set to run until February 2018.
6 Wednesday
7 Thursday Mercury at superior conjunction
Pluto at opposition
8 Friday
9 Saturday Moon occults Jupiter: partially visible from sections of Antarctica
10 Sunday
11 Monday
12 Tuesday First Quarter Moon
13 Wednesday Moon at apogee
14 Thursday
15 Friday
16 Saturday Uranus at west quadrature
17 Sunday
18 Monday
19 Tuesday Full Moon
20 Wednesday
21 Thursday
22 Friday
23 Saturday Moon occults Neptune: visible from about 05:00 UT in central and eastern North America
24 Sunday
25 Monday
26 Tuesday Last Quarter Moon
27 Wednesday Moon at perigee
28 Thursday
29 Friday Moon occults first-magnitude star Aldebaran: visible from about 9:30 UT in Mexico and Central America
30 Saturday The waning crescent Moon should not hamper observations of the Southern δ Aquarid meteor shower. There may be several sub-maxima between 26 July and 31 July.
31 Sunday

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 GeminiCancer

Earth reaches its farthest point from the Sun on 4 July. The date of aphelion can range from 2 July to 6 July. The equation of time reaches a shallow minimum of nearly seven minutes on 25 July.

Mercury GeminiCancerLeo

Invisible at the beginning of the month, Mercury is at superior conjunction on 7 July. It then appears in the evening sky shortly afterwards. The best sunset views of this tiny planet are from southern latitudes. It passes close to the first-magnitude star Regulus on 30 July.

Venus GeminiCancerLeo

Venus is the evening star for the rest of the year. It starts quite close to the horizon for northern hemisphere observers and is not much higher when seen from the southern half of our planet. Venus will remain rather low for most of the year but is best viewed from the southern hemisphere. Look for our nearest neighbour to pass in front of the open star cluster M44, the Beehive Cluster, on 18 July.

Mars Libra

The red planet is well-situated for viewing after nightfall, not setting until after midnight.

Jupiter Leo

The largest planet in the solar system gets another visitor from Earth when the spacecraft Juno enters orbit on 5 July. Jupiter is found in the west as darkness falls and sets earlier every night. Penguins might catch a glimpse of it disappearing behind the Moon's disc on 9 July.

Saturn Ophiuchus

This bright planet is not far from Mars, setting about an hour afterwards.

Uranus Pisces

Rising about midnight at the beginning of the month, Uranus reaches west quadrature on 16 July.

Neptune Aquarius

A small telescope is necessary to view the most distant planet in the solar system. It rises in the evening and is up most of the night as it heads for opposition in early September. Parts of North America can see it being occulted by the Moon on 23 July.

Pluto Sagittarius

A medium-sized telescope and a detailed star chart is necessary to see this magnitude 14 dwarf planet at opposition on 7 July. It is not far from the star π Sgr but much, much fainter.

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