July 2017

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

The Calendar

Date Event
Saturday 1 First Quarter Moon
Sunday 2
Monday 3 Earth at aphelion
Tuesday 4
Wednesday 5
Thursday 6 Jupiter at east quadrature
Moon at apogee
Friday 7
Saturday 8
Sunday 9 Full Moon
Monday 10 Pluto at opposition
Tuesday 11
Wednesday 12
Thursday 13 Moon occults Neptune: visible from Antarctica
Friday 14
Saturday 15
Sunday 16 Last Quarter Moon
Monday 17
Tuesday 18
Wednesday 19
Thursday 20 Moon occults first-magnitude star Aldebaran: visible from around 21:45 UT in far eastern parts of the Middle East and India.
Friday 21 Uranus at west quadrature
Moon at perigee
Saturday 22
Sunday 23 New Moon
Monday 24
Tuesday 25 Moon occults Mercury: visible from the Arctic (daytime event)
Moon occults first-magnitude star Regulus: visible from around 11:45 UT in western Indonesia.
Wednesday 26
Thursday 27 Mars at conjunction
Friday 28
Saturday 29
Sunday 30 Mercury at superior conjunction
The First Quarter Moon should not hamper observations of the Southern δ Aquarid meteor shower.
Monday 31

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 3 July. The date of aphelion can range from 2 July to 6 July.

Mercury GeminiCancerLeo

Southern observers see this tiny planet appear ever higher in the west after sunset. From northern latitudes it appears to rise until mid-month and then sink back towards the Sun.

Venus TaurusOrion

Although the morning star is beginning its slow descent towards the eastern horizon as seen from the southern hemisphere, it is still climbing higher into the dawn sky for viewers in northern latitudes.

Mars GeminiCancer

Mars is at conjunction with the Sun on 27 July and is not visible this month.

Jupiter Virgo

The largest planet in the solar system is at east quadrature on 6 July. With the shadows of Jupiter and its Galilean moons cast slightly to one side, this is an excellent opportunity to observe this solar-system-in-miniature.

Saturn Ophiuchus

Now past opposition, the ringed planet is an evening sky object. It is best seen from southern latitudes.

Uranus Pisces

Rising about midnight at the beginning of the month, Uranus reaches west quadrature on 21 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. The Moon occults Neptune on 13 July but only from vantage points in the Antarctic.

134340 Pluto Sagittarius

A medium-sized telescope and a detailed star chart is necessary to see this magnitude 14 dwarf planet at opposition on 10 July. It is located west of the star π Sgr and is 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