SkyEye

July 2019

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

The Calendar

A spectacular total solar eclipse takes place on 2 July, with a partial lunar eclipse two weeks later. Saturn is at opposition early this month too.

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Date Body Event
1
2 Earth, Moon total solar eclipse
Moon new
3 Moon ascending node
4 Moon, Mars occultation of Mars — visible from parts of the southern Pacific
Moon 0.2° north of the open star cluster M44 (known as Praesepe or the Beehive Cluster)
Earth aphelion
5 Moon perigee
Venus ascending node
6
7 Mercury stationary point: direct → retrograde
Mercury aphelion
Venus maxiumum declination north
8 Mercury, Mars conjunction: 4.1° apart
9 Moon first quarter
Saturn opposition
10
11
12
13 Mars 0.4° south of the open star cluster M44 (known as Praesepe or the Beehive Cluster)
14 134340 Pluto opposition
15
16 Moon, Saturn occultation of Saturn — visible from the southern Pacific and central South America
Moon descending node
Earth, Moon partial lunar eclipse
Moon full
17
18
19
20
21 Moon apogee
Mercury inferior conjunction
22
23
24
25 Moon last quarter
Mercury, Venus conjunction: 5.6° apart
26
27
28
29 Uranus west quadrature
30 Earth Southern δ Aquariid meteor shower
Moon ascending node
31 Mercury stationary point: retrograde → direct
Moon, Venus occultation of Venus

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.

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Sun GeminiCancer

Mercury CancerGemini

Mercury experiences another short bout of retrograde motion this month, from 7 July to the last day of the month. It also reaches aphelion on 7 July. Visible in the west after sunset early in the month, it soon vanishes from view as it undergoes inferior conjunction on 21 July. It re-emerges in the east at dawn before the end of July.

Venus TaurusGeminiCancer

The northern hemisphere may finally have a slight edge when it comes to viewing the morning star but Venus is low in the east before sunrise and despite its brightness (magnitude −3.9), it may vanish in the glow of the dawn sky before the end of the month, leaving the lunar occultation of 31 July unobserved.

Earth and Moon

There are two eclipses this month. The first, a total solar eclipse, occurs on 2 July. The second, two weeks later, is a partial lunar eclipse. Aphelion, the day when Earth is farthest from the Sun, is on 4 July. Finally, a meteor shower, the Southern δ Aquariids peaks on the penultimate day of the month. The waning crescent Moon should not cause any problems with observations of this shower.

Mars CancerLeo

As the Moon overtakes Mars on 4 July, our satellite actually occults the red planet in an event beginning around 03:15 UT. Four days later finds Mercury and Mars in conjunction, just over 4° apart in evening twilight. On 13 July, Mars is only 0.4° south of M44, Praesepe or the Beehive Cluster. This small planet is getting increasingly difficult to see in the western sky as it dims and draws closer to the Sun.

Jupiter Ophiuchus

Now past opposition, Jupiter is an evening sky object, not setting until after midnight. It dims slightly but still outshines every other celestial body in its vicinity. The best views of the gas giant, as has been the case all year, are from the southern hemisphere.

Saturn Sagittarius

Saturn finally reaches opposition on 9 July, just over six months since conjunction. It shines at a magnitude of +0.1 and exhibits a ring tilt of approximately 24°. One week after opposition, a Full Moon occults Saturn in an event beginning at about 05:00 UT. Saturn is visible most of the night but is low to the horizon when viewed from northern temperate latitudes.

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Uranus Aries

A morning sky object, Uranus reaches west quadrature on 29 July. Planet watchers in the southern hemisphere have the best views as the dawn skies are brighter in the northern hemisphere this month.

Neptune Aquarius

A small telescope is necessary to view the most distant planet in the solar system and the southern hemisphere is the best place to be to try to observe Neptune this month. For these favoured locations, Neptune rises well before midnight but planet watchers in the temperate north must wait until after midnight to try to catch a glimpse of this elusive planet.

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 Mid-month Northern Hemisphere Equator Southern Hemisphere
1730 hours (1830 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S
1930 hours (2030 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S
2130 hours (2230 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S
2330 hours (0030 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S
0130 hours (0230 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S
0330 hours (0430 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S
0530 hours (0630 hours summer time) 60° N 50° N 40° N 30° N 20° N 10° N 10° S 20° S 30° S 40° S