Find out what’s up in your night sky during June 2018 and how to see it in this Space.com stargazing guide.
Calendar of Observing Highlights
Sunday, June 3 pre-dawn – Moon Meets Mars
Low in the southeastern sky between 1 a.m. local time and dawn on the morning of Sunday, June 3, the waning gibbous moon will sit 2.5 degrees above bright reddish Mars. Both objects will fit into the field of view of binoculars (orange circle).
Sunday, June 3 late evening – Ceres Kisses the Lion’s Nose
On the evening of Sunday, June 3, in the western sky, the eastward orbital motion of the dwarf planet Ceres (visual magnitude 8.7) will carry it very close to Leo’s brightest star Ras Elased Australis (aka Algenubi). Viewing the encounter through a backyard telescope at medium-high power (yellow circle) will readily show the motion of Ceres (red line). Just after dusk in eastern North America, at around 10 p.m. EDT, Ceres will be positioned 4 arc-minutes southwest of the star. In the Eastern Time zone, the objects will set by the time of closest separation at about 2:30 a.m., when Ceres will move to a position only 30 arc-seconds south of the star. Observers located farther west will be able to see the entire encounter.
Wednesday, June 6 at 2:32 p.m. EDT – Last Quarter Moon
At its last quarter phase, the moon rises around midnight and remains visible in the southern sky all morning. At this phase, the moon is illuminated on its western side, towards the pre-dawn sun. Last quarter moons are positioned ahead of the Earth in our trip around the sun. About 3½ hours later, Earth will occupy that same location in space. After this phase, the waning moon traverses the last quarter of its orbit around the earth, on the way to new moon.
Wednesday, June 13 at 3:43 p.m. EDT – New Moon
At its new phase, the moon is travelling between Earth and the sun. Since sunlight is only reaching the far side of the moon, and the moon is in the same region of the sky as the sun, the moon will be completely hidden from view. A day or two after new moon, look for the slender sliver of the young crescent moon to re-appear just above the western horizon after sunset.
Thursday, June 14 after sunset – New Moon Meets Mercury
Visible for a short time after sunset on the evening of Thursday, June 14, the very young crescent moon, only 33 hours past its new phase, will sit 8 degrees to the southeast (left) of Mercury. Both objects will be immersed in the evening twilight above the northwestern horizon. The best time to see them will be between 9:30 and 9:50 p.m. local time when the sky will become sufficiently dark.
Saturday, June 16 evening – Venus and the Crescent Moon bracket the Beehive
In the western sky during early evening on Saturday, June 16, the young crescent moon will be situated 7 degrees to the upper left of bright Venus. The pair of objects will set together about 11:45 p.m. local time. Look for the huge open star cluster Messier 44, also known as the Beehive, sitting between them in the same binocular field of view (orange circle).
Sunday, June 17 late evening – Moon Meets Regulus
In the western sky in late evening on Sunday, June 17, the waxing crescent moon will be situated approximately 4 degrees to the lower right (west) of Regulus, the brightest star in Leo. Both objects will fit into the field of view of binoculars (orange circle). Observers in the Pacific Ocean region will see the moon pass within one degree of the star before they set.
Tuesday, June 19 pre- dawn – Neptune Reverses Direction
Mars will spend June among the stars of Capricornus, starting the month rising after midnight and remaining observable until dawn in the southeastern sky. After mid-June, Mars will rise before midnight, starting a spectacular summer show that will last through late summer. On June 28, Mars will cease its eastward orbital motion and commence a retrograde loop that lasts until late august. During June, Earth’s orbital motion will continue to reduce our distance from the Red Planet. As a result, Mars will increase in brightness (from visual magnitude -1.2 to -2.3) and its apparent disk diameter will dramatically increase from 15 to 21 arc-seconds. The waning gibbous moon will sit 3 degrees above Mars on June 3. When Mars rises about 11 p.m. local time on June 30, the waning gibbous moon will sit 4.5 degrees to its upper left.
A month past opposition, very bright Jupiter (visual magnitude -2.5) will be observable partway up the southern and western sky after dusk during June. By month’s end, it will be setting before 2:30 a.m. local time. The planet will slowly move westward in central Libra all month, starting the month about one degree from the fine, bright double star Zubenelgenubi. From time to time during June, the little round shadows cast by Jupiter’s four Galilean moons will be visible as they cross the planet’s disk. On Friday, June 15 from 9:25 to 11:34 p.m. EDT, Io’s shadow will transit Jupiter. In the southern sky on the evening of June 23rd, look for the waxing gibbous moon and Jupiter separated by about 4 degrees.
Gibbous: Used to describe a planet or moon that is more than 50 percent illuminated.
Asterism: A noteworthy or striking pattern of stars within a larger constellation.
Degrees (measuring the sky): The sky is 360 degrees all the way around, which means roughly 180 degrees from horizon to horizon. It’s easy to measure distances between objects: Your fist on an outstretched arm covers about 10 degrees of sky, while a finger covers about one degree.
Visual Magnitude: This is the astronomer’s scale for measuring the brightness of objects in the sky. The dimmest object visible in the night sky under perfectly dark conditions is about magnitude 6.5. Brighter stars are magnitude 2 or 1. The brightest objects get negative numbers. Venus can be as bright as magnitude minus 4.9. The full moon is minus 12.7 and the sun is minus 26.8.
Terminator: The boundary on the moon between sunlight and shadow.
Zenith: The point in the sky directly overhead.
Night Sky Observing Tips
- Adjust to the dark: If you wish to observe faint objects, such as meteors or dim stars, give your eyes at least 15 minutes to adjust to the darkness.
- Light Pollution: Even from a big city, one can see the moon, a handful of bright stars and sometimes the brightest planets. But to fully enjoy the heavens — especially a meteor shower, the constellations, or to see the amazing swath across the sky that represents our view toward the center of the Milky Way Galaxy — rural areas are best for night sky viewing. If you’re stuck in a city or suburban area, a building can be used to block ambient light (or moonlight) to help reveal fainter objects. If you’re in the suburbs, simply turning off outdoor lights can help.
- Prepare for skywatching: If you plan to be out for more than a few minutes, and it’s not a warm summer evening, dress warmer than you think necessary. An hour of observing a winter meteor shower can chill you to the bone. A blanket or lounge chair will prove much more comfortable than standing or sitting in a chair and craning your neck to see overhead.
- Daytime skywatching: When Venus is visible (that is, not in front of or behind the sun) it can often be spotted during the day. But you’ll need to know where to look. A sky map is helpful. When the sun has large sunspots, they can be seen without a telescope. However, it’s unsafe to look at the sun without protective eyewear.