This Week’s Sky: July 13 to 19, 2020

All week – Comet NEOWISE

The daily position and path of Comet C/2020 F3 NEOWISE this week, shown in the evening sky at 10:15 p.m. local time. It will be climbing daily towards Ursa Major. The circle represents the field of binoculars. (Chris Vaughan, Starry Night Education)

The long-awaited bright comet C/2020 F3 NEOWISE will become visible after sunset this week.

All you will need to see it are clear skies to the northwest, and a very low horizon that is free of obstructing trees and buildings. If you live in an apartment with western or north-facing windows or a balcony, you’re in luck, too.

You can see this comet with your unaided eyes, but it will become truly spectacular through binoculars and telescopes. What you should expect to see is a small, bright, fuzzy spot, possibly with an orange hue. Binoculars will reveal the comet’s faint tail extending generally upwards, away from the Sun. Actually, look for two tails pointed in slightly different directions — a brighter one composed of debris the comet is dropping behind it and a fainter, blue-tinted one composed of ionized gas. The latter tail will always point directly away from the Sun, since it’s being pushed by the solar wind. While your telescope will magnify the comet’s head nicely, its tail will extend beyond your limited field of view.

The daily position and path of Comet C/2020 F3 NEOWISE this week, shown in the pre-dawn sky at 4:45 a.m. local time. It will be shifting to the left daily towards Ursa Major. The circle represents the field of binoculars. The bright star Capella will aid in locating the comet. (Chris Vaughan, Starry Night Education)

For those who want to see the comet before sunrise, it will rise Monday, July 13 at about 2 a.m. local time. (rise time varies by your latitude). It will be located about two fist diameters to the lower left (or 20 degrees to the celestial east of) the very bright star Capella, over the northwestern horizon. On the coming weekend, the comet will drop lower – moving to the lower right of Merak.

For more on the comet, check out the article “Comet NEOWISE takes an evening shift.”

Monday, July 13 over night – Ceres reverses direction

Ceres reverses direction (Chris Vaughan, Starry Night Education)

On Monday, July 13, the dwarf planet Ceres will stop moving eastward through the stars of Aquarius and commence a westward retrograde loop that will last until October (red path with dates:times). After rising in the east shortly before midnight local time, you’ll find magnitude 7.5 Ceres in the southeastern sky within southern Aquarius, sitting 2.8 degrees to the upper left (northeast) of the medium-bright star 88 Aquarii, and a generous palm’s width to the upper left of the very bright star Fomalhaut.

Monday, July 13 all night – Asteroid Pallas at opposition

Asteroid Pallas at opposition (Chris Vaughan, Starry Night Education)

On Monday, July 13, the main belt asteroid designated (2) Pallas will reach opposition, its minimum distance from Earth for the year. On the nights around opposition, Pallas will rise at sunset and shine with a peak visual magnitude of 8.9 — within reach of binoculars and backyard telescopes. The asteroid will be situated on the border between western Vulpecula and Sagitta, about a fist’s diameter to the right (or 9 degrees to the celestial southwest) of the medium-bright star Albireo.

Tuesday, July 14 all night – Jupiter at opposition

Jupiter at opposition (Chris Vaughan, Starry Night Education)

On Tuesday, July 14, Jupiter will reach opposition among the stars of eastern Sagittarius, rising at sunset, and remaining visible all night long. At opposition, Jupiter will be located 384.8 million miles, 619.2 million km, or 34.4 light-minutes from Earth, and it will shine at its maximum brightness of magnitude -2.75 for 2020. Views of Jupiter’s 48 arc-second wide disk in amateur telescopes will show the Great Red Spot and equatorial bands (inset). Around opposition, Jupiter and its four large Galilean satellites frequently eclipse and occult one another, and cast their round, black shadows on the planet. This year, dimmer Saturn will share the sky with Jupiter.

Wednesday, July 15 all night – Pluto at opposition near Jupiter

Pluto at opposition near Jupiter (Chris Vaughan, Starry Night Education)

On Wednesday, July 15, the dim and distant Pluto will reach opposition for 2020. On that date, the Earth will be positioned between Pluto and the Sun, minimizing our distance from the dwarf planet. At opposition, Pluto will be located 3.05 billion miles, 4.91 billion km, or 273 light-minutes from Earth, and it will shine with an extremely faint visual magnitude of +14.2. That’s far too dim for visual observing through backyard telescopes; but the planet will actually be located in the sky less than two finger widths to the lower left (or 1.75 degrees to the celestial southeast) of the brightest planet, Jupiter. Telescope-owners (red circle) can also look for a magnitude 8.96 star named HIP96913, which will be sitting directly beside Pluto on July 14, and only 1.3 arc-minutes north of Pluto on opposition night. Even if you can’t see Pluto directly, you will know that it is there.

Friday, July 17 from 02:45 to 05:30 GMT – Europa shadow transit with Great Red Spot

Europa shadow transit with Great Red Spot (Chris Vaughan, Starry Night Education)

From time to time, the small, round, black shadows cast by Jupiter’s four Galilean moons can be seen in amateur telescopes as they cross (or transit) the planet’s disk for a few hours. Starting in late evening on Thursday, July 16, observers in the Americas can see Europa’s shadow transiting Jupiter while accompanied by the Great Red spot. The shadow and spot will commence their traverse together at 10:45 p.m. EDT, or 2:45 a.m. GMT. Europa’s shadow will move off of Jupiter at 1:30 a.m. EDT, or 5:30 a.m. GMT, leaving the GRS to complete its passage about 90 minutes later.

Friday, July 17 pre-dawn – Crescent Moon meets Venus

Crescent Moon meets Venus (Chris Vaughan, Starry Night Education)

In the eastern pre-dawn sky on Friday, July 17, the waning crescent Moon will be positioned less than three finger widths to the upper left (or 2.75 degrees to the celestial northeast) of the bright planet Venus. Both objects will appear together in binoculars (red circle) until sunrise, and will make a nice photograph when composed with an interesting foreground landscape. Under magnification, Venus will show a crescent phase similar to the Moon’s.

Sunday, July 19 pre-dawn – Old Moon near Mercury

Old Moon near Mercury (Chris Vaughan, Starry Night Education)

For a short period before dawn on Sunday, July 19, sharp-eyed skywatchers with a clear view of the east-northeastern horizon might spot the very slender crescent of the old Moon sitting four finger widths to the left (or 4.8 degrees to the celestial east) of Mercury. Start your search after about 4:45 a.m. local time, when the pair, which will both appear in the field of binoculars (red circle), will sit less than a fist’s diameter above the horizon.

Chris Vaughan is a science writer, geophysicist, astronomer, planetary scientist and an “outreach RASCal.” He writes Astronomy Skylights, and you can follow him on Twitter at @astrogeoguy. He can also bring his Digital Starlab portable inflatable planetarium to your school or other daytime or evening event. Contact him through AstroGeo.ca to tour the universe together.