What's Up in the Night Sky?

July 2020 - Vol. 24, No. 7

Astra's Star Gate

This Month's Night Sky - NOTE: The next paragraph describes the sky as it appears at 10 pm EST (11 pm EDT) near mid- month. The sky also looks this way at 11 pm EST (midnight EDT) during the beginning of the month and at 9 pm EST (10 pm EDT) by month's end.

Bright blue-white Vega (Lyra) shines high overhead as it "leads" the Summer Triangle across the night sky. The "Triangle" is the summer’s most prominent asterism and is made up of three stars: Vega, the brightest, Deneb (Cygnus) and Altair (Aquila). In the SW, Arcturus (Bootes) is dropping towards the horizon as Spica (Virgo) vanishes from sight below. Also look for Antares (Scorpius) low in the SW. The stars of constellations Scorpius and Sagittarius, embedded in the "Milky Way" (part of one of the spiral “arms” of our galaxy), are at their best this month. Look for another famous asterism, "the teapot" (Sagittarius). The "Great Square of Pegasus" asterism, now appears on the E horizon just before the onset of morning twilight. These are the stars of autumn that will take over when the northern summer wanes!

MERCURY emerges from inferior conjunction on the 1st, entering the morning sky and reaching greatest enlongation W. on the 22nd. VENUS prominent in the morning sky reaching -4.7 in the constellation of Taurus. MARS opens the month shining at -0.5 mag. By month's end it will rise at midnight and shine at -1.0 magnitude. JUPITER reaches opposition on July 14, shining at -2.7 in Sagittarius. SATURN also reaches opposition in Sagittarius on July 20. URANUS rises in the morning sky, about halfway between Venus and Mars as from the northern hemisphere. NEPTUNE in Aquarius is in the morning sky.

Review how to determine Angular Measurement.

Calendar of Events

NOTE: For those observers not in the ET zone, convert the calendar times to your zone's time by subtracting one hour for CT, two for MT and three for PT. Don't forget to adjust for Daylight Savings Time when necessary by subtracting one hour from your planisphere's time. Dawn and dusk times must also be corrected. See your local newspaper, TV news, or cable TV's Weather Channel for sunrise and sunset times or check with the U.S. Naval observatory. Unfortunately some of these events may occur during daylight hours in your area.

01 Mercury at inferior conjunction.
04 Earth at aphelion, closest to the Sun this year.
05 Penumbral lunar eclipse. Yes, another penumbral eclipse on the same day as last month! Not in the northern hemisphere, but best seen in Argentina, if it can be noticed at all.
This month's full moon is called the "Buck" moon because deer are beginning to grow their antlers.
Jupiter 1.9 deg. N. of Moon. The full moon is low in the sky during the summer months.
06 Saturn 2 deg. N. of Moon.
08 Mars at greatest heliocentric lat. S.
10 Venus greatest illuminated extent.
11 Mars 2 deg. N. of Moon.
Venus at aphelion.
12 Mercury stationary.
Venus 1.0 deg. N. of Aldebaran
Moon at apogee.
13 Mercury at greatest heliocentric lat. S.
14 Jupiter at opposition.
Uranus 4 deg. N. of Moon.
15 Pluto at opposition.
17 Venus 3 deg. S. of Moon.
19 Mercury 4 deg. S. of Moon.
20 Saturn at opposition.
22 Mercury at greatest elongation W. (20 deg.)
25 Moon at perigee.
28 S. Delta Aquariid meteors peak, this shower produces up to 20 meteors at its peak.

Lunar Almanac for July 2020

Phases of the Moon Phase and Date(s) Best viewed before local midnight
new moon New
Deep Space Objects
first quarter moon 1st. Qtr
Planets & Moon
full moon Full
last quarter moon Last Qtr
Deep Space & Planets

Topic of the month: C/2020 F3 (NEOWISE)

NEOWISE C/2020 F3 is a naked eye comet, but you will need a dark sky to see it well. Unfortunately because it is summer in the northern hemisphere, many observers will struggle with the long daylight hours. The comet will probably look best in binoculars and I have even seen pictures of it taken from city streets.

For many astronomers, predicting whether or not a comet will be very bright is a tough challenge. In 2020, Comet C/2020 F3 took astronomers by surprise when it brightened up tremendously after its perihelion visit to the Sun. This sleeper was discovered on March 27, 2020 by the NEOWISE space telescope. The comet was a 16-mag object when discovered. It was 2.1 au from the Sun at that time. It brightened quickly and reached 10th magnitude by the end of April. Perihelion was on July 3 and it will be 0.69 au at its closest approach to Earth around July 22.

As of this writing, the comet has grown a second tail. Observers around the world are posting pictures all over the internet. The comet is heading toward the Big Bear, the astronomical constellation known as Ursa Major. By mid-month, it will visible be all night, although it is low on the horizon.

This starchart below was plotted using the date of July 1, 2020 by Tom Ruen, licensed under CC BY-SA 4.0. I downloaded the image to present here at the Gate. The yellow line represents the ecliptic. The partially filled circles on dates after perihelion help to define the direction of the Sun.

C/2020 f3 neowise comet finder chart by Tom Ruen

Because it's such a timely topic, I've found some links to some good pages on the comet NEOWISE

--See You Under the Stars!
Astra for Astra's Almanac

This installment of "What's Up?" is ©2020 by Dawn Jenkins for Astra's Stargate. View Ron Leeseburg's Farewell Issue for information on where to find information such as is presented in this almanac.

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