What's Up in the Night Sky

August 2024 - Vol. 28, No. 8

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). Scorpius and the bright star Antares occupy the southern sky. Look for another famous asterism, "the teapot" (Sagittarius). 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.

MERCURY returns to the Sun this month, reaching inferior conjunction on the 19th. VENUS continues to rise in the evening sky, although it will not be visible for most northern latitude observers. MARS is in Taurus, rising earlier in the morning sky, has a close conjunction with Jupiter on the 14th. JUPITER in Taurus, continues to rise in the morning twilight. SATURN rises in the evening sky, heading toward next month's opposition. URANUS rises around midnight. NEPTUNE resides in Pisces, heading for oppositon on September 21 (autumnal equinox.)

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.

DATE	EVENT
03	Alpha Geminorum, Pollux, 1.8 deg. N. of Moon.
04	Mercury stationary. Venus 1.1 deg. N. of Alpha Leonis, Regulus.
05	Venus 1.7 deg. S. of Moon.
09	Moon at apogee.
10	Alpha Virginis, Spica, 0.7 deg. S. of Moon, occultation from parts of E. Europe, western Russia, most of Asia, northern Indonesia, S. Japan, and western Micronesia.
12	The Perseid meteor shower peak occurs when the Moon is at first quarter, setting around midnight. The meteors are the result of dust ejected as Comet 109/Swift-Tuttle has crossed Earth's orbit repeatably over many thousands of years. Our atmosphere encounters these particles at about 37 miles per second causing the streaks of light we enjoy every August.
14	Alpha Scorpii, Antares, 0.004 deg. N. of Moon, occultation from Micronesia, Melanesia, Polynesia (not New Zealand or Hawaii), and the Galapagos islands. Mars 0.3 deg. N. of Jupiter.
16	Mercury at greatest heliocentric latitude S.
19	Mercury in inferior conjunction. August's full moon is often called the "Sturgeon Moon" because it is the time of year that lake sturgeon were very abundant and easy to catch in the Great Lakes and Lake Champlain in North America. Unfortunately, they are nearly extinct today but, conservation efforts are helping to restore their numbers.
20	Asteroid Vesta in conjunction with the Sun.
21	Moon at perigee. Saturn 0.5 deg. S. of the Moon, occultation from northern S. America, Galapagos Is., S Central America, Cape Verde Is., Azores, northwest Africa, and most of Europe. Neptune 0.7 deg. S. of Moon, occultation from north and central Africa, Middle East, parts of Europe, northwestern China, most of Mongolia, and most of Russia.
26	Moon in the Pleiades star cluster (M-45). Uranus 4 deg. S. of Moon. Asteroid Ceres stationary.
27	Jupiter 6 deg. S. of Moon.
28	Mercury stationary. Mars 5 deg. S. of Moon.
30	Alpha Geminorum, Pollux, 1.7 deg. N. of Moon.

Lunar Almanac for August 2024

Phases of the Moon	Phase and Date(s)	Best viewed before local midnight
	New 04	Deep Space Objects
	1st. Qtr 12	Planets & Moon
	Full 19	Moon
	Last Qtr 26	Deep Space & Planets

The Blaze Star, Awaiting the Outburst of T Coronae Borealis

Astronomers call it, "Blaze Star" because of its volatile nature, it seems to produce a nova about every 80 years. Ordinarily a tiny 10th magnitude star in a small northern constellation, T Corona Borealis (aka T CrB) is a legend among variable star observers. It was discovered as a nova star in May of 1866 by three astronomers and soon after spectroscopic analysis was used to separate it into two components. This double star pair consists of a white dwarf and a red giant star that are located about 3000 light years from earth. It is believed the white dwarf pulls matter off of the aging red giant, building up an accretion disk around the white dwarf until the material compresses and ignites a runaway nuclear explosion. During nova phase, T CrB rises to 2.0 magnitude, observable by the naked eye in a dark sky. The two stars are known to have a period of 227.57 days, but it is disrupted by the nova phase.

The Blaze star is labeled T in the constellation of Corona Borealis, the northern crown. It is small semi-circle of stars, most of them around 4th magnitude, except for the alpha star that is the brightest jewel of the crown, called "Alphecca" or (my favorite) "Gemma". Alphecca is the brightest star of the constellation, shining at 2.2 but when T CrB hits its temporary magnitude of 2.0, it outshines Alphecca. This does not last long and ten hours later, the brightness begins to fade. To enjoy this special reoccurring nova, observers need to look for Corona Borealis and study its normal appearance so they can identify the nova star.

As soon as twilight ends and the sky is dark this month (~10 pm local time in mid-North America) Corona Borealis can be found directly overhead. We have provided a finder chart, showing Corona Borealis between the constellations of Boötes and Hercules.

finder chart for Corona Borealis — Corona Borealis Finder Chart

T Corona Borealis (may be called, "T-Cor-Bor") is expected to erupt sometime before the end of September 2024, but the actual date is unknown. If you haven't started looking for it yet, go out and find the northern crown constellation and study it so you can enjoy the sight of a "new star"!

The observations that have given us the information of the T Corona Borealis is largely gathered by amateurs astronomers and others that are members of the American Association of Variable Star Observers (AAVSO). If you are interested in contributing, they would be happy to help you get started.

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