What's Up in the Night Sky

July 2025 - Vol. 29, No. 7

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 southwest, Arcturus (Bootes) is dropping towards the horizon as Spica (Virgo) vanishes from sight below. Also look for Antares (Scorpius) low in the South. The stars of constellations Scorpius and Sagittarius, embedded in the Summer "Milky Way" are at their best this month. Look for another popular asterism, "The Teapot", made up of the brightest stars of Sagittarius. Also the "Great Square of Pegasus" now appears on the Eastern horizon just before the onset of morning twilight. These are the stars of autumn that will take over when the northern summer wanes!

MERCURY, in the evening sky, favors observers in the southern hemisphere until it reaches inferior conjunction at month's end. VENUS, in the morning sky favors southern observers. MARS, visible in the evening sky, starts the month at +1.4 magnitude and ends the month at +1.6 magnitude. The red planet moves from Leo into Virgo this month. JUPITER returns to the morning sky mid-month. SATURN rises after midnight, reaches its first stationary point on the 14th. URANUS rises in the morning sky with the constellation Taurus. NEPTUNE in the morning sky, reaches its first stationary point on July 5. (You'll need a telescope to observe Neptune.)

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	Mercury 1.5 deg. S. of Beehive cluster (M-44.) Earth at aphelion. Alpha Virginis, Spica, 0.8 deg. N. of Moon, occultation from easternmost Polynesia, S. part of S. America, and most of Antarctica.
04	Venus at greatest heliocentric lat. S. Venus 2 deg. S. of Uranus. Mercury at greatest elongation E. (26 deg.)
05	Moon at apogee. Neptune stationary.
07	Alpha Scorpii, Antares, 0.4 deg. N. of Moon, occultation from S. tip of Africa, Kerguelen Is., E. Antarctica, and SW Australia.
10	July's full moon is often called the "Buck Moon" because it is the time of year that young buck deer begin showing antlers in North America.
14	Saturn stationary.
15	Mercury at aphelion.
16	Saturn 4 deg. S. of Moon. Neptune 3 deg. S. of Moon.
17	Mercury stationary.
20	Moon 0.8 deg. N of the Pleiades star cluster (M-45). Moon at perigee.
23	Jupiter 5 deg. S. of Moon.
25	Pluto at opposition.
26	Alpha Leonis, Regulus 1.3 deg. S. of Moon, occultation from SE Iceland, Faroe Is.
28	Mars 1.3 deg. N. of Moon, occultation from westernmost Antarctica.
29	S. Delta Aquariid meteors peak, this shower produces up to 20 meteors at its peak.
31	Alpha Virginis, Spica, 0.5 deg. N. of Moon, occultation from extreme SW. tip Australia, Kerguelen Is., most of Antarctica.

Lunar Almanac for June 2025

Phases of the Moon	Phase and Date(s)	Best viewed before local midnight
	New 24	Deep Space Objects
	1st. Qtr 02	Planets & Moon
	Full 10	Moon
	Last Qtr 17	Deep Space & Planets

Topic of the month: Boötes and Corona Borealis

As night falls in the Spring sky a bright northern star appears in the East. Truly the brightest star in the northern sky, Arcturus boasts of −0.05 magnitude. Throughout the evening, Arcturus marches prominently across the sky as Spring gives way to Summer. Its home is the constellation of Boötes, a kite-shaped constellation, referred to as "The Herdsman" or sometimes "The Plowman". Stargazers can find it by following the "arc" of the stars on the handle of "The Big Dipper" by the memorable instructions, "arc to Arcturus."

Arcturus and Boötes have colorful history. The name Boötes comes from the Greek word for herdsman. This is an ancient name for the constellation as later skywatchers also called the constellation, the "bear watcher", no doubt because it is close to the constellation Ursa Major (the Great Bear.) There are few interesting astronomical objects in this area because the constellation is far from the plane of the Milky Way galaxy. A small globular cluster, NGC 5466 can be found in the constellation, shining at 9.7 magnitude.

Another nearby constellation is Corona Borealis, also known as the "northern crown." The brightest jewel in the northern crown is the second magnitude star, Alphecca. Alphecca is the alpha star of the constellation and is also known by another name, Gemma. Alphecca has a magnitude of 2.2. A semi-circle of seven stars form a small crown-shaped constellation. It is fairly easy to spot from a dark site.

The Herdsman and the Crown — Corona Borealis and Boötes

finder chart for T Corona Borealis — T Corona Borealis Finder Chart

Corona Borealis has attracted astronomers' attention recently, as a recurrent variable star exists in this constellation. The star, T Corona Borealis is expected to brighten suddenly, up to magnitude 2.0. Although it was thought the star would erupt before September 2024, but that hasn't happened yet. Popularly called, "T Cor Bor", it's normally about 10th magnitude. Because of these outbursts, the star is known as the "Blaze Star"

In July of 2024, Astra's Stargate monthly topic covered the Blaze Star. That article includes a large finder chart and more information. Go to the article The Blaze Star, Awaiting the Outburst of T Coronae Borealis by following the link. Even from the city, a pair of binoculars can be used to discover whether or not the nova has occurred. When the news of its nova spreads over the internet, make sure you look quickly because it will only shine bright enough to be seen by the naked eye a short time.

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

The star chart above was generated by Stellarium, a free open source planetarium program. The above image was created by Dawn Jenkins, using Stellarium and a graphic editing program to format the image for this web page. Editing was done for educational purposes only. Stellarium offers much more to amateur astronomers and is being used in planetariums and to guide telescopes in the field. Simple charts like the one above can be used on the internet for non-profit, illustration purposes. Proper credit is due of course! Thank you to the makers of this fine program from Astra's Star Gate.