July Skies by Dick Cookman

Highlights:  Comet Journal, Martian Landers, Meteor Showers, Planet Plotting, July Moon 

Focus Constellations: Ursa Major, Ursa Minor, Draco, Cepheus, Cassiopeia, Camelopardalis, Lynx, Leo Minor, Leo, Virgo, Coma Berenices, Bootes, Ophiucus, Hercules, Lyra, Aquila, Cygnus 

  • Comet Journals 

Comets C/2023 E1 (ATLAS) and C/2021 T4 Lemmon are at 8th magnitude in July skies. The former is an inner Kuiper Belt object and is currently in Ursa Minor. It will circuit through northern hemisphere skies and will reach Cepheus by the 31st. It will pass perihelion on July 1 and be closest to Earth on August 18. Comet Lemmon is an Oort Belt comet. It is in Sculptor in southern hemisphere skies and will be closest to Earth on July 20 and then pass perihelion on the 31st. It will enter northern hemisphere skies at the end of the year as it retreats into the outer solar system.

  • Mars Landers

Despite the rover and satellite evidence for Martian underground ice, polar ice, and water bearing minerals, no liquid water has been found on the planet. Yet copious evidence for water erosion in the many gullies and canyons found on the planet raises questions about how they were formed. Current understanding of Martian climate history favors an early episode of a warmer and wetter climate with lakes, rivers, and possibly, oceans. Then, about 3 billion years ago, drier and colder conditions accompanied by massive decrease in atmospheric density prevailed. How then did all the gullies and canyons of apparently relatively recent origin develop? 

Like Earth, Mars has long term orbital and orientation changes. Earth’ s variation in orbital eccentricity, rotation of its elliptical orbit, and variation in tilt of its axis appear to influence the twentyfold advances and retreats of glaciers in the last two million years. 

Mars has much more drastic orbital/axial variations. Instead of Earth’s paltry 21.5 to 24.5 degree variation in axial tilt over 40,000 years, the absence of a stabilizing large moon and the gravitational influence of giant Jupiter causes Mars to undergo a 15 to 35 degree variation in axial tilt over 2.5 million years. At the latter extreme, Brown University researchers conclude that the poles could be bathed in sunlight causing them to sublimate H2O and CO2 greenhouse gases into the atmosphere within the last few hundred thousand years, creating a denser, warmer, more humid atmosphere possibly producing sufficient rain to develop erosive water flows.

  • Meteor Showers

July 9: Pegasids. Active July 7-13. Radiant 22h40m +15°. ZHR 3. 70 km/sec. 1st Quarter Moon. Progenitor: C/1979 Y1 (Bradfield).

July 28: Delta Aquarids Active July 12-Aug 19. Radiant 22h36m -16°. ZHR 20. 41 km/sec. Waning Crescent Moon. Progenitor: Comet 96P / McCholtz

July 30: Alpha Capricornids Active July 3-Aug 15. Radiant 20h28m -10°. ZHR 0 to 100+. 23 km/sec. Waning Crescent Moon. Progenitor: Comet 169/P Neat

  • Planet Plottings

July pre-dawn planets includes Uranus (+5.8) in Aries, Jupiter (-2.1 to -2.2) in Aries, Neptune (+7.9) in Pisces, and Saturn (+.08 to +0.6) in Aquarius. From Uranus above the eastern horizon and brilliant Jupiter dominating the southeastern sky, to dim Neptune in the south, and Saturn high in the southwest, the sky is bespeckled with the outer gas giant planets. Saturn is visible all night long, rising soon after sunset. The other giant planets rise in the evening and are best viewed before dawn.

The inner terrestrial planets rise after the Sun and appear in evening skies. Venus (-4.3 to -4.1) is at its brightest for 2023 on the 9th, and is within 5.0° of dimmer Mars (+1.7 to +1.8) on the 26th when they are just above the western horizon in Leo after sunset. After its superior conjunction with the Sun on the 1st, Mercury joins Venus and Mars during the last third of July, when the inner planets get together in Leo.

From the 6th to the 12th, the waning Moon passes the outer planets, then the waxing crescent passes the inner planets on the 19th and 20th.




Planet Passages




Taurus, Gemini


New Moon

2:32PM EDT



Gemini, Leo

-2.1 to +0.1

Superior Conjunction

Venus, 5.0°S

1:00AM EDT

9:00AM EDT





-4.3 to -4.1

Mercury, 5.0°N

9:00AM EDT




+1.7 to +1.8



-2.1 to -2.2



+0.8 to +0.6




Venus, 1.6°N

9:00AM EDT




+7.9 to +7.8

  • July Moon

July’s New Moon in Gemini on the 17th at 2:32PM EDT marks the start of Lunation 1244, which ends 29.63 days later with the New Moon of August in Leo on the 16th at 5:38AM EDT. The Full Moon is in Sagittarius on the 3rd at 7:39AM EDT. The July Moon is called the “Thunder, or Hay Moon” . It was called the “Mead Moon” in Medieval England and for Celts it was the “Moon of Claiming”. In China, it is the “Hungry Ghost Moon”. Colonial Americans called it “Summer Moon”. Anishnaabe (Odawa and Ojibwe) first people recognize the 7th Moon of the year as the Flower Moon and as “Miin-giizis” (Berry Moon).
Earth Haven Farm in Ontario documents the cultural teaching which explains the cycle of life and nature of the July Grandmother Moon of Creation as follows: “The seventh moon of Creation is Raspberry Moon, when great changes begin. By learning gentleness and kindness, we may pass through the thorns of its bush and harvest its fruit, knowledge that will help in raising our families.”
Lunar Perigee distance (minimum lunar distance) is 223,786 mi. (56.47 Earth radiil) on the 4th at 6:25PM EDT. Lunar Apogee (maximum lunar distance) is on July 20 at 2:57AM EDT when the Moon’s distance is 252,456 mi. (63.70 Earth radii). A waning gibbous Moon appears to pass Saturn on the 6th and Neptune of the 8th. The waning crescent passes Jupiter on the 11th and Uranus on the 12th. The waxing crescent passes Mercury on the 19th, and Mars and Venus on the 20th.




Moon Passages

Moon Phase

Moon Age

Sun Gemini


2:32PM EDT, 7/17 New 0 Days
Mercury Cancer


4.0°N, 5:00AM EDT, 7/19 Waxing Crescent 1.60 Days
Venus Leo


8.0°N, 5:00AM EDT, 7/20 Waxing Crescent 2.60 Days
Mars Leo


3.0°N, Midnight EDT, 7/20 Waxing Crescent 2.39 Days
Jupiter Aries


2.0°N, 5:00PM EDT, 7/11 Waning Crescent 23.68 Days
Saturn Aquarius


3.0°S, 11:00PM EDT, 7/6 Waning Gibbous 18.93 Days
Uranus Aries


2.0°N, 2:00PM EDT, 7/12 Waning Crescent 24.56 Days
Neptune Pisces


1.7° S,10:00AM EDT, 7/8 Waning Gibbous 20.39 Days