The Night Sky This Month – October 2025
(Looking for last month’s ‘Night Sky’? Find it at this link…)
October offers the best stargazing of the year for observers both north and south. The Milky Way lingers in the southwestern sky while Pegasus and Andromeda dominate overhead and the bright stars of Taurus, Auriga, and Orion emerge above the eastern horizon after midnight. Saturn remains prominent in the evening sky this month while Jupiter and Venus shine brightly in the morning. This October also brings a series of double shadow transits on Jupiter that reward telescopic observation (check your favorite ephemeris or try this link to see the particular timing of these events).
We may also get a chance to see two new comets this month! Discovered by a Ukrainian amateur astronomer from publicly available images from the Solar Wind Anisotropies (SWAN) instrument on the orbiting Solar and Heliospheric Observatory (SOHO), the newly catalogued Comet C/2025 R2 (SWAN) brightened to 7th magnitude and revealed a 2o long tail in mid-September and may reach naked-eye brightness in by the second week of October. And a second comet discovered in January 2025, Comet C/2025 A6 (Lemmon), may grow even brighter as it sails under the Big Dipper through October. Bob King at Sky & Telescope has an update on the position and visibility of these two promising comets.
5 October 2025. Saturn lies about 2.5o south of the waxing gibbous Moon tonight. The planet lies just over the border in Aquarius while the Moon lies in Pisces. Just past opposition last month, Saturn remains in a prime viewing position as it shines at magnitude +0.7. Its rings continue to appear nearly edge-on. Eighth-magnitude Neptune sits about 2o east of the Moon tonight and presents its blue-green hue at moderate magnifications in a telescope.
Oct. 7. Full Moon, 03:48 UT (the full ‘Harvest Moon’). This full Moon falls near perigee which means it appears about 7% larger than average.
13 Oct. Last Quarter Moon, 18:13 UT
14 Oct. The Moon, just past last quarter, make a small equilateral triangle with Jupiter and Pollux in the early-morning sky. The bright and dazzling stars of Orion, Taurus, and Auriga lie further west.
16 Oct. A waning crescent Moon rises about 4° west of the bright star Regulus in the early morning sky.
19 Oct. Look for a thin crescent Moon low in the eastern sky before sunrise along with brilliant Venus about 4o to the east-northeast. Venus has dimmed and shrunk a little as seen from Earth, shining now at magnitude -3.9. Its featureless and nearly full disk has an apparent size of 10.6”.
19-31 Oct. Over the next two weeks, northern-hemisphere observers with very dark sky can see the zodiacal light in the east about 90-120 minutes before sunrise. This whitish wedge of light appears to thrust upward from the horizon towards the constellations Gemini and Cancer. The zodiacal light is simply sunlight reflected off tiny dust particles in the inner solar system.
20-21 Oct. The Orionids, one of the best meteor showers of the year, peak in the early morning hours today. They usually show as many as 20-40 fast-moving meteors per hour in dark sky. These meteors can appear anywhere in the sky and trace their paths back to the radiant near the top of the club of Orion. Maximum activity usually occurs between midnight and dawn. The new Moon offers ideal conditions to see the faintest meteors this year. Like the Eta Aquariids in May, the Orionids are tiny pieces of Comet 1/P Halley that strike the upper atmosphere as the Earth passes through the famous comet’s debris field.
21 Oct. New Moon, 12:25 UT
23 Oct. Mercury makes its best evening apparition of the year in the southern hemisphere. Look for the little planet along with Mars and a slender waxing crescent Moon in the western sky after sunset. The trio make a tight triangle about 5o long. Binoculars help you pull this vista out of the evening twilight. The scene is more challenging for northern-hemisphere observers as the planets lie closer to the western horizon.
24 Oct. Look to the southwest after sunset to see the crescent Moon near the red supergiant star Antares in Scorpius. Observers in Australia and New Zealand see the Moon occult the star – detailed timing at this link.
29 Oct. First Quarter Moon, 16:21 UT