Venus will be the brightest object in the western evening sky as September begins, but will be hard to spot just above the horizon by month’s end.
Before that, however, Venus will be at its maximum brightness at -4.8 apparent magnitude.
Very distant Neptune, so dim at +7.7 magnitude, will reach opposition [opposite the sun in the sky from our viewpoint on Earth] on Sept. 25. This means that it will rise in the eastern sky when the sun sets in the western sky.
Though we cannot see Neptune without optical aid, binoculars should bring it into view.
Neptune will be among the dim stars of Pisces, but brighter Saturn will be just 10 degrees to its east [left]. Drawing an imaginary line down from the left [eastern] side of the Square of Pegasus [above Pisces] will point right to Neptune.
Use binoculars to scan this area for a distinctly blue object among various yellow and white stars around it.
Further help will come from the full moon of September being just to the lower right of Saturn. Neptune will be 10 degrees — the width of a clenched fist held against the sky — to the right of the ringed planet.
Saturn itself will brighten all month as its own opposition approaches in October.
Saturn rises around 9 p.m. above the eastern horizon on Sept. 1 and by 7 p.m. on Sept. 30.
The best time to look for Saturn and Neptune together would be from 10 p.m. to midnight when they are both higher up in the sky. Saturn’s rings will come in clearly with telescopes.
Mars lies among the stars of Gemini the twins in September early, moving into Cancer later in the month.
Mars rises into the eastern sky around 2 a.m. on Sept. 1 and around 1 a.m. on the 30th.
Look for the waning crescent moon to be just above the red planet in the early morning sky of Sept. 6.
Mars will brighten during the month but is still too far away for telescopes to reveal much detail. It will reach opposition in February 2027 when it will be much closer to Earth.
Jupiter also will be found in the pre-dawn eastern sky, rising around 4 a.m. The waning crescent moon will be near it on Sept. 8.
The autumnal equinox occurs on Sept. 23 at 8:05 p.m. Fall officially begins and the sun at noon will be right on the celestial equator [the sky’s equator], which appears at 50 degrees above the southern horizon here at our latitude in Maryland.