this month provides an early evening of a trio of planets: mercury, venus, and mars. venus is the brightest (magnitude -4) of these three as they all shine in the west, disappearing quickly as the sun goes down. here's the view for the evening of monday, september 1st:
the best viewing will be from southern points on earth like australia, south africa, argentina, and southern chile, but folks at northern latitudes should be able to spot these planets with a bit of care and quickness!
the moon moves up and to the left (12 degrees) in the sky each night. although it is a tiny little crescent sliver right now, it will help you find the trio of our three nearest neighbor planets!
the moon passes very nearby the bright star, antares, on september 7th. viewers in south america might see the moon occult antares (or pass right in front of it).
the moon will pass below a bright jupiter on september 9th.... look south.
on september 11, venus is just 0.3 degrees north of mars.
sky & telescope has created a very cool movie (HERE) showing the western horizon and the motion of the planets since the beginning of august all the way thru the end of september! you'll see saturn at the beginning of august, then it disappears below the horizon, while the other three planets approach each other for their closest pass beginning september 13th and going until september 19th. you can check this movie for the alignment of the plants on any given night this month!
this year's harvest moon, the full moon nearest to the autumnal equinox, occurs on september 15th.
on september 20, the moon is a single degree north of the pleiades (M45) star cluster.