September 2018

Welcome to Observing With Webb, where a high school astronomy teacher tells you what you’re looking at, why it’s so cool, and what you should check out later this month…at night.  Don’t forget to check out my Podbean page, YouTube Channel, and Twitter feed, or get my podcast feed on Stitcher, or iTunes.

Looking for Venus, Jupiter, Saturn, or Mars? This is your last good month to see all of them at the same time. Also, get ready for some longer nights, the astronomical start of Fall, and a shallow dive into Sagittarius, the Summer Triangle, and Cassiopeia.


Naked-eye PLANETS...

  • Around Sunset – Venus (WSW), Jupiter (SW), Saturn (S), Mars (SSE)
  • Throughout the night – Saturn (SW), Mars (SEàSW)
  • Morning – None



  • Get your binoculars out the first week of September around 5:30am – 6am to look east in search of Mercury.


  • Venus enters the final phase of its half-year-or-so long appearance this month. Look West  and find the brightest source of light in that direction, about a fist-width above the horizon. If you have a telescope, you can watch Venus go from half phase to a beautiful big crescent.


  • Mars is already in the SSE around sunset, left of Sagittarius, traveling toward the SW and setting around 2am.


  • Up in the SW around sunset, hanging out in Libra, setting right around 9pm in the WSW.


  • Already up around sunset. Look about 25˚ above the S horizon in evening or low in the SW before midnight, at the top of Sagittarius. Rings are close to maximum tilt.



Last Quarter Moon – 2nd (Visible from midnight into the morning)

New Moon – 9th (darkest skies)

12th Close EncounterMoon, Venus – If you have a clear view of the horizon in the West, you can catch a thin crescent Moon 10˚ above Venus.

13th Close EncounterMoon, Jupiter – Find the Moon around sunset and you’ll also find Jupiter about 5˚ below and to the left, with dimmer Zubenelgenubi (Libra’s brightest star), directly below the Moon.

15th Close Encounter Saturn, Moon, Jupiter, Antares – Find the Moon and you’ll see Saturn off to the left about 20˚, Jupiter to the right about the same distance, and Scorpio’s brightest star Antares below the Moon.

First Quarter Moon – 16th (Visible until midnight)

17th Close EncounterMoon, Saturn – Find the Moon after sunset and you’ll also find Saturn only 4˚ to the right. A great chance to see two really bright objects right near each other, with the teapot of Sagittarius right below.

19th Close EncounterMoon, Mars – Looking for Mars? If you’re out on the 19th, find the Moon and then look about 3 finger-widths below for the red dot that is Mars. It’ll now be getting smaller and dimmer as the months pass by.

22nd– Fall Equinox – When all locations on Earth experience a day of almost exactly 12 hours and a night of almost exactly 12 hours.  It is the astronomical first day of fall, even though meteorologically it typically starts in the beginning of September.

Full Moon – 24th (Visible all night)



(see sky map link at the bottom for a Star Map for this month)   

After Dinner:

Sagittarius – Use binoculars (or even a telescope) and a star chart to scan through the southern constellation of Sagittarius.  Currently the home constellation of Saturn.      There are at least 7 easily visible clusters and nebulas up and to the right of the “teapot” of Sagittarius.

The Summer Triangle: Lyra, Cygnus, Aquila, Delphinus - Look straight up before 10pm and you’ll be able to see Lyra (the Harp), Cygnus (the Swan), Aquila (the Eagle), (and Delphinus the Dolphin.)  These three constellations have the three brightest stars of the summer constellations (Vega, Deneb, Altair – respectively.)  Those bright stars create the summer triangle.  Off to the east of this is the small but beautiful constellation of Delphinus. If you’re under dark skies (away from city lights) you may just catch a glimpse of the Milky Way passing through Cygnus and Aquila.  If you’re looking past 10pm, they’ll be moving toward the West and lower in the sky.

Before Work:

Cassiopeia – Just a few degrees below the zenith, in the North, is the Queen. Just look North and tilt your head almost all the way up, and you’ll see the 5 bright stars that form an M or upside down W in the sky, depending on what font you normally use. The angle on the left will be ALMOST a right angle, with the one on the right being obtuse.

Use a sky map from to help you out.

Share | Download(Loading)