Gilbert Rotary Centennial Observatory
- In the Sky for September 2017 -

Source: EVAC September Newsletter

The Moon & Planets: 

  • On Saturday, September 2, the Moon occults two double stars in Capricornus. The first, Pi, happens at 11:09 PM. Pi is listed as magnitudes 5.2 and 8.5, separated by 3 arc-seconds. The second, Rho, happens at 12:18 AM (Sunday). Rho is listed as magnitudes 4.8 and 6.9, separated by 2 arc-seconds. Pi emerges from the bright limb of the Moon at 12:09 AM (Sunday) and Rho at 1:33 AM (Sunday).

  • On Tuesday, September 5, at 6:46 PM, the full Moon rises spoiling any chance of seeing faint fuzzies for the night. As you would expect from last month's total solar eclipse, there is almost an eclipse of the Moon this month and you can expect very at illumination of this full Moon.

  • On Tuesday, September 12, the Moon occults Aldebaran. At 4:48 AM the bright limb of the Moon covers it, at 6:02 AM (during twilight) it reappears. Later that evening the Moon is at last quarter phase and rises at 11:29 PM.

  • On Wednesday, September 13, if you are out between 4:00 and 5:30 AM, you can see the northern part of the Moon at its best. In particular, now would be the time to hunt for those illusive craterlets in the oor of the crater Plato.

  • On Monday, September 18, about 5:30 AM, you can see a lot of objects lined up. Starting at the top, brilliant Venus, Regulus, the very thin crescent Moon, Mars, and Mercury form an almost vertical line. Mars and Mercury are close on September 16. Venus and Regulus are close on September 20.

  • On Tuesday, September 19, it is new Moon and you have all night to hunt for faint fuzzies.

  • On Wednesday, September 27, the Moon is at first quarter phase and sets at 11:34 PM.

Evening Planets (after sunset): 

  • Jupiter, W
  • Saturn, S
  • Neptune, SE

Morning Planets (before sunrise): 

  • Neptune, W
  • Uranus, SW
  • Venus, E
  • Mars, E
  • Mercury, E

Phases of the Moon: 

Phase Date Time Current Moon Info
Full Moon September 6 12:03 AM MT

Description: Description: Description: Description: Click for Gilbert, Arizona Forecast

Last Quarter Moon September 12 11:25 pm MT
New Moon September 19 10:30 pm MT
First Quarter Moon September 27 7:54 am MT


There are no comets brighter than magnitude 8 visible this month.


There no notable meteor showers in September.