Southern Colorado Skies / September 10-16, 2017

Consider a planetarium program to help you plan your observations. There are many commercial products available; an excellent program (STELLARIUM) is available free at


Pegasus and Andromeda are coming into view now – if you’ve never seen the Andromeda Galaxy (M31) now is a great opportunity. M31 is easily visible in binoculars and under dark skies it’s visible without any optical aid – not bad considering it’s 2-1/2 light-years away! (For more information about Messier objects, see my short article at


Look for Mars and Mercury near the eastern horizon early in the morning on the 16th. Mercury will be less than 1/2 degree from dimmer Mars. Binoculars may be required for this appartition, but be careful of the rising Sun! Also, the waning crescent Moon makes an appearance near M44 (The Beehive Cluster) on Saturday, as shown on the graphic.


Tuesday, September 12

The last-quarter Moon occults Aldebaran in the east before and during dawn. Aldebaran disappears on the Moon’s bright limb about 6:05 a.m. MDT and reappears from behind the dark limb about 7:24 a.m. (times are for Denver).

Thursday, September 14

Saturn is at eastern quadrature, which means that it’s 90 degrees east of the Sun in the evening sky. Through a telescope you can see the shadow of Saturn spreading farthest eastward onto the rings behind it, thus giving Saturn a 3-D appearance.

Friday, September 15

Saturn’s major moon, Titan, appears about four ring-lengths to Saturn’s east.

Saturday, September 16

Before sunrise, Mercury will be less than 1/2 degree from Mars, as discussed above.




Mercury and Mars (both in Leo):

Mercury’s brightness more than doubles this week, from Magnitude +0.2 to –0.8, and passes close to Regulus on the morning of September 10th. On September 16th, Mercury will be within 1/2 degree of Mars, as discussed above.

Venus (in Leo):

Look in the east before and during dawn.

Jupiter (in Virgo):

Jupiter is very low on the west-southwestern horizon during sunset and then sets as night begins.

Saturn (in Ophiuchus):

Saturn is visible in the south-southwest after nightfall.

Uranus (in Pisces):

High in the east by late evening.

Neptune (in Aquarius):

High in the southeast by late evening.


The following data are based on my location in Pueblo West, Colorado. If you live well outside this area, you should consider checking this information for your location in order to be assured of accurate times, elevations, etc. If you’re unfamiliar with Iridium flares, check out my article at:

Monday (September 11) 6:11:23 a.m. / Magnitude -4.6 / S / Elevation 56 degrees

Tuesday (September 12) 6:05:19 a.m. / Magnitude -3.3 / S / Elevation 56 degrees


These are too numerous to list here! If you’re serious, load the ISS DETECTOR app on your smart phone or tablet.

Carpe noctem

Dave Furry

Pueblo West, Colorado

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