Southern Colorado Skies / September 17-23, 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


Look for Mercury, Mars, the crescent Moon, Regulus, and Venus on the eastern horizon early in the morning on the 18th.

Monday (September 18)

Venus, Regulus, the crescent Moon, Mars and Mercury line up nearly vertically early this morning in the east. Binoculars will help you see the entire spectacle. (See above graphic.)

Tuesday (September 19)

New Moon at 11:30 p.m. MDT.

Friday (September 22)

Next to the thin waxing crescent Moon is low in the west-southwest during twilight is Jupiter. Look about 7 degrees (a little less than a fist’s width held at arm’s length) to the Moon’s lower right (west).

There is an exceptionally bright Iridium flare this evening. See the details below.

Autumn begins in the Northern Hemisphere at 2:02 p.m. MDT.




Saturday (September 23)

Saturn’s brightest moon, Titan, is about four ring-lengths to Saturn’s west.



Mercury and Mars and Venus (all in Leo):

Mercury is low but bright this week. Look to the east at dawn. Early in the week look for a spectacular planet/Moon/bright star lineup, as discussed above and as shown in the graphic.

Jupiter (in Virgo):

Jupiter is very low on the west-southwestern horizon during sunset and sets as night begins. Look for Jupiter about 7 degrees west of the thin crescent Moon to the west on the evening of September 22.

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 18) 5:38:11 a.m. / Magnitude -2.1 / SSW / Elevation 52 degrees

Friday (September 22) 7:36:11 p.m. / Magnitude -7.9 / N / Elevation 47 degrees


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

Carpe noctem

Dave Furry

Pueblo West, Colorado

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