SCAS – Southern Colorado Skies / September 11 – 17, 2016

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


Many people think that summer in our northern hemisphere is warmer than winter because the sun is closer to us in the summer; in fact, the sun is closer to us in January, and not by much. Our seasonal changes in warmth are caused primarily by the varying amount of the sun’s energy is spread out over the earth’s surface (another factor, but less important, is the time the sun is above the horizon).


















As you can see from the attached diagrams, the sun’s rays spread less over the ground near Pueblo in the summer than in the winter; therefore, the amount of solar energy reaching the surface per unit surface area (called insolation) is greater in the summer. In the winter the opposite is true and Pueblo receives less energy per unit area which makes it colder outside.


The Summer Triangle is very evident in the early evenings this week, with Vega (in Lyra) nearly at the zenith. Look for Deneb (in Cygnus) to thes east-northeast of Vega, and Altair (in Aquila) ro the southeast.

For early birds this week,  the sky displays the same constellations as it will at dusk next February. Just before dawn Orion is high in the south, Sirius is to its lower left (follow the stars in Orion’s belt downward), and Gemini is high east.

Friday, September 16

Full Moon at 1:05 p.m. MDT.


Mercury (in Virgo)

Hidden by the glare of the Sun.

Venus (in Virgo)

Very low in the west about 20 or 30 minutes after sunset.

Mars and Saturn (both in Ophiuchus)

Mars continues to move to the left (eastward) and away from Saturn and Antares (below Saturn). Look in the south-southwest at nightfall.

Jupiter (in Virgo)

Now out of sight in the Sun’s glare.

Uranus (in Pisces)

High in the southeast after midnight.

Neptune (in Aquarius)

High in the south after midnight.


Alas, there are no particularly bright Iridium flares predicted for this week.


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

Have fun!

Dave Furry, SCAS Director of Education

SCAS rework Logo 3 Color copy

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