Southern Colorado Skies / October 8-14, 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 http://www.stellarium.org/.

THE ANOMALY

The darkness and cold of the winter season can be depressing to some people, but it’s not all bad news for them. Did you know that winter season in the northern hemisphere is actually shorter than summer season? This is known as THE ANOMALY.

Because the Earth orbits in an ellipse and not a perfect circle, it is closer to the Sun in the winter than in the summer (the opposite is true in the southern hemisphere). [Kepler’s First Law: The orbit of a planet is an ellipse with the Sun at one end of the two foci.]

 Also because its orbit forms an ellipse, the Earth travels faster in the winter than in the summer. Therefore, it makes the trip in this part of its orbit in less time. [Kepler’s Second Law: A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.]

 

It’s true! Add up the number of days from equinox to equinox, and you will see that autumn and winter have fewer days than spring and summer, respectively.

THIS WEEK

Thursday (October 12)

First-quarter Moon at 6:27 a.m. MDT.

DAYLIGHT

PLANETS

Mercury (Virgo):

Mercury is hidden in the glare of the Sun this week.

Venus (in Virgo) and Mars (in Leo):

Venus is still a brilliant “morning star” before and during dawn, but it is dropping fast in elevation. Venus appears close to and just above much dimmer Mars – see photo below from last Wednesday – but the two planets are separating fast.

 

Jupiter (in Virgo):

Jupiter is now hidden in the sunset.

Saturn (in Ophiuchus):

Saturn is visible in the south-southwest just after nightfall. (See the graphic from last week’s blog.)

Uranus (in Pisces):

High in the east by mid-evening.

Neptune (in Aquarius):

High in the southeast by mid-evening.

BRIGHT IRIDIUM FLARES

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: http://scaspueblo.com/blog/2017/02/25/iridium-flares/.

Monday (October 9) 5:44:01 a.m. / Magnitude -1.1 / S / Elevation 42 degrees

Monday (October 9) 7:57:12 p.m. / Magnitude -2.8 / NNE / Elevation 38 degrees

Tuesday (October 10) 7:50:59 p.m. / Magnitude -1.3 / NNE / Elevation 41 degrees

Tuesday (October 10) 7:51:36 p.m. / Magnitude -3.4 / NNE / Elevation 40 degrees

Thursday (October 12) 7:38:42 p.m. / Magnitude -1.1 / NNE / Elevation 43 degrees

Saturday (October 14) 5:23:00 a.m. / Magnitude -3.4 / SSW / Elevation 38 degrees

INTERNATIONAL SPACE STATION (ISS)

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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