Today’s Astronomical Events – August 5th, 2015

The planets have been orbiting the Sun for billions of years. Each planet orbits our parent star in an anti-clockwise direction but at different distances and at different speeds. Consequently, each night presents us with a different scene, depending upon where each planet is in relation to the Earth.

Both Mercury and Venus orbit closer to the Sun and are known as the “inner” planets. Consequently they’re never visible at midnight and, at best, they can be seen in either the evening or the pre-dawn sky. Both planets orbit the Sun more quickly than the Earth; Mercury takes just 88 days while Venus, farther out, takes slightly less than 225.

Mars is the first of the “outer” planets, so-called because it orbits at a greater distance from the Sun than the Earth. Unfortunately, it currently appears too close to the Sun to be visible in even the pre-dawn sky but since it moves at a slower pace, the Earth will catch up to the red planet and it will slowly become visible in the pre-dawn sky.

As the gap between Earth and Mars closes, Mars will rise earlier and earlier and will eventually become visible at midnight. How long will this take? About ten months… it will be May 22nd next year before it is at “opposition” (i.e., when it is opposite the Sun in the sky.) At that point, it will rise at sunset and set at sunrise and will therefore be visible throughout the night.

As for the other outer planets – Jupiter, Saturn, Uranus and Neptune – Jupiter is hiding behind the Sun, Saturn is easily visible in the evening sky, Uranus can be seen in the pre-dawn sky and Neptune is almost at opposition. Observers with a telescope can enjoy the distant blue world throughout the night around September 1st.

(Click on an image to enlarge. Adapted from 2015: An Astronomical Year, available in Kindle and paperback formats from Amazon in the US, Canada and the United Kingdom.)

Images courtesy of Mobile Observatory.



01:14 UT – The waning gibbous Moon passes asteroid 4 Vesta. (Vesta: magnitude 6.7. Cetus, pre-dawn sky.)

09:49 UT – Mercury appears 8.2° north of Venus. (Mercury: 90% illuminated, magnitude -0.8, diameter 5.1”. Venus: 4% illuminated, magnitude -4.2, diameter 54.8”. Leo, not visible.)

11:29 UT – The waning gibbous Moon passes Uranus. (Uranus: magnitude 5.8, diameter 3.6”. Pisces, pre-dawn sky.)

Mars leaves Gemini and enters Cancer. (99% illuminated, magnitude 1.7, diameter 3.6”. Not visible.)



Events in bold involve objects and/or events that are visible with the naked eye.

All times are in Universal Time (UTC). To convert the time to your timezone, click here.

2015 An Astronomical Year (Kindle Edition) 2016 An Astronomical Year Paperback Cover 2016 The Night Sky Sights The Astronomical Almanac 2015-2019

2015: An Astronomical Year

2016: An Astronomical Year 2016: The Night Sky Sights The Astronomical Almanac (2015-2019) The Amateur Astronomer’s Notebook (Pocket Edition)

(Kindle & Paperback)

(Kindle & Paperback) (Kindle & Paperback) (Kindle & Paperback)


Amazon – US

Amazon – US Amazon – US Amazon – US Amazon – US
Amazon – UK Amazon – UK Amazon – UK

Amazon – UK

Details of all available books across the world can be found here or by visiting the author’s page on Amazon. If you have any comments or questions, please feel free to contact me at astronomywriter “at”


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