Observing The Solar System

Written by Shawn Funk

Ever see an unusually bright “star” in the sky and wonder why you might not have noticed it before? Well, you didn’t notice it because it wasn’t there before. Wait. So, stars just appear out of nowhere? No, those aren’t stars. They are the planets in our solar system.

The word “planet” is a Greek word which translates to “wandering star,” in reference to the way planets slowly move across the stellar space-scape, sometimes appearing to move in a retrograde (backward) motion (Bennet et. al., 2014).

Of the eight planets, five are easily seen with the naked eye: Mercury, Venus, Mars, Jupiter, and Saturn.

How to Find a Planet

Planets are among the brightest objects in the night sky. You could easily spot one with a quick scan of the sky. However, an astute enthusiast will refer to the ecliptic line to find objects in our solar system. The ecliptic is the line that our Sun appears to take when it ‘crosses’ the sky; it is also the line where you will find the twelve constellations of the zodiac patterning the stellar backspace. Nearly every object that orbits the Sun can be found within a few degrees above or below the ecliptic line (Dickinson, 2006). Depending on the orbital position of a given planet, it might not be visible at night. Mercury and Venus are only visible at dusk or dawn, while Mars, Jupiter, and Saturn can be viewed throughout the night at specific times of the year. Each planet has distinct visual characteristics that I will note below, making identification very easy.

Lastly, if you know the constellations of the zodiac, you can find information online that will indicate which zodiacal constellation a given planet can be found in. This last approach is very helpful when trying to find the fainter planets, such as Neptune and Uranus, that can’t be seen with the naked eye.

How to Identify the Planets

  1. Mercury:

Of the five, Mercury is the most elusive. Because Mercury is so close to the Sun, glare renders the planet invisible for most of the year. Thus, it is a rewarding observation for any backyard astronomer. Twice a year for about two weeks, Mercury can be seen either rising from the east along the ecliptic just before sunrise or at dusk, plunging toward the horizon after the Sun. Find Mercury in the evening sky close to the horizon after the Sun sets during the last weeks of March 2024 (Dickinson, 2006).

If you miss that date, you can spot Mercury again in the predawn sky rising before the Sun in the first weeks of September 2024 (Dickinson, 2006). If you are using binoculars or a small telescope, try to identify Mercury’s phase. Like the Moon, Mercury and Venus go through phases that can be identified with higher magnifications.

  1. Venus:

Venus is the brightest object in the sky apart from the moon. It is often erroneously referred to as the evening or morning star. Venus is very similar to Mercury in the manner of observation for three reasons. First, the glare from the Sun obscures views of Venus for parts of the year, making observations impossible during that time. Second, Venus orbits close to the Sun, meaning that observations can occur only at dawn or dusk. Lastly, the phases of Venus are observable with a decent telescope. Find Venus rising from the east in the predawn sky until early March 2024.

You will have another chance to see Venus in October 2024 setting in the west (Dickinson, 2006). Remember to look along the ecliptic line.  

  1. Mars:

Mars is easily identified by its rusty red-ochre hue. Unlike Mercury and Venus, when Mars comes out of the glare of the Sun, it is observable for months. However, the brightness of Mars varies greatly depending on its orbital position. Every 26 months, Earth and Mars reach their closest approach; this is called opposition, and it is the best time to observe Mars because it will be at its brightest (Dickinson and Dyer, 2013). Take note that not all oppositions are equal. Because of the elliptical orbit of Mars, the distance between Earth and Mars at opposition can vary greatly (Powell, 2020).

Unfortunately, the next opposition isn’t until January of 2025, but don’t wait to observe it (Powell, 2020). You can find Mars in the Pisces constellation beginning in May of 2024 (Dickinson, 2006).

  1. Jupiter:

Jupiter shines with a creamy brilliance and is the brightest planet next to Venus. Through a cheap pair of old binoculars, the four largest moons of Jupiter, Io, Europa, Ganymede, and Callisto, are observable, appearing as a miniature solar system within the solar system.  Discovered by Galilieo, these moons are referred to as Galilean Moons (Dickinson, 2006). Despite its distance from Earth, details of the planet’s surface, storm bands and moon shadows, and the great red spot can be studied with a small telescope.

Find Jupiter in the zodiac constellation Aries until March 2024, then wait until June where it will reappear in the zodiac constellation Taurus until the end of 2024 (Dickinson, 2006).

  1. Saturn:

While Saturn can be easily seen with the naked eye because of its brilliance, the real show occurs when you put it to some magnification, revealing its spectacular rings. Its colour is like Jupiter, yet much fainter, blending in with some of the brightest stars in the sky. Interestingly, Saturn will appear to lose its rings later this year as it does every fifteen years when Saturn’s rings align edge-on towards Earth, revealing a thin line across the center of the gas giant (Dickinson and Dyer, 2013).

Find Saturn in the zodiac constellation Aquarius as it begins its march across the night sky starting in May 2024 (Dickinson, 2006).

References 

Bennett, Jeffrey, et al. The Cosmic Perspective. 7th ed., Pearson, 2014. 

Dickinson, Terence, and Alan Dyer. The Backyard Astronomer’s Guide. Firefly Books, 2013. 

Dickinson, Terence. Nightwatch: A Practical Guide to Viewing the Universe. 4th ed., Firefly Books, 2006. 

Powell, Martin J. Mars Oppositions from 2012 to 2027, 2020. www.nakedeyeplanets.com/mars-oppositions.htm. Accessed 9 Feb. 2024. 

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