Whether you’re a first-time stargazer or professional astronomer, the new Sky Guide Africa South 2017 will undoubtedly broaden your horizons. Wild asked Auke Slotegraaf, editor of the new guide, to highlight 2017’s top five astronomical events.
One of the great pleasures of visiting Wild Card parks and reserves is looking up at the sky at night. Because protected areas are generally far removed from city lights, they offer unrivalled stargazing. In particular, wilderness areas such as the Cederberg, as well as parts of Kruger National Park and Hluhluwe-iMfolozi Park, have almost no light pollution – perfect for astronomy. Protected areas in the drier northwest of South Africa are especially good for stargazing as the dry, clear air improves visibility. Just another reason to visit national parks such as Namaqua, Mokala, Augrabies, Kgalagadi and the Richtersveld.
If you want to make the most of your evenings in our parks and reserves, just look up. Spectacular starry skies are yours to enjoy for free. To make sure you don’t miss out on the most noteworthy sigtings, Wild called on Auke Slotegraaf, editor of Sky Guide Africa South 2017, to highlight the top celestial events.
Now in its 71st year of publication, the new Sky Guide Africa South 2017 offers:
- The year’s planetary movements, predicted eclipses, meteor showers and much more
- Reference charts, illustrations, pictures and tables
- Star charts for each season
- Tips on basic night-sky gazing
Astronomy lovers, mark these events on your 2017 calendar:
The Evening Star shows off
A celestial beacon shining brilliantly in the evening twilight is a great way to start the year, which is exactly what we’re gifted with in 2017. Venus is radiant in the west after sunset, visible each evening from January until early March, earning it the nickname Evening Star. Adding to the picturesque scene is the crescent moon, which lies near Venus at dusk on 1 and 2 January, as well as 31 January, 1 February, and 1 March. After March, Venus moves into the morning sky where it can be enjoyed as the Morning Star. During July, the tiny and rapidly-moving planet Mercury stands in as Evening Star. July is the best time this year to glimpse the little planet. On the evenings of 24, 25 and 26 July, the crescent moon joins Mercury at dusk.
Eclipse of the sun
A solar eclipse – when the moon lies between us and the sun – shows off the dynamic nature of our solar system. On the afternoon of 26 February 2017, as seen from southern Africa and southern South America, the moon partially obscures the sun. The eclipse begins at 14:10 and ends at 19:36.
Sometimes, the Earth’s shadow falls on the moon, and a lunar eclipse can be witnessed. There is one such eclipse during 2017, on the evening of 7 August, but it won’t be particularly striking since the moon just skims the edge of the Earth’s shadow and the subsequent darkening is only slight.
Visit the Astronomical Society of Southern Africa’s website for safe methods to view an eclipse.
When the Earth is located between the sun and the moon, we see the moon fully illuminated with sunlight, hence a full moon. On the day of a full moon, as the sun sets behind the western horizon, the moon is just rising above the eastern horizon. As the twilight deepens into night, the moon seems to loom above the eastern horizon, and is a great opportunity to have a good howl. For an even better view, look the day before full moon: the almost-full moon will then be above the horizon as twilight falls, presenting an excellent photo opportunity with enough light to capture terrestrial subjects with the moon in the background.
But be aware of the ‘moon illusion’! This sneaky optical illusion fools the mind into thinking the moon is much larger than it really is. Your camera, however, isn’t fooled at all, and on a typical photograph of the full moon low on the horizon, the moon appears much smaller than expected. To recreate the massive moon effect with a camera, use a powerful zoom lens and include a distant object in the frame next to the Moon: voila!
As the moon orbits the Earth, it follows an elliptical path, meaning that the distance to the Moon is constantly changing. It takes the moon about 27 days and 8 hours to complete a single orbit. Also, as the position of the moon and sun as seen from Earth changes, the moon appears to go through a cycle of shadow phases, from New to Full and back again. From one phase to the next is about 29 days and 13 hours. This combination of orbital period and cycle of phases – close but not exact – means that Full Moons don’t always happen at the same distance from the Earth. Sometimes the Full Moon is nearer to us than at other times. During 2017, the largest Full Moon is on 3 December and the smallest Full Moon is on 9 June.
Again, don’t be confused by the “moon illusion” – this effect only happens in your mind. The real size of the moon depends on how far away it is. Here’s an experiment: take a photograph of the Full Moon on 9 June, use the same camera settings on 3 December and take a second photograph. Compare them for yourself…
Did you know you can also hunt for the Big Five of the African sky? These are the best examples of each celestial object type – star clusters, nebulae (gas clouds) and galaxies – visible from Africa. The five noteworthy specimens are the Southern Pleiades, omega Centauri (a giant star cluster), the eta Carinae Nebula, the Coal Sack (a nebula), and the southern Milky Way. They can all be seen with the naked eye from a dark site, are outstanding when seen using binoculars, and mind-blowing when observed through a telescope. All five can be seen in the morning sky during April, at midnight during June and in the evening sky during August.
Learn more about the celestial Big Five and how to track them down.
Long dark nights under the stars, surrounded by telescopes, stargazers, and the beautiful cosmos, are what star parties are all about. Astronomy enthusiasts, from beginners to experts, gather at several times in different places to observe the sky, discuss astronomical subjects, and share in the camaraderie of their fellow stargazers.
- Summer Southern Star Party: 22–27 February, Leeuwenboschfontein, Western Cape
- Karoo Star Party: 24–28 April, near Britstown, Nothern Cape
- Free State Star Party: 23–25 June, Brandfort, Free State
- MSP Star Party: 21–23 July, near Rustenburg, North West Province
- Spring Southern Star Party: 18–23 October, near Bonnievale, Western Cape
Visit the Astronomical Society of Southern Africa to find out more about these star parties and how you can take part.
Win a copy
Wild is giving away two copies of Sky Guide Africa South 2017 courtesy of Struik Nature. Email the answer (subject line: Sky Guide) to our question below before 3 December 2016 to stand a chance to win. Remember to include your full names, postal address and contact details. Wild will randomly select the winners. Winners will be notified via email.
Question: Name one of the Big Five of the African sky.
Winners: Brian McQueen, Laurie Kushner
Win a telescope!
Want to win an iOptron Astroboy portable telescope or a selection of Struik Nature books about astronomy? Each Sky Guide Africa South 2017 contains a tear-out entry form. Post your entry by 20 March 2017 for a chance to win. Photocopies will not be accepted.
Auke Slotegraaf is the chair of the Centre for Astronomical Heritage.