Sept. 11 - A Rare Sight for S.A.

If you are in Southern Africa this Saturday, September 11th, you will be able to see a rare sight in the sky - and not at night, mind you, but during the day! It is rare as the next time it is predicted to be seen this well is in 2023.

What you will be able to see on Saturday afternoon is an "Occultation of Venus by the Moon", this means that the Moon will pass directly between Southern Africa and Venus. :)

At the moment the planet Venus, known as the 'Evening Star' is bright enough to see during the day but it is difficult to find it in the wide, bright blue sky. Tomorrow though it will be near the Moon and this will make it easier to find. You will have to look carefully to find the Moon as it is a thin cresent at the moment. (see the Moon-phase gadget on the right sidebar of our blog)

In a nutshell, on 11 September you will be able to see ~
*Venus during the day.
*Venus disappearing behind the Moon - an "occultation of Venus" - and then later re-appearing on the other side of the Moon.
*A spectacular early-evening sight: the young crescent Moon just above a brilliantly bright Venus (the "evening star").

Here are some tips from the Planetarium to help you enjoy your Sky watch tomorrow:
Look for the Moon early morning - rising in the east from about 9am (eastern SA) or 10am (western SA). At this time, Venus will be on the dark side (east) of the Moon, about four Moon-widths below and a bit to the right of the Moon.

As the day goes on the Sun and Moon will move across the sky towards the west (due to the rotation of the Earth); the Moon will be about 40 degrees (twice the size of your outstretched spread-out hand) to the east of the Sun. As the day goes by, the Moon will move noticeably towards Venus. Some time during the afternoon (depending on where you live in SA), the Moon will pass directly in front of Venus, hiding it - this is an "occultation".

The occultation will last from a few minutes (for Musina, on the edge of the "occultation path") up to nearly an hour and a half (for Cape Town, nearer the centre of the path).

By evening the Moon will have passed Venus; after the Sun has set, the crescent will be clearly visible for a couple of hours, just above Venus (Venus is the very bright "evening star"). This will be a beautiful sight, and if you have a small telescope, get it out and see if you can see the crescent shape of Venus - it needs a bit of magnification.

Another tip: while looking for Venus during the day, stand in the edge of the shade of a building - this will help you to avoid accidentally looking at the Sun which is very dangerous and could damage your eyes especially if you are using binoculars or a telescope.
The times of the occultation will depend on where in S.A. you are:
* Musina: 3:02 pm to 3:15 pm
* Johannesburg: 2:37pm to 3:41pm
* Durban: 2:43 pm to 3:57pm
* Cape Town: 2:15 pm to 3:41pm
For other towns, see this list http://www.planetarium.co.za/VenusOccultation2010Sep11.pdf

Have a wonderful day, marvelling at the Lord's Creation! :)