Partial solar eclipse in Cape Town

Yesterday, the morning sky was brilliantly blue and almost entirely free of clouds. It could hardly have been more perfect weather to watch the first solar eclipse of 2009, while welcoming in the International Year of Astronomy. It also happened to be the last big solar eclipse visible in the Western Cape, with approximately 65% coverage of the sun, for at least the next 7 years, so we didn’t want to miss this opportunity.

Poster of IYA 2009

Poster of IYA 2009

We grabbed a quick breakfast and raced down to the South African Astronomical Observatory in, well, Observatory. ‘Raced’ was not entirely correct, as it was 07h30 and half of Cape Town was already on the N2 heading into town. We eventually parked on the small parking lot outside the gates and signed in at the entrance, where we received a handful of pamphlets and two yellow solar viewers.

The SA Astronomical Observatory

The SA Astronomical Observatory

By now we’d missed all the speeches, by Dr Enrico Olivier (a brief talk about the eclipse), Prof Phil Charles, the director of the SAAO (‘Eclipse: first contact’), and the Keynote Address by Mosibudi Mangena, the Minister of Science and Technology:

Programme of speeches

Programme of speeches

Things were happening at several venues all around the grounds of the SAAO:

Map of the grounds

Map of the grounds

We headed down to a little round building, which houses an odd-looking contraption that is apparently called a heliograph (although it’s not used for signalling, like the heliographs described in the Wikipedia). It uses mirrors to project an image of the sun onto a screen, so that you can see the eclipse quite clearly. Unfortunately, we didn’t get a photo of the image as there were so many people inside the small space, waiting their turn. (I just saw a photo of the heliograph’s screen here, and I’ll copy it below). But this is what the contraption looked like:

Heliograph

Heliograph

Looking up

Looking up

Projection on monitor

Projection on monitor

From here we drifted through the auditorium, where a couple of colourful posters were on display, explaining what an eclipse is and how it can be viewed safely.

Colourful poster

Colourful poster

There was also a model of the South African Large Telescope (SALT), which is:

“the largest single optical telescope in the southern hemisphere, with a hexagonal mirror array 11 metres across. Although very similar to the Hobby-Eberly Telescope (HET) in Texas, SALT has a redesigned optical system using more of the mirror array. It will be able to record distant stars, galaxies and quasars a billion times too faint to be seen with the unaided eye – as faint as a candle flame at the distance of the moon.”

Model of SALT

Model of SALT

On a small grassy area beyond the auditorium, we found the Radio Astronomy Telescopes, where Richard’s colleagues from work were using two of the PED dishes to track the sun. The Phased Experimental Demonstrator (PED) is a test radio telescope interferometer constructed by the Karoo Array Telescope (KAT) team (website of the Square Kilometre Array South Africa) during 2007 at the SAAO.

PED dishes

PED dishes

Adriaan from the KAT office was explaining to a couple of school children what radio astronomy is and what science they are trying to do with it. He also explained about the radio astronomy reserve that has been created in the Northern Cape, where the KAT and MeerKAT dishes will be erected over the next couple of years.

Explaining radio astronomy

Explaining radio astronomy

At 08h15 the eclipse was at its maximum, and we got a really nice photo of the moon’s shadow across the sun. Richard held the solar viewer right in front of the camera lens, and used the little fold-out monitor to focus the image:

Eclipse through solar viewer

Eclipse through solar viewer

On the lawns near the McClean telescope, we gazed through a solar telescope. The lens was covered with something that looked alarmingly like tinfoil, but the young astronomer on duty reassured us that it wasn’t tinfoil but a specially manufactured material that made it quite safe to stare into the sun. Gulp…  I have a deep-seated phobia of looking at the eclipse even through ‘accredited’ and ‘safe’ solar viewers – excluding bizarre suggestions like the tin-foil from teabags, and the material you get inside floppy disks (!) – so I was seriously apprehensive of looking through this telescope.

Solar telescope

Solar telescope

Right next to it, we saw this cute little thingamajig called a Sunspotter. I loved it! Calling itself “The safer solar telescope”, this was the perfect gadget for me! And you can so clearly see the shadow of the moon moving across the sun! (I even found a website that explains how you can build your own!)

The sunspotter

The sunspotter

According to the text on the solar viewer, the next solar eclipses in South Africa are:

  • 2009 Jan 26 – 07h10 am – 09h30 am – 25% (Limpopo) to 60% (W Cape) partial eclipse for all SA
  • 2010 Jan 15 – 07h00 am – 08h00 am – 15% (Limpopo) to 3% (Free State) partial eclipse for North East SA
  • 2011 Nov 25 – 06h30 am – 07h00 am – 3% partial eclipse for W Cape
  • 2013 Nov 3 – 15h30 pm – 16h30 pm – 10% (Limpopo) to 2% (Free State) partial eclipse for Northern SA
  • 2015 Sep 13 – 06h45 am – 08h30 am – 10% (Limpopo) to 30% (W Cape) partial eclipse for all SA
  • 2016 Sep 1 – 09h30 am – 12h00 noon – 20% (W Cape) to 45% (Limpopo) partal eclipse for all SA

Websites:

  • Introduction to today’s solar eclipse
  • Video clip about today’s solar eclipse
  • Moonshadow website about solar eclipses
  • A couple of photographs of the event at the SAAO
  • And if you’re curious about learning more about astronomy, the SAAO is running a series of public lectures. Click here for more.

What an interesting and educational morning this had been!

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