Solar eclipses

SOLAR ECLIPSES

Partial Solar eclipse
Tuesday 29 April, 4:00pm – 6:00pm

Partial solar eclipse

WARNING: It is very dangerous to look directly at the Sun, especially through binoculars or telescopes, even during an eclipse. SERIOUS EYE DAMAGE MAY RESULT.

Today, in Sydney will see the Moon take a bite out of the Sun in a partial eclipse of the Sun. This happens when the Moon moves in front of the Sun but only partially blocks it out. From Sydney we will see about an hour of the eclipse before the Sun sets (weather permitting). From Sydney, the eclipse begins at 4.14pm, maximum eclipse is at 5.15pm (52% width of the Sun), and the Sun will set at 5.17pm.

The event to see the eclipse at Sydney Observatory using special solar filters on binoculars and telescopes and special eclipse glasses is fully booked but we are planning to live stream video of the eclipse here.

In the case that our website goes down due to the high number of visitors keen to see this exciting astronomical event, you can get updates about the eclipse on Sydney Observatory’s Twitter (@sydneyobs) and Facebook accounts (sydneyobservatory).

Or you can try the live streams from the following websites:
Virtual Telescope 2
Perth Observatory
Slooh live event

Fun Sun facts
- The last partial solar eclipse visible from Sydney was seen on 10th May 2013.
- During a total solar eclipse the Moon completely blocks out the Sun.
- The next total solar eclipse to be visible from Sydney will be on 22nd July 2028.
- An annular solar eclipse can happen when the Moon is at it’s farthest from the Earth in its orbit, and it does not block the sun completely. Then when the Moon appears centred on the Sun we can see the so-called ‘Ring of Fire’ effect.
- The plane of the ecliptic (the path the Sun takes across the sky) is so called because eclipses can only occur when the Moon crosses that plane.

How solar eclipses occur
A solar eclipse occurs when the Moon, in the course of it’s orbit around the Earth, casts it’s shadow on to the Earth. When viewed from the surface of the Earth the Moon blocks all or part of the Sun’s disc. Only by observing from within the cone-shaped umbra of the Moon’s shadow can we see the Sun’s disc completely obscured; from within the lighter penumbra at least part of the Sun remains visible and we witness only a partial eclipse.

Annular or partial solar eclipse

Annular or partial solar eclipse; image courtesy Astronomical Society of Australia’s factsheet #26

Although a solar eclipse of some kind occurs somewhere on Earth at least twice each year,
in only some of these events does the Moon completely cover the Sun; usually the umbra misses the Earth altogether, passing ‘above’ or ‘below’ our planet. Even when the umbra does intersect the Earth, we are very close to its end where the width of the shadow is very small. So as the Moon’s shadow moves from west to east across the Earth’s surface due to the orbital motion of the Moon, it traces out a quite narrow path – at most about 270 km wide.

Here is a fact sheet produced by the Australian Astronomical Association to help you better understand Solar eclipses.

Total eclipse of the Sun
22 July 2028

Should you be in Sydney on 22 July 2028 at 2.00pm you can view a total eclipse of the Sun. For 3 minutes and 50 seconds the Moon will fully cover the Sun, called totality, turning daytime into night time. This event is rarely visible from a large city like Sydney because large cities are less likely to be in the direct line of the eclipse than smaller towns from which the total eclipse could be visible. This is simply because there are many more smaller towns than there are larger cities, so a larger number of smaller towns would have the potential for a view of the total eclipse. Interestingly a similar eclipse happened on 26 March 1857. The astronomer Rev. William Scott travelled to South Head at the entrance to Sydney Harbour. At 6:50am he tried to observe the eclipse, for the 3 minutes that the Moon fully covered the Sun. As sunrise was at 6.00am, the Sun was only 9 degrees about the eastern horizon. Luck was not on his side as clouds made it impossible to directly view the eclipse.