Partial eclipse of the Sun on Tuesday

A PARTIAL ECLIPSE WILL BE VISIBLE across Australia on Tuesday afternoon, April 29. It will be highest in the sky in Western Australia, including Perth and Albany, and it will be visible low in the sky near sunset in Melbourne and Sydney.

A small bit of Antarctica, an inaccessible part, will experience an annular eclipse, which occurs when the Moon is a little farther than average from the Earth so that it doesn’t entirely cover the Sun, instead leaving a thin ring of sunlight visible.

Partial solar eclipse

A partial solar eclipse will be experienced across Australia on the afternoon of April 29. Image courtesy Jay Pasachoff.

At an annular or a partial solar eclipse, the sky never gets dark, and to view it directly you must use a special, safe solar filter or project the image onto a wall or screen and then look away from the eclipse at the screen. Don’t be tempted to use ‘backyard’ filters such as looking through exposed film or X-rays – they are dangerous and you can end up blinded.

At Perth and Albany in Western Australia, where the Sun’s diameter will be 60%-65% covered by the Moon, the eclipse will start at 1:15pm local time and end at 3:59pm, with maximum coverage at 2:41pm. This means that the whole event will be visible.

In Melbourne, the eclipse will occur from 3:58pm to and will be about halfway through by the time the Sun sets.

In Sydney, it will start at 4:13pm, and again, the Sun will set while it is still halfway through.

In Adelaide, it will begin at 3:26pm local time, with mid-eclipse at 4:37pm and sunset at 5:34pm.

In Hobart, it will begin at 3:51pm, with mid-eclipse at 5:01pm and sunset at 5:16pm.

In Darwin, it will start at 4:22pm local time, with mid-eclipse at 4:56pm and the end of the eclipse at 5:28pm.

In Brisbane, it will begin at 4:31pm, with mid-eclipse and sunset happening at the same time, 5:17pm.

In Cairns, it will begin at 4:57pm with mid-eclipse at 5:32pm and sunset at 5:58pm.

French amateur astronomer Xavier Jubier has put a Google map online that can be zoomed into, and you can click to find out what you would see from any particular location.

Safe solar viewing

you should never look directly at the Sun, either normally or when there is an eclipse. The Sun’s visible and invisible rays can blind you very quickly. It is particularly important to not use any kind of optical aid to view the Sun — instant blindness will result. Do not use dark glasses, pieces of exposed film and so on — none of these things work.

There are three safe ways to witness a solar eclipse.

First, if you have some special ‘eclipse glasses’ from a previous eclipse, you can use those – as long as they are in good condition and don’t have any holes or scratches.

The second way is to make a ‘pinhole camera’ from two sheets of white cardboard. Using a pin or a needle, punch a hole in the middle of one of the sheets. Then, standing with your back to the Sun, so that the sunlight is coming over your shoulder, with one hand hold the sheet of cardboard with the pinhole in it up to one side of your head. Then with the other hand, hold the other sheet out at about arm’s length in front of you. Arrange it so that the sunlight goes through the pinhole and falls onto the second sheet of cardboard. You’ll see a small image of the Sun on the second sheet. When the eclipse is happening, you’ll see a chunk taken out of the round Sun. Experiment to get the right distance between the sheets of cardboard.

The third way is to view it online, as there will telescopes videocasting it on the internet – see below for details.

Here are some links to information on how to safely view solar eclipses, total or partial, including how to make a pinhole camera:

Solar viewing safety advice from the Queensland government

How to build a pinhole camera

How to build a different kind of pinhole camera

View the eclipse online

Slooh will broadcast the partial phases of the eclipse live from Australia. Viewers can watch free on Slooh.com or by downloading the Slooh iPad app. Coverage will begin on Monday, April 28th, starting at 11pm US PDT on April  28, which is 2am US EDT on the 29th, 6am GMT on the 29th and 4pm Australia Eastern Standard Time.

The live image stream will be accompanied by commentary from scientists. Viewers can ask questions during the show by using the hashtag #Slooh.

The deepest part of the eclipse, where the Moon might be viewed as being completely enveloped by the larger-seeming and more distant Sun, can only be observed from deep within Antarctica, in a remote uninhabited region. This is why this eclipse has been nicknamed the ‘penguin’ eclipse.

A sequence of images showing an annular solar eclipse

A sequence of images showing an annular solar eclipse. Unfortunately, this time, no one will get to see the annular or ‘ring of fire’ parts of the eclipse, but Australians will be treated to the partial phases. Image courtesy of Jay Pasachoff.

Says Slooh astronomer Bob Berman, “Researchers at the Amundsen-Scott South Pole Station will not view any kind of solar eclipse. After all, their long six-month night began over a month ago, and the Sun is below the horizon for them. If they could somehow rise off the icy surface and stretch their necks into space, they’d see a central annular eclipse, as it sweeps into space, narrowly missing our planet.”

“But hundreds of miles farther north, where the very low Sun still sits on the horizon, barely up, well, anyone there would see the Moon covering the slightly larger-seeming Sun behind it. The result is a lopsided, off-centre ring of fire surrounding the inky Moon.”

“However, no human will be in that small region of Antarctica. Thus, this is one of the few annular eclipses that will most likely only be seen by penguins.”

More information:

eclipses.info

totalsolareclipse.org

Melbourne Planetarium

Adapted from information issued by Williams College and Slooh. Images courtesy Jay Pasachoff and Slooh.

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