When a blood moon lights the sky next Saturday morning, the Riverina may have the clearest view.
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So long as the winter frost and fog stay away.
The blood moon will be visible between 5:30 and 7:13 on July 28. It will look different depending on the timezone, but in Wagga, the moon will set at the exact moment when the sun rises.
“The thing about an eclipse is, we all sit it at the same time, but the time of the moon set will vary, depending on where you are and that will effect what you see,” said Melbourne Planetarium astronomer Dr Tanya Hill.
In Wagga, the sun will rise at 7:13, which is the exact moment the moon will be in totality, that’s a pretty neat coincidence.
- Dr Tanya Hill
When the moon sits low on the western horizon, the sun will begin it journey in the east.
A lunar eclipse of this type is created when the moon slips into the earth’s shadow as they orbit together around the sun.
Only once the moon is entirely in the earth’s shadow does the sunlight refract through the earth’s atmosphere to generate the red hue.
“If the earth had no atmosphere, well we wouldn’t be able to live on it, but when the moon falls into shadow, it would just be in shadow. There would be no red,” said Dr Hill.
Lunar eclipses generally last longer than solar eclipses, but next Saturday’s celestial event is expected to be the longest in a century.
It will last one hour and 43 minutes, a nudge shorter than the record one hour and 46 minutes.
The length is thanks to the earth’s ‘aphelion’, and the moon’s ‘apogee’.
“The moon is moving deep through the earth’s shadow, because the earth is orbiting at its furthest point away from the sun, and the moon is orbiting at its furthest point from the earth,” said Dr Hill.
“When that happens, the orbit isn’t steady, it slows as it’s further away and it speeds up as it comes closer.
“The deepest part of the shadow – the Moon’s umbra – that part gets longer and wider and it adds a couple minutes as it moves through the centre.”
This eclipse may also appear larger than other lunar events because of the ‘Ponzo illusion’ and ‘Ebbinghaus effect’.
The brain estimates the size of an object based on the space around it.
“Things look bigger at the horizon,” said Dr Hill.
“Obviously, the moon is the same size it’s always been, but our eyes and our brain tells us the things are bigger in the background than in the foreground.
When the moon is overhead, it’s surrounded by empty space, with maybe a house or a tree in the foreground to make it look bigger. Couple that with the beautiful red and it’s just magical.
- Dr Tanya Hill
The rest of the night’s sky is expected to turn on the works during the eclipse.
“Mars will be sitting above and to the right, and at the moment, it’s at its brightest in 15 years,” said Dr Hill.
“Mars is outshining Jupiter at the moment, and Venus – or the evening star – is also incredibly bright.
“So what we’ll see is the little red planet and the big red moon.”