Cosmic trio gather in Libra

Ian Griffin
Ian Griffin
I hope that at least least some readers got to enjoy the close conjunction between Mars and Jupiter early last Sunday.

This week, I'm asking you to consider getting up early once again, because there's another magnificent planetary gathering to witness in the hours before dawn on Friday, when the moon, Mars and Jupiter are all in close proximity within the constellation Libra, the Scales.

Babylonian astronomers knew Libra as Mul Zibanu (the ''scales'' or ''balance''), or alternatively as the Claws of the Scorpion. These scales were held sacred to the sun god Shamash, who was also the patron of truth and justice.

Libra is not exactly the easiest collection of stars to pick out, so this week's celestial coming together conveniently presents stargazers with a chance to tick off another constellation on their bucket list.

It also offers an opportunity to spot (and hopefully to say out loud) two of my favourite Arabic names for stars: Zubenelgenubi (which means ''in the scorpion's southern claw'') and Zubeneschamali (which translated from Arabic means ''in the scorpion's northern claw'').

These names reflect the stars' proximity to the constellation Scorpius, which can be seen directly to the southeast of Libra.

Jupiter and Mars both clear the horizon just after 2am and moonrise occurs just over 40min later.

As our chart shows, at 4am on Friday morning, the waning crescent moon will be approximately five degrees (that's the distance subtended by your three middle fingers held at arm's length) away from the yellow/white Jupiter and the red-coloured Mars, with all three objects being inside the boundary of Libra. This cosmic trio will create a highly photogenic triangle low in the eastern sky.

The moon will be 24% illuminated, but even its dark surface should be visible, thanks to the ghostly illuminating effect of earthshine, which, you may remember, is the name given by astronomers to sunlight reflected on to the moon from Earth.

I am sure early-rising photographers will have a field day capturing images of this captivating scene.

-By Ian Griffin

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