You’ll see red tonight!

Grocott's Mail - - OUTSIDE - By STEVEN LANG

South Africans will be treated to a rare to­tal eclipse of the moon on Fri­day night, and for­tu­nately, skies over Makana are ex­pected to be cloud-free dur­ing most of the eclipse.

The full moon will rise just after sun­set in the evening and then at 7:13 pm, it will start mov­ing into the par­tial (penum­bral) shadow of the Earth. At first you may no­tice the moon dim­ming in the lower part of its disc as less sun­light is re­flected off the east­ern part of our clos­est ce­les­tial neigh­bour.

At 8.24pm the moon will ap­pear to change shape as it starts mov­ing into the full shadow (um­bral) of our planet. The shadow will creep over the moon’s sur­face un­til 9:30 pm when it will be to­tally eclipsed. The shadow of the Earth will com­pletely cover the face of the moon and it will re­main cov­ered un­til 11.13pm.

This means that if there hap­pens to be clouds in your area at the be­gin­ning of the eclipse you will have just over two hours to wait for a clear­ing.

The moon will leave the Earth’s um­bral shadow at 00:19 am on Sat­ur­day and by 01.30am it will be fully lit as it leaves the Earth’s penum­bral shadow.

The eclipse will last for three hours and 55 min­utes, mak­ing it the long­est eclipse of this cen­tury.

Even though this type of event is known as a to­tal eclipse, because the en­tire sur­face of the moon facing Earth will be cov­ered, it will not be com­pletely dark – in fact it will ap­pear as a red­dish cir­cle. Some­times peo­ple re­fer to the phe­nom­e­non as a ‘blood­moon’ because of the red tinge.

The bloody cir­cle is caused by the sun’s rays that bend through the Earth’s atmosphere as they move to­wards the moon. Our atmosphere, laden with dust and ash par­ti­cles, af­fects red light more than blue light, hence the moon takes on a red­dish hue.

Luck­ily, un­like a so­lar eclipse, you do not need any spe­cial eqip­ment to ob­serve a lu­nar eclipse.

You will see it per­fectly well with the naked eye, but a pair of binoc­u­lars could make it more ex­cit­ing.

If you are keen on tak­ing pho­to­graphs, it is ad­vis­able to use a tele­photo lens and a tri­pod. If you do hap­pen to take some spe­cial pho­tos of this spec­tu­aular event, please send them to Gro­cott’s Mail so that we can pub­lish them on our web­site.

For in­for­ma­tion on this, and other fas­ci­nat­ing as­tro­nom­i­cal ob­ser­va­tion op­por­tu­ni­ties, visit the As­tro­nom­i­cal So­ci­ety of South­ern africa web page at: http://assa. saao.ac.za/lunare­clipse2018/

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