Orion’s re­turn to our night sky her­alds start of sum­mer


Weekend Argus (Saturday Edition) - - GOODMOVIES - CASE RIJSDIJK

THE MONTH starts with a thin wan­ing cres­cent Moon that be­comes new on the 3rd, with the first cres­cent be­com­ing vis­i­ble the fol­low­ing evening af­ter sun­set.

The sum­mer sol­stice is on the 21st and is the day that we have the long­est “day” and so also the short­est night. It is, how­ever, not the time of ear­li­est sun­rise and lat­est sun­set. Ear­li­est sun­rise was on the 6th and lat­est sun­set will be on Jan­uary 7th. The rea­son for this is that Earth does not travel at a con­stant speed around the Sun since its or­bit is an el­lipse.

This month there will no doubt be quite some pub­lic­ity about Comet Ison. Un­for­tu­nately it will not re­ally be vis­i­ble from the south­ern hemi­sphere. It passed close to the Sun (per­i­he­lion) on Thurs­day, when it was only 1.86 mil­lion kilo­me­tres above the Sun’s sur­face. Af­ter round­ing the Sun, it be­comes vis­i­ble again ( north­ern hemi­sphere) early next month and it might be very bright, or it might not. For those in­ter­ested there will be in­for­ma­tion on the Astro­nom­i­cal So­ci­ety of South­ern Africa web­site: http://assa.saao.ac.za.

The ar­rival of sum­mer is her­alded by the re­turn of the con­stel­la­tion of Orion, the Hunter, to the evening sky, ans also marks the be­gin­ning of a more in­ter­est­ing night sky. By mid-month, Orion will be vis­i­ble low in the north east af­ter sun­set. For the Tswana, the stars of Orion’s sword were “dintsa le Dikolobe”, three dogs chas­ing the three pigs of Orion’s belt. Warthogs have their young while Orion is prom­i­nent in the sky at this time of the year, and usu­ally have lit­ters of three. This I think makes this name far more ap­pro­pri­ate for us in South Africa.

To the west, or left, of Orion is the small clus­ter of the Hyades in the con­stel­la­tion of Taurus the Bull with the bright orange-red star Alde­baran in the fore­ground. Only 60 light years away it is the eye of the Bull. Still fur­ther west is the small and bright clus­ter of isiLimela, also known as the Pleiades or the Seven Sis­ters, and be­yond that is the Great Square of Pe­ga­sus. A line from the three bright “belt stars” in Orion, through Alde­baran and isiLimela will end up at the An­dromeda galaxy to the lower right of the Great Square.

Venus is still vis­i­ble af­ter sun­set, shin­ing un­mis­tak­ably brightly low in the western sky, and be­tween the 14th and 17th a wax­ing gib­bous Moon will be pass­ing by the Hyades in the north. To the south, the South­ern Cross and the two Point­ers, al­pha and beta Cen­tauri, are vis­i­ble low above the hori­zon. Our two near­est neigh­bour­ing gal­ax­ies, the Large and Small Mag­el­lanic Clouds are clearly vis­i­ble well above the Cross, but you will need dark skies to spot th­ese two fuzzy patches.

Archenar is nearly over­head while Cano­pus, the sec­ond bright­est star in the sky, is vis­i­ble in the south-east, and is also known as Naka or Nanga, the Horn star. Among the Venda, the first per­son to see Nanga ( Cano­pus) in the morn­ing sky an­nounced his dis­cov­ery by climb­ing a hill and blow­ing a sable an­te­lope horn (Pha­laphala).

There is the usual open night at the Ob­ser­va­tory on De­cem­ber 14 at 8pm. Visi­tors will have a chance to look at the night sky and at­tend a lec­ture by Dr Chris­tian Het­t­lage on “The star of Beth­le­hem”.

The Sky Guide Africa South is now avail­able from most good book­sellers and is the ideal Christ­mas present for read­ers with an in­ter­est in the night skies of south­ern Africa. I find it in­dis­pens­able and a copy trav­els with me wher­ever I go.

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