A view of the south­ern sky in May

The Timaru Herald - - COMMENT&OPINION - FREIDL HALE

Wow, it is al­ready cold at night lately, at least at my house. Be sure to rug up be­fore you go out so that the cold doesn’t drive you back in­side be­fore your eyes even have time to ad­just to the dark.

Speak­ing of the dark, af­ter sun­set (also be­fore sun­rise but in the op­po­site or­der) the sky goes through 3 com­monly ref­er­enced stages of twi­light be­fore it is con­sid­ered dark. They are called Civil, Nau­ti­cal, and As­tro­nom­i­cal Twi­light or Dusk.

They are roughly based on how far be­low the hori­zon the Sun has moved. Their length de­pends on the sea­son of the year.

You may see the bright plan­ets like Venus and Jupiter be­fore the end of evening Civil Twi­light. Stars ap­pear dur­ing Nau­ti­cal twi- light, and, by the end of it, if you are at sea you can no longer dis­cern the hori­zon as the sea and sky blend.

At the end of evening As­tro­nom­i­cal Twi­light light from the Sun is no longer in­ter­fer­ing with light from the stars.

How­ever, in pop­u­lated ar­eas, light po­lu­tion and air po­lu­tion can wipe out light from all but the bright­est objects.

Of course the ap­pear­ance of the Moon as it moves through its var­i­ous phases has a great im­pact on what can be seen as well.

This month be­gins with the Moon wax­ing to­ward full which will oc­cur dur­ing the morn­ing of the 11th, re­sult­ing in an al­most equally full and bright Moon on both nights, the 10th and 11th. Your dark­est sky for view­ing will be later in the month.

New Moon will oc­cur around mid­night on the 26th. But start­ing from the 17th the Moon will not rise un­til af­ter 10:30pm and later each night. As­tro­nom­i­cal Twi­light will be end­ing around 7pm giv­ing you rea­son­able view­ing time from the 17th through al­most to the end of the month at which point the Moon will brighten in the evening sky.

This month will present one of two good op­por­tu­ni­ties you will have this year to see Mer­cury in a dark sky, how­ever you will have to be up well be­fore the Sun.

All month Mer­cury will rise in the east be­fore the be­gin­ning of dawn As­tro­nom­i­cal Twi­light, be­fore the dim glow of the com­ing sun­rise be­gins to in­ter­fere.

It will rise just af­ter 6am on the 1st, just be­fore 5:25 on the 15th, and around 6am again on the 31st. Mer­cury will be joined by a tiny sliver of wan­ing moon on the 24th and 25th.

Venus also will be there as a bril­liant Morn­ing ‘‘Star’’, higher in the dark sky hav­ing risen by 4am.

If you pre­fer an evening view­ing of Mer­cury it will be set­ting in a fully dark western sky in July and Au­gust. Mer­cury spends most of its time in the twi­light of the ris­ing or set­ting Sun, and be­cause it is a rel­a­tively dim ob­ject it is usu­ally hard to see.

Mars con­tin­ues to hold in the west near the end of evening Nau­ti­cal Twi­light, set­ting about an hour af­ter the Sun and mak­ing it dif­fi­cult to see. By mid-July it will dip lower and set with the Sun.

Jupiter con­tin­ues to move west­ward in the evening and night sky, fol­lowed in around 3 hours by Saturn. You will see Jupiter due north and high in the sky at 11pm on the first and be­fore 9pm at the end of the month. Saturn will rise in the east at 8:08pm, on the 1st, and two hours ear­lier, just an hour af­ter sun­set, on the 31st.

We usu­ally hear on the 6 o’clock news about an­niver­saries of ma­jor events like the Apollo 11 Moon land­ing. We tend to for­get the peo­ple and events that paved the way.

This month is a good time to con­sider Apollo 10, BE­FORE hu­man be­ings ac­tu­ally landed, left their tiny space­craft, and dared the next step, walk­ing on a alien world.

On 18 May, 1969 three ex­pe­ri­enced as­tro­nauts left Earth for a suc­cess­ful 8-day ‘‘dress re­hearsal’’ in prepa­ra­tion for the land­ing to come two months later.

Eu­gene Cer­nan flew the lu­nar lan­der, call sign Snoopy, while mis­sion com­man­der Thomas Stafford and pi­lot John Young re­mained in or­bit in the com­mand mod­ule, Char­lie Brown.

The lan­der went as low as 15 kilo­me­tres above the lu­nar sur­face be­fore re­turn­ing to dock with the com­mand mod­ule, a fi­nal test of crit­i­cal equip­ment and pro­ce­dures. Imag­ine be­ing so close to the goal but not ac­tu­ally get­ting to land.

Cer­nan and Young both re­turned to the Moon in com­mand of later Apollo mis­sions.

If you have any ques­tions, would like to re­ceive or share in­for­ma­tion, or just share a stargaz­ing ex­pe­ri­ence or a thought about our place in space, please email me at night­skysouth@gmail.com.

Clear night skies.

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