HERMANUS ASTRONOMY CENTRE THE SKY THIS MONTH : MARCH 2016 http://www.hermanusastronomy.co.za/ 1. SKY MAPS E VENING SK Y MID MARCH at 21 h 0 0 1
PLEASE NOTE: All events predicted below are as observed from Hermanus, Western Cape, South Africa 2. THE SOLAR SYSTEM Sun & Planets MARCH 2016 1 st 31 st Sun Constellation: Aquarius to Pisces Length of day 12h48 to 11h44 Mercury phase 88% to 95%, ϕ 5 Constellation Capricornus to Pisces Magnitude: -0.3 to -1.5 Venus phase 91% to 95%, ϕ 11 to 10 Constellation: Capricornus to Aquarius Magnitude: -3.9 Mars phase 90% to 93%, ϕ 6 to 12 Constellation: Libra to Scorpius Magnitude +0.3 to -0.5% Jupiter ϕ 44 Constellation: Leo Magnitude: - 2.5 to -2.4 Saturn ϕ 16 to 17 Constellation: Ophiuchus Magnitude: + 0. 5 t o + 0. 4 Uranus ϕ 3 Constellation: Pisces Magnitude: + 5.9 Neptune ϕ 2 to 3 Constellation: Aquarius Magnitude: +8.0 Pluto Constellation: Sagittarius Magnitude + 14.2 Rises: 06h31 06h55 Transits: 12h56 12h48 Sets: 19h20 18h39 Rises: 05h03 07h33 Transits: 11h51 13h17 Sets: 18h38 19h00 Rises: 04h31 05h31 Transits: 11h21 11h45 Sets: 18h11 17h58 Rises: 22h53 21h25 Transits: 05h51 04h30 Sets: 12h46 11h32 Rises: 19h39 17h31 Transits: 01h30 23h13 Sets: 07h16 05h00 Rises: 00h03 22h03 Transits: 07h05 05h09 Sets: 14h08 12h12 Rises: 09h29 07h39 Transits: 15h13 13h21 Sets: 20h57 19h03 Rises: 06h25 04h32 Transits: 12h50 10h57 Sets: 19h16 17h21 Rises: 02h16 00h20 Transits: 09h18 10h57 Sets: 16h20 17h21 Mercury Venus Mars Jupiter Saturn Uranus Neptune Pluto Visible low in the east before sunrise but moving too close to the sun during the month The Morning Star Visible in the morning sky well placed for observation throughout the night Visible in the morning sky Visible in the evening sky but moving too close to the sun during the month Initially too close to the sun but later in the month becomes visible in the morning sky Visible low in the east before sunrise 2
3. THE MOON Sky Guide readers (SGAS) will see March s highlight is Mare Nectaris (the sea of nectar). Location: east of the moon s centre. Type: dark basaltic plain formed by volcanic eruptions. Diameter: 360 km. Age: over 3.8 billion years. Best seen 5 days after New Moon. The picture to left depicts the internationally accepted convention for the orientation of the cardinal points. Note that the E and W points are opposite to our accustomed celestial orientation ECLIPSES 9 th March a total solar eclipse, not visible from Hermanus. 23 rd March a penumbral lunar eclipse, not visible from Hermanus.. 3
4. MARCH HIGHLIGHTS FROM THE SKY GUIDE Date Time I t e m 1 Jupiter double-shadow event 2 01h11 Last quarter Moon 08h53 Moon north of Saturn 3.9º 3 16h19 Moon furthest south (-18.2º) 4 Moon north of Pluto 3.2º 7 12h54 Moon north of Venus 3.5º 8 Moon north of Mercury 3.7º, north of Neptune 1.9º 11h58 Jupiter at opposition, Jupiter double-shadow event 10 09h02 Moon at perigee (359 500 km) 11 Moon south of Uranus 1.8º, Mercury and Neptune 82.7 apart (12º west of Sun) 13 Gamma (γ) Normid meteor shower (see METEOR SHOWERS below) 14 15h44 Moon north of Aldebaran 0.3º 15 19h03 First quarter Moon 16 07h01 Moon furthest north (+18.2º), Jupiter double-shadow event 17 Comet 252P/LINEAR at perihelion 20 06H31 Equinox 21h05 Moon south of Regulus 2.8º, Venus and Neptune 29.5 apart (20º west of Sun) 21 Comet 252P/LINEAR close approach to Earth 05h57 Moon south of Jupiter 2.3º 23 14h01 Full Moon 22h05 Mercury at superior conjunction, Moon occults β Virginis 24 Jupiter double-shadow event 25 16h16 Moon at apogee (406 100 km), Moon north of Spica 4.9º, Saturn stationary, Jupiter double-shadow event 26 Earth Hour 28 20h45 Moon north of Mars 4.6º 29 16h58 Moon north of Saturn 3.8º 30 ASSA nominations 1 31 17h17 Last quarter Moon 00h12 Moon furthest south -18.2º, Mercury and Uranus 33.5 apart (9º east of Sun) 1 ASSA nominations for the Gill Medal, McIntyre Award, President s Award, Long Service Award and Honorary Membership close on 31 st March. 5. METEOR SHOWERS Name Date & Time of Max Duration Radiant ZHR vel. Observing Prospect Gamma (γ) Normids 13 th March 00h00 to 04h30 25 th February to 22 nd March Near γ Normae +/- 20º NE of α Cen 8 56 favourable Key to the table above: ZHR zenithal hourly rate vel. - velocity in km per second For more details regarding meteor watching, please see the Sky Guide Africa South (SGAS), pp 86-87 4
6. DEEP SKY In place of the normal Constellation of the month, I have pasted last year s GALAXY OF THE MONTH. I feel a revisit of this article will not go amiss. 1. GALAXY OF THE MONTH THE MILKY WAY The Galaxy offers an amazing range of different types of objects to be observed and... allows all sorts of observations to be undertaken for sheer enjoyment, rather than for serious scientific purposes. The naked eye is more than adequate indeed it is admirably suited to take in the overall splendour of the Milky Way itself in its course across the sky, provided dark sky conditions can be found away from the bane of street lighting. Those persons who are fortunate enough to live... south of the Equator, where the magnificent star clouds of the Milky Way stretch from Sagittarius all the way round to Carina, are indeed to be envied. [Extracted from one of our library books, Amateur Astronomy (kindly donated by Salette Crighton)] So there you have it: we are sometimes the envy of the Northern Hemisphere. And here we are in the Overberg, out in sticks, away from the city and only, at most, 10 minutes from dark skies. Just how lucky can we get? We hear people speak of The Big 5 and lions and elephants, etc., come to mind. But we now hear the same phrase applied to our wild African skies. I paste below an extract from Nightfall the deep-sky observing newsletter of the ASSA. THE BIG 5 OF THE AFRICAN SKY What are the Big 5? The Big 5 of the African Sky are five celestial objects that represent the best specimens of each type of deep-sky class: the Southern Pleiades (an open star cluster), omega Centauri (a globular cluster), the eta Carinae Nebula (a bright nebula), the Coal Sack (a dark nebula) and the Milky Way (a galaxy). Where can I see the Big 5? The Big 5 are visible anywhere from within the southern hemisphere. Two of the Big 5 lie in Carina, one lies in Centaurus, and one in Crux. The fifth the Milky Way lies in a narrow band dividing the sky in half. The brightest parts of the Milky Way are in Sagittarius, Scutum, Norma and Carina. The accompanying table gives their celestial coordinates and basic data. Two star maps illustrate their general location, with one map devoted specifically to the Milky Way. Basic stats of the Big 5 of the African Sky Object names & catalogue designations Type RA & Dec (J2000.0) Constellation Southern Pleiades, IC 2602, Lac II.9 open cluster 10h 43.2m, 64 24.0 Carina eta Carinae Nebula, NGC 3372, Lac III.5/6 bright nebula 10h 44.3m, 59 53.4 Carina Coal Sack, Caldwell 99 dark nebula 12h 31.3m, 63 44.6 Crux omega Centauri, NGC 5139, Lac I.5 globular cluster 13h 26.8m, 47 28.6 Centaurus Milky Way, the Galaxy, Via Lactea galaxy 10h 45m, 60 Carina 16h 18m, 53 Norma 18h 00m, 29 Sagittarius 18h 45m, 07 Scutum 5
19h 30m, + 30 Cygnus The Milky Way circles the entire sky so a single position cannot represent it. The last five rows of the table list the positions of the five brightest portions. The Galactic centre is in Sagittarius. 6
When can I see the Big 5? All five objects will not be visible at the same time. This is mainly because the Milky Way is a large object and it will take more than one session to see it at its full extent. There are a number of tools you can use to find out when a particular region of sky is visible. You could, for example, use the Southern Star Wheel planisphere, a free DIY download. Your favourite planetarium program (e.g. Stellarium ) or app (e.g. Google Sky Map, Sky Safari ) are also great options. The following table gives a general indication of when the Big 5 can be seen. Visibility periods Big 5 Evening visibility Midnight visibility Morning visibility Southern Pleiades Jan to late-aug mid-nov to early Jul mid-sep to early May eta Carinae Nebula early Jan to mid-aug late Nov to early Jul late Sep to early May Coal Sack Nebula Feb to late-sep mid-dec to early Aug mid-oct to early Jun omega Centauri Mar to mid-sep mid-jan to early Aug mid-nov to early Jun Milky Way (Car) early Jan to mid-aug late Nov to early Jul late Sep to early May Milky Way (Nor) early Apr to end-oct late Feb to mid-sep late Dec to mid-jul Milky Way (Sgr) late May to early Nov mid-apr to late Sep mid-feb to late Jul Milky Way (Sct) late Jun to early Nov early May to late Sep Mar to late Jul Milky Way (Cyg) early Aug to mid-oct late Jun to late Aug late Apr to early Jul 7
Keep in touch Please don t forget to have a look at our excellent website, edited by Derek Duckitt. http://www.hermanusastronomy.co.za/ Also... ASSA Deep-Sky Section Whatsapp chat group: [ 074 100 7237 ] Official Big 5 of the African Sky web page Official Big 5 Facebook group ASSA Deep-Sky Section mailing list Contact ASSA Get in touch with officers of the Society - we're real people with a passion for astronomy, so contact us and let's talk! You can also find us on Facebook, Twitter, the ASSA_Info mailing list and the ASSA_Discussion mailing list. Grateful thanks to the following, without whom this publication could not have materialised: Johan Retief ASSA Ofentse Letebele of Iziko Planetarium Auke Slotegraaf Sky Guide Africa South 2015 Ian Ridpath Stellarium Compiled by Peter Harvey e-mail: petermh@hermanus.co.za Tel: 081 212 9481 8