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The sky.

Go to the end of this article to find more detailed information about the Star Chart, how to use the chart, and a table of Moon phases. Use this table of phases to help you with the timing of successful astronomy evenings for students. The best time for an astronomy evening is usually six days after New Moon.

[FIGURE 1 OMITTED]

Significant events

(All times are UTC, Universal Time). Where time of day is relevant, each of the following event occurs at about 8.00pm local time on the given date, unless shown otherwise.

16 March--Palm Sunday

20 March--Vernal Equinox, Autumn begins at 05h 48'

21 March--Good Friday

23 March--Easter Day

20 April--First Day of Passover (Pesach)

23 April--Moon occults Antares around 17h. Visible from southern Australia

1 May--Saturn and Regulus close

1 May--Ascension Day--Holy Thursday

6 May--Eta Aquarid meteor shower, best in the early morning

11 May--Whit Sunday; Pentecost

18 May--Trinity Sunday

22 May--Corpus Christi

9 June--Saturn and Moon close to Regulus

9 June--Feast of Weeks (Shavuot)

20 June--Southern Winter Solstice; Winter begins 23h 59'

14 July--Moon occults Antares around 12h. Visible from southern Australia

16 August--A partial eclipse of the Moon is visible from all of Australasia. The umbral eclipse begins at 19h 36' and ends at 22h 45". The time of maximum eclipse is 21h 10' when 0.81 of the Moon's diameter is obscured.

22 September--Southern Spring Equinox; Spring begins at 15h 44'

21 December--Southern Summer Solstice; Summer begins 12h 04'

All Jewish and Islamic dates above are tabular dates, which begin at sunset on the previous evening and end at sunset on the tabulated date.

The sky at about 8.00pm local time

In April evenings the Milky Way lies across the zenith, but it is the thinner part of our galaxy, so contains fewer interesting objects than the other half of our Milky Way galaxy that crosses the zenith in the evenings in September.

Saturn and Mars are both well worth looking at through a medium telescope at this time, but they are currently situated in that part of the ecliptic that lies significantly to the north of the zenith as we see it from the southern hemisphere. Even a decent pair of binoculars will show that Saturn is a ringed planet. Binoculars affixed to a tripod give the best image.

Also worth doing at this warmer time of the year is to look for Iridium flares. The more than 66 Iridium communication satellites cause these flares because each satellite has three polished, flat, door-sized antennas, 120[degrees] apart. Occasionally an antenna will directly reflect sunlight down to the Earth, creating a predictable and quickly moving bright flare in the sky, with a duration of a couple of seconds. The satellites orbit at an altitude of about 780 kilometres.

[FIGURE 2 OMITTED]

The best way to find out which flares to look for is to visit http://www.heavensabove.com/. Before you go there you, and your students, should determine the latitude and longitude of the sites from which you plan to look for these flares. Determine the coordinates as decimal degrees to four decimal places. For latitude, use negative degrees for southern latitudes, such as -32.984, and not -32[degrees]59'2" or 32.984S. For longitude, use decimal degrees, positive for east of Greenwich, such as 116.392 and not 116[degrees]23'31" or 116.392E.

Also determine your elevation above sea-level in metres, if you have significant elevation. Last, you need to choose your time zone from a list, because the site generates all of its predictions in local time. For Iridium flares the site will calculate predictions for up to seven days ahead. The site can also calculate lots of other data, such as visibility of major satellites and the International Space Station.

I have seldom had students who were not intrigued by sighting Iridium flares. To sight the flares students also need to know something about compass directions and elevation.

How to use the star chart

To use the sky chart go outside at the appropriate date and time, and hold the chart, upside down above your head. Then turn around till the direction marks around the chart's edge are pointing in the correct compass directions. Now the chart should give you a condensed view of the sky that you see beside the chart.

Because no single sky chart will do for all localities in Australia, I have generated one for a position about 100 kilometres east of Adelaide. It shows what the sky should look like at 35[degrees] south latitude anywhere in Australia at around 8:00pm local time on 12 April 2008. If you are situated further north you may not be able to see those objects in the far south of the chart. Similarly, observers further south may not be able to view the northernmost objects on the chart. Use the chart

4 minutes earlier than 8:00pm for every day after 12 April, and 4 minutes later for every day before 12 April.

Enjoy looking up!

Ray Forma teaches science at Methodist Ladies College in Claremont, WA.
Table 1. Phases of the Moon 2008/2009.
The times are UTC (Universal Time)

    New Moon          First Quarter

6 Apr 2008 04:05    12 Apr 2008 18:30
5 May 2008 12:35    12 May 2008 03:50
3 Jun 2008 19:35    10 Jun 2008 15:05
3 Jul 2008 02:15    10 Jul 2008 04:30
1 Aug 2008 10:00    8 Aug 2008 20:15
30 Aug 2008 19:50   7 Sep 2008 14:00
29 Sep 2008 08:15   7 Oct 2008 09:00
28 Oct 2008 23:30   6 Nov 2008 04:00
27 Nov 2008 17:10   5 Dec 2008 21:25
27 Dec 2008 12:25   4 Jan 2009 11:55
26 Jan 2009 07:40   2 Feb 2009 23:10
25 Feb 2009 01:20   4 Mar 2009 07:40

    Full Moon         Last Quarter

20 Apr 2008 10:30   28 Apr 2008 14:15
20 May 2008 02:15   28 May 2008 03:05
18 Jun 2008 17:35   26 Jun 2008 12:15
18 Jul 2008 08:00   25 Jul 2008 18:45
16 Aug 2008 21:15   23 Aug 2008 23:55
15 Sep 2008 09:10   22 Sep 2008 05:15
14 Oct 2008 20:05   21 Oct 2008 12:05
13 Nov 2008 06:25   19 Nov 2008 21:40
12 Dec 2008 16:40   19 Dec 2008 10:35
11 Jan 2009 03:30   18 Jan 2009 02:45
9 Feb 2009 14:50    16 Feb 2009 21:35
11 Mar 2009 02:35   18 Mar 2009 17:50
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Title Annotation:hands on
Author:Forma, Ray
Publication:Teaching Science
Geographic Code:1USA
Date:Sep 22, 2008
Words:1115
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