Southward Solstice (Spring Solstice) 23 Sep 13.10 AEST
Mercury, Venus Mars and Saturn are low in the evening western sky over this period. By the end of July Mars and Saturn pass each other. Venus is at it’s brightest, Mag. -4.6 during September. Greatest elongation from the Sun 20th August. Mercury is at it’s greatest elongation 7th August. Venus, Spica and Mars form a close group on 2nd September.
Jupiter rises earlier over this period becoming an evening object by mid August. Jupiter is at it’s largest diameter at opposition on the 21st September.
Meteor Showers - Reference IMO 2010 Meteor Calendar
The Antihelion Source (ANT) is a large, roughly oval area around α = 30 deg by δ = 15 deg in size, centred about 12 deg east of the solar opposition point on the ecliptic, hence its name. It is not a true shower at all, but is rather a region of sky in which a number of variably, if weakly, active minor showers have their radiants. Until 2006, attempts were made to define specific showers within this complex, but this often proved very difficult for visual observers to achieve. IMO video results from the last decade have shown why, because even instrumentally, it was impossible to define distinct radiants for many of the showers here! It is currently best for observers to simply identify meteors from these streams as coming from the ANT alone. At present, the July-August α –Capricornids (CAP), and particularly the δ –Aquariids (SDA), should remain discretely-observable visually from the ANT, so they have been retained on the IMO working List, but time and plenty of observations will tell, as ever. Later in the year, the strength of the twin Taurid showers (STA and NTA) means the ANT should be considered inactive while the Taurids are underway, from late September to late November.
The ANT is the chief focus for visual attention during most of July, as its radiant area moves steadily through eastern Sagittarius, then across northern Capricornus into south-west Aquarius. Results suggest the Source may not be especially recognisable after the first few days however, as ZHRs for most of the month seem < 2, and for a time in mid-month even < 1! Activity appears to improve somewhat, with ZHRs ∼ 2 to 3, by late July and through the first half of August. Despite the large ANT radiant area overlapping that of the minor α -Capricornids (CAP) in July-August, these ZHR levels may make it more practical to still identify CAP meteors, particularly near the CAP maximum, due around July 30th or 31st. That is unlikely to be the case this year though, due to the waning gibbous Moon in late July. The δ -Aquariids (SDA) are strong enough, and the Piscis Austrinids (PAU) have a radiant probably distant enough from the ANT area, that both should still be separable from it too, particularly from the southern hemisphere. Moonlit maxima are due from both around July 28th, the PAU possibly on July 29th instead, while VID indicated the SDA peak might fall alternatively around λ ⊙ = 128 deg , 2010 July 31st.
By August, ANT ZHRs will likely have dropped back below 2 again, as the radiant tracks on through Aquarius, and into western Pisces by the α -Aurigid maximum on the August-September boundary, probably this year peaking around 0700 hours UT on September 1st (with a very problematic last quarter Moon). The possible very weak δ -Aurigid peak, perhaps between September 24th to October 4th, will be lost to the bright waning Moon. There have been significant discrepancies found in these showers’ details as determined by recent video results. For most of September, ANT rates continue from their radiant in Pisces, albeit with ZHRs probably no better than 2–3, but remember that from September 25th, Antihelion meteors are no longer to be recorded as such, as both Taurid showers take over the near-ecliptic shower baton until late November.
Observing the Zodiacal Light
The Zodiacal light is sunlight reflected from the dust particles which are concentrated along the ecliptic. The best time to view this light is when the ecliptic is most vertical, at the equinoxes. The tepee shaped Zodiacal Light Pyramid stretches up to 90 degrees from the Sun. Opposite the Sun is a counter glow called the Gegenschein, a large oval patch of light stretching about 15 by 10 degrees along the ecliptic and centered at 180 degrees from the Sun. The Zodiacal pyramid is best seen in spring just before morning twilight in the East and in autumn after evening twilight in the West.
The Zodiacal pyramid and Gegenschein are joined over head by an extremely faint Zodiacal Band. A dark site is best if you want to see these Phenomena.
Comets
Comet McnaughtC2009R1 is an early morning object and worth a look in Early July and into August.
|
McNaught |
(C/2009 R1) |
|
|
|
|
|
|
|
Date |
RA |
Declination |
Dist Sun |
Dist Earth |
mag |
Elong |
Const |
|
1 Jul |
07h03m07.32s |
+38 22' 03.5" |
0.4081 |
1.2710 |
4.6 |
16.1 |
Aur |
|
6 Jul |
07h38m45.11s |
+30 54' 55.1" |
0.4136 |
1.3484 |
4.8 |
12.1 |
Gem |
|
11 Jul |
08h03m11.20s |
+23 18' 38.4" |
0.4594 |
1.4229 |
5.4 |
10.2 |
Cnc |
|
16 Jul |
08h20m56.50s |
+16 12' 30.9" |
0.5322 |
1.4918 |
6.1 |
11.2 |
Cnc |
|
21 Jul |
08h34m58.73s |
+09 46' 52.7" |
0.6191 |
1.5565 |
6.9 |
13.8 |
Cnc |
|
26 Jul |
08h46m54.72s |
+03 59' 16.7" |
0.7122 |
1.6188 |
7.6 |
17.0 |
Hya |
|
31 Jul |
08h57m35.63s |
-01 15' 56.5" |
0.8076 |
1.6798 |
8.2 |
20.2 |
Hya |
|
5 Aug |
09h07m29.46s |
-06 04' 21.6" |
0.9030 |
1.7400 |
8.8 |
23.3 |
Hya |
|
10 Aug |
09h16m52.29s |
-10 30' 40.9" |
0.9975 |
1.7998 |
9.3 |
26.3 |
Hya |
|
15 Aug |
09h25m53.63s |
-14 38' 40.8" |
1.0907 |
1.8593 |
9.7 |
29.0 |
Hya |
|
20 Aug |
09h34m39.49s |
-18 31' 19.4" |
1.1822 |
1.9186 |
10.1 |
31.6 |
Hya |
|
25 Aug |
09h43m14.10s |
-22 10' 58.4" |
1.2722 |
1.9777 |
10.5 |
34.0 |
Hya |
|
30 Aug |
09h51m40.56s |
-25 39' 32.7" |
1.3604 |
2.0368 |
10.9 |
36.2 |
Hya |
|
4 Sep |
10h00m01.17s |
-28 58' 35.6" |
1.4470 |
2.0958 |
11.2 |
38.3 |
Ant |
|
9 Sep |
10h08m17.47s |
-32 09' 23.4" |
1.5321 |
2.1547 |
11.5 |
40.3 |
Ant |
|
14 Sep |
10h16m30.39s |
-35 12' 55.6" |
1.6157 |
2.2135 |
11.8 |
42.2 |
Ant |
Path of Comet McNaughtC2009 R1 beginning from 1st July
