The Sun begins the month in the constellation of
Leo, but on the 17th at 02h00, crosses the astronomical border which separates Leo from Virgo, in which constellation it remains till the month ends.
The Autumnal Equinox on Sept 23rd at 07h51 marks the official start of Autumn. Day and night are almost equal in length again, and in the northern hemisphere, autumn lasts for 89.85 days. The Earth-Sun distance
at this time is 150 125 903 km.
September is the best month to observe the ethereal Zodiacal Light during the early mornings when the Moon is not present in the sky, and you are well
away from light pollution. Look towards the east before the onset of morning twilight, around 03h30, and you should see a faint cone of light pointing southwards at a steep angle of 60°. This phenomenon is caused by the Sun illuminating the disc of fine
dust, which is the remnant of solar system formation 4.5 thousand million years ago. The best days to observe this morning cone are from Aug 30th to Sept 13th, and again on the last two days of the month.
The Moon is at apogee, its farthest from the Earth, on the 13th
at around 13h (diameter of the moon 30’ of arc) and at perigee (nearest to the Earth) at 02h00 on the 28th (diameter of the moon 33 mins of arc).
First Quarter Moon takes place at 03h11 on the 6th, in Ophiuchus, and is one of the lowest FQ Moon of the year, and is near to Jupiter.
Full Moon at 04h34 on the 14th, is in the eastern part of Aquarius, beneath the ‘Great Square of Pegasus’ and the circlet of stars outlining
the ‘western fish’ of Pisces. This Moon is called the “Harvest Moon”, since, before the days of mechanisation, harvest was a long process and the labourers would have to work well into the night. For several nights before and after
Full, the Moon rises at about the same time each evening as the sun sets and so its light enabled the harvesters to continue their labours into the night. Look for the Harvest Moon rising almost due east at sunset at this time.
Last Quarter Moon is at 02h42 on the 22nd almost exactly on the Taurus/Orion/Gemini borders. This is one of the highest LQ Moons of the year.
New Moon is on the 28th at 18h27, in the constellation of Virgo, passing 5° above the Sun.
Earthshine may be seen on the dark hemisphere of the waning crescent Moon from the 23rd to the 28th, and it may also
be glimpsed on the night hemisphere of the waxing crescent from the first and last few days of September.
Although Mercury lies to the east of the Sun, the planet sets only 20 mins after the Sun and cannot be seen due to the bright
twilight. Superior conjunction is on the 4th of September.
Venus also lies too near to the Sun to be observed
during this month, although you may be able to locate it in binoculars very near the horizon at around 18h00 at the end of the month in the western sky after the Sun has set.
Mars is in conjunction with the Sun on the 2nd, and so will be difficult to observe before sunrise in the bright twilight of the morning sky.
Jupiter lies in the constellation of Ophiuchus and is visible in the SSW sky as night falls. The Moon will be seen approaching Jupiter on the evening of the 5th,
when at 21h they are just over 5° apart, parallel with, and 5° above the SW horizon. Take the opportunity to observe the Galilean satellites; Io, Europa, Ganymede and Callisto as the configuration changes on a nightly basis. Identification of the satellites
is to be found on the Front Page of the Sky Notes.
Saturn, in the constellation of Sagittarius, culminates in the
early evening at around 20h at the south meridian. Its angular altitude from northern England, is some 15° above the horizon. Any small telescope will show the widely opened rings at this time. Also, try to spot the largest of Saturn’s moons, Titan,
when it is at eastern elongation from the planet on the 5th and 21st, and when it is at western elongation on the 13th and 29th. Titan has a visual magnitude of +8. The Moon lies to the east of Saturn on the 8th.
At this time the two are separated by an angular distance of 3°, Saturn lying to the upper right of the waxing gibbous Moon. The two objects lie directly beneath the ‘Summer Triangle’ of stars, made up by Vega, Altair and Deneb.
Uranus lies in Aries beneath the stars Hamal and Sheratan in that constellation. See the Remote Planets page to find its position.
The visual magnitude of Uranus during the month is +5.7, and through an astronomical telescope has the appearance of a tiny greyish green disc
Neptune is at opposition and its nearest to the earth this year on the 10th. It lies in the constellation of Aquarius, beneath the circlet of stars which
makes up the pattern of the ‘western fish’ of the neighbouring constellation of Pisces. The opposition magnitude of Neptune is +7.83. like Uranus, Neptune presents an even smaller disc and is bluish in colour.
In order to locate this remote planet, you are encouraged to visit the Remote Planets page accessible via the MENU above. The planet is visible all night and culminates (crosses the south meridian) around midnight at an altitude of
Therefore in September there are four planets visible during the hours of darkness to be observed; Jupiter and Saturn which are readily visible to the unaided eye, and the remote planets
Uranus and Neptune, planets which require optical aid in order to identify and locate them.
Constellations visible in the south
around midnight, mid-month, are as follows: Aquarius, the western fish of Pisces, sometimes known as ‘The Circlet’ because of its shape, and the large autumn square of Pegasus. Almost overhead are the great galaxy in Andromeda and the ‘W’
shaped constellation of Cassiopeia.
All times are GMT 1° is one finger width at
The phenomena of the month : SEPTEMBER 2019
are given in UT for SCARBOROUGH (0° 25' 0" W, 54° 16' 3" N, zone 0 UNIVERSAL TIME).
Description of the phenomenon
yyyy mm dd hh:mm
2019 09 01 09:11 Meteor shower
: Alpha Aurigids (6 meteors/hour at zenith; duration = 8.0 days)
2019 09 01 10:43 Minimum of the variable star Algol (beta Persei)
2019 09 02
10:46 CONJUNCTION between Mars and the Sun (geoc. dist. centre to centre = 1.1°)
2019 09 04 01:39 SUPERIOR CONJUNCTION of Mercury with the Sun (geoc. dist. centre to centre = 1.7°)
2019 09 04 07:32 Minimum of the variable star Algol (beta Persei)
2019 09 05 07:04 Maximum of the variable star delta Cephei
2019 09 06 03:10 FIRST QUARTER OF THE MOON
2019 09 06 13:21 Opposition of the asteroid 135 Hertha with the Sun (dist. to the Sun = 1.942 AU; magn. = 9.5)
2019 09 07 04:20 Minimum of the variable star Algol (beta Persei)
2019 09 07 14:58 Maximum of the variable star eta Aquilae
2019 09 08 03:37 Minimum of the variable star beta Lyrae
2019 09 09 18:58 Maximum of the variable star zeta Gemini
2019 09 09 20:10 Meteor shower : Sept. Perseids (5 meteors/hour at zenith; duration = 16.0 days)
2019 09 10 01:09 Minimum of the variable star Algol (beta Persei)
2019 09 10 07:24 OPPOSITION of Neptune with the Sun
2019 09 10 15:51 Maximum of the variable star delta Cephei
2019 09 11 00:06 Beginning of occultation of 22-eta Cap (magn. = 4.82)
2019 09 11 01:17 End of occultation of 22-eta Cap (magn. = 4.82)
2019 09 12 21:57 Minimum of the variable star Algol (beta Persei)
2019 09 13 13:32 Moon at apogee (geocentric dist. = 406377 km)
09 13 20:32 Close encounter between the Moon and Neptune (topocentric dist. centre to centre = 4.2°)
2019 09 14 04:33 FULL MOON
09 14 19:13 Maximum of the variable star eta Aquilae
2019 09 14 19:18 End of occultation of 30 Psc (magn. = 4.37)
2019 09 14
20:12 Beginning of occultation of 33 Psc (magn. = 4.61)
2019 09 14 21:20 End of occultation of 33 Psc (magn. = 4.61)
2019 09 15 18:46
Minimum of the variable star Algol (beta Persei)
2019 09 16 00:38 Maximum of the variable star delta Cephei
2019 09 17 23:42 Close
encounter between the Moon and Uranus (topocentric dist. centre to centre = 5.0°)
2019 09 18 15:34 Minimum of the variable star Algol (beta Persei)
09 19 22:33 Maximum of the variable star zeta Gemini
2019 09 20 22:23 Beginning of occultation of 97 Tau (magn. = 5.08)
2019 09 20
22:41 End of occultation of 97 Tau (magn. = 5.08)
2019 09 21 02:12 Minimum of the variable star beta Lyrae
2019 09 21 09:25
Maximum of the variable star delta Cephei
2019 09 21 12:23 Minimum of the variable star Algol (beta Persei)
2019 09 21 23:28 Maximum
of the variable star eta Aquilae
2019 09 22 02:41 LAST QUARTER OF THE MOON
2019 09 22 22:33 Opposition of the asteroid 247 Eukrate
with the Sun (dist. to the Sun = 2.271 AU; magn. = 10.4)
2019 09 23 01:22 Beginning of occultation of 36 Gem (magn. = 5.28)
2019 09 23 01:33
End of occultation of 36 Gem (magn. = 5.28)
2019 09 23 07:50 AUTUMN EQUINOX
2019 09 24 09:12 Minimum of the variable star Algol (beta
2019 09 26 18:13 Maximum of the variable star delta Cephei
2019 09 27 06:00 Minimum of the variable star Algol (beta Persei)
2019 09 28 02:27 Moon at perigee (geocentric dist. = 357802 km)
2019 09 28 13:56 Opposition of the asteroid 21 Lutetia with the Sun (dist. to
the Sun = 2.084 AU; magn. = 9.4)
2019 09 28 18:26 NEW MOON
2019 09 29 03:43 Maximum of the variable star eta Aquilae
2019 09 29 08:47 Close encounter between Mercury and Spica (topocentric dist. centre to centre = 1.3°)
2019 09 30 02:07 Maximum of the variable star
2019 09 30 02:49 Minimum of the variable star Algol (beta Persei)