Dundee Astronomical Society
Sky Notes for September 2015
Sky Map for 15th September 22:00
Looking back to last month, NLC season has closed more with a whimper than a bang with Ken
Kennedy (BAA Coordinator) reporting a drop in reported NLCs. Also Comet 67P/Churyumov –
Gerasimenko has now passed perihelion and images from Rosetta show some outburst from the
comet waxing and waning, what a sight that would be up close. Let’s hope Philae, at some point,
shows some sign of life - no matter how brief.
The 12th and 13th August saw the Perseids Meteor shower with many of our members reporting good
sightings and sharing some images, far too many to include here! Our Webmaster has already put
some up on a new gallery in the DAS webpages so if you haven’t already had a look, well worth
doing so. The weather has not been particularly kind recently but 12/13th skies were very clear.
Some members have already sent the DofObs sighting reports and these will be collated for inclusion
on the website.
The nights are starting to close in now and hopefully clearer nights will allow more observing to be
carried out. The Mills observatory Planetarium evenings will be starting in October with an
opportunity for the Society to give visitors to the Mills an opportunity to have a look through a
telescope.
The Summer Triangle is still very prominent in the evening sky to the south with many interesting
objects to look at. Ursa Major to the north just cannot be missed and most people recognise this
constellation but are unaware of the beauties contained within and around it, so keep your eyes
open but watch where you are putting your feet!!
Illustration Courtesy of www.heavensabove.com
Andromeda is now quite prominent in the evening sky and visible with the naked eye, binoculars and
telescope. The diagram below shows a basics means of viewing it. Give it a go, it certainly won’t
disappoint, but don’t think you will get a colour image similar like those on the internet; however
still a beautiful sight.
The Planets
Mercury
Unfortunately Mercury is not visible this month.
Venus
Visible in the morning, around 05:30 UT in the South East, and rising before the Sun this is an
impressive sight to view with the best time around the 30th of the month. Venus is located in Leo at
an altitude of 28deg and it should be easy to find.
Mars
Located in Leo at an altitude of 19deg towards the end of the month, Mars is another morning
object and the best time to view is about 05:00 ut. On the 25th of the month Mars will be 47
arcminutes from Regulus.
Jupiter
Now becoming a morning object, low in the sky at the beginning of the month, Jupiter is also
situated in Leo at an altitude of 18deg, and, similar to Mars, is best viewed at 05:00 ut on the 30th of
the month. Venus will still outshine Jupiter but both will be magnificent sights to view in the
morning sky.
Saturn
Being really low to the horizon and at an altitude of only 11deg Saturn can be found located in Libra
to the southwest look around the 1st of the month at 20:00ut.
Uranus
As September rolls on, the planet continues to move further westward and very low in the evening
sky with an elevation of approximately 44deg in the constellation Pisces. Uranus can still be viewed
with a telescope to the south west and, if we are lucky with good clear skies, you should be able to
make out its greenish blue hue. Probably the best time to view is around the 30th of the month at
01:00 UT.
Neptune
This month Neptune comes to opposition with the best time to view on the 1st at approximately
00:00 UT. Located in Aquarius at an altitude of 28deg and looking south it should be visible with a
medium to large scope.
The Moon
Third Quarter
September 5th
New Moon
September 13th
First Quarter
September 21st
Full Moon
September 28th. This Phase of the Moon is also known as a Full or
Super-Moon. The early Native American Indian tribes also knew it
as the Full Corn Moon as this was the time when they harvested
their corn. We also know it as the Harvest Moon as it is the time of
year when the full Moon occurs closest to the September Equinox.
The Moon will be at its closest approach to Earth and may look
slightly larger and brighter than usual. Of course we shouldn’t
ignore that there is also a total Lunar Eclipse on the same date
(28th). The Eclipse begins at 01:07 UT until ending at around 03:23
UT. So if the sky is clear, here is an outstanding opportunity to view
the Eclipse and if possible, take some images.
Meteor Showers
The Piscid meteor shower will reach its maximum on the 9th September with a maximum ZHR
(Zenithal hourly rate) of about 10, this shower seems to have two maxima, one on the 9th and
another on the 21st September with a third peak quoted for October.
The following quote is from Dominic Ford:
Some shooting stars associated with the shower are expected to be visible each night from Sep to
Oct. The Moon will be 26 days old at the time of peak activity, and so will present minimal
interference. The radiant of the Piscid meteor shower is at around right ascension 00h10m,
declination +07°, as shown by the green cross on the planetarium above. At midnight, it appears 34°
above your south-eastern horizon from Kirkcaldy.
Unfortunately I have been unable to get a graphic for this shower.
The September Perseids (sometimes referred to as the Epsilon Perseids) will also peak around the
9th of the month. The shower is observable from the UK around 22:00 UT, and it should be possible
to observe them all night.
Jim’s Focus of the Month
Cassiopeia
Cassiopeia is a constellation in the northern sky, named after the Greek mythological vain Queen
Cassiopeia, who boasted about her unrivalled beauty. Cassiopeia is one of the 48 constellations
listed by the 2nd-century Greek astronomer Ptolemy.
Cassiopeia is visible all year in the Northern hemisphere. With its simple 'W' shape and the
brightness of its stars it makes Cassiopeia one of the most easily recognisable constellations in the
night sky. There are several interesting deep sky objects in the constellation such as:
NGC 457, also known as the Owl cluster, discovered by William Herschel in 1787. It is also known as
the ET Cluster.
M52 is another open cluster which can be viewed with binoculars situated slightly west of Ruchbah.
M52 was discovered in 1774 by William Herschel. A nice cluster easy to view as you don’t need
sophisticated equipment
M103 is yet another open cluster and is positioned approximately 1 deg east of Ruchbah with a
magnitude of 2.66. It has been described as a sparkling open cluster which can be seen as a fuzzy
patch through binoculars. M52 was discovered by Pierre Mechain in 1781.
Remember the Milky Way passes through Cassiopeia so have a look and tell us what you see.
Did You Know?
3rd Sept 1976 Viking 2 landed on Mars.
20 Sept 1957 the first living animals, 1 monkey and 11 mice returned safely from a rocket flight.
24th Sept 1970, Luna 16 sample capsules brought back 3.6 oz of lunar soil.
29th Sept the first Canadian satellite was launched.
NLC’s
Of course by the time you read this, NLCs will have come to an end.
Below is an abstract from Ken Kennedy (Director Aurora Section BAA).
During the season several observers commented that they had a feeling that NLC activity was less
than in recent years and the Director had the same feeling, probably generated by fewer received
reports, although personally recording as many displays as in previous years. The average number of
nights during the seasons 2007 to 2015 is 60 and this year NLC was recorded on 59 nights which is
not significantly lower than the average, especially considering the very active NLC years of 2007 –
2009 when solar activity was at its lowest. From data received this year, most observers would
probably agree that displays were not as extensive as in previous years and the brightness of
displays, which is always difficult to estimate, seemed to be lower. The images recorded by the CIPS
instrument of the AIM satellite clearly showed ice in the mesosphere from May 19 and it was still
quite extensive by mid-August which suggests that poor weather and sky conditions over UK and
Europe may have been contributory to the smaller number of reports received this year. The jet
stream spent some time during the summer months close to northern Spain and this would have
produced more cloud to the north of it.
As full details emerge I will post them here as work is still continuing worldwide to analysing all the
gathered details.
Jim Barber
Director of Observations
Dundee Astronomical Society