Sky notes are compiled by Dundee Astronomical Society's Director of Observations Jim Barber
Sky Map for 15th July 22:00
Well here we are in July and with the nights becoming longer again so I suppose now is the time to start planning our Autumn - Winter observing. However, let’s not be too hasty as there are still wonderful objects to view in the night sky. Vega to the South, Deneb to the east and slightly above Vega and Altair well below, all forming the asterism ‘The Summer Triangle’. Contained here are four constellations - Lyra, Cygnus, Vulpecula and Sagitta. Let’s begin with Lyra - there is M57 the Ring Nebula a fabulous object to image, next comes the double-double start Epsilon Lyrae. Easy to see the double but difficult to see the double-double star. For this, in my experience, you will need access to at least an 8” telescope and quite a high magnification, but well worth the view. Let’s now move to Cygnus the Swan. Deneb represents the tail and Albireo the Swan’s beak - this is also a very nice double star with a lovely blue and orange pair. As you move down from Deneb you will see Gamma Cygni where the body and wings meet where you will come across M29 an open cluster. Cygnus is also known as the Northern Cross. Moving on again we come to Vulpecula where the first object to view is M27 the Dumbbell Nebula and like M57 it makes a nice image to capture. Moving to the west of M57 is my favourite object to view in Binoculars, the Coathanger. Now moving down to Sagitta, we come across M71 an open cluster. Of course, we shouldn’t forget the Milky Way as it flows North to South through the Summer Triangle. Good hunting and enjoy.
Mercury In Cancer and best seen at the beginning of the Month around the 7th just below and to west of Venus.
Venus In Leo, a very bright object in our night sky just North of West and starting to lose altitude.
Mars In Capricornus Reaching opposition on the 27th of the month, Mars remains low in our sky.
Jupiter In Leo, best time view 1st July around 21:40 UT still high in our Southern sky at present, good viewing if you get a chance.
Saturn In Sagittarius, getting close to its best for the year, unfortunately never gets high in our sky, but still worth having a look. Try looking out for it on
the 1st around 00:00 UT.
Uranus In Aries and is slowly creeping back into view just above the head of Cetus the Whale. Best viewed on the 31st around 01:15 UT
Neptune Resident in Aquarius, probably seen close to the end of the month.
Dundee Astronomical Society
Third Quarter 6th July
New Moon 13th July
First Quarter 19th July
Full Moon 27th July
Look out for a Lunar eclipse on the 27th of the month when the Moon will rise fully eclipsed at sunset. Totality will occur at 19:30 UT, and end at 21:13 UT. Lets hope for clear skies and that we can see this event.
Delta Aquarids - is an average shower that can produce up to 20 meteors per hour at its peak. It is produced by debris left behind by comets Marsden and Kracht. The shower runs annually from July 12 to August 23 and it peaks this year on the night of July 28 and morning of July 29. The nearly full moon will be a problem this year, blocking out all but the brightest meteors.
Ken's July Moon
Summer is a difficult time for dark sky observation and it's often said that "there's always the Moon". Well, yes, the Moon is around but phases between first quarter and last quarter find the Moon very low in the southern sky. Phases from new to first quarter and from last quarter to new can be observed but by the time the Sun is low enough and the sky dark enough the elevation of these phases is not great either.
The days leading to first quarter will be best seen between the 16th and 19th July while the phases from last quarter will be best from the 6th to the 9th, but these will require an early start- around 4am to avoid bright skies.
With the relatively low position of the Moon and bright skies it will be more difficult at this time of year to look at any really fine detail on the Moon so let's have a look at the major craters on or near the terminator on the morning of July 7th and the evening of July 18th.
An early rise at around 4.30am on July 7th will see the phase of the Moon at 23 days in the south-east. Moving from north to south the terminator bisects Mare Imbrium with Sinus Iridum being well placed to see the sweep of the bay. It's worth looking at this alone as you will be familiar with it as seen on the waxing Moon but the shadow cast by Promontorium Laplace gives quite a different appearance to this feature. Further north the Mare Imbrium is broken by the Montes Carpatus and then we find Copernicus sitting just on the bright side of the terminator. The shadows cast by the central peaks will be quite elongated and not so familiar at this lunar phase. Copernicus at this time is worth a close study with, if atmospheric conditions permit, high magnification. I think the next crater northwards to catch the eye is Bullialdus, only 61 km in diameter but a beautifully formed and striking crater. Nearly in line with the obvious, and larger, crater Gassendi, Bullialdus is worth examining under higher magnification. Observers have mentioned a conspicuous radial structure on the outside of the crater, but I can't say I have been aware of this. Moving southwards you will reach the chaotic southern cratered region and one of my favourites, Clavius, is emerging from shadow. Look carefully at what is exposed of the floor of Clavius as this is the time to see detail which you will not see at other phases. Look for small craters which you may just pick up with good seeing - a fine test of any telescope.
A much more civilised time for observation on the 18th July from about 9.30pm and looking south-west with the Moon 6 days old. Again, moving from north to south you may just see the eastern end of the crater Aristoteles (a) emerging from shadow. 87 km in diameter it has terraced walls and any large crater is worth looking at as it emerges into lunar morning. Southwards the terminator bisects Mare Serenitatis (b) and in the passing note the winding Dorsa Smirnov (c), a prominent lunar wrinkle ridge running north - south for 130 km. These ridges are only about 100 m high and give the impression that they have been formed by cooling and contraction of mare basalt. Just north of mid-way along the terminator we see the craters to the west of Mare Nectaris which I have described previously. The chain of Theophilus, Cyrillus and Catharina (d) is always striking with the Rupes Altai (e), or Altai Scarp as it is more popularly known, running north-eastwards and prominent at this phase. As you move north from the Altai Scarp the lunar landscape becomes pitted with craters, but none is particularly large or notable on the six-day old terminator.
At this time of year, it is worth generally getting to know the key features, the maria and craters, on the Moon so that you can concentrate on details later in the year as the skies darken and the position of the Moon is more favourable. Unfortunately, autumn is not the best time to view the Moon at a civilised hour as the waxing Moon tends to be low in the sky and the Moon towards last quarter is more favourably placed- but at unfavourable hours!
I have used one of my own images which is nearest to the phase on 18th July and labelled features as in the text from north at right of image. I could not find a good likeness to the phase for July 7th, so you will have to dig out a moon map!
We have the first sightings of NLC's this season. Ken Kennedy captured this image on June 1st - 2nd just after midnight and again on the evening of the 18th at 22:40 UT. Good one Ken. If you see or capture an NLC, please send details to Ken and/or, myself, including date, time (please state UT or Local) and location.
Comet spotting. Comet 21p/Giacobini - Zinner is in our skies this month, Starting at Mag +10.9 at the start of the month increasing to +8.9 by the end of the month. You will need, at least, a pair of binoculars but I would suggest a medium telescope to view with any certainty (weather dependant). Its track is shown in the image below (courtesy of Sky At Night Magazine). Have a go and give us any updates.
Jim's Focus of the Month
M51 The Whirlpool Galaxy in Canes Venatici (magnitude +8.5), is a beautiful spiral galaxy with a small companion nearby NGC51954. When viewed with a medium to large scope both galaxies can be seen, but I would imagine you need good seeing conditions to fully appreciate the majesty of this pair. To find M51 it is south and to the right of Alkaid in the handle of the plough and therefore is quite high in the sky. If you have difficulty in making out any detail, try using averted vision, this often works. Go have a look and enjoy the view.
Stop Press - Annie Maunder
The Royal Observatory Greenwich (ROG) is to start studying the sky again after a break of 60 years. The new telescope is named after a forgotten giant of UK astronomy, Annie Maunder, who had to battle the prejudice and conventions of her time (the end of the 19th and beginning of the 20th Century). The move should help highlight her contributions for a new generation.
Did You Know?
4th July 2016 Juno arrived at Jupiter to understand the evolution of the planet.
10th July 1962 Telstar 1 a US communications satellite beams the first live transatlantic telecast.
15th July 1972 Pioneer 10 on its way Jupiter becomes the first spacecraft to travel through the Asteroid Belt.
15th July 1975 First Joint USSR-US mission The Soyuz Apollo Test Project is launched.
20th July 1976 Viking 1 lands on Mars and returns the first pictures of the planets surface.
21st July 2011 Space Shuttle Atlantis lands safely, ending the space shuttle program
Director of Observations
Dundee Astronomical Society