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Home -> Astronomy News -> Events -> July 2015
Post Info TOPIC: July 2015
Blobrana


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RE: July 2015
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Highlights
 
JULYROBOT.jpg
The Summer Triangle-- Vega, Deneb, and Altair -- holds the central position, high in the south. The scorpion sits low to the south and slightly west. Directly to the arachnid's east is Sagittarius, the Archer, and between the two lies the direction toward the Milky Way galaxy's centre. The ribbon of soft light that delineates our galaxy flows up from the south, through the Triangle, and then cascades toward the northern horizon.
 
Trifid and Lagoon Nebulas
By mid-month the distinctive "Teapot" of Sagittarius should be hovering above the southern horizon.
Looking towards the right of the lid of the teapot and a little to the right is the delicate Trifid Nebula, "M20". A nebula is simply a cloud of interstellar dust and gas, the raw materials that stars are made of. If there are already stars embedded in the cloud it will glow with an eerie ghostlike appearance forming such vistas as the Great Orion Nebula, or this one, the Trifid. Sporting two patches of nebulosity, one red the other blue, this is one of the finest objects in the sky and very easy to find in binoculars. Just slightly below M20, is the rosy red Lagoon Nebula, which goes under the profoundly less romantic name of "M8". This is one of the best diffuse nebulas for naked eye observers, surrounding the small young star cluster NGC6530. The nebula is known for having a number small dark globules of material believed to be stars at the very beginning of formation, sometimes called protostars. Overall M8 is over 100 light years across, with its central regions a more modest 50 light years in diameter. It is also one of the largest in the sky, challenging the full moon for size.
 
M51 The Whirlpool Galaxy
Summer is the time for the galaxies.
As the earth swings around in its orbit the night skies are aimed away from the centre of our own galaxy, the Milky Way. No longer does the body of the Milky Way block the skies, now we can look out into the depths of space. One of the most spectacular is M51, better known as the Whirlpool Galaxy located right below the handle of the "Big Dipper". This was the first ever to be seen as in the classic spiral form, in the mid-19th century. While visible in the smallest instruments, its twisted nature will not show in anything less than an eight-inch telescope. With a luminosity of 10 billion suns and a diameter of 100,000 light years, M51 is roughly equivalent to M31, the great Andromeda galaxy and in turn, our own home. The Whirlpool is about 35 million light years away and glows at a genial eighth magnitude. In the sky it is seen face on and is about 1/3rd of the visual width of the Moon. It should be visible as a dim fuzzy patch in a pair of binoculars in a very dark sky. If you are lucky in that regard, step outside and see what you can see tonight.
 
Notable Messier objects
M3 is one of more heavily studied globular clusters due to its position in the galaxy, putting it far above the interstellar dust and gas that dim its light. More than 200 variable stars have been observed out of a total of near 50,000. Being one of the brightest
globulars, M3 is regarded as one of the most striking in the sky. A 60mm scope will begin to reveal hundreds of its magnitude 11 stars, while larger instruments may show arms or branches radiating from the sides.
M5: A Nice Globular Cluster
Located in the "head" half of the split constellation, Serpens, you will find the smashing globular cluster, M5. These are round, concentrated clusters of old stars which usually collect into halos surrounding galaxies. They contain between 100,000 to 10 million stars and are typically 100 light years across. Globulars are wonderful objects in small telescopes due to their perfectly rounded shape and the delicate glistening of the nucleus.
Omega Centauri in the southern skies is by far the best. northerners can relish M13 in Hercules, M3 and now M5, which are, considered one of the finest in the sky. It's 13 billion year age makes M5 one of the oldest clusters known. Easily visible in binoculars it takes at least a four-inch telescope to be able to resolve some of its ½ million stars.


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Blobrana


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Meteor Showers

July has three main meteor shower: the Capricornids are active over July with peaks on the 8th, 15th and 26th, although the maximum rate is only about 5 meteors per hour. The Delta Aquarids are active from 15 July with a peak on the 29th of 10-20 per hour. The Alpha Cygnids will peak on the 21st July when you can see up to 5 shooting stars per hour.

ShowerActivity PeriodMaximumRadiantVelocityZHR
  DateR.A.Dec.km/s 
Beta Taurids(daylight)June 5-July 1829th June79.4 °21.2 °  
Capricornids8th8th July °  
July Phoenicids10th -19th July10th July    
Ophiuchids15th15th July18.9h-22.6°13.4km/s5
Alpha Capricornids 16th July    
Perseids17th July - Aug 24th10-14 August    
Alpha Cygnids 21st July   5
Capricornids26th26th July    
Kappa Cygnids 27th July    
S. Delta-AquariidsJuly 14-Aug 1830th July3.9h-51.8d14 km/s11.2
Scorpius-Sagittariids 31th July20.2h-24.6°10.5km/s5



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Blobrana


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Mercury: at magnitude -0.2, starts the month in the constellation of Taurus.  Mercury is at Perihelion on 16th. The planet is at superior Conjunction on 23rd.  
(On July 1st, RA= 5h07m29s  Dec=+20°36.9' (J2000) Distance=0.965AU  Phase k=52%  Diameter=7.0")

Venus: is at magnitude -4.6. The planet is in the evening sky in the constellation Leo at the start of the month. Venus is close to Jupiter on the 1st. Venus is near to the star Regulus on 15th July.
(On July 1st, RA= 9h35m50s  Dec=+14°51.1' (J2000) Distance=0.514AU  Phase k=33%  Diameter=32.5")

 phase.gif

 

Earth: The Earth-Moon barycentre is at aphelion (1.0167 AU) at 12.42.1 UT, 5th.  The Earth reaches aphelion (its farthest point, 1.0167 AU, from the Sun) at 19:40.8 UT, 6th July.

The Moon:  Full moon at 02:19.6 UT, 2nd July, and again at 10:42.9 UT, 31st July. Lunar perigee is at 19:00.5 UT, 5th July.  Last Quarter Moon is at 20:24.0 UT 8th July.  The New Moon is at 01:24.3 UT, 16th July. Lunar apogee is at 11:07.2 UT, 21st. First Quarter Moon at 04:04.0 UT, 24th July, 2015.

Mars: at magnitude 1.6 starts the month in the constellation Gemini. The planet is mostly unobservable this month. Mars is in conjunction (separation ~8') with Mercury on 16th July. .
(On July 1st, RA=13h07m31s  Dec= -7°43.3' (J2000) Distance=0.994AU  Phase k=87%  Diameter=9.4")

Jupiter: The planet is at magnitude -1.8 in the constellation Leo.  The Moon is 6° from the planet on the 18th.
Transit times of the Great Red Spot are posted in a separate thread.
(On July 1st, RA= 9h36m44s  Dec=+15°08.6' (J2000) Distance=6.086AU  Diameter=32.3")

Saturn: at magnitude 0.3 sits in the constellation Libra. Saturn is about 6° from the Moon on the 25th. Saturn's rings are tilted ~24 degrees to our line of sight.
(On July 1st, RA=15h48m19s  Dec=-17°50.9' (J2000) Distance=9.192AU  Diameter=18.0")

Uranus: is in the constellation Pisces. Uranus at magnitude 5.8, has a bluish-green hue and appears 3.5 arcseconds wide. Uranus is stationary on the 26th.  
(On July 20th, RA= 1h15m52s  Dec= +7°19.2' (J2000) Distance=19.833AU  Diameter=3.5")

Neptune: is at magnitude 7.8 in the constellation Aquarius.
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Pluto: is in the constellation Sagittarius (mag 14.1). Normally, a finder chart is necessary to help in identifying the 0.13" diameter dwarf planet. The dwarf planet is at opposition on the 6th July.
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The Sun enters the zodiac sign of Leo at 03:30 UT on the 23rd July, 2015.



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