* Astronomy

Blobrana · L

July 2012

Blobrana · L

Eyes on the Sky: July 2 thru July 8

How to find the elusive Mercury this week in the evening sky, as well as a star cluster nearby and how to see the phases of Mercury. The Moon is full on July 3rd, washing out many deep sky object opportunities, but there are still ways to enjoy the Moon itself - and! - how to do some real science on lunar craters! All that, plus how to spot the changing motions of Mars, Saturn, Jupiter and Venus this week.

Blobrana · L

                                 July
 d  h                                  d  h
 1  1  Mercury greatest elong E(26)   15 14  Venus 3.8S of Moon
 1 14  Antares 5.1S of Moon           16  1  Moon furthest North (21.6)
 1 17  Moon at perigee                19  4  NEW MOON
 2  4  Moon furthest South (-21.7)    20  7  Mercury 0.5N of Moon    Occn
 3 12  Pluto 1.0N of Moon      Occn   21 17  Regulus 5.5N of Moon
 3 18  FULL MOON                      24 19  Mars 4.0N of Moon
 5  2  Earth at aphelion              25 15  Saturn 5.7N of Moon
 7  9  Neptune 5.7S of Moon           25 16  Spica 1.1N of Moon      Occn
 9  7  Venus 0.9N of Aldebaran        26  8  FIRST QUARTER
10  4  Uranus 5.0S of Moon            28 20  Mercury inferior conjunction
11  1  LAST QUARTER                   28 21  Antares 5.2S of Moon
13 16  Uranus stationary              29  8  Moon at perigee
13 17  Moon at apogee                 29 12  Moon furthest South (-21.5)
14  5  Mercury stationary             30  5  Jupiter 4.7N of Aldebaran 
15  2  Jupiter 0.5S of Moon    Occn   30 20  Pluto 0.9N of Moon      Occn
15  8  Aldebaran 4.9S of Moon

Blobrana · L

Local time of Rise and Set (Scotland)

 Date        Sun        Mercury       Venus         Mars      
          Rise  Set    Rise  Set    Rise  Set    Rise  Set    
Jul  1    3 11 21  0   5 40 22 11   1 48 17 53  11 10 23 32   
Jul  6    3 16 20 57   5 52 21 50   1 33 17 37  11  7 23 14   
Jul 11    3 23 20 52   5 55 21 25   1 21 17 26  11  4 22 57   
Jul 16    3 31 20 46   5 46 20 57   1  9 17 19  11  2 22 40   
Jul 21    3 39 20 38   5 24 20 26   0 59 17 15  10 59 22 23   
Jul 26    3 48 20 29   4 50 19 55   0 50 17 13  10 58 22  7  
Jul 31    3 58 20 19   4 10 19 28   0 43 17 14  10 56 21 50

 Date       Jupiter       Saturn       Uranus      Neptune
          Rise  Set    Rise  Set    Rise  Set    Rise  Set
Jul  1    1  8 17 59  13 29  0 18  23 34 12 17  22 48  8 39
Jul  6    0 51 17 45  13  9 23 58  23 14 11 58  22 28  8 19
Jul 11    0 34 17 31  12 50 23 39  22 54 11 38  22  8  7 59
Jul 16    0 17 17 17  12 32 23 19  22 34 11 18  21 48  7 38
Jul 21    0  0 17  3  12 13 22 59  22 15 10 58  21 28  7 18
Jul 26   23 43 16 48  11 55 22 40  21 55 10 38  21  8  6 57
Jul 31   23 26 16 33  11 37 22 20  21 35 10 18  20 48  6 37

Blobrana · L

Venus is close to Jupiter in the morning sky

Blobrana · L

Mercury is at its Greatest Eastern Elongation (26 Degrees) on the 1st July, 2012.

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Asteroid (20) Massalia is at Opposition on the 6th July
Asteroid (19) Fortuna is at Opposition on the 14th July
Asteroid (67) Asia is at Opposition on the 21st July

Blobrana · L

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 21^stJuly when you can see up to 5 shooting stars per hour.

Shower	Activity Period	Maximum	Radiant		Velocity	ZHR
		Date	R.A.	Dec.	km/s
Beta Taurids (daylight)	June 5-July 18	29th June	79.4 °	21.2 °
Capricornids	8th	8th July		°
July Phoenicids	10th -19th July	10th July
Ophiuchids	15th	15th July	18.9h	-22.6°	13.4km/s	5
Alpha Capricornids		16th July
Perseids	17th July - Aug 24th	10-14 August
Alpha Cygnids		21st July				5
Capricornids	26th	26th July
Kappa Cygnids		27th July
S. Delta-Aquariids	July 14-Aug 18	30th July	3.9h	-51.8d	14 km/s	11.2
Scorpius-Sagittariids		31th July	20.2h	-24.6°	10.5km/s	5

Blobrana · L

Highlights

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.

Blobrana · L

Mercury: at magnitude 0.6, starts the month in the constellation of Cancer. Mercury is at Greatest Elongation (25.7° East) at 2:00 UT, 1st July. Mercury is best seen from 21.5h -22.1h. The planet is at aphelion (distance to sun: 0.4667 AU) at 04:20 UT, 12th July. Mercury is at inferior conjunction on the 28th July, 2012.
(On July 1st, RA= 8h33m23s Dec=+18°45.6' (J2000) Distance=0.818AU Elongation= 26° Phase k=39% Diameter=8.2")

Venus: is at magnitude -4.4. The planet is in constellation Taurus at the start of the month. It is best seen from 2.0h -17.9h. Venus is close to Jupiter on the 1st July. Venus is close to Aldebaran on the 9th July. The planet is at aphelion (distance to sun: 0.7282 AU) on the 11th July. The Moon is close to Venus on the 15th July.
(On July 1st, RA= 4h25m49s Dec=+17°29.0' (J2000) Distance=0.374AU Elongation= 32° Phase k=16% Diameter=44.6")

Earth: The Earth is at aphelion (distance to sun: 1.0167 AU) at 3:32.1 UT, 5th July.

The Moon: Full Moon (diameter: 32.695') at 18:51.9 UT, 3rd July. Lunar perigee (distance: 356007.1 km, apparent diameter: 33'34.0") at 18:10.6 UT, 1st July. Last Quarter Moon (declination: 10.89°) at 1:47.9 UT, 11th July. Lunar apogee (distance to moon center: 398368.4 km, apparent diameter: 29'59.9") at 16:50.6 UT, 13th July, 2012. New Moon (diameter: 30.459') at 4:24.0 UT, 19th July. First Quarter Moon at 8:56.2 UT, 26th July, 2012.

Mars: at magnitude 0.9 starts the month in the constellation Virgo. Mars (+1.0 mag.) passes 3° from the double star Gamma Virginis (Porrima) on the 22nd July. The Moon is close to Mars on the 24th July, 2012.
(On July 1st, RA=11h56m55s Dec= +0°46.4' (J2000) Distance=1.424AU Phase k=88% Diameter=6.6")

Jupiter: is in the constellation Taurus. At magnitude -2.1, the planet is obserable in the morning sky. A thin crescent Moon is close to Jupiter on the 15th July, 2012.

Transit times of the Great Red Spot are posted in a seprate thread.
(On July 1st, RA= 4h09m03s Dec=+20°12.6' (J2000) Distance=5.805AU Diameter=33.9")

Saturn: at magnitude 0.7 sits in the constellation Virgo. The planet is best seen from 21.5h - 0.2h. Saturn is at quadrature on the 15th July, 2012. The Moon is close to Saturn on the 25th July.
(On July 1st, RA=13h27m30s Dec= -6°26.0' (J2000) Distance=9.475AU Elongation=102° Diameter=17.5")

Uranus: is in the constellation Cetus. Uranus at magnitude 5.8, has a bluish-green hue and appears 3.6 arcseconds wide. Uranus is stationary: Getting Retrograde on the 13th July. Asteroid (2) Pallas is close to Uranus (+5.8 mag) on the 14th July.
(On July 19th, RA= 0h31m49s Dec= +2°38.3' (J2000) Distance=19.726AU Diameter=3.6")

Neptune: is at magnitude 7.8 in the constellation Aquarius. The planet is best seen the morning sky. Neptune is stationary: Getting Retrograde on the 4th June, 2012. The Moon is close to Neptune on the 10th June, 2012.
(On December 1st, RA=22h01m53s Dec=-12°38.9' (J2000) Distance=30.174AU Elongation= 79° Diameter=2.2")

Pluto: is in the constellation Sagittarius (mag 14.0). Normally, a finder chart is necessary to help in identifying the 0.13" diameter dwarf planet. The dwarf planet is best seen from 22.6h - 1.7h. Pluto was at Opposition on the 29th June.
(On May 1st, RA=18h39m14s Dec=-19°13.3' (J2000) Distance=31.684AU Diameter=0.1")

The Sun enters the zodiac sign of Leo at 10:01 UT on the 22nd July, 2012.