The Night Sky in June 2007

Sunrise and Sunset Times for the UK

	Edinburgh Sunrise Sunset		Manchester Sunrise Sunset		London Sunrise Sunset
June 01	04:38	21:43	04:48	21:25	04:50	21:06
June 15	04:29	21:57	04:41	21:37	04:44	21:18
June 30	04:32	22:00	04:44	21:41	04:47	21:21

To find out today's sunrise and sunset times for where you are, click here

Phases of the Moon (June 2007)


Full Moon Friday 1st	Last quarter Friday 8th	New Moon Friday 15th	First quarter Friday 22nd	Full Moon Saturday 30th

Click HERE to see the phase of the Moon on each day of the month.

What's happening in the June night sky?

As we approach mid-summer we are seeing well over 17 hours of daylight each day. However, for those of you that miss the dark nights, the Summer Solstice (or longest day) on the 21st June will see the days slowly start to shorten in length again. The long days mean that you will have to stay up quite late to be in with a chance of seeing the night sky, and even then you will see the faint glow of the Sun skirting below the northern horizon.

Maps of the current night sky can be seen by clicking HERE

June 1st and 30th - Two Full Moons this month

Because the moon's phase cycle is around 28 days, every so often we will get two full moons in one month. These are fairly rare events and only happen every 3 years on average. The second moon of the month is called a blue moon - hence the term 'once in a blue moon'. The last month when this occured was July 2004, but the next time won't be until December 2009.

June 21st - Summer Solstice (Longest Day)

Height of Sun at noon

The summer solstice, or mid-summers day, is the point during Earth's orbit around the Sun when we in the northern hemisphere experience the longest period of daylight, and hence the shortest night. The change in the length of daylight is all down to the tilt of the Earth in relation to the Sun, but without such a tilt we would have no seasons. Solstice literally means a stopping or standing still of the Sun. In summer (June 21st) it marks the point where it stops rising and in winter (December 21st), where it stops falling.

The small animation shows the average height of the midday Sun for each month of the year. In winter, the Earth tilts away from the Sun and thus it appears low in the sky at noon. In summer the tilt is toward the Sun such that it rises much higher and sticks around longer. Although the solar peak is in June, the warmest months tend to come in July and August. The reason being that the energy received during the summer months is stored in the soil, buildings, water and rocks. As more energy is added, this thermal store continues to build beyond June and peaks during July and August, before reducing again as we approach winter.

Remember that whilst we are enjoying the longest day in the northern hemisphere, the reverse is true for countries in the southern hemisphere like Australia and South Africa, where their winter is at its worst during June, July and August.

What are the planets up to?

Click HERE and start the Electric Orrery to see where all the planets are today in relation to each other.

Mercury - starts the month as an evening object, sitting above the west-northwest horizon for around two hours after sunset. It reaches greatest elongation (separation from the Sun) on the 2nd June, and from then on appears to get closer to the Sun as it prepares to pass infront of it on the 28th June. This means that Mercury will be lost in the glare of the Sun from the third week onwards.

Venus - remains an evening object right through until August 2007 as it slowly catches us up on its inside orbit. In early June it can be found high above the western horizon for around 2.5 hours after sunset, setting in the west-northwest close to midnight. This moves forward an hour as the month moves on and Venus closes the apparent gap between it and the Sun. Because of its brightness, there is little chance of missing Venus on a clear evening, outshining everything in the western sky.

Mars - starts the month rising in the east around 2 hours before sunrise. This increases by a good hour towards the end of June, when Mars can be found high above the east-southeast horizon close to sunrise. Mars is increasing in both size and brightness as we continue to catch it up on our inside track. It is fairly easy to identify by looking for a reddish star shining more steadily (i.e. not twinkling as much) than the others. Mars is now a suitable target again to observe with the robotic Liverpool Telescope.

Jupiter - rises in the southeast close to sunset and can be found low above the southern horizon around 1.00 am. This time moves forward a couple of hours by the end of the month as Jupiter passes opposition (opposite side of Earth to the Sun) on the 5th June. This means that June provides the best chance for getting a decent image of Jupiter, so you might want to request an image now using Go Observing.

Saturn - continues to decrease in size and brightness as we move slowly away on our inside orbit. It can be found high above the west-southwest horizon shortly after sunset and sets in the west-northwest close to 1.00 am. This moves forward to 11.00 pm by the end of the month, meaning that June will be the last chance of getting a reasonable image of Saturn for 5 or 6 months. Why not use the Electric Orrery to see how Earth and Saturn move apart.

Constellation of the month

Each month, a new constellation is highlighted for you to identify in the night sky.

This month, we are going to see if we can find the constellation of Aquila (the Eagle) and an object known as the Summer Triangle. The summer triangle is not actually a constellation, but three bright stars called Vega, Altair and Deneb, which make up a triangular shape during the summer months. Once you've identified the triangle, it's then easy to spot the Aquila constellation because it's marked by one of the points of the triangle - the star Altair.

June Night Sky

If you could get away from streetlights and look at the night sky, you would find that our galaxy, the Milky Way, is at its brightest in the northern hemisphere in the region around the summer triangle. The image below shows how many thousands of stars in the plane (or disk) of our galaxy can appear like a fuzzy bright band stretching across the sky. You can also see dark patches within the Milky Way, which are vast clouds of dust and gas from which new stars can form.

Thankfully, you can still pick out the summer triangle stars because they are brighter and closer than most of the other stars in the picture. Note that the triangle in the image below is rotated compared to the one shown above. As a result, Vega appears at the top, Altair to the bottom right and Deneb on the left.

Summer Triangle

Because Vega, Altair and Deneb all look about the same brightness, it's easy to think that they are about the same distance away. However, Deneb is actually 100 times more distant than Altair, which is only 17 light years away. Thus for Deneb to appear almost as bright as Altair in our sky means that Deneb must be far brighter than Altair in terms of true light output. In fact astronomers estimate that it pumps out around 60,000 times more light than our Sun, while Altair outshines the Sun by just 13 times. Vega, by comparison, is 25 light-years away and some 50 times brighter than the Sun. The reason Deneb is so bright is because it's a type of star known as blue supergiant, whose size is around 200 times larger than the Sun. Because supergiants are in the last stages of their lives, it's likely that Deneb will become a supernova in the next couple of million years.

Mythology: Aquila

Aquila, the pet eagle of Zeus, showed the gentler side of his nature when he carefully carried up Ganymede to Mount Olympus to be cup-bearer to his master. However, when considering the myth surrounding Prometheus, the ferocious, darker side of Aquila is very evident. Prometheus was one of the last Titan gods who became an advisor to Zeus. He was protective of humankind and, seeing how they suffered because they had no fire, he stole a ray from the Sun which he smuggled down to earth in a hollow stem. Zeus did not believe that man was worthy of such a gift, and was furious that Prometheus had acted without his permission. The well-meaning Titan was chained to the side of a mountain, stripped of his garments, and was continually attacked by Aquila. Since he was immortal, his dreadful wounds healed themselves every evening, only to be opened up again the next day by Aquila. After many years Prometheus was saved by Hercules, who agreed with his kind deed to mankind. Using his bow and arrow, he killed Aquila, who was then placed by Zeus to soar in the heavens.