October 2018 Cygnus

October 2018

The observing season is back into full swing this month as October 28th marks the end of British Summer Time.

The Sun

When I first saw how the size of our sun compares to some other stars I was taken aback. (See diagram.) Our star, the sun, is of average size but it is still about 100 times wider than the Earth. It is so important and necessary to our life, yet we still have so much to discover about it. Over the summer, NASA’s Parker Solar Probe was launched as humankind’s first mission to touch the sun’s outer atmosphere or corona. The probe is about the size of a family car but not a road trip that any of us would want to make due to the intense heat and radiation. The Earth is 93 million miles away from the sun but the orbit of the probe will be much closer. However, it will still be 3.9 million miles away from the sun and take until 2024 to get there! On its journey it will have to withstand temperatures of 2500 degrees Fahrenheit. In getting there it will reach 430,000 mph and become the fastest manmade object ever. The main objective of the mission is to track the energy that drives the sun’s atmosphere such as its corona and solar winds. Solar winds are important to understand and predict as they can cause massive disruption for parts of our modern everyday life, such as the loss of electrical power or communication as they become ever more vital in our society.

The Mysteries of Cygnus.

Cygnus, the swan, is a constellation easily seen due west after 9pm in the middle of the month. On a clear night it appears to be flying along the Milky Way from the Pole Star. Its main star, Deneb, the tail of the swan, is a supergiant star 200 times larger than the diameter of our sun. Part of this constellation is also known as the Northern Cross. Cygnus has been surveyed by the Kepler satellite in the search for other planets outside our solar system (appropriately called extrasolar planets). There are over a hundred stars in this region which have been identified as having planets. The most famous being the Kepler-11 system which contains at least 6 planets. There are many deep sky objects to observe in Cygnus and of particular note is the North America Nebula, so called because it really does resemble the North American continent. It is very large but quite dim and can really best be seen with binoculars.

In 1964 during a rocket flight, a very strong and strange signal was discovered coming from Cygnus. Strange because the signal indicated that it should have come from a very large object much bigger than our sun but no known object resembled this type of signal. The signal eventually was established to be one of the strongest X-ray sources recorded from Earth. It is now regarded to be a black hole (Cygnus X-1) circling a massive companion star, slowly pulling material away from it until it eventually devours its neighbour completely! So Cygnus is truly a mysterious region in the night sky. New worlds are being discovered and old ones are being ripped apart.

3 Planets to spot.

About half way through the month you will have the chance to spot 3 planets. Be sure to catch them in the early evening before they set. Jupiter, Saturn and a very bright and red Mars close to the moon in the south to south-west direction.

Stories in the Sky

September 2018

The Night Sky

The stories that are told about the patterns seen in the night sky are not exclusive to western culture. However, Greek Myths are familiar and well documented. These tales cleverly orientate the positions of what would be random white dots set against a black sky.

So during September, looking almost directly above you is what looks like a large W shape overhead. This is the constellation of Cassiopeia named after a queen, wife of King Cepheus who ruled Ethiopia. A legend exists that she proclaimed her daughter (Andromeda) to be more beautiful than the sea-nymphs. This upset the sea-god Poseidon who sent a massive wave to awaken Cetus the monster to defend the honour of the sea nymphs by eating the young people of the country! The only acceptable alternative was to sacrifice Andromeda, who was chained to the rocks, to the monster. Fortunately, she was saved by Perseus (arriving on the horse Pegasus) a now familiar figure to regular readers of these articles. All of these famous characters can be seen laid out above your head around this famous constellation. It is all collectively called the Perseus family group.

We Are Stardust

Looking closely at Cassiopeia you will see a central star that is believed to be over 50,000 times brighter than our sun. In relatively recent history two other stars within the constellation have exploded into super-novae. This is the point at which a star ends its life in a gigantic explosion. When Super-novae happen, many of the elements that are crucial to life as we know it are formed under intense and unimaginable forces. Indeed, stars during their life and death are responsible for the creation of the heavier elements that are part of us all, echoed in a popularised phrase of the 60s and song line ‘we are stardust’. It is incredible to think that part of us all have been created by elements that are only formed when stars die. Equally incredible that they then are distributed across space in such a way that they merge to make us!

Andromeda.

Andromeda has its own constellation and it contains our nearest major neighbouring galaxy, M31 appropriately called the Andromeda Galaxy. It is very similar to our own home galaxy, the Milky Way, and is the most distant object visible to the naked eye and at 2.5 million light years away, that is a long way! At the time when the light set off from this galaxy here on earth we were making stone tools. If you do see get to see Andromeda the light that enters your eyes has been travelling since then. It contains at least 200 billion stars. In the 1920s it was thought that our Milky Way galaxy was all there was out there. It wasn’t until 1925 that a man called Edwin Hubble (of the Hubble telescope fame) discovered that certain fuzzy patches in the sky were far too distant to be in our own galaxy. This finding was very radical as suddenly our universe became much, much bigger. On a clear, moonless evening in Embsay it is possible to see the central part of the galaxy with night adapted vision (see last month’s article) but it stretches much further across the sky and with binoculars or telescope you will see an oval shaped galaxy clearly, provided you know where to look. See my diagram. I’ve included a 200 second exposure I took of it last year through a telescope. The galaxy is in fact on a collision course with our own and are approaching each other at about 70 miles per second. Together they will form a larger merged elliptical galaxy at some time in the distant future….in billions of years time.

August 2018 Perseid Meteor Shower

The Night Sky August 2018

Lovely, long summer days mean hardly any real darkness, for me quite a dilemma! I am sure you don’t need to be told that during this month there is only true night darkness of 3 to 4 hours ‘astronomical twilight’. Not to worry though, as we can focus on remarkably bright objects that can be seen even without total darkness or a telescope.

Perseid Meteor Shower.

If you had no luck spotting meteors earlier this year then 11-12 August is a period to circle in your diary. This is the best time to observe the annual Perseid meteor shower, one of the best of the year. Also, it coincides with a new moon and that doesn’t happen very often! This shower can have a rate of up to 100 per hour and sometimes more. This is when the Earth passes through the debris of the great comet of 1862 known as Comet 109P/Swift-Tuttle. Looking roughly North East and half way up in the sky you find the ‘radiant’, where they will appear to originate. Follow my instructions from the April issue to help you enjoy, relax and spot meteors.

The Summer Triangle

This is a pattern that is created by 3 stars in the summer evenings. Deneb, Vega and Altair. It can be seen even in our light nights. It is important to bear in mind that this is a large pattern but easy to spot as they are almost the first stars to shine through as most are too dim at this time of year. Deneb is a huge star at least 100 times that our own sun and is famous for being the most rapidly rotating star known. Vega is one of the closest stars to our solar system and Altair also spins so quickly that it bulges out and is flattened at the poles. There are quite a few wonderful deep sky objects near or within the triangle. I’ve just picked out two that I photographed recently. If you get chance to spot the Ring Nebulae (M57) through a telescope it is very odd. Instead of seeing a bright point of light, a very distinct ring appears and it seems so out of place. After observing for a few seconds the wonderful colours of the ring emerge . This is the result of a dying star that has used up all of its fuel and has ejected its gas and dust surrounding it into space. Another unusual object to observe is the Dumbbell Nebula (M27). Through binoculars you will see a disc shape but with a telescope an hour-glass shape comes into view, again not what you expect to see! At the centre of it is a star (a white dwarf.) Research has speculated that the Nebula was created nearly 10,000 years ago, a relative youngster in astronomical terms!

Planets

Again there is quite a feast of planets to observe this month so here are a few pointers as to where and when to find Venus, Mars, Saturn and Jupiter.

Venus and Jupiter can be seen low in the south-west in the middle of the month.

Saturn low in the south between 20-21st

Mars low in the south-east around the 23rd

The Full Moon is on 26th

Adapting to the Darkness when it returns!

Giving yours eyes time to adapt to darkness is important if you want to see faint objects in the night sky. You may remember from school that our eyes contain light sensitive cells called rods and cones. Cones are what we use mainly during the daytime to see colour and brightness. When you first go into a dark environment the cones start to become more sensitive but after 10 minutes they are as sensitive as they are going to be. However, the rods continue to become more sensitive and reach their maximum in half an hour. A sudden bright light can spoil the sensitivity of both and you will have to get them used to the dark again. But by using a dim red your dark adapted vision remains intact.