I am a Freelance Writer-Photographer and Novelist. I travel to find inspiration, wherever the distant horizons lead.
Published February 11th 2015
Unravel the night sky's mysteries and learn about astronomy
After the last article, I am hoping budding astronomers have been outside and know where to find the major compass points. It is assumed you will be outside between 9pm and midnight, allowing it to become completely dark, and it should be noted that the stars in question will move a good distance across the sky as the night progresses. The sky will look completely different if you make an early morning vigilante.
From areas within several hundred kilometres of Melbourne, it is mid-summer, and the first thing you will notice in the north is the dominating constellation of Orion the Hunter. Being a constellation invented by people of the northern hemisphere, he is upside-down from our perspective. Most people may recognise his belt and sword and refer to them as the Saucepan. His shoulders and knee-caps are marked by 4 brighter stars seen further from the belt and sword, and named clockwise from bottom-right; Betelgueuse, Bellatrix, Rigel, and Saiph. Orion's head is marked by a triangle of 3 fainter stars at the bottom of the figure, keeping in mind he is standing on his head! See the photo to the right and see if you can start by finding the Saucepan. It may even help if you take your computer outside. A moonlit night will help, being a constellation of brighter stars, it will stand out better. I hope you have a notebook, tablet or phone with a good screen.
The most notable feature of the constellation is the middle star of the sword. It is the Orion Nebula, a gaseous cloud some 1300 to 1600 light years distant and it is illuminated by the stars within. As we see the nebula today, we are looking at history from light traveling through space for some 1300 to 1600 years; opinions seem to vary considerably. A light year is the distance traveled by light in a year (light travels at about 300,000 kilometres per second). Distance expressed on a cosmological scale really is mind boggling and will leave you in awe of our vast universe. The new stars in our universe are born of the gas that surrounds them, such as the Orion nebula. The nebula can be seen as a faint fuzzy patch, even through small telescopes. The object was listed by Charles Messier circa 1765, who compiled a list of 110 stellar objects not to be confused with comets. The Orion Nebula is referred to as M42, Messier's listed item number 42.
To best see M42, use the averted vision technique; which involves looking to the side of the object being viewed, and the light falls on a more sensitive part of the retina inside our eye. You will need a telescope of at least 50mm diameter, to gather enough light for it to be visible. In addition, learn to keep both eyes open when looking through a telescope, to reduce eyestrain. The mind soon learns to ignore the unused eye's input.
The Coal Sack is dust and debris blocking light from the distant arm of our galaxy, the Milky Way.
Another point of interest is in the constellation of the Southern Cross. If you are located well away from city and town lights, you may see the Coal Sack, a darker patch caused by dust and debris in space. This dust and debris is blocking the faint, hazy light of the distant Milky Way behind it. It must be dark enough for the Milky Way to be visible, and city lights will blot it out. The Milky Way is the local arm of our own spiral type galaxy. Refer to the time-lapse photo to the left.
The Magellanic Clouds, seen near the Southern Cross.
There is a spectacular and lesser known sight in the southern skies, that being 2 irregular galaxies that lie just outside our own. These can be seen clearly on a dark night as larger fuzzy patches, even to the unaided eye. To find them, first look due south and find the Southern Cross. This is approximately 40 degrees to the west of the South Celestial Pole and is pointing roughly toward the Magellanic Clouds, our irregular galaxies. These are about the same distance from the South Celestial pole to the east, and slightly higher than the Southern Cross. Refer to the photo to the right.
In the east, a very bright star is rising just after sunset. Other than the sun, the brightest star in the sky seen from earth is Sirius A, and that is in the Constellation of Canis Major to the northwest of Orion. That means the rising star, that is even brighter that Sirius A, must be a planet. It is the planet Jupiter and a tiny disk can be seen in most small telescopes. The 4 small dots of light close by are the 4 Galilean moons (only visible through your telescope), named so as they were discovered by Galileo Galilei, the Italian astronomer in 1610 A.D.
A 30 second exposure of the Southern Cross and Pointers.
If you are already eyeing-up your budget and contemplating a telescope, the next step maybe a book on astronomy for more in-depth knowledge. A good local supplier for telescopes is Optics Central and to see their website, click here. Their service is great, they are helpful and informative. To find a good specialist astronomy book supplier click here. Another good tool is a good calendar that marks the phases of the moon. Note that the moon will blot out faint stars, nebula and galaxies for roughly half the month. However, some of your most amazing observations with a telescope could be of the craters of the moon along the shadow edge. The sharp relief and shadows highlight the rugged lunar landscape, and some of the deepest craters and highest mountains will have you enthralled. Observe the shadow edge progressing across the lunar landscape and the daily change in position will highlight many different lunar features. Whichever way you look at it, our universe provides endless fascination, which can be a lifelong pursuit. To see an online star chart click here.
Pleiades is the small star cluster on the tree tops.
The right-hand photo shows the star cluster the Seven Sisters as it sets in the northwest. It is an open type star cluster and is visible to the naked eye. It is located in the constellation of Taurus and has an alternate name of Pleiades. Have a look through a good pair of binoculars if you do not have a telescope. You will be surprised!
The next article will discuss star charts, other planets, star observations, brightness and how to tell what stars your telescope will allow you to see.