Saturday 22 September 2012

The Orion Nebula


You know that the summer is gone and winter is not too far off when the Orion constellation once more adorns our night sky in all its glory. If you want a friend, acquaintance or even your six-year old son to become enraptured with backyard astronomy, there are four things you should show him through your telescope - the Moon, Jupiter, Saturn and, the crowning jewel of them all - the Orion Nebula.

Even the non-astronomer will probably be able to spot the famous line of three stars pictured below, known as Orion's Belt. Just below that 'belt' is another line of stars - Orion's Sword, and the Orion Nebula is right in the middle of that 'sword'.


'Just' 1,300 light years away from us, the Orion Nebula is the closest nebula to us, and the brightest, so it can be seen with the naked eye. What you'll probably see is pictured below - a tenuous, but clearly visible, hazy patch of light. a few rather bright stars. These stars are what illuminates the clouds of dust and gases of the nebula, which otherwise would not be visible at all. The brightest of these stars are Theta–1 and Theta–2.


With a telescope, though, and in good observing conditions, you will be able to see the full extent of the nebula and perhaps even glimpse it's greenish blue hue, perhaps even a reddish tint. 


However, you will need either time-lapse or long exposure photography to view the nebula in all its colour and glory. The picture at the top of this article was produced using afocal photography, viz. a camera attached by adapters and T-Rings to a 26mm eyepiece on the telescope and operated remotely by computer. I took 24 exposures, with each exposure lasting 3 seconds (to minimize the star-trailing), and the 24 images were then 'stacked' together  


in black and white, as in the picture below, you can see that the contrast improves and one can actually make out the areas of swirling black clouds of nebular gas.


The nebula is a vast, cold cloud of gases and dust that does not emit light and is composed mainly of hydrogen (91%), helium (9%), carbon (0.05%), oxygen (0.02%), and nitrogen (0.02%), as well as smaller quantities of sulphur, neon, chlorine, argon, and fluorine. The gases and dust reflect the light of the nearby stars, but in the vicinity of the hot young stars the gases in the nebula are excited by the ultraviolet light emitted by these stars and so emit their own light. Although the nebula may appear tenuous and transparent, this 'clouds' actually contains the matter of 10,000 Sun-like stars! It is from such 'clouds' that stars like our sun and even planets like ours are 'born' and the Orion Nebula has revealed much to astronomers about the process of how starsand planetary systems are formed from collapsing clouds of gas and dust.

All photographs on this page  © Sabri Zain 2012.

Mystery object passing Jupiter


While taking a series of four 3-second time lapse photographs of Jupiter and its moons on Thursday night, I captured an object moving which I cannot fully explain. You can see the object moving below Jupiter in the video above, moving in the opposite direction of Jupiter rising in the night sky. This series of pictures was taken over a period of about two minutes, so it's too slow or distant to be an earth-bound aircraft. It is headed in the opposite direction as the motion of the night sky, so it's not a star or solar system object. And it's not a reflection of light on the lens, hot pixel or other photographic artefact, as these would be stationary and not appear to move. So what in the Universe could it be? The mind boggles.

Below are the four photographs taken, so you can have a closer look and perhaps help me work out what exactly that object is. These were taken afocally,  viz. a camera attached by an adapter and T-Ring to a 26mm eyepiece on the telescope and operated remotely by computer. Each exposure was for 3 seconds. Unfortunately, I could not take any further photos of the object, as it had gone past the eyepiece's field of view after the fourth shot.





All photographs on this page  © Sabri Zain 2012.