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NASA Image of the Day
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| The latest NASA "Image of the Day" image. |
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Cloud streets off of the Aleutian Islands
Strong winds polished the snow of southwestern Alaska and stretched marine stratocumulus clouds into long, parallel streets in early January, 2012. After crossing Bristol Bay, the winds scraped the clouds across the tall volcanic peaks of the Aleutian Islands. As the wind impacted the immobile mountains, the airflow became turbulent, swirling in symmetric eddies and carving intricate patterns into the clouds on the leeward side of the islands. At the top of this image, the bright white color indicates a thick layer of snow overlying the land of southwestern Alaska. The pristine white is broken by the rugged Ahklun Mountain Range in the east, which is partially covered by a bank of clouds. Off the coast of Alaska, sea ice floats in Bristol Bay, cracked and chipped by the flow of the waters which lie underneath. A few cloud streets – parallel lines of clouds – can be seen in the far northwest over land. The clouds increase over the sea ice and become thick over open water, where row upon row of clouds lie close in perfectly parallel formation. The Aleutian Islands stretch from northeast to southwest across the image. Sea ice, which is bright white here, lies on the windward side of the islands. A few of the tallest volcanic peaks can be seen rising from the icy islands. The character of the cloud streets change as they impact the Aleutians, especially near the center of the image, where two rows of beautifully symmetric swirls of eddies in the clouds stretch across the sky. These swirling formations are known as von Karman vortex streets. This true-color image was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite on January 11, 2012. Image Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team
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Townsville Astronomy Group
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Written by Lex
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Wednesday, 21 December 2011 09:06 |
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You may think about astronomy for awhile and then one morning you wake to the idea of scope ownership and what a great idea it is, but!!! There is a whole heap of things to be considered before you take that step towards purchase of your optical device. Firstly, is it a knee jerk reaction – have you recently viewed the galaxy (or a very small portion of it) in a friends ‘super’ telescope, possibly a 10-12 or 14” or maybe viewed a television documentary on the universe or some such. Please don’t get me wrong, in fact, join the club. Most of us start off in a similar fashion. You must however, realise that the image you were looking at was through a large aperture telescope or enhanced for TV and you won’t achieve that same image quality in a smaller instrument, or at least not immediately. My first telescope was indeed a ‘Tasco’ 60mm Refractor with a small battery motor on the RA Axis and when I eventually learned how to align it correctly on ‘Celestial South’ – the views of the Moon, Venus and Jupiter etc. simply blew me away. It wasn’t long though before my 60 odd year old eyes were yelling at me for a larger aperture device, which came along in the form of a ‘Skywatcher’ of slightly larger dimensions. My new scope was a 130mm, 1000mm Focal Length Newtonian which I enjoyed to the fullest. Suddenly my targets were clearer and the objects I viewed were larger and I reckon more detail was evident in the eyepiece. You can now see where I’m heading with this but more about my experience later.
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Written by Lex Howard
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Thursday, 17 November 2011 17:44 |
The sun is our ‘giver of life’ but it will take it very quickly if given cause, our friend and enemy, the governor of seasons and master weather maker-controller. Master irrigator, the sun can and does move vast amounts of moisture around our planet with impunity aided by wind currents etc.
In days gone by I have been astounded by the amount of water it could move or indeed remove from one of our major cities water supply dams – tens of millimetres in one day spread over the entire dams surface is one ‘heck’ of a lot of water.
If one was to take note of that sort of evaporation on a smaller water supply such as ‘farm’ dams for instance, the water loss can be catastrophic and in places over seas such as north eastern Africa, to mention only one spot (Ethiopia for instance) life is lost every day to thirst and dehydration. However, that same evaporation on a really grand scale is, in another location on earth the devastating flood that seems to generate and strike from nowhere.
Imagine if you would how much water is sucked skyward from a position such as ‘Lake Eyre’ in South Australia without mentioning of course the vast oceans that surround our planet. So couple ‘Sol’ with wind and other weather factors and you have life’s governor’s who are for ever at work somewhere on our planet. These forces can be managed
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Last Updated on Thursday, 17 November 2011 17:55 |
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Written by Lex
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Wednesday, 16 June 2010 23:32 |
Light Pollution Problem
I was reading in ‘The Sun’ news paper (which we receive a couple of times a year – but that’s a delivery problem) that a Cairns company has developed a wrap-around skin for low power ‘light poles’ with imbedded photo voltaic's as an earth friendly way to generate ‘clean’ power and good for them, well done!

Our electricity distribution people have suggested that they will wait a year to see how it goes (very admirable) considering that in our end of Cambridge Street, Gulliver alone there are no less than thirty (30) street lights in around 1km and by their own admission there are millions of the things throughout the country, a fact that any ‘lover’ of the heavens knows only too well.
These lights are all unshielded lights with only a small amount of their radiated light doing the job they were supposedly designed to do, the rest is scattered in every direction including up. Now we get to my point as a ‘stargazer’ or amateur astronomer hopeful!
Folks, we have lost our beautiful skies. There is no longer a lovely ‘Milky Way’ above our cities and large towns. If we have lights to light up our streets
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Last Updated on Sunday, 01 August 2010 10:55 |
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The Mystery of Our Universe |
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Written by Lex
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Sunday, 01 August 2010 10:12 |
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Questions abound regards its origin and most of them remain unanswered at least with any clarity or in a way that would make sense to the ordinary person. The dedicated stargazer at least starts to achieve some albeit, minor understanding of the vastness of what lies outside our super delicate atmosphere. In our small way with our study of the closer galaxies and nebulae we begin to understand how stars and planets in all their many and varied forms come to exist and for how long they endure in the hostile environment in which they spend their long lonesome lives.
In comparison if indeed one can be made in this case we the human race have been in existence for less than a blink in time and there is every chance that we won’t make it for as long as the shortest lived one of the abovementioned stars or their remains (the nebula) which I might add is one of our main targets to view at this point.
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Last Updated on Sunday, 01 August 2010 10:55 |
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Written by Vince Legge
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Monday, 15 March 2010 11:44 |
![]() Some Notes on Filters
Introduction: Essentially a filter is an optical device that blocks undesirable wavelengths of light and therefore only allowing light of desirable wavelengths for a given target, therefore "enhancing" that target. However a filter does not increase available light: it decreases the total light passing through the light path of your telescope and eyepiece configuration A filter is not a magic wand.
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Last Updated on Monday, 15 March 2010 12:37 |
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