Astronomy

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Astronomy is the study and graphing/plotting of skyward objects such as stars, planets and other object that are found in our heavens. Astronomy also is important for timekeeping and global positioning when all electronics fail. Since the earth is a sphere rotating around a star and itself spinning, simple geometry can help figure out ones position globally. If you're interested in Astronomy, you may or may not have an interest in Satellites.


Light pollution

Urban lights pollute the night sky which is extremely unfortunate.

Campaign to darken the UK skies

Polaris, the North Star

When you live in the northern hemisphere you most likely know what the big dipper looks like. Not far from the big dipper at 5 times its length in the sky is Polaris, the north star. It may not be seen from the southern hemisphere. If you need some aid in finding the north star take a look at the flag of the state of Alaska, it is a scaled distance of the relationship of the Big Dipper to Polaris. Polaris will always show north and its elevation from the horizon in degrees indicates your latitude as well (best seen near equinoxes).

Also as you watch the night sky as the earth rotates on its own axis it will appear that everything rotates around Polaris. When it is said that Polaris shows north it is the geographic north not the magnetic which is just west of Alert, Nunavut (Canada).

Summer/Winter Solstice

The Solstice indicates an extreme point in the elevation of the sun relative to the viewing horizon. The earth is tilted 23.45 degrees and the tilt is fixed into a certain direction in space. As we complete an orbit around the sun the sun at high noon will appear to shift higher and lower. The highest point is called the summer solstice and the lowest point the winter solstice. It is vice versa south of the equator (australia for example). Summer solstice is usually on June 23rd and Winter Solstice is usually on December 20th.

Yes you guessed it. Because of this tilt we have seasons, wherever the sun is highest in the sky is where summer is and the other winter. Equatorial regions have very little differences between summer and winter but the sun travels even here. Solstice on polar regions means either 24 hour daylight or 24 hour night depending on which pole you're on. See equinox for the time when you'll have sunrise/sunset.

Vernal and Autumnal Equinox

The point in time when the tilt of the earth is at a 90 degree angle with the sun and the sun is exactly above the equator at a 90 degree angle is called an equinox. At high noon at the highest sun peak of the day the sun should be at exactly south. This is also the median of the day between sunrise and sunset. Photographing the sun for a year every day and showing the path of the sun is called an analemma and where the path of sun crosses itself is where the equinoxes cross. Vernal Equinox is on March 20th, and Autumnal Equinox is on September 23rd.



The Sky Sweeper

You could use a fisheye lens to map the entire path of the sun with a webcam. But if you mistrust sillycon (glass) and want to approach the problem from the perspective of a honeybee then perhaps the following idea may work for you as posted on the [centroid.eu blog/xlog].

Imagine the following scenario. The earths magnetic field fails and navigation systems on cars, airplanes and ships fail, when they don't rely on GPS. Or instead of failing the poles reverse direction for the entire earth. This scenario was predicted by some scientists who I read were studying the moving north pole in northern Canada. How do you get an exact bearing? I have thought of a machine that can track objects such as the sun and the moon across the entire sky and determine their angle, and do this relatively cheap.

File:Sky-sweeper.jpg

As you can see there is 2 axiis. One can be a used turntable/record phonograph that spins at 33 revolutions per minute. The other could be a bike wheel with a mounted USB camera which serves 30 frames per second. There is two permanent light sources that the camera passes these are mounted at a known angle (preferably 90 degrees) to any axis. As the camera passes these light points it knows exactly how long a full revolution (or period) will take, a computer connected to the USB cable records this. Every frame then represents a certain degree as the camera spins around the given axiis. When a large light source such as the moon or the sun pass the camera, this gets recorded and because a revolution is not completed it's able to pinpoint exactly that this is another light source, and then determine the angle.

So what good is knowing the angle of the sun or moon? Once you have measured where the sun is at its highest point in the sky (the peak) you know that it is noon (or high noon) and you also know that the sun must be exactly south in the northern hemisphere and exactly north in the southern hemisphere. This gives you a bearing. You can also use this as a clock now. Mapping the 2 yearly solstices and equinoxes now is not that hard, and it is automated meaning you don't have to attend it all the time. This isn't the only good function. Pretend the camera is infrared, or ultraviolet or other rays that are emitted by our sun not visible to the eye. You can now track the sun behind cloud cover (at least theoretically), this is important for regions that are overcast often (some parts of europe perhaps?). Once you plotted the sun and the moon you should be able to plot your own position to be absolutely sure where on earth you are, without requiring GPS, and doing it in a very reliable manner. If the camera picks up stars, or bright planets as well that's a bonus. I have purchased a few cameras on ebay to see this idea become a reality in time. When this construct is finished I'll give you an update.

PS: You can have GPS, but if GPS fails then your reliance is left to the elements. Similarily a GPS system can be encrypted at will by the USA, or the sun may cause such a solar storm that knocks out the electronics on all or partially all GPS satellites. You can fake electromagnetic sources with electricity, so a compass may not help much. One can pollute the atmosphere with smoke or steam in order to cover up the sun or moon but there will be times when wasting energy on such a level isn't always available. Sun and moon cannot so easily be moved by any invention of mankind, and this solidifies where you are, without reliance and dependance on others. The use of this is extremely important.

File:Sky-sweeper-building.jpg

Above is a sky sweeper in the building phase, (will be finished before summer solstice).