Astronomy - Revision history

Franks at 01:18, 8 February 2011

2011-02-08T01:18:00Z

← Older revision		Revision as of 18:18, 7 February 2011
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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]].		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 ==		== Light pollution ==

Pbug: /* Summer/Winter Solstice */ remove summer/winter references to solstice as it doesn't specify for what hemisphere, it's that complicated. Happy December Solstice!

2010-12-20T18:16:24Z

Summer/Winter Solstice: remove summer/winter references to solstice as it doesn't specify for what hemisphere, it's that complicated. Happy December Solstice!

← Older revision		Revision as of 11:16, 20 December 2010
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	== Summer/Winter Solstice ==		== 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.		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). June solstice is usually on June 23rd and December 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.		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.

62.75.160.180: asterisms

2010-07-06T07:39:31Z

asterisms

← Older revision		Revision as of 00:39, 6 July 2010
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	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 [http://antwrp.gsfc.nasa.gov/apod/ap061223.html 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 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 [http://antwrp.gsfc.nasa.gov/apod/ap061223.html 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.


			== Asterisms ==

			An asterism is a pattern of stars in the night sky which aren't an official constellation.

			* Big Dipper
			* [http://solarscale.de/public/astronomy/20100207/ Winter Hexagon]
			* [http://solarscale.de/public/astronomy/20100627/ Summer Triangle]

			The above are a few asterisms known.

Pbug: /* Orion the Hunter */

2010-02-28T11:12:19Z

Orion the Hunter

← Older revision		Revision as of 04:12, 28 February 2010
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	[[Image:orion.gif]]		[[Image:orion.gif]]

	Orion is seen in the ~~Winter~~ sky usually in the southern ~~hemisphere~~. It's distinctive Orion's belt is three stars in series and is a good marker to find constellations and stars in the ~~Winters~~ night sky.		Orion is seen in the winter sky usually in the southern sky. It's distinctive "Orion's belt" is three stars in series and is a good marker to find constellations and stars in the winters night sky.

Pbug: Orion

2010-02-27T23:26:06Z

Orion

← Older revision		Revision as of 16:26, 27 February 2010
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	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 [http://antwrp.gsfc.nasa.gov/apod/ap061223.html 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 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 [http://antwrp.gsfc.nasa.gov/apod/ap061223.html 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.


			== Orion the Hunter ==

			[[Image:orion.gif]]

			Orion is seen in the Winter sky usually in the southern hemisphere. It's distinctive Orion's belt is three stars in series and is a good marker to find constellations and stars in the Winters night sky.

Pbug: /* The Sky Sweeper */ whoops wrong action before

2009-07-01T22:39:40Z

The Sky Sweeper: whoops wrong action before

← Older revision		Revision as of 15:39, 1 July 2009
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	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 [http://antwrp.gsfc.nasa.gov/apod/ap061223.html 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 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 [http://antwrp.gsfc.nasa.gov/apod/ap061223.html 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 [[http://centroid.eu 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.

	~~[[Image: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.

	~~[[Image:sky-sweeper-building.jpg]]~~

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

Pbug: /* A beginners tools */ take this out...

2009-07-01T22:38:24Z

A beginners tools: take this out...

← Older revision		Revision as of 15:38, 1 July 2009
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	~~== A beginners tools ==~~

	~~[[Image:astronomy-beginner.jpg]]~~

	The picture above shows a simple handymans scale for measuring angles, taking distance measurements up to 20 cm and level scales that I bought for under 10 euros. For a beginner this is extremely useful. You don't need a huge telescope. I use the small PVC tube you see with this as I maskin tape this tube to the scale and with a tripods help I'm able to get a fairly accurate readout of what the sun, moon and stars are at give or take 3 degrees. Astronomy is about geometry, this means math. In a bit I'll show you some other constructs of mine on to the next levels (binoculars perhaps). My main interests are sun, moon and stars for positioning and time tracking though.

	One nice way to find out the degrees of the sun is to use the shadow of the PVC tube. It is about 12 cm long and as light goes through it the slimmer the shadow along the edges of the tube are on a piece of paper held behind the tube the easier you can tell that the bearing is ok. (never look into the sun, unless you got a pretty good filter which you should get information about first).

	~~As you take notes on degrees of elevations from horizon, taking notes on bearing (magnetic and geographic) and the time isn't a bad idea.~~

	~~[[Image:laser-scope.jpg]]~~

	Above is my home-built laser scope. Basically I'm sick of the rough granularity of the degrees that I can get with the handymans tool. So the laser will help with the figuring out of the angle of objects such as stars that I put into the visor of the PVC tube. The laser is a laser pointer and points backwards and down. When a star is in sight I turn on the laser and measure the point where the laser shines. Because of Pythagoras theorem (grade 10 math geometry) you know the angle of a right triangle after the [[SOHCAHTOA]] principle. In my case I know the height of the laser after measuring it. After measuring the distance where the laser beams to I can figure out a fairly accurate angle with the inverse tan button on my calculator. When I want to increase the speed of this I can make the laser pointer point a little higher and thus the point it marks is further away.. using an ultra sound distance measuring tool (they claim to go to around 12 meters) could help speed this up, but consider the accuracy is somewhere within 5 cm (2-3 inches) so one probably won't get an extremely accurate calculation (but it could be fun),

	== The Sky Sweeper ==		== The Sky Sweeper ==

Franks: /* Light pollution */

2007-07-26T08:09:43Z

Light pollution

← Older revision		Revision as of 01:09, 26 July 2007
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	== Light pollution ==		== Light pollution ==

	Urban lights pollute the night sky which is extremely unfortunate. ~~Please inform yourself about this~~ [http://www.britastro.org/dark-skies/index.html ~~here], it's about an effort~~ to darken ~~our cities in~~ the UK.		Urban lights pollute the night sky which is extremely unfortunate.

			[http://www.britastro.org/dark-skies/index.html Campaign to darken the UK skies]

	== Polaris, the North Star ==		== Polaris, the North Star ==

Franks at 08:07, 26 July 2007

2007-07-26T08:07:26Z

← Older revision		Revision as of 01:07, 26 July 2007
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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.		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]].

Franks: /* Polaris, the North Star */

2007-03-13T18:16:05Z

Polaris, the North Star

← Older revision		Revision as of 11:16, 13 March 2007
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	[[Image:125px-Flag_of_Alaska.svg.png]]		[[Image:125px-Flag_of_Alaska.svg.png]]

	When you live in the northern hemisphere you most likely ~~will be knowledged with how~~ 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).		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).		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).