 Greetings and welcome to the Introduction to Astronomy. In this video we are going to look at the basic coordinates and seasons lab and look at how that can help us to understand, first of all, coordinates on the Earth and in the sky, and a little bit about how the seasons work. So there are a number of different simulators that we will look at here and there are, of course, there's the globe and the flat map explorer for the terrestrial coordinates and similar ones for celestial coordinates and then there is also the seasons and ecliptic simulator. So you'll use all of these as part of your exercises and don't forget that some of these you will need to use to answer some of the questions on the basic information. You won't be able to find everything directly just in the simulators. So let's take a quick look at the first simulator here, which would be the flat map map explorer and this is a terrestrial coordinate one and as we look at it it'll just show a map of the Earth and allow you to move the coordinates around. So you can actually drag this coordinate around and figure out what the latitude in the blue and the longitude in the red will be for any different point on Earth and there are a number of things you can do which include showing some major cities so if you need to find the coordinates of Lima, Peru, then you can pull the dot over there and it will tell you what the latitude and longitude are on that and you can also show features like the Arctic circles, the equator, and the primaridian. So if you need to show any of those you can click those boxes to show them. The other thing that you'll see here is that it will show it in decimal form as it's shown here at 13.6 degrees but you can also use the sex adjustable which will do it in degrees and minutes so you may find cases where it asks you to put it in that specific type of form as well. Now we can also look at this with the globe map so if we actually go back here to the globe explorer then we do a very similar thing in fact it's exactly the same except you're looking at it on a globe and you may be asked some questions as to how it compares what are the differences between looking at it on a flat map as compared to a globe but otherwise everything you do here is exactly the same. Drag that around if you're looking for a specific city you can have those identified and then you can then find out for example what the coordinates of Washington DC are so very similar to the other one as well just done in a globe and then we'll see two for the same thing with the sky so here is the for the sky showing the right ascension and declination and just as you could on the earth you can pick out any point pick out a star to identify and you pick out the point there and then you can then find that it has a certain right ascension going left to right here measured in hours and a certain declination going north and south measured in degrees you can also change it from decimal to sex adjustable if you need to show that and you can also show where various things are such as the celestial equator the ecliptic the equinoxes the galactic equator and the constellations of the zodiac so if you need to show any of those things you just use the little checkboxes there and as with this we can also do this on a globe explorer again everything is exactly the same you just pull it to the star you want to identify and it gives you the coordinates now the other thing that we want to look at here is the season's and ecliptic simulator so this has a couple of different boxes to look at and what we're going to see is a number of things first of all it gives you the view here so what is it look like from space here is a little close up of the earth showing the location of the person on it the direction of the sun's rays and on earth we would see the direction that the rays appear to come from so depending on where the observer is at this case it's 10 degrees north latitude which would be very close to the equator and you can then look at how things would change over the course of the year you can just run the animation if you want to let it run and watch how things slowly change as you go over the course of a year from this location so at this point you would see the the altitude the sun getting higher and higher in the sky and in fact getting straight overhead and then getting lower in the sky actually going further to the north so you can watch how the angles change of the sunlight but you'll note that near the equator they always stay very very steep the sun is always very close to overhead and that is why the equator equatorial regions are very hot now you can also change the location of the person in this so if you decide to move the person here you can move them up or down and if you put someone very close to the poles you will see that those angles get lower and lower and eventually if you're close enough to the pole the sun's altitude will go down below zero and there will be a period of a few months where the sun never rises so why are the poles so cold? well there are times when the sun never rises and no matter what time of year it is the sun always hits you at a very very shallow angle so the energy from the sun is always spread out and then we find of course a few months later the sun rises again and the angles will start to get a little bit steeper but nothing like we saw with the when you were close to the equator so you can look at this and you're going to have to change a few things around you can look at the different location if you need to label anything if you're not sure what the objects are you can turn on the labels if that helps and you can also view if you're looking directly from the sun you can change the view in terms of looking from the sun and this object here is just the sub solar point you have the option of turning that on and off if you need it but if you're wondering what that is that is the point on earth where the sun would be directly overhead at that time if you don't want or don't need to see that that can easily be turned off just by unchecking the box there and turning it off so you just need to go through the simulation and answer the various questions that are given to you in the worksheet based on what you learn from this simulation so that concludes this session on the coordinates and seasons simulator we'll be back again next time to look at another one of these demos so until then have a great day everyone and i will see you in class