Calculating+Red+Shift

Now that you found what emission lines got you your ratio now you need to find which one is which. It’s easy enough to find which emission line is which. The emission lines that go horizontally along the top of the table are the stronger wavelengths you measured for the ratio while the ones going vertically down are the weaker wavelengths you measured. Once you've figured out which emission line which you can label them on your graph in the Graphical Analysis program. What you do is go to the Insert tab and choose Text. This will make a text box appear on the graph. You can move this box and change its size anyway you'd like. Next type the emission line's abbreviation in the box for example if the emission line was oxygen three you'd type O [III] in the text box. Then move the text box above the emission line indicating what type of emission line it is. Now to figure out the redshift of the graph you only need to do a little math. Red shift is when wavelengths increase shifting them in to the red part of the spectrum. This is due to the other galaxies slowly moving from us. To find redshift is fairly simple. First you choose one of your emission lines you labeled and find its rest wavelength. After you have these you divide your observed wavelength by the rest wavelength. You then subtract one from that answer and there is your first redshift. Now you do the same process with the other emission lines you labeled finding the tentative redshift for each line. Then you average each line’s tentative red shift to find what is known as the object’s tentative red shift. The object’s tentative redshift is the one adopted as the actual redshift. Then look for other emission lines using the tentative redshift, if you don’t find any other emission lines your redshift might be off and you should calculate a new tentative redshift.