Creative Commons License Copyright © Michael Richmond. This work is licensed under a Creative Commons License.

Paths of Solar Eclipses

In this lab we will look carefully at the path of a total solar eclipse Professor Davis saw as a kid in 1970 near Spartanburg, SC.

Open Sky Map Pro, looking at the sky as seen from Valdosta, Ga., on March 7, 1970, at 1:00PM. Find center, and lock on the sun. Step ahead by 1 minute intervals and estimate the times of start and end of totality, as seen at this location.

Now, we wish to answer several questions using this software package. Your instructor will give you a page from an atlas which shows the area around Valdosta, Ga. Mark some of your answers on the page.

  1. In what constellation did the eclipse take place? What bright stars and planets (if any) were in the vicinity of the sun at that time? (Remember that your approximate field of view with the naked eye is 55 degrees)

  2. Where is the path of totality? It runs roughly to the northeast; you'll have to "hunt and peck" a bit to find some other locations where the eclipse was total.

  3. How wide was the path of totality? Choose some locations along a line perpendicular to the path of totality, step through time and see if the eclipse was ever total there. Can you name any other towns that also saw the eclipse to be total at the same time as Valdosta?

  4. How far away could you have been from the path of totality and have seen a partial eclipse in which the sun was 75% covered? (You'll have to estimate what "75% covered" means.) How wide was the penumbra? Hint: it's lots bigger than you might think !!

  5. At what speed did the umbra move across the Earth in this eclipse? How did you determine this? Use this speed and the size of the umbra to find the time of totality. Is this result consistent with what you found earlier?

  6. Make a sketch of the path of the eclipse up the Eastern seaboard, showing your estimates of the umbral path.

  7. When should there be a "similar" eclipse in this general area? Find 2 cities that you could go to and observe this particular eclipse and tell me when it will happen (to the nearest minute) in each city. Hint: some of us may not be able to wait long enough to see this one!

  8. Extra credit. Hey, it must be eclipse season since the line of the nodes coincided with the Earth-Sun line!! Was there a total lunar eclipse associated with this solar eclipse? Look at the next and the previous full moon and determine if there was or wasn't a lunar eclipse. I don't think you can do this in Sky Map Pro. Downstairs in the Gosnell computer labs, there's a program called Voyager on the Macintoshes that will allow you to show the location of the Earth's umbral shadow on the sky. Find the starting and ending times of any lunar eclipses (total or partial), and give one location from which it could be seen. Hint: in the Planets window the symbol grey circle means "show the moon," and the symbol concentric circles means "show the Earth's umbral and penumbral shadows projected on the sky."

    Creative Commons License Copyright © Michael Richmond. This work is licensed under a Creative Commons License.