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explorelogo.jpg (11394 bytes) Apogee-Perigee

Apogee - Moon far from Earth  

Perigee - Moon close to Earth

The orbit of the moon is not circular. Sometimes the Moon is closer to Earth and sometimes farther from Earth.  Make a Prediction!  What will be different about the apparent size of the Moon at apogee as compared to perigee?


Explain your thinking....


To investigate this phenomena, HOU teacher, Fred Page requested images in January 2003 of the moon near apogee and near perigee. We made mosaics to show the composite images for each date.

  1. Open HOU-IP software.
  2. Open image moon-near-apogee030111.fts and image moon-near-perigee030124.fts
  3. Flip one of the images horizontally. (Manipulation, Flip, Horizontally)
  4. Add the apogee and perigee images together.  (Manipulation, Add, Displayed Image. Select other image. Save result in a new window. OK.)

 Was your prediction correct?  ________________   What is your evidence?


Could you calculate the percent change?  Hint: Look in Data Tools, Image Info, keyword DISTANCE. 


Compare side by side pictures of apogee and perigee.

Teachers: Link to Class Lessons for this activity by HOU Teacher, Fred Page.

Link to apogee and perigee images in .fts format.

astroline.jpg (9796 bytes)

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