thumb|right|240px|Oblique view from [[Apollo 17]]

thumb|right|240px|Map of O'Day crater

O'Day is a prominent lunar impact crater that is located on the far side of the Moon. It intrudes into the northwestern edge of Mare Ingenii, and the rim is lower on that side. To the northwest is the crater pair of Holetschek and Sierpinski. Southwest of O'Day lies the crater Seidel. It is named in honour of the American physicist Marcus O'Day.

Due to its prominent rays, O'Day is mapped as part of the Copernican System.

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Sources

  • Reprint:
  • Lunar Map 103, showing O'Day and surroundings (Regional maps at the Lunar and Planetary Institute.)