The Partial Lunar Eclipse of 2006 September 7/8

Theodore Lunar Observatory Australia

The next lunar eclipse will provide a great opportunity to check the oblateness of the umbra.

In the diagram below the oblate umbra is smaller in radius at the South pole and when the Moon is near first contact, the predicted time of contact adopting the Geoid umbra is 108 seconds too early.

By observing the eclipse near first contact the effect of an oblate umbra will confirm the true value of its oblateness. The 2006 Ephemeris suggests that first contact will occur at 18h 05m 01s (UT) or 4h 05m 01s am Australian Eastern Standard Time (AEST) on September 8 using the Geoid oblateness value for this prediction.

By adopting a value of oblateness of 1/102, the time of first contact should be very near 4h 06m 49s am AEST.

Please observe and photograph this event and forward all details to me by mail.