Post by Centaur on Oct 16, 2007 21:09:38 GMT -6
During the evening of 2007 OCT 27 the Moon will occult the Pleiades cluster (M45). The event will be essentially over as the 95% illuminated waning gibbous Moon rises on the Chicago lakefront at 18:33 CDT. However, I’ve calculated that the graze path of Atlas, the second brightest Pleiad at magnitude 3.6, will pass through Chicagoland. Alcyone, the brightest member at mag 2.9, will emerge at 18:53:28 for lakefront viewers. All the rest of the principle stars in the group will have emerged before the Moon rises over Chicagoland.
Atlas’ southern graze path will include Plainfield, Woodridge, La Grange, Berwyn, Oak Park, Lincoln Park in Chicago and points in between. The rising star will only be 3° above the east-northeastern horizon at the time of the Chicagoland portion of the graze. Observers on the lakefront may get the best view. The graze path is only a few kilometers wide. Observers north of the path will see a full occultation. Those south of the path will see a close passage. But those on the path will have a rare opportunity to see a star winking on and off as hills and valleys of the lunar south polar region pass by.
Here are a few points I've calculated for the graze path at separations of 0.1° in longitude.
19:01:16 CDT - W 88.3° - N 41.58344°
19:01:17 CDT - W 88.2° - N 41.63676°
19:01:17 CDT - W 88.1° - N 41.69025°
19:01:18 CDT - W 88.0° - N 41.74393°
19:01:19 CDT - W 87.9° - N 41.79779°
19:01:19 CDT - W 87.8° - N 41.85183°
19:01:20 CDT - W 87.7° - N 41.90605°
19:01:21 CDT - W 87.6° - N 41.96046°
19:01:22 CDT - W 87.5° - N 42.01506°
Linear interpolation should be sufficient, but I’ll be happy to provide even more detailed data for those who reply with specific longitudes.
Below is a graphic I've created to illustrate how the graze would look from Lincoln Park on the lakefront. Atlas is on the lower right limb of the Moon.
Atlas’ southern graze path will include Plainfield, Woodridge, La Grange, Berwyn, Oak Park, Lincoln Park in Chicago and points in between. The rising star will only be 3° above the east-northeastern horizon at the time of the Chicagoland portion of the graze. Observers on the lakefront may get the best view. The graze path is only a few kilometers wide. Observers north of the path will see a full occultation. Those south of the path will see a close passage. But those on the path will have a rare opportunity to see a star winking on and off as hills and valleys of the lunar south polar region pass by.
Here are a few points I've calculated for the graze path at separations of 0.1° in longitude.
19:01:16 CDT - W 88.3° - N 41.58344°
19:01:17 CDT - W 88.2° - N 41.63676°
19:01:17 CDT - W 88.1° - N 41.69025°
19:01:18 CDT - W 88.0° - N 41.74393°
19:01:19 CDT - W 87.9° - N 41.79779°
19:01:19 CDT - W 87.8° - N 41.85183°
19:01:20 CDT - W 87.7° - N 41.90605°
19:01:21 CDT - W 87.6° - N 41.96046°
19:01:22 CDT - W 87.5° - N 42.01506°
Linear interpolation should be sufficient, but I’ll be happy to provide even more detailed data for those who reply with specific longitudes.
Below is a graphic I've created to illustrate how the graze would look from Lincoln Park on the lakefront. Atlas is on the lower right limb of the Moon.