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[Centaur]

The 86% illuminated waning gibbous Moon will occult stars in the Pleiades cluster (M45) during the night of 2006 OCT 09/10 for observers in the Americas. Immersions will occur on the bright limb and emersions on the dark limb. Grazes can be seen by those located on the narrow (2-3 km) paths. During a graze one can witness a star winking on and off as lunar hills and valleys sweep by.

Your photos, drawings or descriptions of the event will be welcome additions to this thread. For predictions applicable to your location, please feel free to reply within this thread with your latitude, longitude, altitude and time zone.

I’ve created a map of the Americas showing the graze paths of the seven brightest Pleiades stars. I’ve also drawn a graphic previewing the event as seen from Chicago at the time when Alcyone will be most deeply occulted. Both images can be viewed by going to:

www.curtrenz.com/astronomical.html

Of the 21 Pleiades stars no dimmer than sixth magnitude, 18 will be occulted. But fewer occultations will be observed at specific locations. Six will be seen from Chicago.

Below are my calculations for occulted stars in order of brightness for an observer at Chicago’s Adler Planetarium, W 87°36’24”, N 41°51’59”, alt 180 m. The stars’ coordinates are for the date of the event (not 2000.0). Times are CDT. The Zenith Angle (ZA) is the location of the star on the lunar limb measured counter-clockwise from the zenith.

#1 Mag 2.9 Alcyone
RA 03:47:54.4 Dec 24°07’43”
CDT 00:07:58 ZA 169.9° Immersion
CDT 00:49:55 ZA 244.4° Emersion

#3 Mag 3.7 Electra
RA 03:45:17.8 Dec 24°08’14”
CDT 22:55:47 ZA 109.2° Immersion
CDT 23:56:43 ZA 309.2° Emersion

#4 Mag 3.9 Maia
RA 03:46:14.9 Dec 24°23’29”
CDT 23:37:40 ZA 076.4° Immersion
CDT 00:25:18 ZA 340.6° Emersion

#5 Mag 4.2 Merope
RA 03:46:44.8 Dec 25°58’19”
CDT 23:37:09 ZA 181.4° Immersion
CDT 00:07:04 ZA 236.3° Emersion

#10 Mag 5.4 Celaeno
RA 03:45:13.5 Dec 24°18’48”
CDT 23:13:32 ZA 067.5° Immersion
CDT 23:51:59 ZA 351.2° Emersion

#17 Mag 6.3 24 Tauri
RA 03:47:46.3 Dec 24°08’23”
CDT 00:02:11 ZA 162.9° Immersion
CDT 00:50:17 ZA 251.6° Emersion

[Chicago Astronomer - Astro Joe]

Curt,

Excellent data on the event.

With clear skies, this should be a good one.

Thanks for the post!...

[Centaur]

admin said:

With clear skies, this should be a good one.

Today the long range Chicagoland forecast indicates a few showers for Monday and cloudy skies on Tuesday. Let's hope there is an opening during the night. The weather gods have been frowning on us during the current Pleiades occultation series. In any event, there will be another opportunity for observers in the Americas during the evening of December 3.

For the October event, the southern graze path of the second brightest Pleiades star, Atlas, will pass through Los Angeles. It will enter land at Santa Monica then sweep through Beverly Hills, Burbank, Verdugo City and La Crescenta. Listed below are the graze points I’ve calculated for several meridians across the metropolitan area.

Atlas -- Mag 3.6 -- RA 03:49:35.0 -- Dec N 24°04’36”
Lon W ----- Lat N ------ PDT --- Zenith Angle
118.5° -- 34.00988° -- 22:37:31 -- 217.9°
118.4° -- 34.08551° -- 22:37:38 -- 217.9°
118.3° -- 34.16123° -- 22:37:46 -- 217.8°
118.2° -- 34.23704° -- 22:37:54 -- 217.7°

Here's a formula for calculating the graze path in the LA area only:

W = Longitude - 118
Latitude = 34.38895 - 0.76048 W + 0.0047 W²