Post by Centaur on Dec 29, 2005 21:03:15 GMT -6
This thread contains specific information I've developed for Chicagoland observers of the Pleiades occultation occurring during the evening of Monday 2006 JAN 09. Data and a map for the Pleione graze path through the area are provided, including details for those planning to observe the graze from Chicago’s Lincoln Park. 
The apparent disk of the waxing gibbous Moon will be 82% illuminated. Therefore, occulted stars will disappear behind the Moon’s dark limb and reappear from its bright limb. Relative to the stars, the Moon will appear to be moving toward the upper left when viewed from greater Chicago. Although relative to the ground the Moon will seem to be moving toward the lower right due to the Earth’s rotation.
To see the graphics I’ve created previewing the occultation and presenting both the general North American and detailed Chicagoland graze maps, click:
www.curtrenz.com/astronomical.html
The 2nd, 15th, 16th and 20th brightest stars in the asterism will become fully occulted throughout the Chicago area. Pleione, the 7th brightest, will present a narrow graze path that passes through Chicagoland. Those observing from the graze path will witness Pleione blinking on and off as hills and valleys along the northern lunar limb pass by. Observers to the south of the graze path will see Pleione fully occulted; those to the north will have to be content with a near miss.
Immediately below are the data I’ve predicted for the five stars as viewed from the Adler Planetarium listed in order of the time of immersion. The apparent Right Ascensions, Declinations and Stellar Magnitudes of the stars for the date of the event (not 2000.0) are posted. The figure after the Central Standard Time is the Zenith Angle, which is the position of the star on the lunar limb as measured counter-clockwise from the zenith. The first time listed is that of immersion (disappearance). The second is that of emersion (reappearance). Please reply within this thread to request data for other locations (provide your Longitude, Latitude, Time Zone & approximate Altitude above sea level.)
Mag 6.5 - 26 Tauri (non-member foreground star)
RA 03:49:19.1 – Dec N 23°52’41”
20:14:32 – ZA 068.1° - Immersion
21:39:28 – ZA 216.1° - Emersion
Mag 6.2 - HD 23923
RA 03:50:05.7 – Dec N 23°43’58”
20:45:00 – ZA 100.1° - Immersion
21:46:42 – ZA 167.0° - Emersion
Mag 3.6 - Atlas
RA 03:49:31.9 – Dec N 24°04’28”
20:45:44 – ZA 010.1° - Immersion
21:45:30 – ZA 255.8° - Emersion (Note: Before HD 23923)
Mag 5.0 - Pleione
RA 03:49:33.4 – Dec N 24°09’28”
21:17:06 – ZA 315.7° - Immersion
21:25:06 – ZA 301.8° - Emersion
Mag 6.2 – HD 24802 (Jan 10)
RA 03:57:48.7 – Dec N 24°28’55”
01:27:32 – ZA 346.0° - Immersion
02:13:14 – ZA 254.3° - Emersion
Next are my calculated coordinates for the points on Pleione’s graze path in northeastern Illinois separated by 10 minutes of geographic longitude. The times are CST. ZA is the star’s Zenith Angle on the lunar limb. The posted longitudes are precisely defined. The corresponding sexagesimal latitudes are less precise than their decimal equivalents. The assumed altitude is 200 meters.
21:18:58 - ZA 310.9°
W 88°50’ – N 41°41’30” (41.69155)
6 kilometers southeast of Shabbona Lake
21:19:16 - ZA 310.6°
W 88°40’ – N 41°43’31” (41.72526)
6 kilometers southeast of Hinckley Airport
21:19:33 - ZA 310.3°
W 88°30’ – N 41°45’31” (41.75854)
1 kilometer southwest of Aurora Airport
21:19:51 - ZA 310.0°
W 88°20’ – N 41°47’29” (41.79139)
North Aurora, Calico Dr. & Sandy Ln.
21:20:09 - ZA 309.8°
W 88°10’ – N 41°49’26” (41.82381)
Warrenville, Winfield Rd., 700 meters south of Butterfield Rd.
21:20:26 - ZA 309.5°
W 88°00’ – N 41°51’21” (41.85581)
Lombard, south end of Rochdale Cir.
21:20:44 - ZA 309.2°
W 87°50’ – N 41°53’15” (41.88739)
Maywood Park, Des Plaines River, 30 meters south of railroad tracks
21:21:01 - ZA 308.9°
W 87°40’ – N 41°55’07” (41.91854)
Chicago, Mendell St., 50 meters north of Armitage Ave.
21:21:18 - ZA 308.7°
W 87°30’ – N 41°56’57” (41.94928)
Lake Michigan, 12 kilometers east of Lincoln Park
Additionally, I’ve determined three graze locations around Chicago’s Lincoln Park separated by 12 seconds of geographic longitude. The assumed altitude is 180 meters.
21:21:04 - ZA 308.9°
W 87°38’12” – N 41°55’27” (41.92415)
West side of Lincoln Park W, 50 meters north of Belden Ave.
21:21:04 - ZA 308.9°
W 87°38’00” – N 41°55’29” (41.92477)
West side of Cannon Dr., 100 meters south of Fullerton Pky.
21:21:05 - ZA 308.9°
W 87°37’48” – N 41°55’31” (41.92539)
Shore of Lake Michigan, 100 meters southeast of end of Fullerton Pky.
Finally, here is my graze interpolation algorithm, which is quite accurate between 87.5° and 88.8° of western longitude, when the result is rounded to five places after the decimal point. The only input value is the western longitude. All values are decimal, including the hours. Nevertheless, please feel free to reply within this thread to learn the graze output data that go with any specific Chicagoland longitudes you provide.
W = Western Longitude (input)
N = Northern Latitude (output)
H = Hours CST (output)
Z = Zenith Angle (output)
L = W – 88 (L is a negative value when W is less than 88)
N = 41.8558132 – 0.19074381 L – 0.007636581 L²
H = 21.3406141 – 0.02908514 L – 0.000411255 L²
Z = 309.480155 + 1.63937196 L + 0.009475733 L²
The apparent disk of the waxing gibbous Moon will be 82% illuminated. Therefore, occulted stars will disappear behind the Moon’s dark limb and reappear from its bright limb. Relative to the stars, the Moon will appear to be moving toward the upper left when viewed from greater Chicago. Although relative to the ground the Moon will seem to be moving toward the lower right due to the Earth’s rotation.
To see the graphics I’ve created previewing the occultation and presenting both the general North American and detailed Chicagoland graze maps, click:
www.curtrenz.com/astronomical.html
The 2nd, 15th, 16th and 20th brightest stars in the asterism will become fully occulted throughout the Chicago area. Pleione, the 7th brightest, will present a narrow graze path that passes through Chicagoland. Those observing from the graze path will witness Pleione blinking on and off as hills and valleys along the northern lunar limb pass by. Observers to the south of the graze path will see Pleione fully occulted; those to the north will have to be content with a near miss.
Immediately below are the data I’ve predicted for the five stars as viewed from the Adler Planetarium listed in order of the time of immersion. The apparent Right Ascensions, Declinations and Stellar Magnitudes of the stars for the date of the event (not 2000.0) are posted. The figure after the Central Standard Time is the Zenith Angle, which is the position of the star on the lunar limb as measured counter-clockwise from the zenith. The first time listed is that of immersion (disappearance). The second is that of emersion (reappearance). Please reply within this thread to request data for other locations (provide your Longitude, Latitude, Time Zone & approximate Altitude above sea level.)
Mag 6.5 - 26 Tauri (non-member foreground star)
RA 03:49:19.1 – Dec N 23°52’41”
20:14:32 – ZA 068.1° - Immersion
21:39:28 – ZA 216.1° - Emersion
Mag 6.2 - HD 23923
RA 03:50:05.7 – Dec N 23°43’58”
20:45:00 – ZA 100.1° - Immersion
21:46:42 – ZA 167.0° - Emersion
Mag 3.6 - Atlas
RA 03:49:31.9 – Dec N 24°04’28”
20:45:44 – ZA 010.1° - Immersion
21:45:30 – ZA 255.8° - Emersion (Note: Before HD 23923)
Mag 5.0 - Pleione
RA 03:49:33.4 – Dec N 24°09’28”
21:17:06 – ZA 315.7° - Immersion
21:25:06 – ZA 301.8° - Emersion
Mag 6.2 – HD 24802 (Jan 10)
RA 03:57:48.7 – Dec N 24°28’55”
01:27:32 – ZA 346.0° - Immersion
02:13:14 – ZA 254.3° - Emersion
Next are my calculated coordinates for the points on Pleione’s graze path in northeastern Illinois separated by 10 minutes of geographic longitude. The times are CST. ZA is the star’s Zenith Angle on the lunar limb. The posted longitudes are precisely defined. The corresponding sexagesimal latitudes are less precise than their decimal equivalents. The assumed altitude is 200 meters.
21:18:58 - ZA 310.9°
W 88°50’ – N 41°41’30” (41.69155)
6 kilometers southeast of Shabbona Lake
21:19:16 - ZA 310.6°
W 88°40’ – N 41°43’31” (41.72526)
6 kilometers southeast of Hinckley Airport
21:19:33 - ZA 310.3°
W 88°30’ – N 41°45’31” (41.75854)
1 kilometer southwest of Aurora Airport
21:19:51 - ZA 310.0°
W 88°20’ – N 41°47’29” (41.79139)
North Aurora, Calico Dr. & Sandy Ln.
21:20:09 - ZA 309.8°
W 88°10’ – N 41°49’26” (41.82381)
Warrenville, Winfield Rd., 700 meters south of Butterfield Rd.
21:20:26 - ZA 309.5°
W 88°00’ – N 41°51’21” (41.85581)
Lombard, south end of Rochdale Cir.
21:20:44 - ZA 309.2°
W 87°50’ – N 41°53’15” (41.88739)
Maywood Park, Des Plaines River, 30 meters south of railroad tracks
21:21:01 - ZA 308.9°
W 87°40’ – N 41°55’07” (41.91854)
Chicago, Mendell St., 50 meters north of Armitage Ave.
21:21:18 - ZA 308.7°
W 87°30’ – N 41°56’57” (41.94928)
Lake Michigan, 12 kilometers east of Lincoln Park
Additionally, I’ve determined three graze locations around Chicago’s Lincoln Park separated by 12 seconds of geographic longitude. The assumed altitude is 180 meters.
21:21:04 - ZA 308.9°
W 87°38’12” – N 41°55’27” (41.92415)
West side of Lincoln Park W, 50 meters north of Belden Ave.
21:21:04 - ZA 308.9°
W 87°38’00” – N 41°55’29” (41.92477)
West side of Cannon Dr., 100 meters south of Fullerton Pky.
21:21:05 - ZA 308.9°
W 87°37’48” – N 41°55’31” (41.92539)
Shore of Lake Michigan, 100 meters southeast of end of Fullerton Pky.
Finally, here is my graze interpolation algorithm, which is quite accurate between 87.5° and 88.8° of western longitude, when the result is rounded to five places after the decimal point. The only input value is the western longitude. All values are decimal, including the hours. Nevertheless, please feel free to reply within this thread to learn the graze output data that go with any specific Chicagoland longitudes you provide.
W = Western Longitude (input)
N = Northern Latitude (output)
H = Hours CST (output)
Z = Zenith Angle (output)
L = W – 88 (L is a negative value when W is less than 88)
N = 41.8558132 – 0.19074381 L – 0.007636581 L²
H = 21.3406141 – 0.02908514 L – 0.000411255 L²
Z = 309.480155 + 1.63937196 L + 0.009475733 L²
. Be prepared for UFO reports soon afterward