Solar Eclipse Prime Page

Hybrid Solar Eclipse of -1642 Sep 21 (1643 Sep 21 BCE)

Fred Espenak

Introduction

eclipse map

The Hybrid Solar Eclipse of -1642 Sep 21 (1643 Sep 21 BCE) is visible from the geographic regions shown on the map to the right. Click on the map to enlarge it. For an explanation of the features appearing in the map, see Key to Solar Eclipse Maps.

The instant of greatest eclipse takes place on -1642 Sep 21 at 21:09:39 TD (10:34:26 UT1). This is 2.7 days before the Moon reaches perigee. During the eclipse, the Sun is in the constellation Virgo. The synodic month in which the eclipse takes place has a Brown Lunation Number of -44084.

The eclipse belongs to Saros 8 and is number 53 of 73 eclipses in the series. All eclipses in this series occur at the Moon’s descending node. The Moon moves northward with respect to the node with each succeeding eclipse in the series and gamma increases.

The solar eclipse of -1642 Sep 21 is one of the rare hybrid solar eclipses. In this particular case the eclipse path starts out as annular. Further down the track it changes to total and then back to annular before the path ends. It is a very short hybrid eclipse with a duration at greatest eclipse of 00m22s. The eclipse magnitude is 1.0057, while Gamma has a value of 0.9209.

The hybrid solar eclipse of -1642 Sep 21 is followed two weeks later by a total lunar eclipse on -1642 Oct 05.

These eclipses all take place during a single eclipse season.

The eclipse predictions are given in both Terrestrial Dynamical Time (TD) and Universal Time (UT1). The parameter ΔT is used to convert between these two times (i.e., UT1 = TD - ΔT). ΔT has a value of 38112.5 seconds for this eclipse. The uncertainty in ΔT is 2363.0 seconds corresponding to a standard error in longitude of the eclipse path of ± 9.87°.

The following links provide maps and data for the eclipse.

The tables below contain detailed predictions and additional information on the Hybrid Solar Eclipse of -1642 Sep 21 .

Eclipse Data: Hybrid Solar Eclipse of -1642 Sep 21

Eclipse Characteristics
Parameter Value
Eclipse Magnitude 1.00570
Eclipse Obscuration 1.01144
Gamma 0.92086
Conjunction Times
Event Calendar Date and Time Julian Date
Greatest Eclipse -1642 Sep 21 at 21:09:38.9 TD (10:34:26.4 UT1) 1121580.940583
Ecliptic Conjunction -1642 Sep 21 at 20:59:56.1 TD (10:24:43.6 UT1) 1121580.933838
Equatorial Conjunction -1642 Sep 21 at 20:15:44.3 TD (09:40:31.8 UT1) 1121580.903146
Geocentric Coordinates of Sun and Moon
-1642 Sep 21 at 21:09:38.9 TD (10:34:26.4 UT1)
Coordinate Sun Moon
Right Ascension11h01m13.6s11h02m59.0s
Declination+06°24'31.6"+07°12'16.8"
Semi-Diameter 16'09.4" 16'09.1"
Eq. Hor. Parallax 08.9" 0°59'16.5"
Geocentric Libration of Moon
Angle Value
l -3.3°
b -1.1°
c 21.7°
Prediction Paramaters
Paramater Value
Ephemerides JPL DE406
ΔT 38112.5 s
k (penumbra) 0.2725076
k (umbra) 0.2722810
Saros Series 8 (53/73)

Explanation of Solar Eclipse Data Tables

Penumbral Shadow Contacts and Extremes: Hybrid Solar Eclipse of -1642 Sep 21

Contacts of Penumbral Shadow with Earth
Contact Event Contact Time
TD		 Time
UT1		 Latitude Longitude
First External ContactP118:57:02.708:21:50.364°39.2'N049°20.4'W
Last External ContactP423:22:31.612:47:19.107°50.8'N078°56.7'E
Extreme Northern and Southern Path Limits of Penumbra
Contact Event Contact Time
TD		 Time
UT1		 Latitude Longitude
North Extreme Path Limit 1N119:27:48.308:52:35.950°29.3'N051°06.1'W
South Extreme Path Limit 1S122:51:41.612:16:29.106°39.9'S085°01.5'E

Explanation of Penumbral Shadow Contacts and Extremes Tables

Umbral Shadow Contacts and Extremes: Hybrid Solar Eclipse of -1642 Sep 21

Contacts of Umbral Shadow with Earth
Contact Event Contact Time
TD		 Time
UT1		 Latitude Longitude
First External ContactU120:28:44.809:53:32.381°09.2'N167°47.8'E
First Internal ContactU220:28:55.509:53:43.081°05.6'N167°20.2'E
Last Internal ContactU321:50:57.611:15:45.238°27.2'N106°04.1'E
Last External ContactU421:51:03.511:15:51.138°24.3'N106°02.0'E
Extreme Northern and Southern Path Limits of Umbra
Contact Event Contact Time
TD		 Time
UT1		 Latitude Longitude
North Extreme Path Limit 1N120:28:55.109:53:42.781°05.4'N167°19.3'E
South Extreme Path Limit 1S120:28:45.109:53:32.781°09.4'N167°48.7'E
North Extreme Path Limit 2N221:50:57.811:15:45.438°27.3'N106°04.0'E
South Extreme Path Limit 2S221:51:03.311:15:50.938°24.1'N106°02.1'E

Explanation of Umbral Shadow Contacts and Extremes Tables

Central Line Extremes and Duration: Hybrid Solar Eclipse of -1642 Sep 21

Extreme Limits of the Central Line
Contact Event Contact Time
TD		 Time
UT1		 Latitude Longitude
Extreme Central Line Limit 1C120:28:50.109:53:37.781°07.4'N167°33.9'E
Extreme Central Line Limit 2C221:51:00.611:15:48.138°25.7'N106°03.0'E

Explanation of Central Line Extremes Table

Greatest Eclipse and Greatest Duration
Event Time
TD		 Time
UT1		 Latitude Longitude Sun
Altitude		 Sun
Azimuth		 Path Width Central
Duration
Greatest Eclipse21:09:38.910:34:26.458°07.4'N081°18.7'W 22.5° 244.0° 50.2 km00m22.18s
Greatest Duration21:11:18.910:36:06.457°19.5'N078°14.9'E 22.5° 245.0° 50.7 km00m22.21s

Explanation of Greatest Eclipse and Greatest Duration

Polynomial Besselian Elements: Hybrid Solar Eclipse of -1642 Sep 21

Polynomial Besselian Elements
-1642 Sep 21 at 21:00:00.0 TD (=t0)
n x y d l1 l2 μ
0 0.36299 0.85108 6.4093 0.54643 0.00027 135.5331
1 0.49205 -0.26927 -0.0158 -0.00010 -0.00010 15.0035
2 -0.00002 -0.00009 -0.0000 -0.00001 -0.00001 0.0000
3 -0.00001 0.00000 - - - -
Tan ƒ1 0.0047231
Tan ƒ2 0.0046996

At time t1 (decimal hours), each besselian element is evaluated by:

x = x0 + x1*t + x2*t2 + x3*t3 (or x = Σ [xn*tn]; n = 0 to 3)

where: t = t1 - t0 (decimal hours) and t0 = 21.000

Explanation of Polynomial Besselian Elements

Links for the Hybrid Solar Eclipse of -1642 Sep 21 (1643 Sep 21 BCE)

Links to Additional Solar Eclipse Information

Calendar

The Gregorian calendar (also called the Western calendar) is internationally the most widely used civil calendar. It is named for Pope Gregory XIII, who introduced it in 1582. On this website, the Gregorian calendar is used for all calendar dates from 1582 Oct 15 onwards. Before that date, the Julian calendar is used. For more information on this topic, see Calendar Dates.

The Julian calendar does not include the year 0. Thus the year 1 BCE is followed by the year 1 CE (See: BCE/CE Dating Conventions). This is awkward for arithmetic calculations. Years in this catalog are numbered astronomically and include the year 0. Historians should note there is a difference of one year between astronomical dates and BCE dates. Thus, the astronomical year 0 corresponds to 1 BCE, and astronomical year -1 corresponds to 2 BCE, etc..

Eclipse Predictions

Predictions for the Hybrid Solar Eclipse of -1642 Sep 21 were generated using the JPL DE406 solar and lunar ephemerides. The lunar coordinates were calculated with respect to the Moon's Center of Mass. The predictions are given in both Terrestrial Dynamical Time (TD) and Universal Time (UT1). The parameter ΔT is used to convert between these two times (i.e., UT1 = TD - ΔT). ΔT has a value of 38112.5 seconds for this eclipse. The uncertainty in ΔT is 2363.0 seconds corresponding to a standard error in longitude of the eclipse path of ± 9.87°.

Acknowledgments

Some of the content on this website is based on the book Thousand Year Canon of Solar Eclipses 1501 to 2500. All eclipse calculations are by Fred Espenak, and he assumes full responsibility for their accuracy.

Permission is granted to reproduce eclipse data when accompanied by a link to this page and an acknowledgment:

"Eclipse Predictions by Fred Espenak, www.EclipseWise.com"

The use of diagrams and maps is permitted provided that they are NOT altered (except for re-sizing) and the embedded credit line is NOT removed or covered.