Solar Eclipse Prime Page

Annular Solar Eclipse of -1745 Oct 20 (1746 Oct 20 BCE)

Fred Espenak

Introduction

eclipse map


The Annular Solar Eclipse of -1745 Oct 20 (1746 Oct 20 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 -1745 Oct 20 at 06:19:58 TD (19:06:23 UT1). This is 1.3 days after the Moon reaches apogee. During the eclipse, the Sun is in the constellation Scorpius. The synodic month in which the eclipse takes place has a Brown Lunation Number of -45357.

The eclipse belongs to Saros 25 and is number 17 of 71 eclipses in the series. All eclipses in this series occur at the Moon’s ascending node. The Moon moves southward with respect to the node with each succeeding eclipse in the series and gamma decreases.

The solar eclipse of -1745 Oct 20 is an exceptionally long annular eclipse with a duration at greatest eclipse of 09m50s. It has an eclipse magnitude of 0.9160.

The annular solar eclipse of -1745 Oct 20 is preceded two weeks earlier by a partial lunar eclipse on -1745 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 40414.4 seconds for this eclipse. The uncertainty in ΔT is 2727.5 seconds corresponding to a standard error in longitude of the eclipse path of ± 11.40°.

The following links provide maps and data for the eclipse.

The tables below contain detailed predictions and additional information on the Annular Solar Eclipse of -1745 Oct 20 .


Eclipse Data: Annular Solar Eclipse of -1745 Oct 20

Eclipse Characteristics
Parameter Value
Eclipse Magnitude 0.91599
Eclipse Obscuration 0.83904
Gamma 0.64048
Conjunction Times
Event Calendar Date and Time Julian Date
Greatest Eclipse -1745 Oct 20 at 06:19:57.5 TD (19:06:23.2 UT1) 1083988.296101
Ecliptic Conjunction -1745 Oct 20 at 06:27:39.0 TD (19:14:04.6 UT1) 1083988.301442
Equatorial Conjunction -1745 Oct 20 at 05:55:37.5 TD (18:42:03.1 UT1) 1083988.279203
Geocentric Coordinates of Sun and Moon
-1745 Oct 20 at 06:19:57.5 TD (19:06:23.2 UT1)
Coordinate Sun Moon
Right Ascension12h43m00.8s12h43m42.9s
Declination-04°43'36.9"-04°10'44.4"
Semi-Diameter 16'15.3" 14'43.3"
Eq. Hor. Parallax 08.9" 0°54'01.6"
Geocentric Libration of Moon
Angle Value
l -0.5°
b -0.8°
c 24.9°
Prediction Paramaters
Paramater Value
Ephemerides JPL DE406
ΔT 40414.4 s
k (penumbra) 0.2725076
k (umbra) 0.2722810
Saros Series 25 (17/71)

Explanation of Solar Eclipse Data Tables

Penumbral Shadow Contacts and Extremes: Annular Solar Eclipse of -1745 Oct 20

Contacts of Penumbral Shadow with Earth
Contact Event Contact Time
TD
Time
UT1
Latitude Longitude
First External ContactP103:28:47.716:15:13.441°44.0'N151°11.8'W
Last External ContactP409:11:17.021:57:42.706°19.4'N061°33.4'W
Extreme Northern and Southern Path Limits of Penumbra
Contact Event Contact Time
TD
Time
UT1
Latitude Longitude
North Extreme Path Limit 1N104:23:56.617:10:22.321°32.0'N167°19.1'W
South Extreme Path Limit 1S108:15:57.621:02:23.313°56.8'S046°00.4'W

Explanation of Penumbral Shadow Contacts and Extremes Tables

Umbral Shadow Contacts and Extremes: Annular Solar Eclipse of -1745 Oct 20

Contacts of Umbral Shadow with Earth
Contact Event Contact Time
TD
Time
UT1
Latitude Longitude
First External ContactU104:44:27.017:30:52.756°11.5'N167°14.9'W
First Internal ContactU204:53:23.517:39:49.158°55.4'N168°41.5'W
Last Internal ContactU307:46:50.420:33:16.023°38.2'N041°59.8'W
Last External ContactU407:55:44.420:42:10.020°53.2'N043°57.3'W
Extreme Northern and Southern Path Limits of Umbra
Contact Event Contact Time
TD
Time
UT1
Latitude Longitude
North Extreme Path Limit 1N104:51:45.017:38:10.659°39.6'N168°02.8'W
South Extreme Path Limit 1S104:46:13.017:32:38.755°24.8'N167°53.6'W
North Extreme Path Limit 2N207:48:29.220:34:54.824°23.1'N042°29.0'W
South Extreme Path Limit 2S207:53:58.520:40:24.120°05.9'N043°26.4'W

Explanation of Umbral Shadow Contacts and Extremes Tables

Central Line Extremes and Duration: Annular Solar Eclipse of -1745 Oct 20

Extreme Limits of the Central Line
Contact Event Contact Time
TD
Time
UT1
Latitude Longitude
Extreme Central Line Limit 1C104:48:52.517:35:18.157°30.3'N167°59.3'W
Extreme Central Line Limit 2C207:51:20.120:37:45.822°12.5'N042°58.8'W

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 Eclipse06:19:57.519:06:23.233°13.9'N096°24.3'E 50.0° 201.1° 411.2 km09m50.26s
Greatest Duration06:22:05.119:08:30.732°51.6'N094°08.1'W 49.9° 202.9° 412.8 km09m50.33s

Explanation of Greatest Eclipse and Greatest Duration

Polynomial Besselian Elements: Annular Solar Eclipse of -1745 Oct 20

Polynomial Besselian Elements
-1745 Oct 20 at 06:00:00.0 TD (=t0)
n x y d l1 l2 μ
0 0.03500 0.66112 -4.7229 0.57499 0.02868 272.0495
1 0.48002 -0.15315 -0.0165 -0.00002 -0.00002 15.0032
2 0.00001 -0.00000 0.0000 -0.00001 -0.00001 -0.0000
3 -0.00001 0.00000 - - - -
Tan ƒ1 0.0047534
Tan ƒ2 0.0047298

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 = 6.000

Explanation of Polynomial Besselian Elements

Links for the Annular Solar Eclipse of -1745 Oct 20 (1746 Oct 20 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 Annular Solar Eclipse of -1745 Oct 20 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 40414.4 seconds for this eclipse. The uncertainty in ΔT is 2727.5 seconds corresponding to a standard error in longitude of the eclipse path of ± 11.40°.

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.