Solar Eclipse Prime Page

Total Solar Eclipse of -1778 Jul 27 (1779 Jul 27 BCE)

Fred Espenak

Introduction

eclipse map

The Total Solar Eclipse of -1778 Jul 27 (1779 Jul 27 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 -1778 Jul 27 at 20:57:44 TD (09:31:32 UT1). This is 0.8 days after the Moon reaches perigee. During the eclipse, the Sun is in the constellation Leo. The synodic month in which the eclipse takes place has a Brown Lunation Number of -45768.

The eclipse belongs to Saros 17 and is number 37 of 74 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 -1778 Jul 27 is an exceptionally long total eclipse with a duration at greatest eclipse of 06m01s. It has an eclipse magnitude of 1.0658.

The total solar eclipse of -1778 Jul 27 is preceded two weeks earlier by a penumbral lunar eclipse on -1778 Jul 13, and it is followed two weeks later by a penumbral lunar eclipse on -1778 Aug 12.

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 41172.1 seconds for this eclipse. The uncertainty in ΔT is 2850.1 seconds corresponding to a standard error in longitude of the eclipse path of ± 11.91°.

The following links provide maps and data for the eclipse.

The tables below contain detailed predictions and additional information on the Total Solar Eclipse of -1778 Jul 27 .

Eclipse Data: Total Solar Eclipse of -1778 Jul 27

Eclipse Characteristics
Parameter Value
Eclipse Magnitude 1.06580
Eclipse Obscuration 1.13594
Gamma-0.03511
Conjunction Times
Event Calendar Date and Time Julian Date
Greatest Eclipse -1778 Jul 27 at 20:57:43.8 TD (09:31:31.7 UT1) 1071850.896895
Ecliptic Conjunction -1778 Jul 27 at 20:57:22.7 TD (09:31:10.6 UT1) 1071850.896650
Equatorial Conjunction -1778 Jul 27 at 20:57:51.2 TD (09:31:39.1 UT1) 1071850.896981
Geocentric Coordinates of Sun and Moon
-1778 Jul 27 at 20:57:43.8 TD (09:31:31.7 UT1)
Coordinate Sun Moon
Right Ascension07h16m19.0s07h16m18.7s
Declination+22°43'24.1"+22°41'15.8"
Semi-Diameter 15'53.7" 16'39.2"
Eq. Hor. Parallax 08.7" 1°01'07.1"
Geocentric Libration of Moon
Angle Value
l 2.7°
b -0.0°
c 9.5°
Prediction Paramaters
Paramater Value
Ephemerides JPL DE406
ΔT 41172.1 s
k (penumbra) 0.2725076
k (umbra) 0.2722810
Saros Series 17 (37/74)

Explanation of Solar Eclipse Data Tables

Penumbral Shadow Contacts and Extremes: Total Solar Eclipse of -1778 Jul 27

Contacts of Penumbral Shadow with Earth
Contact Event Contact Time
TD		 Time
UT1		 Latitude Longitude
First External ContactP118:19:24.806:53:12.700°33.3'N013°36.7'W
First Internal ContactP220:09:44.008:43:32.002°12.5'S040°01.9'W
Last Internal ContactP321:45:42.910:19:30.805°49.7'S112°35.9'E
Last External ContactP423:36:04.812:09:52.703°04.0'S086°10.5'E
Extreme Northern and Southern Path Limits of Penumbra
Contact Event Contact Time
TD		 Time
UT1		 Latitude Longitude
North Extreme Path Limit 1N119:35:34.508:09:22.528°58.4'N045°49.9'W
South Extreme Path Limit 1S119:23:38.607:57:26.529°39.7'S015°37.9'W
North Extreme Path Limit 2N222:19:54.610:53:42.525°27.2'N117°59.7'E
South Extreme Path Limit 2S222:31:47.111:05:35.033°10.2'S087°39.1'E

Explanation of Penumbral Shadow Contacts and Extremes Tables

Umbral Shadow Contacts and Extremes: Total Solar Eclipse of -1778 Jul 27

Contacts of Umbral Shadow with Earth
Contact Event Contact Time
TD		 Time
UT1		 Latitude Longitude
First External ContactU119:13:16.007:47:03.900°03.5'S026°49.3'W
First Internal ContactU219:15:49.207:49:37.100°06.3'S027°26.4'W
Last Internal ContactU322:39:39.511:13:27.403°43.5'S100°00.1'E
Last External ContactU422:42:10.711:15:58.703°40.8'S099°23.4'E
Extreme Northern and Southern Path Limits of Umbra
Contact Event Contact Time
TD		 Time
UT1		 Latitude Longitude
North Extreme Path Limit 1N119:14:43.707:48:31.700°33.9'N027°26.6'W
South Extreme Path Limit 1S119:14:22.607:48:10.500°43.7'S026°48.8'W
North Extreme Path Limit 2N222:40:44.111:14:32.103°03.9'S100°00.6'E
South Extreme Path Limit 2S222:41:04.911:14:52.904°20.5'S099°23.2'E

Explanation of Umbral Shadow Contacts and Extremes Tables

Central Line Extremes and Duration: Total Solar Eclipse of -1778 Jul 27

Extreme Limits of the Central Line
Contact Event Contact Time
TD		 Time
UT1		 Latitude Longitude
Extreme Central Line Limit 1C119:14:32.607:48:20.500°04.9'S027°07.6'W
Extreme Central Line Limit 2C222:40:55.111:14:43.003°42.2'S099°41.8'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 Eclipse20:57:43.809:31:31.720°50.3'N135°02.9'W 88.1° 2.1° 215.3 km06m00.60s
Greatest Duration20:56:35.109:30:23.020°51.6'N036°34.7'E 88.0° 20.4° 215.3 km06m00.63s

Explanation of Greatest Eclipse and Greatest Duration

Polynomial Besselian Elements: Total Solar Eclipse of -1778 Jul 27

Polynomial Besselian Elements
-1778 Jul 27 at 21:00:00.0 TD (=t0)
n x y d l1 l2 μ
0 0.02078 -0.03584 22.7232 0.53386 -0.01224 135.5432
1 0.58078 -0.01981 -0.0053 0.00005 0.00005 14.9990
2 -0.00001 -0.00016 -0.0000 -0.00001 -0.00001 0.0000
3 -0.00001 0.00000 - - - -
Tan ƒ1 0.0046460
Tan ƒ2 0.0046229

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 Total Solar Eclipse of -1778 Jul 27 (1779 Jul 27 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 Total Solar Eclipse of -1778 Jul 27 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 41172.1 seconds for this eclipse. The uncertainty in ΔT is 2850.1 seconds corresponding to a standard error in longitude of the eclipse path of ± 11.91°.

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.