Solar Eclipse Prime Page

Total Solar Eclipse of 2017 Aug 21

Fred Espenak

Introduction


The Total Solar Eclipse of 2017 Aug 21 is visible from the following geographic regions:

  • Partial Eclipse: North America, north South America
  • Total Eclipse: north Pacific, U.S., south Atlantic

The map to the right depicts the geographic regions of eclipse visibility. 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 2017 Aug 21 at 18:26:40 TD (18:25:32 UT1). This is 3.2 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 1171.

The eclipse belongs to Saros 145 and is number 22 of 77 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 total solar eclipse of 2017 Aug 21 is preceded two weeks earlier by a partial lunar eclipse on 2017 Aug 07.

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 68.5 seconds for this eclipse.

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 2017 Aug 21 .


Eclipse Data: Total Solar Eclipse of 2017 Aug 21

Eclipse Characteristics
Parameter Value
Eclipse Magnitude 1.03059
Eclipse Obscuration 1.06211
Gamma 0.43671
Conjunction Times
Event Calendar Date & Time Julian Date
Greatest Eclipse 2017 Aug 21 at 18:26:40.3 TD (18:25:31.7 UT1) 2457987.267728
Ecliptic Conjunction 2017 Aug 21 at 18:31:19.6 TD (18:30:11.0 UT1) 2457987.270961
Equatorial Conjunction 2017 Aug 21 at 18:14:22.8 TD (18:13:14.3 UT1) 2457987.259193
Geocentric Coordinates of Sun and Moon
2017 Aug 21 at 18:26:40.3 TD (18:25:31.7 UT1)
Coordinate Sun Moon
Right Ascension10h04m03.9s10h04m30.6s
Declination+11°51'43.0"+12°16'32.8"
Semi-Diameter 15'48.7" 16'03.4"
Eq. Hor. Parallax 08.7" 0°58'55.7"
Geocentric Libration of Moon
Angle Value
l 4.6°
b -0.6°
c 21.9°
Prediction Paramaters
Paramater Value
Ephemerides JPL DE406
ΔT 68.5 s
k (penumbra) 0.2725076
k (umbra) 0.2722810
Saros Series 145 (22/77)

Explanation of Solar Eclipse Data Tables

Penumbral Shadow Contacts and Extremes: Total Solar Eclipse of 2017 Aug 21

Contacts of Penumbral Shadow with Earth
Contact Event Contact Time
TD
Time
UT1
Latitude Longitude
First External ContactP115:47:59.915:46:51.330°32.7'N153°05.5'W
First Internal ContactP218:13:05.618:11:57.078°02.9'N094°48.0'E
Last Internal ContactP318:40:33.418:39:24.857°00.0'N009°45.8'E
Last External ContactP421:05:31.921:04:23.401°42.4'N044°59.8'W
Extreme Northern and Southern Path Limits of Penumbra
Contact Event Contact Time
TD
Time
UT1
Latitude Longitude
North Extreme Path Limit 1N118:07:23.418:06:14.877°34.0'N071°32.2'E
South Extreme Path Limit 1S116:34:08.016:32:59.508°38.9'N159°19.4'W
North Extreme Path Limit 2N218:46:18.218:45:09.761°56.6'N012°39.5'E
South Extreme Path Limit 2S220:19:10.720:18:02.120°16.9'S038°12.3'W

Explanation of Penumbral Shadow Contacts and Extremes Tables

Umbral Shadow Contacts and Extremes: Total Solar Eclipse of 2017 Aug 21

Contacts of Umbral Shadow with Earth
Contact Event Contact Time
TD
Time
UT1
Latitude Longitude
First External ContactU116:49:44.516:48:36.039°37.5'N171°25.4'W
First Internal ContactU216:50:44.616:49:36.039°51.0'N171°45.3'W
Last Internal ContactU320:02:48.020:01:39.511°07.5'N027°18.3'W
Last External ContactU420:03:42.820:02:34.310°55.0'N027°34.7'W
Extreme Northern and Southern Path Limits of Umbra
Contact Event Contact Time
TD
Time
UT1
Latitude Longitude
North Extreme Path Limit 1N116:50:30.016:49:21.539°59.7'N171°44.8'W
South Extreme Path Limit 1S116:49:59.216:48:50.739°28.8'N171°26.0'W
North Extreme Path Limit 2N220:03:01.320:01:52.811°15.6'N027°19.8'W
South Extreme Path Limit 2S220:03:29.320:02:20.810°46.9'N027°33.1'W

Explanation of Umbral Shadow Contacts and Extremes Tables

Central Line Extremes and Duration: Total Solar Eclipse of 2017 Aug 21

Extreme Limits of the Central Line
Contact Event Contact Time
TD
Time
UT1
Latitude Longitude
Extreme Central Line Limit 1C116:50:14.516:49:06.039°44.2'N171°35.4'W
Extreme Central Line Limit 2C220:03:15.420:02:06.911°01.2'N027°26.5'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 Eclipse18:26:40.318:25:31.736°58.0'N087°57.5'W 63.9° 197.9° 114.7 km02m40.12s
Greatest Duration18:22:57.618:21:49.037°34.6'N089°06.6'W 63.8° 192.5° 114.5 km02m40.25s

Explanation of Greatest Eclipse and Greatest Duration

Polynomial Besselian Elements: Total Solar Eclipse of 2017 Aug 21

Polynomial Besselian Elements
2017 Aug 21 at 18:00:00.0 TD (=t0)
n x y d l1 l2 μ
0 -0.12958 0.48542 11.8670 0.54211 -0.00403 89.2454
1 0.54064 -0.14164 -0.0136 0.00012 0.00012 15.0039
2 -0.00003 -0.00009 -0.0000 -0.00001 -0.00001 0.0000
3 -0.00001 0.00000 - - - -
Tan ƒ1 0.0046222
Tan ƒ2 0.0045992

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 = 18.000

Explanation of Polynomial Besselian Elements

Links for the Total Solar Eclipse of 2017 Aug 21

Links to Additional Solar Eclipse Information

Eclipse Predictions

Predictions for the Total Solar Eclipse of 2017 Aug 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 68.5 seconds for this eclipse.

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.