April 1968 lunar eclipse

Total Lunar Eclipse
April 13, 1968
(No photo)
Lunar eclipse chart close-1968Apr13.png
The moon passes west to east (right to left) across the Earth's umbral shadow, shown in hourly intervals.
Series 131 (31 of 72)
Duration (hr:mn:sc)
Totality
Partial
Penumbral
Contacts
P1 UTC
U1
U2
Greatest
U3
U4
P4

A total lunar eclipse took place on April 13, 1968, the first of two total eclipses in 1968, the second being on October 6, 1968. The tables below contain detailed predictions and additional information on the Total Lunar Eclipse of April 13, 1968.

Eclipse Characteristics
Parameter Value
Penumbral Magnitude 2.07253
Umbral Magnitude 1.11164
Gamma -0.41732
Epilson 0.426º
Opposition Times
Event Calendar Date & Time Julian Date
Greatest Eclipse 1968 Apr 13 at 04:48:00.8 TD (04:47:22.2 UT1) 2439959.699563
Ecliptic Opposition 1968 Apr 13 at 04:52:17.8 TD (04:51:39.2 UT1) 2439959.702537
Equatorial Opposition 1968 Apr 13 at 05:10:26.5 TD (05:09:48.0 UT1) 2439959.715139
Geocentric Coordinates of Sun and Moon
1968 Apr 13 at 04:48:00.8 TD (04:47:22.2 UT1)
Coordinate Sun Moon
Right Ascension 01h26m19.6s 13h25m32.2s
Declination +09°03'48.7" -09°26'23.0"
Semi-Diameter 15'56.9" 16'35.8"
Eq. Hor. Parallax 08.8" 1°00'54.7"
Geocentric Libration of Moon
Angle Value
l -2.6°
b 0.6°
c 20.2°
Earth's Shadows
Parameter Value
Penumbral Radius 1.2936°
Umbral Radius 0.7620°
Prediction Paramaters
Parameter Value
Ephemerides JPL DE406
ΔT 38.5 s
Shadow Rule Danjon
Shadow Enlargement 1.010
Saros Series 131 (31/72)

VisibilityEdit

It was visible from North and South America, as well as Africa and western Europe.

 

Related lunar eclipsesEdit

Lunar year seriesEdit

Lunar eclipse series sets from 1966–1969
Descending node   Ascending node
Saros Date
Viewing
Type
Chart
Saros Date
Viewing
Type
Chart
111 1966 May 4
 
Penumbral
 
116 1966 Oct 29
 
Penumbral
 
121 1967 Apr 24
 
Total
 
126 1967 Oct 18
 
Total
 
131 1968 Apr 13
 
Total
 
136 1968 Oct 6
 
Total
 
141 1969 Apr 2
 
Penumbral
 
146 1969 Sep 25
 
Penumbral
 
Last set 1965 Jun 14 Last set 1965 Dec 8
Next set 1970 Feb 21 Next set 1969 Aug 27

Saros seriesEdit

It is the second total lunar eclipse of the series.

Lunar Saros series 131, has 72 lunar eclipses. Solar Saros 138 interleaves with this lunar saros with an event occurring every 9 years 5 days alternating between each saros series.

This eclipse series began in AD 1427 with a partial eclipse at the southern edge of the Earth's shadow when the Moon was close to its descending node. Each successive Saros cycle, the Moon's orbital path is shifted northward with respect to the Earth's shadow, with the first total eclipse occurring in 1950. For the following 252 years, total eclipses occur, with the central eclipse being predicted to occur in 2078. The first partial eclipse after this is predicted to occur in the year 2220, and the final partial eclipse of the series will occur in 2707. The total lifetime of the lunar Saros series 131 is 1280 years. Solar Saros 138 interleaves with this lunar saros with an event occurring every 9 years 5 days alternating between each saros series.

Because of the ⅓ fraction of days in a Saros cycle, the visibility of each eclipse will differ for an observer at a given fixed locale. For the lunar Saros series 131, the first total eclipse of 1950 had its best visibility for viewers in Eastern Europe and the Middle East because mid-eclipse was at 20:44 UT. The following eclipse in the series occurred approximately 8 hours later in the day with mid-eclipse at 4:47 UT, and was best seen from North America and South America. The third total eclipse occurred approximately 8 hours later in the day than the second eclipse with mid-eclipse at 12:43 UT, and had its best visibility for viewers in the Western Pacific, East Asia, Australia and New Zealand. This cycle of visibility repeats from the initiation to termination of the series, with minor variations. Solar Saros 138 interleaves with this lunar saros with an event occurring every 9 years 5 days alternating between each saros series.

Lunar Saros series 131, repeating every 18 years and 11 days, has a total of 72 lunar eclipse events including 57 umbral lunar eclipses (42 partial lunar eclipses and 15 total lunar eclipses). Solar Saros 138 interleaves with this lunar saros with an event occurring every 9 years 5 days alternating between each saros series.

Greatest First
 
The greatest eclipse of the series will occur on 2094 Jun 28, lasting 102 minutes.[1]
Penumbral Partial Total Central
1427 May 10 1553 July 25 1950 Apr 2 2022 May 16
Last
Central Total Partial Penumbral
2148 Jul 31 2202 Sep 3 2563 Apr 9 2707 Jul 7
1901–2100
1914 Mar 12 1932 Mar 22 1950 Apr 2
           
1968 Apr 13 1986 Apr 24 2004 May 4
           
2022 May 16 2040 May 26 2058 Jun 6
           
2076 Jun 17 2094 Jun 28
       

Inex seriesEdit

The inex series repeats eclipses 20 days short of 29 years, repeating on average every 10571.95 days. This period is equal to 358 lunations (synodic months) and 388.5 draconic months. Saros series increment by one on successive Inex events and repeat at alternate ascending and descending lunar nodes.

This period is 383.6734 anomalistic months (the period of the Moon's elliptical orbital precession). Despite the average 0.05 time-of-day shift between subsequent events, the variation of the Moon in its elliptical orbit at each event causes the actual eclipse time to vary significantly. It is a part of Lunar Inex series 35.

Series events from 1500–2500
Descending node Ascending node Descending node Ascending node
Saros Date
Chart
Saros Date
Chart
Saros Date
Chart
Saros Date
Chart
115 1505 Feb 18
 
116 1534 Jan 30
 
117 1563 Jan 9 118 1591 Dec 30
119 1620 Dec 9 120 1649 Nov 19 121 1678 Oct 29 122 1707 Oct 11
123 1736 Sep 20 124 1765 Aug 30 125 1794 Aug 11 126 1823 Jul 23
127 1852 Jul 1 128 1881 Jun 12 129 1910 May 24
 
130 1939 May 3
 
131 1968 Apr 13
 
132 1997 Mar 24
 
133 2026 Mar 3
 
134 2055 Feb 11
 
135 2084 Jan 22
 
136 2113 Jan 2 137 2141 Dec 13 138 2170 Nov 23
139 2199 Nov 2 140 2228 Oct 14 141 2257 Sep 24 142 2286 Sep 3
143 2315 Aug 16 144 2344 Jul 26 145 2373 Jul 5 146 2402 Jun 16
147 2431 May 27 148 2460 May 5
 
149 2489 Apr 16
 

Half-Saros cycleEdit

A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).[2] This lunar eclipse is related to two annular solar eclipses of Solar Saros 138.

April 8, 1959 April 18, 1977
   

See alsoEdit

NotesEdit

  1. ^ Listing of Eclipses of cycle 131
  2. ^ Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros

External linksEdit