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Eclipses in the Solar System
Author: Bill Kramer
Last update: April 24 2018

Planets in Study Distance to Sun (KM)
Angular Size of Sun (Degrees)
Planet name Radius (KM) Moons Perihelion Average Aphelion
Earth63711147,100,000
0.54195
149,600,000
0.53289
152,100,000
0.52413
Mars33902206,600,000
0.38587
227,900,000
0.34981
249,200,000
0.31991
Jupiter6991150740,500,000
0.10766
778,600,000
0.10239
816,600,000
0.09763
Saturn58232531,352,600,000
0.05894
1,433,500,000
0.05561
1,514,500,000
0.05264
Uranus25362272,741,300,000
0.02908
2,872,500,000
0.02775
3,003,600,000
0.02654
Neptune2462284,444,500,000
0.01794
4,495,100,000
0.01774
4,545,700,000
0.01754

= = = > Jump to summary

Planet Moon Size (radius KM) Distance (KM)
Periapsis/Apoapsis
Angular Size (moon)
Periapsis/Apoapsis
Angular Size (Sun)
Aphelion/Perihelion
Ratio Sun/moon
EarthMoon1,737.1356,924
405,503
2,007.7
1,767.2
1,886.9
1,951.0
0.940
1.104
JupiterCallisto2,408.41,799,610
1,895,879
552.1
524.1
351.5
387.6
0.637
0.740
SaturnJanus90.492,180
152,532
404.6
244.5
189.5
212.2
0.468
0.868
SaturnEpimetheus58.391,827
152,785
261.9
157.4
189.5
212.2
0.724
1.348
SaturnPandora40.682,873
142,295
202.1
117.7
189.5
212.2
0.938
1.803
UranusCordelia20.124,423
49,815
339.5
166.5
95.6
104.7
0.281
0.629
UranusOphelia21.427,905
54,333
316.4
162.5
95.6
104.7
0.302
0.644
UranusBianca25.733,785
59,253
313.8
178.9
95.6
104.7
0.304
0.585

^^^ Jump to top of table


Summary data

Found Earth-like eclipse conditions for: Earth/Moon, Saturn/Epimetheus, Saturn/Pandora
Moons investigated: 141
Maximum Solar/Moon ratio: 28,954.3
Minimum Solar/Moon ratio: 0.037332
Total eclipses: 31 - where the Sun is completely covered at both apoapsis and periapsis.
Annular eclipses: 107 - where Sun is visible around occulting moon at both apoapsis and periapsis.
Extreme totals (moon over 2x size of Sun): 30
Extreme annulars (Sun over 2x size of moon): 104
Number of very interesting eclipses, where moon appears less than twice the size of the Sun allowing a view of the corona, is 8 with 3 making a near perfect fit (one to one) - annular at apoapsis, total at periapsis.
Of the moons in the solar system, 22.0% were total only, 75.9% were annular only and 5.7% are ideal.

Click here for the related Study - Do other planets see solar eclipses?


Comparing the angular sizes

Using data from the NASA Planetary Fact Sheets about the moons, the table shows the angular size of the moon at the extremes of the orbit. The angular sizes are compared to the angular size of the Sun. The comparison is accomplished in terms of a ratio. Angular sizes of the moon are divided into the angular size of the Sun. If the ratio is greater than 1.0 then an annular eclipse event can take place. For ratios less than one, a total eclipse event can take place.

The program searched for where the ratios bridge the value of one. That is if any value is greater than one and another is less than one. Under those conditions, both total and annular eclipse are possible and this is considered to be the most Earth-like.


Columns in table

Planet is the name of the planet.
Moon is the name of the moon in orbit about the planet.
Size (radius KM) is the size of the moon's radius in kilometers.
Distance (KM) Periapsis/Apoapsis is the distance, in kilometers, from the surface (or cloud tops) of the planet to the moon. There are two values. The top value is the distance from the surface of the planet facing towards the Sun when the moon is closest or at periapsis. The second value is the distance from the surface of the planet at the pole to the moon when the moon is farthest or apoapsis.
Angular Size (moon) is the apparent size in seconds of arc. There are two values. The top is when the moon is closest or periapsis. The bottom value is when the moon is furthest or apoapsis.
Angular Size (Sun) Aphelion/Perihelion is the apparent size of the Sun as seen from the planet measured in seconds of arc. The top value is when the Sun is furthest or aphelion. The bottom value is when the Sun is furthest or perihelion.
Ratio Sun/moon is the value of the the angular size of the Sun divided by the angular size of the moon. A value greater than one indicates the conditions for an annular eclipse. A value less than one indicates the conditions for a total solar eclipse. The top value is the ratio when the moon is closest (biggest) to the surface of the planet and Sun furthest away (smallest). The bottom value is the ratio when the moon is smaller (furthest) and the Sun largest (closest).


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