<p>The length of an eclipse season is between 31 and 37 days (<a href="https://en.wikipedia.org/wiki/Eclipse_season#Details" rel="nofollow noreferrer">Wikipedia</a>). But when is it shorter and when is it longer?</p>
<p>My thoughts:</p>
<p>When the Moon is closer to us it has a bigger angular size, which would make the eclipse region bigger, thus making the eclipse season longer.
But when it comes to the Sun-Earth distance, I'm not sure what its effect would be. On one hand, when the Sun is closer to us it has a bigger angular size. On the other hand, when Earth is near perihelion it moves faster, and it may leave the eclipse region faster.</p>
<p>(Also I would appreciate if one can give more precise values for the length of the eclipse seasons than whole days.)</p>

CC BY-SA 4.0
2023-12-07T22:49:19.120Z
The term "eclipse season" is weakly defined.  Notice the wilipedia article does not explicity cite a source for a definition.  The term is frequently used, as the article states, to describe a period for when the moon is near one of its nodes.  But "near" is a vague term to use.
Greg Miller
CC BY-SA 4.0
2023-12-08T07:03:42.317Z
This may be helpful: https://www.eclipsewise.com/solar/SEhelp/SEperiodicity.html & https://eclipsewise.com/lunar/LEhelp/LEperiodicity.html
PM 2Ring
CC BY-SA 4.0
2023-12-08T14:22:17.017Z
@PM2Ring It looks like both pages have the same content.
George Lee
CC BY-SA 4.0
2023-12-08T15:07:23.330Z
The two pages do have a lot in common, but there are some differences. Eg, from the solar page: "If an eclipse occurs within °9.5° to 10.9° of a node, the eclipse will be central (annular, hybrid, or total)". From the lunar page: "If a lunar eclipse occurs within 9.4° to 11.0° of a node, the eclipse will be partial. A lunar eclipse within 4.2° to 5.0°of a node will be total".
PM 2Ring
CC BY-SA 4.0
2023-12-08T19:27:46.143Z
@PM2Ring From the information in your links it looks like Eclipse seasons should range from 30.1 days to 33.3 days (15.2*0.99*2=30.1 & 16.8*0.99*2=33.3), which is very different from the values stated at Wikipedia. Obviously there's some information missing there, if not wrong information.
George Lee
CC BY-SA 4.0
2023-12-11T03:22:16.273Z
@George For a total lunar eclipse, the Moon has to be completely inside the Earth's shadow. You can generally trust [Fred Espenak](https://en.wikipedia.org/wiki/Fred_Espenak)'s eclipse info and calculations. He doesn't claim that there are no mistakes, but he is *very* thorough, and has been calculating eclipses for decades.
PM 2Ring
CC BY-SA 4.0
2023-12-11T15:15:25.530Z
@PM2Ring Oh, it was my mistake (but 9.4 to 11 is still less).
George Lee
<eclipse>
What determines the length of an Eclipse season?
George Lee
# What determines the length of an Eclipse season?

(Asked by: username_0 on 2023-12-07)

The length of an eclipse season is between 31 and 37 days ([Wikipedia](https://en.wikipedia.org/wiki/Eclipse_season#Details)). But when is it shorter and when is it longer?

My thoughts:

When the Moon is closer to us it has a bigger angular size, which would make the eclipse region bigger, thus making the eclipse season longer.
But when it comes to the Sun-Earth distance, I'm not sure what its effect would be. On one hand, when the Sun is closer to us it has a bigger angular size. On the other hand, when Earth is near perihelion it moves faster, and it may leave the eclipse region faster.

(Also I would appreciate if one can give more precise values for the length of the eclipse seasons than whole days.)

**Tags:** eclipse

> **Comments:**
> **username_1**: The term "eclipse season" is weakly defined.  Notice the wilipedia article does not explicity cite a source for a definition.  The term is frequently used, as the article states, to describe a period for when the moon is near one of its nodes.  But "near" is a vague term to use.  
> **username_2**: This may be helpful: https://www.eclipsewise.com/solar/SEhelp/SEperiodicity.html & https://eclipsewise.com/lunar/LEhelp/LEperiodicity.html  
> **username_0**: @PM2Ring It looks like both pages have the same content.  
> **username_2**: The two pages do have a lot in common, but there are some differences. Eg, from the solar page: "If an eclipse occurs within °9.5° to 10.9° of a node, the eclipse will be central (annular, hybrid, or total)". From the lunar page: "If a lunar eclipse occurs within 9.4° to 11.0° of a node, the eclipse will be partial. A lunar eclipse within 4.2° to 5.0°of a node will be total".  
> **username_0**: @PM2Ring From the information in your links it looks like Eclipse seasons should range from 30.1 days to 33.3 days (15.2*0.99*2=30.1 & 16.8*0.99*2=33.3), which is very different from the values stated at Wikipedia. Obviously there's some information missing there, if not wrong information.  
> **username_2**: @George For a total lunar eclipse, the Moon has to be completely inside the Earth's shadow. You can generally trust [Fred Espenak](https://en.wikipedia.org/wiki/Fred_Espenak)'s eclipse info and calculations. He doesn't claim that there are no mistakes, but he is *very* thorough, and has been calculating eclipses for decades.  
> **username_0**: @PM2Ring Oh, it was my mistake (but 9.4 to 11 is still less).  

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