I could have sworn there was a discussion of eclipses somewhere in ArM5, but I don't seem to be able to find it.

Last summer there was a good deal of news coverage of the eclipse that crossed the USA. This set me to considering the impact of an eclipse in Mythic Europe. I'm mainly thinking of solar eclipses here, but I suspect the effect of a lunar eclipse should be the same.

I don't know that Hermetic magi have much to say about eclipses. They're rare events - only five total eclipses in Europe from 1221 to 1300, and fleeting.

Still, I'd think they'd have a real impact on those under the eclipse. Perhaps Twilight is more likely, or perhaps they grant a single Warping point? Could Gifted births be more common to mothers touched by an eclipse? Perhaps Magic Theory can extract some rare benefit under an eclipse.

Eclipses strike me as Magical events; they are impersonal, relentless, and weird. While I'm sure they have an effect in all the Realms, they seem more magical to me.


Was it possible to predict eclipses at the time, or would magi have been as surprised as farmers when one happens?

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The first is very readable, but I don't know about the credibility. The second is not as good a read, but it is hosted by NASA, giving me some confidence. It is more critical and pessimistic, but largely confirms the first.

It seems that both the Chinese and the Greek could predict solar eclipses in ancient times, at least to some extent. It is hard to do, and requires very accurate models, because the area of a total eclipse is only 300km wide. I think it is fair to say that it would be possible to do in medieval Europe, but you would be very unlikely to find a scholar who could actually do it. In mythic Europe, we might well imagine a line of mystics and scholars who have preserved the Greek arts and records, and are able to do the prediction.

My limited understanding is that eclipses could be predicted to within months; not very useful. Even if magi are better at it, they'd be down to perhaps weeks or days.

In my saga I have a plot that may allow a highly accurate prediction of eclipses (among other calculations) due to synchronization of Ptolomaic models, if this-and-that happens due to PC action.

Solar or lunar, and what effect do they have on day or month durations? For example if a lunar eclipse conts as a new moon during a full moon that would end any moon duration spell. Would a solar eclipse end sun duration effects as well?

My vote would be that the eclipse does not affect duration. Sun duration is defined by sunset and sunrise. At an eclipse, the sun dies; it neither sets nor rises.

Moon is a little lesss obvious, but a full or new moon ends duration whether or not the moon is on the visible sky. Thus the magi are bound to know the moon's cycle, independent of individual observations.

However, the story decides. Eclipses are rare enough that there is no great need for canon.

If nothing else, I believe that Divine Heaven's Aspect and a decent score in Artes Liberales should allow a rather accurate prediction of an Eclispe. The spell does not give the moment of the eclipse, but should be giving information that are accurate enough to make an accurate calculation of when one would occur.

As loke said

Divine Heaven's Aspect will allow to gather accurate data. Up to the astronom to come with the right model.

Obviously, building an armillary sphere with the proper enchantments will be a tremendous help and allows astronomy to progress much faster, baring religious considerations that could interfere with their theory & models :slight_smile:

I agree. It can be done.
I would be happy to accept that a starting PC with the right background and a story flaw as Heretic (or something) could be able to do it.

If a PC wanted to do it in game, I would say that it takes several seasons, maybe years, of dedicated research. The limitation of the spell is that Hermetic magic cannot scry on the past. To gather the data, one would actually need to apply the spell over a long period of time. Searching out the best mundane libraries in Europe to search for old Greek texts might be quicker than collecting the data for oneself.

It is an interesting character concept.

Yes. I agree with you.

Eclipses are known. Attempt to predict them have been made with a certain degree of (in)accuracy.
Magical tools are available to have accurate measurement.

All the elements are there. But an accurate model is missing. I don't know if I would require a specific virtue or flaw to do this research, but it would require an extensive research. To invent such model and theory, I would probably handle it like minor breakthrough, but instead of having to invent spells/enchantment, the researcher would write essay, tractatus and such. He will have to dig into old archives to gather data on previous eclipse.

All depends on how complicated and how central to your campaign you want to make it.

It sounds like a saga in its own right. An old-fashioned grand Quest type of campaign. Travel all over Europe and the Mediterranean to seek out the leading scholars of philosophia and artes liberales and forgotten libraries of ancient Greek texts. Step by step building up an understanding.

PbP anyone?

Maybe because casting a spell or finishing ritual casting exactly during an eclipse would allow to bypass some hermetic limits ?


The theory (Almagest Book VI) is taught at cathedral schools and universities, and should be found in all the larger Hermetic libraries as well: in Latin latest from 1200 on. The problem with predicting eclipses is the required precision of the model: and TMRE p.47ff Hermetic Astrology provides all the means a magus needs to reach that.

I wouldn't understand, why eclipses - being local occurrences - should affect Hermetic spell and effect durations. But there might be other magical traditions working differently, which can lead to adventures and even sagas.


Why would that be?

Does lunar sphere cease to be during a lunar eclipse, so that it would no longer pose a limit for Hermetic magic?

Most of the troupe I am with would point to the movie "LadyHawk".

LadyHawke seems to have an Until duration.

Alternately, the spell has overlap; part of the enchantment was that the two lovers could see each other for a moment at twilight; an eclipse seems to suspend or extend the moment of the balance for the duration of the eclipse.

I suspect the eclipse in LadyHawke is nonhistorical, so Divine intervention. I don't doubt that such eclipses can happen in Mythic Europe, but they are not predictable and so they can be ignored.

Edit -

There are six eclipses in Medieval France from 1000 AD to 1500 AD:


The first three are in southern France, the last three crossing central France. I don't remember if there's a more specific year-era-century-historic event mentioned in the film, but based on the look of the times, I suppose it could be any of the last four. I'll still go with Divine Intervention.

Exactly. That's why they could both be human at the same time, and why the curse could be broken during the eclipse.

Because it has interesting story potential. :smiley:

Also, such occurrence are so rare, that it is reasonable to consider that Bonisagus theory did not (fully ?) cover the impact on hermetic magic. I know that there is nothing canon there. However, as SG, I am using any extraordinary circumstances as potential story seed.

Also, magic is sensitive to astrological/natural phenomenon (example is the environmental trigger) and considering how rare are solar eclipse, a case can be made on their impact on magic and the fact that is has not been thoroughly studied.

As I said, the story decides. :slight_smile:

I suppose there is no point in letting the party experience an eclipse, without having some sort of supernatural, unexpected effect to throw at them. Just let's hope that no one every concocts a canon for it, lest it no longer be unexpected.