The Voynich Ninja

Quote:I'm not sure I understand what you mean exactly by "possible to predict"? It certainly wasn't possible to predict if the eclipse would be visible in Europe, the math for this was only developed in the XVIII century, as far as googling suggests. And I'm still not sure "invisible" eclipses really were considered important, do you have a quote for this? We have a lot of extant astrological works from the time, do they contain something like the chart/table of all the eclipses?

Yes, there are tables. Here's a relevant excerpt from A History of Horoscopic Astrology: From the Babylonian Period to the Modern Age, James Herschel Holden, 2006:

"How did a medieval astrologer make a horoscope for his client? Fairly easily if the client knew his birthdate in whichever calendar the astrologer's tables were based upon. The astrologer would need to have some knowledge of the Julian calendar, and of the eras used by Western Europeans and the Greeks, as well as the Muslim calendar used by the Arabs and the rest of the Islamic countries. 

A set of planetary and ascension tables was a prerequisite, since ephemerides were not generally available. In Arabic-speaking countries there were a number is such sets of tables available [...] Planetary tables were of two types: (1) those that required calculation of the positions from tables of the elements of the orbits; and (2) those that in effect contained abbreviated ephemerides for certain periods of years for each body, which could be used to obtain approximate positions for other years by adding or subtracting recurrence periods from the required date to bring it within the range of tables. The latter type was most popular. 

The Arabic tables of Cordovan astronomer al-Zarqālî (c. 1029-1100), called Arzachel in Latin, were translated into Latin under the name Toledan Tables. [...] The Toledan Tables remained in use for two or three centuries, but were eventually supplanted by the Alphonsine Tables, prepared c. 1272 by order of the Spanish King Alphonso X the Wise (1226-1284), who was a great patron of astronomy and astrology. However, the latter tables apparently did not become well-known until the middle of the 14th century and did not immediately displace the older tables as we see from Chaucer."

You are not allowed to view links. Register or Login to view.. 

With regards to visibility, there are many sources on this, I'm just picking one close to hand. Here we see a set of criteria given for assessing eclipse qualities, with visibility as an additional consideration after the fact, not a prerequisite:

"Accordingly, as regards the regions and cities, it is fitting to consider the twelfth-part in which the eclipse occurs, which sort are affiliated to it by a triangular or square figure, and similarly, for what cities the phosphoresences and the hour-markings are harmonious with the place of the eclipse. As for those [regions and cities] whose time of founding is not discovered, one must consider, with regard to the Midheaven of those who are the leaders of kings at that time, whether it has sympathy for the same place. So, for as many regions and cities as we find the prescribed affiliation, for all of these one must suppose that the event will, on the whole take place; but especially for those which have a relationship to the twelfth-part of the eclipse itself, and in as many of them as the eclipse appeared above the earth." 

- Apotelesmatics Book I, Hephaestio of Thebes trans. Schmidt 1994.

Quote:I think it's very simple, if we are still talking about the Voynich MS. Either European astrologers were well aware of the eclipse of April 1419, for which we have no proof so far, or it's not very likely this eclipse is referenced in the Voynich MS.

That's fine, personally I don't think we can tell one way or another. If it is 1419, that cluster is likely the Pleiades.

The nuance of eclipse doctrine is relevant in decoding an astrologer's intentions, as such it could constitute one avenue of investigation for the VMs. Perhaps this folio is not depicting an eclipse at all. However, it is incorrect to implement different astrological criteria for the importance of such an event to the author. To suggest that the folio might be personal astrological work is no more outlandish than the suggestion it could contain personal herbal and medical notes. If there is evidence that the manuscript must concern grand international matters of monarchy, I've not come across it. Astrologers have always been people, and although many sold their services to elite figures, this doesn't represent the whole of the tradition. Most of it was about figuring out if your wife would recover from illness, and so on.

(25-07-2026, 01:56 PM)NosDa Wrote: You are not allowed to view links. Register or Login to view.Yes, there are tables.

I'm not sure you have provided a single medieval example of a table of eclipses from Europe? Ordinary planetary charts are not enough to compute the eclipses, this requires some advanced computation not available before the XVIII century or some historical records and application of the saros cycles.

I don't think there is any evidence so far that in the XV century Europe:
1) there was a known way to precompute eclipse months (and thus dates) for all solar eclipses regardless of their geographic location 
2) invisible eclipses (those that were only visible outside of Europe or other places of interest) were considered important for astrology

Unless there are direct quotes from any medieval sources to the contrary, I don't think we can assume these above are true.

(25-07-2026, 02:47 PM)oshfdk Wrote: You are not allowed to view links. Register or Login to view.

(25-07-2026, 01:56 PM)NosDa Wrote: You are not allowed to view links. Register or Login to view.Yes, there are tables.

I'm not sure you have provided a single medieval example of a table of eclipses from Europe? Ordinary planetary charts are not enough to compute the eclipses, this requires some advanced computation not available before the XVIII century or some historical records and application of the saros cycles.

I don't think there is any evidence so far that in the XV century Europe:
1) there was a known way to precompute eclipse months (and thus dates) for all solar eclipses regardless of their geographic location 
2) invisible eclipses (those that were only visible outside of Europe or other places of interest) were considered important for astrology

Unless there are direct quotes from any medieval sources to the contrary, I don't think we can assume these above are true.

That's fine, I'm more than happy to leave this discussion. And the forum at large, after this interaction. All the best to you in your endeavour to decipher this hermetic work. I leave this topic in your capable hands.

(25-07-2026, 02:53 PM)NosDa Wrote: You are not allowed to view links. Register or Login to view.That's fine, I'm more than happy to leave this discussion. And the forum at large, after this interaction. All the best to you in your endeavour to decipher this hermetic work. I leave this topic in your capable hands.

Critical thinking is a core component of the scientific method. In my opinion it is the only way to advance in the decipherment of the VMS. If you don't like it, that's your own problem.

(25-07-2026, 02:47 PM)oshfdk Wrote: You are not allowed to view links. Register or Login to view.I'm not sure you have provided a single medieval example of a table of eclipses from Europe? Ordinary planetary charts are not enough to compute the eclipses, this requires some advanced computation not available before the XVIII century or some historical records and application of the saros cycles.

I don't think there is any evidence so far that in the XV century Europe:
1) there was a known way to precompute eclipse months (and thus dates) for all solar eclipses regardless of their geographic location 
2) invisible eclipses (those that were only visible outside of Europe or other places of interest) were considered important for astrology

Unless there are direct quotes from any medieval sources to the contrary, I don't think we can assume these above are true.

It appears it was possible. I got this from Gemini:

Mnemonic and Diagrammatic Charts
In medieval manuscripts, eclipse diagrams (rotae or tables) were often used to illustrate the underlying geometry of the universe rather than just serve as a practical night-by-night weather forecast. Because these tables were pedagogical, they included theoretical eclipse points along the Saros or Metonic cycles regardless of local visibility.

Why Astronomers Calculated Them

1. Checking Mathematical Consistency: Computing non-visible eclipses was the ultimate test of an astronomical table's underlying geometric model (such as Ptolemy’s Almagest). If a table skipped non-visible eclipses, the mathematical cycles would break.
   
2. Long-Distance Calibration: Astronomers knew Earth was round and that time differed by longitude. Knowing that an eclipse occurred at a specific time—even if below the local horizon—allowed scholars to cross-reference observations sent by correspondents in Persia, India, or North Africa to measure differences in terrestrial longitude.
   

The raw astronomical calculations for syzygy (mean and true conjunction) yielded a real eclipse event. In a full set of ephemerides generated for 1419, this entry would either be flagged as occurring sub terra (below the earth) or listed with zero local magnitude.

Anyone using tables based on Paris, Toledo, or Oxford meridians to calculate upcoming conjunctions for 1419 would produce mathematical parameters showing a valid solar eclipse at syzygy. However, applying the standard medieval tables for solar parallax (parallaxis lunae) would reveal that, from European latitudes, the Moon’s apparent disc shifted completely clear of the Sun's disc.

By 1419, early 15th-century astronomers (particularly in places like Vienna, Prague, and Oxford) were heavily focused on refining lunar-solar tables:

Johannes von Gmunden (a pioneer of the Vienna School of Mathematics/Astronomy) was actively compiling and re-calculating astronomical tables and eclipse ephemerides around 1415–1425.

Prophatius Judaeus’ and John of Linières’ auxiliary tables were widely copied in manuscripts at this exact time to streamline calculating whether a syzygy was a visible or invisible eclipse.

When medieval computers calculated 1419, they routinely worked through the math for syzygies regardless of local night/day or parallax, meaning the numbers for non-visible eclipses like those of 1419 were recorded in their working notebooks and master tables before being filtered out for practical local calendars.

In late medieval astronomy, these appeared in three distinct formats depending on who compiled the manuscript and how far they carried the calculations:

1. Comprehensive Master Tables (Tabulae Syzygiarum)
In master computing tables derived from the Alfonsine Tables—such as those produced by Johannes von Gmunden in Vienna around 1415–1420—every single mean and true syzygy (conjunction) was calculated mathematically.

In these master reference tables:

The conjunction for March 26, 1419 and September 19, 1419 would appear in the chronological ledger of true solar-lunar conjunctions.

They included calculated parameters such as the true position of the Sun and Moon, the argument of latitude, and the distance to the Moon's nodes (Ω). Because the angular distance to the node fell within the "eclipse boundary" (≈106
′
−110
′
  for solar eclipses), the table mathematically flagged the conjunction as a valid eclipse event.

2. Ephemerides & Almanacs (With Parallax Adjustments)
When an astronomer moved from master astronomical tables to compiling a practical almanac (a year-by-year ephemeris for local use in Oxford, Paris, or Prague), they applied the local parallax tables (parallaxis lunae).

When applying European latitude coordinates to the 1419 events, two things happened in the manuscript tables:

The September 19, 1419 Eclipse: The calculated time of true conjunction fell during night hours for European longitudes. In full eclipse lists, it would be explicitly written in Latin as sub terra ("below the earth" / invisible).

The March 26, 1419 Eclipse: The parallax calculation showed that from European latitudes, the Moon’s apparent displacement shifted its disc out of alignment with the Sun. Manuscripts handling this either noted the eclipse magnitude as 0 digits (0 digiti—meaning non-visible locally) or listed the event alongside a notation like non apparebit in his regionibus ("will not appear in these regions").

3. Geographical Coordinate & Shadow Tables
Because Islamic and Late Medieval European astronomy accounted for long-distance geographical differences, master tables often included auxiliary tables for different climate zones (climata).

If a 15th-century scholar recalculated the March 26, 1419 eclipse for meridians further east or south (such as Cairo, Baghdad, or Mecca), the tables yielded a positive eclipse magnitude (partial/annular visibility), proving that while invisible to Central Europe, the eclipse was physically real.

(26-07-2026, 05:47 PM)Linda Wrote: You are not allowed to view links. Register or Login to view.It appears it was possible. I got this from Gemini:

This doesn't include any specific citations though and the text seems to suggest that somehow it was possible in the XV century to compute whether an eclipse would be visible in Europe or not, which I think wasn't possible until three hundred years later when Newtonian mechanics of the solar system allowed for precise enough computations of the orbits.

Saros tables existed before the XV century at least in the Arabic/Greek world, but these only covered the eclipse series for which precedents (past eclipses in the same series) had been recorded. We need an example of a saros eclipse table from the XV century Europe, I haven't seen any yet.

Overall, how sure are you of the validity of this analysis by Gemini?

I did a little more digging and found this, it is a notation of the eclipse itself. 

The book was partly written by, and belonged to, one of the family of Holdenby, or Haldenby (of Isham in Northamptonshire)

The late 14th century text bound within Trinity Ms R.15.18 includes tables of eclipses between 1406-1462. The solar eclipses are depicted in red and gold and the lunar eclipses which follow in blue and gold.

You are not allowed to view links. Register or Login to view.

You are not allowed to view links. Register or Login to view.


The columns read down, it is the third one down from the middle column on the first page, you can see the year is 1419, took me awhile to realize it says 24 dies (March) (not the 26th as our tables tell us now).

(26-07-2026, 08:35 PM)Linda Wrote: You are not allowed to view links. Register or Login to view.I did a little more digging and found this, it is a notation of the eclipse itself. 

Thanks, this is a great find! Just for the reference, a link to the blog article where the image comes from: You are not allowed to view links. Register or Login to view.

I took the table from You are not allowed to view links. Register or Login to view. to find out about the types of eclipses described there. First of all, it's certainly not an exhaustive list of eclipses, You are not allowed to view links. Register or Login to view. lists 53 solar eclipses between 1401 and 1424, this table only has 9.

I've added NASA information for these 9 eclipses in the image below. Looks like all of them were visible to some extent from Europe or North Africa (notably all of eclipses centered on Australia, Antarctica, Pacific are absent, and these are the majority in the NASA list), even distant ones like the eclipse of 1416 centered in the Atlantic off the coast of Brazil was visible from Spain (I've added the eclipse map for this one to the image below).

I'm not sure if the table is about future eclipses or the record of past eclipses? It starts with 1406 and ends somehow abruptly with the year of 1462 (just to clarify, I've only used the first section of the table in the image below, the full table is three sections long and goes up to 1462). With no further information I would assume this is a list of recorded eclipses and not a prognostic table.

[attachment=16789]

EDIT: One thing is clear now, the eclipse of 1419 was known in Europe. However, when seen from Europe it was only a partial eclipse with ~30% coverage, so not only stars were not visible, you won't even notice any difference from the bright day without looking at the sun (never look at the sun without special goggles, by the way).

I think it is a mix of past and future. Perhaps it was only the future when they were first being made?

Found many in the form of a folded almanac. This one says it was made between 1415 and 1425, starts with 1384, and has the March 1419 eclipse as the last one of the bunch on one side, but continues on into the future on the other side, starting with 1424, going into the 1460's.