Galileo's Use of the Colon

Latin after CDLXXVI
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Wilbur
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Galileo's Use of the Colon

Post by Wilbur »

Referring to Sidereus Nuncius, how is the colon used and what does it signify?

For example, at the bottom of his page 17, two lines above the diagram, are two colons separating three clauses. It seems to me that the two clauses after the first colon run together across the second colon for me to make sense of the later two clauses. I think he's trying to say, very roughly, "there are two of equal magnitude and one of them was brighter." But there is colon in the way. What am I missing?

I've seen colons in a lot of Latin and I've normally just looked at them as similar to commas, but a harder break, and not how we would use them in English. Maybe that's not right.

Hylander
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Re: Galileo's Use of the Colon

Post by Hylander »

Here's my rough translation:

[The little stars adjacent to Jupiter], while they were believed by me to be counted among the fixed stars, nevertheless elicited significant admiration, because they seemed to be disposed in a line that was exactly straight and parallel to the ecliptic : and [to be] brighter than the rest [fixed stars] of comparable magnitude : and their configuration among themselves and to Jupiter was such. [Diagram follows.]

The colons seem to be separating the individual points that he's making, as if they were modern bullet points.

". . . brighter than the rest of comparable magnitude" puzzled me at first, but I think he's comparing the brightness of the Jovian satellites to fixed stars of comparable apparent size/diameter (as seen through his telescope), not brightness.
Last edited by Hylander on Thu Jun 09, 2022 2:46 pm, edited 1 time in total.
Bill Walderman

Wilbur
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Re: Galileo's Use of the Colon

Post by Wilbur »

Thanks Hylander,
I think he's comparing the brightness of the Jovian satellites to fixed stars of comparable apparent size/diameter (as seen through his telescope), not brightness
That's an interesting take. I interpreted it to mean he was comparing the brightness of the Jovian moons among themselves. Typically, in modern scopes, stars are points with no angular size; but maybe his scope showed small disks.

When I use my astronomical software to look at Jupiter and its moons on Jan 7, 1610 from Padua (I think he was there at the time), I find the moons to be of slightly different brightness (magnitude), with one brighter than the other two, which were comparable. I also find that two of the moons were very close to each other, but that Galileo likely would not have been able to resolve them with the quality of his telescope. So, four were viewable, but he saw only three. Also, there are no stars near Jupiter as bright as the its moons at that time. (I can post a snip if you'd like to see it.)

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Re: Galileo's Use of the Colon

Post by Hylander »

. . . intulerunt admirationem, eo quod secundum exactam lineam rectam atque Eclypticae parallelam dispositae videbantur : ac caeteris magnitudine paribus splendidiores : eratque illarum inter se & ad Iouem talis constitutio.

I think splendidiores, plural, here applies to all three of the Jovian satellites he saw (or thought he saw) on 1/7/1610. I don't read this as singling out any one of the three apparent satellites as brighter than the others. So I think caeteris magnitudine paribus must refer to the rest of the stars -- i.e., the fixed stars -- of comparable "magnitude." magnitudine is ablative of comparison with paribus.

His crude -- by modern standards -- telescope would definitely not have produced pinpoint images of fixed stars, but rather, I think, fuzzy discs whose apparent diameters or dimensions would be roughly correlated with apparent brightness. He must have seen both the Jovian satellites and the fixed stars as fuzzy discs having dimensions, because he describes the Jovian satellites as exiguas, "tiny," while believing at first that they were e numero inerrantium, "from among the number of fixed stars," "to be classified as fixed stars." So again, I think he's saying that all of the Jovian satellites he saw were brighter than the fixed stars of comparable (apparent) dimensions.

The stellulae were in any case tiny. I wonder whether he would have been able to discern any difference in apparent brightness among them (as opposed to comparing their apparent brightness with that of the fixed stars).

I'd be curious to see the software snip.
Bill Walderman

Wilbur
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Re: Galileo's Use of the Colon

Post by Wilbur »

Hylander,

I believe you have the correct interpretation of his comparisons. And your assessment of his telescope’s capabilities. Although I have not done extensive research on this topic, I know that it was about 20x and had a field of view of about ¼ of a degree. And, as you say, he would have seen stars as small disks.

As far as snips go, the FAQ page tells me I can't upload images without permission and I don't see anything that tells me I have permission. So, I need some instruction on how to do that.

The other option is to send them to you via PM.

Any ideas?

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Re: Galileo's Use of the Colon

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To upload images, upload to imgur.com, and copy the "bbcode" share link and paste it here. The tag will begin with "[img]..."
"Here stuck the great stupid boys, who for the life of them could never master the accidence..."

Joel Eidsath -- jeidsath@gmail.com

Wilbur
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Re: Galileo's Use of the Colon

Post by Wilbur »

Jeidsath, thanks for the tutorial. Pretty straight forward.

Hylander,
I haven't done any research on his observation times. So, the following are just some guesses.

The end of astronomical twilight on Jan 7 was around 6:30pm, so I took a time after that as being a good observing time. The snips are from 7:00pm local time Padua. His view would have been hampered by a moon nearby and which was close to full.

The first is a broader view showing the ecliptic and how the moons were parallel to it as he states. I suppressed stars of magnitudes less than 7 to show that the moons are actually brighter than any stars nearby. The moons are magnitude 5-6. So, they would be brighter than other stars as he states.

The second shows a closer-in view. I added labels except for Io which is just east of Europa. He clearly did not resolve Io and Europa. But the disk of the two should have appeared brighter/bigger than the other moons. In fact, you can see the pair look brighter in the first picture if the software is any indication.

Incidentally, his next diagram in from Jan 8. When I scoot the sky to the next night, I find that all four moons were visible, but that he shows only three. Curiously, he missed Callisto which was quite far to the east. I plan on putting these snips in my humble translation at some point.

Any comments or corrections are welcome.

Jan 7 with ecliptic
Image
Jan 7 close in
Image
Jan 8
Image

Hylander
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Re: Galileo's Use of the Colon

Post by Hylander »

Thanks for posting these, Wilbur. I wonder whether Callisto was in his field of view on Jan. 8.

I'm enjoying his narrative, which captures his excitement of discovery!
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Re: Galileo's Use of the Colon

Post by jeidsath »

Hylander wrote: Sun Jun 12, 2022 2:31 am I'm enjoying his narrative, which captures his excitement of discovery!
This is possibly the most exciting line I've ever seen in a science paper: "Mensibus abhinc decem fere, rumor ad aures nostras increpuit, fuisse a quodam Belga Perspicillum elaboratum..." It reads like Jules Vernes.

These too:

...Lunê superficiem, non perpolitam, êquabilem, exactissimêque sphêricitatis existere, ut magna philosophorum cohors de ipsa deque reliquis corporibus cêlestibus opinata est, sed, contra, inêqualem, asperam, cavitatibus tumoribusque confertam...

...nunc enim, nedum Planetam unum circa alium convertibilem habemus, dum ambo magnum circa Solem perlustrant orbem, verum quatuor circa Iovem, instar Lunê circa Tellurem, sensus nobis vagantes offert Stellas, dum omnes simul cum Iove, 12 annorum spatio, magnum circa Solem permeant orbem...
"Here stuck the great stupid boys, who for the life of them could never master the accidence..."

Joel Eidsath -- jeidsath@gmail.com

Wilbur
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Re: Galileo's Use of the Colon

Post by Wilbur »

Hylander,

Below is a snip of the Jan 8 sky with a presumed fov (0.25 degrees) of Galileo's telescope centered over Jupiter. I presume when he saw three moons on Jan 8 he was satisfied because he saw three on Jan 7. Or perhaps he saw Callisto and didn't associate it with Jupiter as it was further away.

Jeidsath,

I find this work very compelling and so enjoyable as well. You can sense his excitement and wonder, which I can relate to as a scientist myself.

Thanks to you both for your comments and help. I appreciate your involvement in my project

Jan 8 with the telescope's fov centered on Jupiter
Image

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Re: Galileo's Use of the Colon

Post by Wilbur »

And Shenoute, thank you too. I didn't mean to leave you out on the previous post. Your comments have also been very useful.
Wilbur

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