After years of collecting antique Earth Globes, Celestial Globes, Alchemist Divination Globes, and Armillaries, I finally found a video that provides a more easy-to-understand and less technical explanation of how to use their many interesting and beautiful features. Thank you so much for the clear instructions on how to use them. Have a great day! Cheers!
Hi, does the band of the ecliptic width cover an arc of about 16 degrees of its circumference, or about 5%, which is about the maximal extension of the planets? Also, am wondering if there would be a way to determine moon positions, since the moon’s extends 5 degrees from the ecliptic, thanks
The ecliptic is offset from the equator by +/- 23.45 degrees. The width of the ecliptic is mostly a product of its physical construction and does not necessarily bound the orbits of each planet. However, certain armillary spheres do feature separate planetary orbits inclined to the ecliptic that account for this variation, thus making the sphere more precise in its demonstrational capacity.
@@BCGnomonics Hi, thanks for your answer. It seems the ecliptic band touches the tropic of Capricorn armillary at the southern end of its band width, when it should the crossing the tropic of Capricorn armillary in the middle of its band; however the ecliptic band seems to correctly cross the tropic of Cancer armillary in the middle of its band: can you confirm this? If so, is there a way to correct this error? perhaps by removing and putting back the band correctly? Also, do you think it would be possible to add some kind of graded ecliptic line in the middle of the ecliptic band with pen or maker or the like? I am looking at some 18th century French armillary spheres and the ecliptic band is always divided in two along its width: the northern half has zodiacal divisons, while the southern half has months of the year. In the middle is a white line with a graded division (by day) ruler along each side. You can see this if you look for "armillary spheres Jean-Baptiste Fortin" and there are some close-up zooms available on the site Gallica. Thanks!
Thank you for pointing out Gallica-a great site I had not seen before! As for the accuracy of the ecliptic, you are correct about the various tropical offsets of this particular model. While it would be possible to remedy this and add the separation you mention, this model is unfortunately not built to be terribly precise. As you have no doubt noticed, the ecliptic is only marked with the 1st and 30th degrees of each sign, with no way to accurately pinpoint individual degrees. The only truly practical armillary sphere on today's market is made by Norman Greene (normgreene.com/armillary.html) and regrettably exceeded the scope of the grant that started the BC Gnomonics project. Vsevolod of Master Terebrus is working on his own design though, which I am particularly looking forward to seeing.
If you notice, the globe earth in the center is featureless. Any idea why?.. The area of interest is the horizontal disc upon which the observable hemisphere rests upon. At that point it's a flat earth and dome model. As most of history agreed.
Conceptualizing the armillary sphere more like a heliodon, it doesn't seem like there's much need for the earth in the center. It makes a bit more sense when you consider that the celestial equator and tropics represented on the sphere are outward projections of those same circles on the earth. While maintaining a geocentric perspective, the armillary sphere zooms out to capture the greater celestial sphere, including aspects of it that are fundamentally grounded on the globe. I believe including the earth makes this relationship a bit easier to model (also remember that the armillary sphere is most fundamentally a demonstrational, educational tool)
@@BCGnomonics the armillary sphere shows you the part of the sky YOU can see. It's a personal reference frame. Where one is at the center, immovable, observing the heavenly sphere move above you in a clock like manner and precision. As you well know, the entirety of history saw the earth as only geocentric. The idea of heliocentrism and the earth as a globe didn't even come into play until 600 bc. And it was a baseless assumption at that. Geocentrism with a stationary earth was obvious until a few hundred years ago.
After years of collecting antique Earth Globes, Celestial Globes, Alchemist Divination Globes, and Armillaries, I finally found a video that provides a more easy-to-understand and less technical explanation of how to use their many interesting and beautiful features. Thank you so much for the clear instructions on how to use them. Have a great day! Cheers!
Thanks for your explanation, I finally understand how it works.😃
Cool looking armillary.
Hi, does the band of the ecliptic width cover an arc of about 16 degrees of its circumference, or about 5%, which is about the maximal extension of the planets? Also, am wondering if there would be a way to determine moon positions, since the moon’s extends 5 degrees from the ecliptic, thanks
The ecliptic is offset from the equator by +/- 23.45 degrees. The width of the ecliptic is mostly a product of its physical construction and does not necessarily bound the orbits of each planet.
However, certain armillary spheres do feature separate planetary orbits inclined to the ecliptic that account for this variation, thus making the sphere more precise in its demonstrational capacity.
@@BCGnomonics Hi, thanks for your answer. It seems the ecliptic band touches the tropic of Capricorn armillary at the southern end of its band width, when it should the crossing the tropic of Capricorn armillary in the middle of its band; however the ecliptic band seems to correctly cross the tropic of Cancer armillary in the middle of its band: can you confirm this? If so, is there a way to correct this error? perhaps by removing and putting back the band correctly? Also, do you think it would be possible to add some kind of graded ecliptic line in the middle of the ecliptic band with pen or maker or the like? I am looking at some 18th century French armillary spheres and the ecliptic band is always divided in two along its width: the northern half has zodiacal divisons, while the southern half has months of the year. In the middle is a white line with a graded division (by day) ruler along each side.
You can see this if you look for "armillary spheres Jean-Baptiste Fortin" and there are some close-up zooms available on the site Gallica.
Thanks!
Thank you for pointing out Gallica-a great site I had not seen before! As for the accuracy of the ecliptic, you are correct about the various tropical offsets of this particular model. While it would be possible to remedy this and add the separation you mention, this model is unfortunately not built to be terribly precise. As you have no doubt noticed, the ecliptic is only marked with the 1st and 30th degrees of each sign, with no way to accurately pinpoint individual degrees. The only truly practical armillary sphere on today's market is made by Norman Greene (normgreene.com/armillary.html) and regrettably exceeded the scope of the grant that started the BC Gnomonics project.
Vsevolod of Master Terebrus is working on his own design though, which I am particularly looking forward to seeing.
Where could I purchase this ? Thank You
I got this one from Punto Vernal (puntovernal.co.uk/p/armillary-sphere-tycho-de-brahe/)
If you notice, the globe earth in the center is featureless. Any idea why?.. The area of interest is the horizontal disc upon which the observable hemisphere rests upon. At that point it's a flat earth and dome model. As most of history agreed.
Conceptualizing the armillary sphere more like a heliodon, it doesn't seem like there's much need for the earth in the center. It makes a bit more sense when you consider that the celestial equator and tropics represented on the sphere are outward projections of those same circles on the earth. While maintaining a geocentric perspective, the armillary sphere zooms out to capture the greater celestial sphere, including aspects of it that are fundamentally grounded on the globe. I believe including the earth makes this relationship a bit easier to model (also remember that the armillary sphere is most fundamentally a demonstrational, educational tool)
@@BCGnomonics the armillary sphere shows you the part of the sky YOU can see. It's a personal reference frame. Where one is at the center, immovable, observing the heavenly sphere move above you in a clock like manner and precision. As you well know, the entirety of history saw the earth as only geocentric. The idea of heliocentrism and the earth as a globe didn't even come into play until 600 bc. And it was a baseless assumption at that. Geocentrism with a stationary earth was obvious until a few hundred years ago.