Starship Asterisk*

jks wrote: ↑Sun Mar 22, 2020 4:29 am deja vu?

APOD 2018 June 4

Edit: If so, I did not mean to sound harsh or critical. The video is spectacular, and it is worth another view!

SpaceCadet wrote: ↑Sun Mar 22, 2020 4:55 am
Can someone please explain the giant Luna through a telescopic lend part?
Did the people there see an ordinary sized moon?

heehaw wrote: ↑Sun Mar 22, 2020 9:30 am
It was almost impossible for Galileo to convince the world that that motion is (mostly) motion of the Earth, NOT motion of the Moon at all...

https://en.wikipedia.org/wiki/Earth%27s_rotation#History wrote:
<<Among the ancient Greeks, several of the Pythagorean school believed in the rotation of Earth rather than the apparent diurnal rotation of the heavens. Perhaps the first was Philolaus (470–385 BCE), though his system was complicated, including a counter-earth rotating daily about a central fire. A more conventional picture was that supported by Hicetas, Heraclides and Ecphantus in the fourth century BCE who assumed that Earth rotated but did not suggest that Earth revolved about the Sun. In the third century BCE, Aristarchus of Samos suggested the Sun's central place. However, Aristotle in the fourth century BCE criticized the ideas of Philolaus as being based on theory rather than observation. He established the idea of a sphere of fixed stars that rotated about Earth. This was accepted by most of those who came after, in particular Claudius Ptolemy (2nd century CE), who thought Earth would be devastated by gales if it rotated.

In 499 CE, the Indian astronomer Aryabhata wrote that the spherical Earth rotates about its axis daily, and that the apparent movement of the stars is a relative motion caused by the rotation of Earth. He provided the following analogy: "Just as a man in a boat going in one direction sees the stationary things on the bank as moving in the opposite direction, in the same way to a man at Lanka the fixed stars appear to be going westward."

In the 10th century, some Muslim astronomers accepted that Earth rotates around its axis. According to al-Biruni, Abu Sa'id al-Sijzi (d. circa 1020) invented an astrolabe called al-zūraqī based on the idea believed by some of his contemporaries "that the motion we see is due to the Earth's movement and not to that of the sky." The prevalence of this view is further confirmed by a reference from the 13th century which states: "According to the geometers [or engineers] (muhandisīn), the Earth is in constant circular motion, and what appears to be the motion of the heavens is actually due to the motion of the Earth and not the stars." Treatises were written to discuss its possibility, either as refutations or expressing doubts about Ptolemy's arguments against it. At the Maragha and Samarkand observatories, Earth's rotation was discussed by Tusi (b. 1201) and Qushji (b. 1403); the arguments and evidence they used resemble those used by Copernicus.

In medieval Europe, Thomas Aquinas accepted Aristotle's view and so, reluctantly, did John Buridan and Nicole Oresme in the fourteenth century. Not until Nicolaus Copernicus in 1543 adopted a heliocentric world system did the contemporary understanding of Earth's rotation begin to be established. Copernicus pointed out that if the movement of Earth is violent, then the movement of the stars must be very much more so. He acknowledged the contribution of the Pythagoreans and pointed to examples of relative motion. For Copernicus this was the first step in establishing the simpler pattern of planets circling a central Sun.

Tycho Brahe, who produced accurate observations on which Kepler based his laws, used Copernicus's work as the basis of a system assuming a stationary Earth. In 1600, William Gilbert strongly supported Earth's rotation in his treatise on Earth's magnetism and thereby influenced many of his contemporaries. Those like Gilbert who did not openly support or reject the motion of Earth about the Sun are often called "semi-Copernicans". A century after Copernicus, Riccioli disputed the model of a rotating Earth due to the lack of then-observable eastward deflections in falling bodies; such deflections would later be called the Coriolis effect. However, the contributions of Kepler, Galileo and Newton gathered support for the theory of the rotation of Earth.>>

SpaceCadet wrote: ↑Sun Mar 22, 2020 4:55 am Can someone please explain the giant Luna through a telescopic lend part? Did the people there see an ordinary sized moon? And does the lens type affect the apparent speed also?

orin stepanek wrote: ↑Sun Mar 22, 2020 11:01 am

jks wrote: ↑Sun Mar 22, 2020 4:29 am deja vu?

APOD 2018 June 4

Edit: If so, I did not mean to sound harsh or critical. The video is spectacular, and it is worth another view!

Sunday APOD's usually are repeats; a day off is nice for everyone!

Chris Peterson wrote: ↑Sun Mar 22, 2020 1:52 pm

SpaceCadet wrote: ↑Sun Mar 22, 2020 4:55 am Can someone please explain the giant Luna through a telescopic lend part? Did the people there see an ordinary sized moon? And does the lens type affect the apparent speed also?

It has nothing to do with the lens, and only the relative distance between the observer, intermediate objects, and the Moon. At arm's length, the Moon is the size of your thumbnail. Across the street, it's the size of your neighbor's chimney. A few blocks away and it's the size of a house. A few miles away, it's the size of a mountain.

For you, the Moon is always the same angular size, about 0.5°. You make a picture like today's by having the people far enough away that they subtend a much smaller angle than that.