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The moons are lovely...
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<blockquote data-quote="Umbran" data-source="post: 7914632" data-attributes="member: 177"><p>Um... the apparent size is <em>determined by</em> the actual size and the orbital distance.</p><p></p><p>Other than the Roche Limit there is no particular correspondence between the moon's size and its orbital distance.</p><p></p><p>The Roche limit is a limit on the orbital radius of large smoons - if a large satellite gets too close to its parent body, the satellite will be ripped apart by tidal forces. You will not find very large moons very close to the planet, as they get ripped apart. </p><p></p><p></p><p></p><p>Human visual acuity can't generally make out any shape at under about 0.02 degrees - roughly the size of hte Intenational Space Station seen from the ground. Anything smaller than that is just a point. Larger than that, you go from a point to a dot, to a spot, to a disk. I don't know if there's an agreed upon limit when something gets called a "disk".</p><p></p><p></p><p></p><p>To quote <a href="https://en.wikipedia.org/wiki/Angular_diameter" target="_blank">WIkipedia on Angular Diameter</a>:</p><p></p><p>[ATTACH=full]118256[/ATTACH]</p><p></p><p></p><p>delta = 2arctan(d/2D)</p></blockquote><p></p>
[QUOTE="Umbran, post: 7914632, member: 177"] Um... the apparent size is [I]determined by[/I] the actual size and the orbital distance. Other than the Roche Limit there is no particular correspondence between the moon's size and its orbital distance. The Roche limit is a limit on the orbital radius of large smoons - if a large satellite gets too close to its parent body, the satellite will be ripped apart by tidal forces. You will not find very large moons very close to the planet, as they get ripped apart. Human visual acuity can't generally make out any shape at under about 0.02 degrees - roughly the size of hte Intenational Space Station seen from the ground. Anything smaller than that is just a point. Larger than that, you go from a point to a dot, to a spot, to a disk. I don't know if there's an agreed upon limit when something gets called a "disk". To quote [url="https://en.wikipedia.org/wiki/Angular_diameter"]WIkipedia on Angular Diameter[/url]: [ATTACH type="full"]118256[/ATTACH] delta = 2arctan(d/2D) [/QUOTE]
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