# Tag Info

40

What you are calling a focal point is the end of the umbra, the point at which the umbra changes to the antumbra. In a total solar eclipse, that point is below rather than above the surface of the Earth. An annular eclipse occurs when that point is above the surface of the Earth. The Moon appears to be smaller than the Sun, leaving an unbroken ring of the ...

15

As the Moon's eccentric orbit around the Earth brings it nearer and farther, current solar eclipses can be total or annular. A few in between are hybrid eclipses: total along the midday part of the path, and annular near the sunrise or sunset end. This happens mostly due to the Earth's surface curvature and partly due to the Moon's orbital eccentricity. ...

11

"Harvest moon" just means the full moon at around the time of the equinox on September 21. The full moon is low in the sky during summer (June and July in the Northern Hemisphere) and high during the winter. So September is a month when the full moon is much higher in the sky than the moon in August. In the past this allowed harvests to continue after dark....

8

Almost certainly Jupiter, if the following are true: The title of the image: Inked20190904_194204.LI.jpg gives the accurate date and time of September 4 2019, 19:42:04. The orientation of the Moon in the image is such that the illuminated portion is on the right side of the image. The circled object is a planet or star, and brighter than any other nearby ...

6

Because the Moon phase changes relatively slowly (especially at the Full Moon), a similar Moon phase can be seen from all places around the world. For example, the Full Moon in September 2019 occurs at 4:33 UT. If the Moon is visible from your location at that time, then you can see the Moon when it is exactly "Full". If Moon is not visible until 5 hours ...

6

I think they did make a mistake. The moon waxes after a new moon and wanes before a new moon. To wax means to grow bigger or stronger (and is cognate with "waist"!). To wane means to become smaller or weaker (cognate with "waste" and "vaccum"). The moon that sets shortly after sunset in the evening is a waxing moon. The moon that rises shortly before ...

6

There are a couple of atmospheric phenomena that can create rings around the moon. Corona are caused by water droplets diffracting the moon's light, they are fairly small, and close to the moon. They are coloured but not as brightly as a rainbow. Our eyes are also not so good at seeing colours in dim light. The 22-degree halo is a larger ring, as big as ...

5

Millimeter and sub-mm observations (110-300 GHz = 2.7-1.0 mm) are sensitive to the thermal emission and provide a brightness temperature of airless bodies like the Moon or asteroids. The radio emission is from just below the surface/skin of the body (down to $\sim10\lambda$ so ~1 cm in this case) and so is also sensitive to the thermal inertia and ...

4

Is it possible that the shadow of the moon is a single dot during solar eclipse? No, because the Moon is not round. Yes. I have to modify my answer after reading @IlmariKaronen's comment(s) below. Mathematically the umbra could collapse to a line segment, arc, or other short 1D shape, or to two or more points, but these are not likely for a randomly ...

3

Is seeing the apollo moon Landers via earth telescope that hard? Yes, it still is. If the resolution of an interferometric telescope is really 0.001 arcseconds, that translates to 4.85E-09 radians. At a perigee of 362,600 km that's 1.8 meters. The top part of the Lunar Modules is about 4.2 meters wide which is a little more than double the resolution, so ...

3

There are no other known natural satellites orbiting the earth. Most of the objects orbiting the earth are man-made and largest object other than the Moon orbiting the earth is the International Space Station which orbits the earth at a height of about 400km from the surface and is about 100m wide. It may be odd to you that there are no other natural ...

2

In the absence of any detailed information, such as @Uhoh asks for, this is just a guess, but here goes. I'm assuming you live at mid northern latitude. The moon rises between south east and north east. If we consider full moons, then during the summer, the full moon will rise in the south east. As we move into the autumn and winter, the full moon ...

2

Let's double-check @barrycarter's conclusion: Ignoring the rest of the solar system and even the Moon's non-negligible mass, the velocity of the Moon's motion around the Earth is on average roughly 1 km/sec per $v=\sqrt{GM_E/a_M}$ (the vis-viva equation). The Earth is about 12760 km in diameter, so the Moon traverses the Earth's projection in about 3.5 ...

2

First of all any body revolving around a planet is known as its satellite, not as an "asteroid". And at this time Earth only has one natural satellite which is the Moon (but there are few theories suggesting that Earth once had two moons but they merged into each other due to gravitational pull between them and formed a single moon). Asteroids are the ...

1

Temporary's have come and gone. https://en.wikipedia.org/wiki/Claimed_moons_of_Earth#Temporary_satellites

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