Celestial Sphere

by Matthew Johnson

When one looks up at our moon, consider the number of moons that continue to be discovered in our solar system.

The inner planets─Mercury and Venus─ both lack a moon. Our Earth has one moon, Mars has two moons-Deimos and Phobos. From there the number of moons increases. Uranus has 27 and Neptune 14. However, in 2019,  astronomers at the Carnegie added another 20 moons to Saturn’s already confirmed and named 62 moons for a total of 82 moons, officially surpassing Jupiter with its 79 moons. Astronomers in the near future expect to find another 20 or so small moons adrift in Saturn’s ring system. Since 2019, a lot of real estate has been added to the solar system. 

The study of our solar system’s moons has had a profound effect on humanity. In future Celestial Sphere articles in Norfolk Now I will discuss this.

Moon Phases for July:

Full Moon: July 5

Last Quarter: appearing as a half-moon on the left side, July 12

New Moon: no moon visible in the sky, July 20

First Quarter: appearing as a half-moon on the right side, July 27

With a little bit of patience, some luck and a pair of binoculars you will possibly be able to glimpse the five brightest naked-eye planets during the month of July.

Mercury and Venus: During the second half of July, planets Mercury and Venus briefly come to view. After July 14, look above but low on the western horizon right after sunset. 

Jupiter is the brightest and easiest of the evening planets to spot. Look toward the west-southwest as dusk deepens on July 8. This evening you’ll find it five degrees (half the length of a fist held straight out in front of you against the sky) to the upper left of a thick crescent moon. Early in the month, the big planet is still high enough during evening twilight to appear sharp and detailed in telescopes.

Mars appears prominent low in the southern evening sky on July 14. This evening, the “god of war,” as Mars is known, can be found eight degrees below the waxing gibbous moon.

Saturn can be located almost due south when night falls on July 15. On this evening, Saturn lies just over two degrees below the waxing gibbous moon. All of July is excellent for telescopic viewing of Saturn. Saturn’s rings are tilted at 26 degrees so they are easily viewed in a small telescope.

On July 4, our earth reaches aphelion, its farthest point from the sun in its orbit, at approximately noon.  Our planet is then 94,512,904 miles (152,103,775 kilometers) from our sun. Even though the earth is farthest from the sun, due to the northern hemisphere being tipped toward the sun, we experience summer in North America. 

Penumbral eclipse of the moon: July 4-5. Beginning at 11:07 p.m. on the night of Saturday, July 4, the earth’s shadow will begin to touch the moon’s face. The maximum of the eclipse occurs at 12:29 a.m. July 5, when the moon is closest to the earth’s shadow. The earth’s penumbra ends at 1:52 a.m.. Look for a slight dimming of the top of the moon. A penumbral eclipse is much more subtle than an umbral or total eclipse of the moon. It can be a bit harder to see, as the shadowed part is only a little bit fainter than the rest of the moon.