Heaven in July 2020

July is summer in the northern hemisphere, so you can watch the sky in the evening and at night without freezing. The sky in July 2020 also has a lot in store. As my inclined readership is used to, in the series "Der Himmel im… " the proverbial highlights.

The sun in the sky in July 2020

Our home planet – according to the current state of science the only inhabited planet – Earth reaches its aphelion on July 4, 2020. On this day, the sun is 152,095,000 km from Earth, farther away than at any other time in 2020. The light of the sun then needs 8:27.33 minutes for the way to earth. If you are aware of this for a moment, we look into the past when we look at sunlight.

The sun in the sky in July 2020 is particularly far away!
This halo was created in May. Ice crystals in the air cause this phenomenon. In July 2020, the Sun will have moved farthest away from Earth.

Why do aphelion and perihelion exist?

If we colloquially say that the inhabited stone we call earth revolves around the sun, this is wrong. We circle the dear sun in an ellipse. That's why our distance from the sun changes over the course of a year. At perihelion (in January), Earth is about 5 million kilometers, or 16.6 light-seconds, closer to the Sun than at aphelion in July. So in winter we are actually closer to the sun, it shines about 7% brighter, but we freeze… CRAZY

Do perihelion and aphelion affect our climate?

If you consider that it is summer here in the northern hemisphere, when the sun is farthest away and we freeze in January, although the sun is 5,000,000 km closer to the earth, you can answer the question with no. In addition, our earth travels through our solar system with an inclined axis. A small influence on the general climate is given, but this is not noticeable for us.

The moon in the sky in July 2020

The waxing June moon in the sky in June 2020.
The waxing moon also shows up in the sky in July 2020.

Moon phases in the sky in July 2020

Full moon in July 2020

The hay moon or buck moon shows up in the sky in July 2020. These are the names of the full moon, which turns night into day for us on July 5, 2020. Other names for the full moon in July are Thunder Moon, Sun Moon, Spice Moon, Bear Moon.

Our Trabant cannot get rid of the legends and myths about werewolves, higher crime and disease rates, because it simply inspires the human imagination. Astronomers and astrophotographers do not particularly like the full moon, because it reflects sunlight throughout the night with such intensity that the visibility of fainter objects and also the Milky Way is impaired.

Geometry is to blame: In order for the moon to be fully illuminated from Earth, the dear sun must be on the opposite side. Therefore, sunsets always take place at the same time as a rising full moon. The moonrise is wonderful to look at, but at night it is too bright for stargazing. Plus, the full moon just isn't that interesting. Since the lunar surface is illuminated directly from "front" from our perspective, a flat bright "disk" without shadows is created, which are usually cast by mountains and craters. Experienced lunar observers make their observations a little earlier or later in the lunar cycle, during the crescent, quarter or three-quarter moon phase.

Further moon phases in July 2020

On July 13, the waning half of the moon appears in the sky. At 1:28 a.m., the moon then diminished half. Now it comes to the famous crescent shape and on July 20, the next lunation begins with the new moon at 19:32. In the sky in July 2020 we will see the waxing crescent moon on 27.07.2020.

Lunar libration with phase Oct 2007 450px.gif
By TomruenLunar_libration_with_phase_Oct_2007.gif, public domain, Source: Wikipedia

Planets in the sky in July 2020

Jupiter and the Moon

I have just described the phases of the Earth's satellite in July. On July 5, 2020 after sunset, it will not only continue with the moonrise. A close encounter between Jupiter and the Moon can be seen in the sky in July 2020. At 23:24 both are visible 10° above the southeastern horizon in the constellation Sagittarius.

Such encounters are commonly referred to as conjunctions when the two objects share either the same ecliptic longitude or right ascension. This may differ slightly from the time when they have the closest distance. The conjunction for the July 5 encounter at 22:53 of Jupiter and the Moon is not visible from my location. Around 11:24 p.m. I will still take a look, as the two protagonists will still appear very close to each other in the sky.

Mars and the Moon

One week after the meeting of Jupiter and the Moon, Mars and the Moon go on a cuddly course. At 01:33 the two celestial bodies appear 9° above the eastern horizon and pass each other within 2.69° in the constellation Cetus. The actual conjunction occurs on July 11 at 22:32, when the moon is below the horizon At 01:33 on July 12, 2020, I will look into the sky in July 2020, because at this time our red neighbor is very close to our satellite.

Jupiter in the sky in July 2020

The Earth passes through its annual orbit and reaches a point where the sun and the planet Jupiter are in opposite directions. At this time, Jupiter is in opposition. This also represents Earth's closest approach to the gas giant.

This arrangement has several advantages:

  • Earth is about 300 million kilometers closer to Jupiter than to the conjunction.
  • Jupiter appears 68% larger and 1.3% brighter.
  • There will also be ample observing time, because when the sun sets at 21:03 on the evening of July 14, Jupiter rises and remains visible throughout the night.

Here, too, it is exciting to know how old the light we will see is. The Sun sends its light to Jupiter over a distance of 778 million kilometers. The light takes 43 minutes for this distance.

During the opposition, the light takes about 35 minutes to travel from Jupiter to Earth. We see the sunlight reflected from Jupiter. Thus, the light is 78 minutes old when we perceive it with our eyes.

In addition to Saturn (1) and Jupiter (2), I have marked Antares (3) in the constellation Scorpio (4) in this image. The Milky Way is also clearly visible.
In addition to Saturn (1) and Jupiter (2), I have marked Antares (3) in the constellation Scorpio (4) in this image. The Milky Way is also clearly visible.

Saturn in the sky in July 2020

Saturn will also go into opposition to Earth on July 21, 2020. That evening, Saturn rises at 20:56 and remains visible throughout the night.

Again, there are a number of advantages in this constellation:

  • Here, Earth is about 300 million kilometers closer to Saturn than to the conjunction.
  • Saturn appears 39% larger and 1.7 magnitudes brighter.
  • It is new moon phase, so the Earth's satellite will not disturb with its light.

In the previous paragraph, I described that the light from Jupiter is about 78 minutes old when we perceive it. How does this behave with Saturn?

Light has already travelled from the Sun to Saturn for 79 minutes, i.e. about as long as the sunlight needs to make its way via Jupiter to us on Earth. Now the light has to return to Earth. For the distance of about 1,354,655,000 km (average distance), the light takes about 75 minutes. So the light is already easily 2:34 h old when we perceive it on earth.

Mercury in the sky in July 2020

On July 22, 2020, the planet Mercury will move into our field of vision. The direct neighbor of the dear sun reaches its greatest western elongation of 20° in the early morning of July 22nd. At 4:03 a.m. the hot stone rises in the east. At sunrise, Mercury is 12° above the horizon. It fades quickly in the brightening sky.

Mercury's orbit is farther inland than Earth's orbit and close enough to the Sun that it never travels far from the Sun across our sky. Most nights, Mercury rises or sets so close to the sun that it's impossible to observe. Only in the time of maximum elongation (angle between planet and sun in the sky) does Mercury remain above the horizon after it has become dark.

I wish you a great July with many clear nights, constellations, satellites, and planets. If you think it was for July, then better read this article about shooting stars in summer.

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