Tag: Mercury

2020, May 8: The Near Conjunction of Venus and Elnath

Venus and Elnath, May 8, 2020
2020, May 8: Venus is 1.9° below Elnath.

Two evenings before its near conjunction with Elnath (β Tauri) – the Northern Horn of Taurus – Venus is 1.9° below the star. After the closest approach, watch Venus make a left turn and separate from Elnath. At the same time, Venus is noticeably lower each evening. For more details see this article.

On May 19, look for Mercury, below Venus. The moon joins the scene on May 23.

Zeta Tauri, the Bull’s Southern Horn, is among the tree branches in the image.

Capella is the bright star to the upper right of Venus.

Read this article for more about Venus as an Evening Star.

2020, May: Venus, Mercury and the Moon

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Mercury enters the May 2020 evening sky as Venus exits.

by Jeffrey L. Hunt

Venus passes between our planet and the sun (inferior conjunction) early next month to emerge into the morning sky. As this occurs, Mercury enters the sky for its short evening appearance. The moon joins the pair on a few nights.

Venus is the brilliant “star” in the west-northwest after sunset. As Mercury enters the sky, it is a bright star, much dimmer than Venus, but visible without optical help. As it rises higher in the sky, a binocular is needed to see it as it dims. Over several evenings, it appears to move from the lower right of Venus to its upper left, while the star Elnath is nearby.

The planets are reasonably low in the sky. Find a clear horizon toward the west-northwest.

YouTube video about Venus and Mercury, May 2020

In the notes that follow, the “m” numbers are measures of the planets’ brightness. The lower the number, the brighter the celestial object. The sun has the lowest value (−26.5) on this scale. Afterall it is so bright it creates daytime on our planet and shines on the moon and other planets in its system. Notice how Mercury’s number increases during the days described. It starts out bright and then dims. At the end of the sequence it is reasonably bright, but it is further dimmed by the brightness of twilight. Use a binocular each evening to first locate the speedy planet and then attempt to locate it without the binocular’s assistance. Mercury is almost always seen during morning twilight or evening twilight.

We measure sizes and separations in the sky with angles, using degrees as we do with a protractor. When we observe the sky, the objects seem to be different sizes because of their actual sizes and their distances. The moon’s apparent size seems large, about 0.5° as measured in angular units. The sun is farther away than the moon, but it appears the same size. Because they appear to be the same size, the moon can cover the sun to create a solar eclipse. The tip of your pinky finger on your outstretched arm easily covers a full moon. Try it the next time you see a brilliant full phase.

The space that your outstretched fist covers is about 10°. On the first date in the description below, Mercury is nearly 5° to the lower right of Venus. That’s about half a fist. On the second day, Venus is about two outstretched finger tips from Venus.

If you have a small telescope, look at Venus. It’ll show a thin crescent! Here’s what to look for:

Mercury and Venus, May 2020
2020, May 19: Mercury enters the scene, 4.9° to the lower right of Venus. Venus is moving away from Elnath. This evening, their separation is 2.7° below the star.

May 19: Forty-five minutes after sunset, Venus (m = −4.4), over 11° up in the west northwest, is 2.7° below Elnath and 4.9° to the upper left of Mercury (m = −0.8). Betelgeuse is less than 5° up in the west. What is the last date that you see it before it disappears into the sun’s glare? Venus sets at the end of evening twilight, nearly 2 hours after sunset.

Mercury and Venus, May 2020
2020, May 20: Venus, Mercury, and Elnath are nearly in a line. Venus is 2.8° from Mercury, and 3.0° from Elnath.

May 20: Forty-five minutes after sunset, Venus is over 10° up in the west-northwest. The Venus – Elnath gap is 3.0°, and Mercury (m = −0.7) is 2.8° to the lower right of brilliant Venus. Through a telescope, the Venus is 53” across and 6% illuminated, a magnificent evening crescent!

Mercury passes Venus, May 2020
2020, May 21: Mercury passes 1.1° to the lower left of Venus.

May 21: Forty-minutes after sunset, Venus (m = −4.3) – over 9° up in the west-northwest – is 1.1° to the upper right of Mercury (m = −0.6), a conjunction. The Venus – Elnath gap is 3.4°.

Mercury and Venus, May 2020
2020, May 22: Mercury is 1.6° to the upper left of brilliant Venus. Elnath is 3.8° above Venus.

May 22: In the early evening sky, Venus, Mercury (m = −0.5), and Elnath make a compact triangle. Venus is 1.6° to the lower right of Mercury; Venus is 3.8° below Elnath; and the Mercury – Elnath gap is 3.4°. Tomorrow evening the moon enters the scene. Jupiter is now rising before midnight CDT.

Mercury and Venus, May 2020
2020, May 23: The crescent moon joins the scene this evening. Mercury is to the left of Venus and Elnath.

May 23: At 45 minutes after sunset, find a clear horizon to view the scene in the west. Venus, 7.0° up in the west-northwest, is 4.5° to the upper right of the crescent moon (1.3 days past the New phase, 2% illuminated). The Venus – Elnath gap is 4.2°. Mercury (m = −0.4) is 3.5° to the upper left of Venus and 3.1° to the lower left of Elnath.

Venus and Mercury, May 2020
2020, May 24: Venus, Mercury, and Elnath make a triangle with the moon nearby.

May 24: Forty-five minutes after sunset, Venus is about 6° up in the west-northwest. Find a clear horizon to see it. The planets and the star make a triangle. Mercury is 5.5° to the upper left of Venus, nearly midway from Venus to the moon that is nearly 12° to the upper left of Venus, although Mercury is above a line that connects Venus and the moon. Elnath is 4.6° above Venus and 3.5° to the upper right of Mercury. Venus’ elongation is 15°.

Mercury and Venus, May 2020
2020, May 25: With Mercury and Venus 7.5° apart, the moon is to the upper left of the pair. Elnath is 5.1° from Venus.

May 25: Forty-five minutes after sunset, Venus (m = −4.1) is about 4° up in the west-northwest. The planet continues to make a triangle with Mercury (m = −0.2) and Elnath. Venus is 5.1° to the lower right of the star, while Mercury is 4.5° to the upper left of Elnath. Venus is 7.5° to the lower right of Mercury. Venus sets at Nautical Twilight – the time when the natural horizon is barely distinguishable –  over an hour after sunset. The observing window is rapidly closing to see Venus during this apparition. The gaps of the two planets and star continue to grow as Venus disappears into brighter twilight. Through a telescope, the brilliant planet is 56” across and 3% illuminated. As the sky darkens to show more stars, the moon (3.4d, 11%) is in central Gemini, over 11° to the lower right of Pollux (β Gem, m = 1.2), and over 17° to the upper left of Mercury.

Mercury and Venus, May 2020
2020, May 26: After sunset, Venus and Mercury are 9.5° apart.

May 26: Forty-five minutes after sunset, Venus – about 3° up in the west-northwest – is 5.7° below Elnath and 9.5° to the lower right of Mercury (m = −0.2). Mercury is 5.7° to the upper left of the star. As the sky darkens further the moon (4.4d, 19%) is 5.9° to the left of Pollux.

Before the days described in this article, Venus passed close to Elnath in a quasi-conjunction.

Read more about that here.

For a semitechnical description of the month’s planet activities, click here.

For more about Venus as an Evening Star, read this article.

2020, July 19: See Moon and 5 Planets

See the moon and 5 planets, July 19, 2020
2020, July 19: The moon and five planets stretch across the sky before sunrise.

See the moon and 5 planets – Mercury, Venus, Mars, Jupiter, and Saturn – simultaneously before sunrise on July 19, 2020.

Forty-five minutes before sunrise, the crescent moon and five planets are visible curved across the morning sky on July 19, 2020.  Find a spot with clear horizons in the east-northeast and the southwest.  A binocular may help finding the moon, Mercury, and Jupiter.

Here’s what to look for:

  • Brilliant Venus blazes in the eastern sky.  The star Aldebaran is nearby.
  • The crescent moon, 28.2 days past the New Moon phase and only 1% illuminated, is very low in the east-northeast.  This is where the binocular might help.
  • Mercury is to the right of the moon, about 5°. Make a fist and stretch your arm. Five degrees is about the distance from your thumb knuckle to your pointer finger knuckle. A binocular will help here as well. Can you see Mercury without the binocular once you find it?
  • Bright Mars, not as brilliant as Venus is the “star” that’s about halfway up in the sky in the south-southeast.
  • Jupiter – brighter than Mars, but low in the sky – is just above the horizon in the southwest.
  • Saturn, dimmer than Jupiter, is about 7° to the upper left of the Giant Planet. Both appear to our eyes as “stars.” Their separation is a little more than the knuckle to pointer distance described above. Don’t confuse Saturn with the star Fomalhaut, farther south, but at about the same altitude as Saturn.
  • UranusNeptune, and Pluto are also in the sky between Venus and Jupiter.  A telescope is needed to see that trio of planets.

Five planets and the crescent moon are in the sky at one time! During the next few mornings five planets are visible, but without the moon. Additionally, Jupiter is quickly leaving the sky. So on successive mornings, look 3-4 minutes earlier each day. You may catch them in the sky until about July 25.

Jupiter and Saturn are headed toward their Great Conjunction on December 21, 2020. Look for them low in the southeast during the early evening hours of July and August 2020.

 

2020, February: Evening Star Venus, Mercury, and Moon

Venus Shines in Southwestern sky
2020, January 19: Venus is visible in the southwest about 40 minutes after sunset. The planet is now setting over 3 hours after sunset.

Brilliant Venus sparkles in the western sky after sunset.  It is so bright that Earth’s neighbor is often mistaken for a passing airplane.  Find Venus throughout February during the early evening hours.

The speedy planet Mercury pops into the evening sky after sunset for its best appearance of 2020.  As Mercury appears higher in the sky, it dims.  Find a clear horizon in the west-southwest and begin looking at about 45 minutes after sunset. It appears as a bright star.  Try to catch it early in its appearance and look for it each evening as it appears higher in the sky, but it is dimmer nearly every evening.  First attempt to look for it with a binocular; then look without optical help.

By mid-month, you’ll need a binocular to find it in the sky, as it much dimmer.

Venus appears high above Mercury.

Venus and Moon February 2020

The moon joins Venus late in the month.  On February 25, find a clear western horizon about 1 hour after sunset.  Each evening the moon is higher in the sky than the previous evening.

The best evening is on February 27, when the moon and Venus seem to appear in a scene of an artist.  Both are nearly at the same altitude above the horizon.  The moon is about 7° to the left of Venus.

You can capture “earthshine” on the night portion of the moon with a tripod-mounted camera.  Exposures ranging from 1 to 10 seconds reveal that the night is gently illuminated by sunlight reflected from Earth.

Here are more details about the moon’s appearance:

  • February 24: The moon returns to the evening sky. Thirty minutes after sunset, the moon (1.4 days past New, 2% illuminated) is nearly 6° up in the west-southwest. It is over 30° below brilliant Venus (m = −4.3).
  • February 25: In the evening sky, one hour after sunset, the moon (2.4d, 5%), over 10° in altitude in the west-southwest, is nearly 20° below Venus.
  • February 26: The moon is at apogee at 5:34 a.m. CST, 252,449 miles away. One hour after sunset, the moon (3.4d, 10%) is over 20° in altitude in the west-southwest. The lunar crescent is about 10° below brilliant Venus.
  • February 27:  In the evening, Venus and the moon (4.4d, 16%) are in a classic artist’s scene. Brilliant Venus is 6.7° to the right of the lunar crescent. Photograph the pair with a tripod-mounted camera. Vary exposures from 1-10 seconds to capture earthshine on the night portion of the moon.
  • February 28:  One hour after sunset, the waxing crescent moon (5.4d, 24%) is over 40° in altitude above the west-southwest horizon. It is nearly 15° to the upper left of brilliant Venus.
  • February 29: Happy Leap Day! In the evening, about one hour after sunset, the thick crescent moon (6.4d, 33%) is over 50° up in the southwest. Brilliant Venus is over 30° up in the west-southwest.

Here are my daily notes for February:

Happy Observing!

2020: The Evening Sky

2020 Setting Sky in west

by Jeffrey L. Hunt

This chart shows the summary of the setting of the naked-eye planets, moon, and bright stars near the ecliptic, the plane of the solar system, for 2020. The chart shows the setting of these celestial bodies compared to sunset for time intervals up to five hours after the sun’s disappearance. The three phases of twilight are displayed as well. On this chart, activity occurs in the western sky, except for the rising curves (circles) of Jupiter, Saturn and Mars. When they rise in the east at sunset, they are at opposition.

As 2020 opens, Venus is the bright Evening Star, appearing in the southwest. Mercury makes its best evening appearance, setting at the end of evening twilight during early February. Mercury’s June elongation is larger, but it sets several minutes before the end of twilight, making it difficult to observe in the brighter sky. After Venus moves past the Pleiades and Aldebaran, it moves toward Elnath (β Tauri), and then plunges toward its inferior conjunction. Jupiter and Saturn pass opposition during July. After Venus disappears from the evening sky, the slow procession of bright stars – Pollux, Regulus, Spica, and Antares – disappears into evening twilight. Jupiter and Saturn appear on the setting chart in late October, just after Mars reaches opposition. The moon has two interesting appearances with the planetary duo on November 19, 2020 and just days before the Jupiter- Saturn Great Conjunction on December 21, 2020.

The chart is calculated from data by the U.S. Naval Observatory, for Chicago, Illinois.

Key to symbols: White square, conjunction; yellow triangle, greatest elongation (GE); yellow diamond, greatest brightness (GB).

 

2020: The Morning Sky

2020 Rising Chart

by Jeffrey L. Hunt

This chart shows the summary of the rising of the naked-eye planets, moon, and bright stars near the ecliptic, the plane of the solar system, for 2020. The chart shows the rising of these celestial bodies compared to sunrise for time intervals up to five hours before the sun’s appearance. The three phases of twilight are displayed as well. On this chart, activity occurs in the eastern sky, except for the setting curves (circles) of Jupiter, Saturn and Mars. When they set in the west at sunrise, they are at opposition.

Early in the year, the morning sky offers the three Bright Outer Planets – Jupiter, Saturn, and Mars – in the eastern predawn sky. As Mars moves eastward it passes Antares, Jupiter and Saturn. On several mornings, the moon passes the planetary trio. The highlight occurs on the morning of February 18 as the moon occults Mars as sunrise approaches in the Central U.S. Venus enters the morning sky at mid-year. The appearance of a lunar crescent with the brilliant planet is a beautiful sight. The moon appears with Mercury as the planet enters the morning sky in late July. On the morning of July 19, the moon and the five naked eye planets are in the sky. As the moon moves toward its evening appearance, Mercury appears higher in the sky, making it a little easier to see. Venus reaches its period of greatest brightness; the mid-brightness date is marked by the yellow diamond. Venus moves past Aldebaran, Pollux, Regulus, and Spica as it moves towards its superior conjunction in early 2021. Mercury’s best morning appearance occurs during November. While this is its smallest morning elongation, the angle of the ecliptic places it higher in the sky.

The chart is calculated from data by the U.S. Naval Observatory, for Chicago, Illinois.

Key to symbols: White square, conjunction; yellow triangle, greatest elongation (GE); yellow diamond, greatest brightness (GB).