Category: Astronomy

Astronomy, Sky Watching April 24, 2019May 8, 2019

2019, May 6-7: Aldebaran, Mars, and the Crescent Moon

(On the chart above, the moon’s size is exaggerated. At this scale, the star Zeta would be covered in May 7.)

The chart shows the western sky at about 1 hour after sunset. Start looking for the moon beginning about 30 minutes after sunset. Check your sources — television, newspaper, or Internet — for the time of your local sunset.

On May 6, the crescent moon (2.1 days past the New phase, 5% illuminated), 11° up in the west-northwest, is 2.2° to the upper right of Aldebaran, the brightest star in Taurus. The moon is nearly 14° below Mars.

An hour after sunset, locate Mars between Elnath and Zeta Tauri, 4.5° to the lower left of Elnath and 3.4° to the upper right of the Bull’s southern horn.

On the next evening, an hour after sunset, the moon (3.1 days old, 11% illuminated) is 0.3° to the lower left of Zeta Tauri. Mars is 3.3° to the upper right of the star.

Use a binocular to look that the moon these two evenings. You’ll notice that the moon’s night portion is slightly illuminated. This is known as Earthshine. From the moon, Earth is nearly full, and would be very bright to an observer on the lunar surface; it is bright enough to cast shadows on the moon’s night portion. Earthshine is from reflected sunlight from Earth’s clouds, land, and oceans. This sunlight gently illuminates the night portion of the moon in the same manner our planet is illuminated when the moon is near its Full phase. Click here for an example of the crescent moon with Earthshine.

2019, May 2: Morning Star Venus Meets Crescent Moon

On the morning of May 2, about 30 minutes before sunrise, the moon (27.1 days past the New phase, 7% illuminated) — a thin waning crescent phase — is 4.3° to the lower right of Venus. Look for them low in the east. Venus is only about 5° up in the east.

Check your local sources — newspaper, television, or internet — for the time of sunrise at your location. Although they are lower at that time, start looking for them about 45 minutes before the time of your local sunrise.

To find this pair, you’ll need a clear eastern horizon. Stand on a hill or in an open spot with no trees or houses nearby.

The time interval between the beginning of morning twilight and sunrise grows 24 minutes from this morning through mid-June. While Venus is rising at the same time interval before sunrise for the next month, it appears in a brighter sky.

The moon is New on May 4. Look for it during the early evening of May 6 in the west as the sky darkens.

Astronomy, Sky Watching April 19, 2019April 26, 2019

2019, April 22-26: The Morning Moon With Jupiter and Saturn

The moon moves past the morning planets — Jupiter and Saturn — during late April 2019. The chart above shows them about one hour before sunrise. Check your local sources — TV, newspaper, Internet — for your local sunrise time. Here are the highlights of the mornings:

April 22: At the beginning of morning twilight, the moon (17.0 days old. 90% illuminated), nearly 28° up in the south-southwest, is over 7° to the upper right of Antares.
April 23: At 12:30 a.m. CDT, the moon (17.9d, 90%), about 10° up in the southeast, is 2.8° to the upper right of Jupiter. At the beginning of morning twilight, the moon (18.0d, 82%) is 1.5° to the upper right of Jupiter, 25° up in the south. Saturn is 20° up in the south-southeast, about 26° east of Jupiter.
April 24: At the beginning of morning twilight, the moon (19.0d, 74%) is nearly between Jupiter and Saturn. The moon is at the top of the lid of the Teapot of Sagittarius, above Kaus Borealis.
April 25: At the beginning of morning twilight, now 105 minutes before sunrise, the moon (20.0d, 65%) is 2.7° to the lower right of Saturn.
April 26: At the beginning of morning twilight, the moon (21.0d, 55%) is 9.8° to the lower left of Saturn.

Astronomy, Sky Watching April 1, 2019April 12, 2019

2019, April 1-30: Mars Moves Through Taurus

This chart shows the motion of Mars against the starry background of Taurus during April 2019.

In the evening sky, Mars is moving through Taurus’ brighter star field. Follow the planet through a binocular as it passes between the Pleiades star cluster and the Hyades star cluster. The “V” of Taurus is nearly vertical this time of year. The stars of winter are making their final stand in the evening sky for the year, capped by an arc of stars – Procyon, Pollux, Castor and Capella. The Gemini Twins stand high in the western sky with their arms around the other twin’s shoulders. Sirius is about 25° up in the southwest. Watch it slowly begin to disappear into bright twilight. Its last appearance in the evening sky occurs in mid-May. The sun is in the sky for nearly 12.75 hours and the sky is dark, from the end of evening twilight to the beginning of morning twilight, for slightly over 8 hours.

In the notes that follow, the brightness of celestial objects is noted. The lower the number the brighter the object. The brightest stars have magnitudes that are rated 1 on the magnitude scale. These can be seen from many bright areas. As you move into suburban areas, magnitudes 2 and 3 are visible. Fourth and fifth magnitude stars are visible from more rural areas.

Additionally, some stars have proper names as well as Greek letter designations, and sometimes numerical designations.

To determine the end of twilight in your area, find the local time in your area. Add 100 minutes to your local sunset time. By that time the sky is dark enough to find the constellations and Mars.

Look in the west about one-third of the way up in the sky, from horizon to overhead. You’ll find Mars there along with the celestial backdrop of Taurus the Bull.

April 1: At the end of evening twilight, Mars, about 28° up in the west, is 3.3° to the left of the Alcyone (η Tau, m = 2.8), the brightest of the Pleiades, and 2.6° below 37 Tauri (37 Tau, m = 4.4). For the next several evenings we have chosen stars in Taurus to reference with Mars.
April 2: At the end of evening twilight, Mars is over 27° up in the west. It is 3.5° to the upper left of Alcyone and 1.9° to the lower right of 37 Tauri.
April 3: At the end of evening twilight, Mars is 1.2° below 37 Tauri.
April 4: At the end of evening twilight, Mars is just below a virtual line that extends from Alcyone to Aldebaran (α Tau, m = 0.8). The planet is 3.5° to the lower right of Omega Tauri (ω Tau, m = 4.9) and 0.6° below 37 Tauri.
April 5: At the end of evening twilight, Mars is 0.3° to the left of 37 Tauri, above a virtual line from Alcyone to Aldebaran.
April 6: After the end of evening twilight, Mars is 0.8° to the upper left of 37 Tauri and 2.5° to the lower right of Omega Tauri.
April 7: At the end of twilight, find Mars, 2.1° to the right of Omega Tauri.
April 8: At the end of evening twilight, the moon (3.7 days old, 14% illuminated) is about 6° to the lower left of Mars. The Red Planet is 4.5° to the lower right of Epsilon Tauri (ε Tau, m = 3.5), which compliments Aldebaran’s position in the head of Taurus at the top right point of the “V.”
April 9: . At the end of evening twilight, Mars is 1.7° to the upper right of Omega Tauri and 4.2° to the right of Epsilon Tauri, just beneath a virtual line that extends from Aldebaran to Epsilon and to the right. The moon (4.7d, 22%) is not far away, 5.3° above Aldebaran.
April 10: At the end of evening twilight, the moon (5.7d, 31%), 41° up in the west, is 3.5° to the upper left of Zeta Tauri (ζ Tau, m = 3.0), the southern horn of Taurus. Mars, 24° up in the west, is 3.8° to the upper right of Epsilon Tauri, just above the imaginary line at that extends from Aldebaran through Epsilon.
April 11: At the end of evening twilight, the moon (6.7d, 42%), over 50° up in the south-southwest, is nearly in the middle of Gemini, about 6° to the upper right of Gamma Geminorum (γ Gem, m = 1.9). Mars is 0.9° to the lower right of Upsilon Tauri (υ Tau, m = 4.2).
April 12: At the end of evening twilight, the moon (7.7d, 53%), nearly 60° up in the southwest, is over 7° to the lower left of Pollux (β Gem, m = 1.2). Mars is 0.3° to the upper right of Kappa1 Tauri (κ1 Tau, m=4.2) and 0.3° below Upsilon Tauri. It also passes 3.5° to the upper right of Epsilon Tauri.
April 13: At the end of evening twilight Mars is 0.4° to the upper left of Upsilon Tauri.
April 15: Mars is nearly midway between Upsilon Tauri and Tau Tauri (τ Tau, m = 4.3). Through a telescope, Mars is only 4” across, much smaller in apparent size than when it appeared at opposition last summer.
April 16: At the end of evening twilight, the moon (11.7d, 92%), nearly 50° up in the southeast, is over 12° to the lower right of Denebola. Mars (m = 1.6) is 1.3° to the right of Tau Tauri.
April 17: At the end of evening twilight, Mars continues its traverse of Taurus. This evening it is 0.7° to the lower right of Tau Tauri.
April 18: At the end of twilight, Mars is 0.3° to the upper right of Tau Tauri.
April 19: At the end of evening twilight Mars, marching through Taurus, is 0.6° above Tau Tauri.
April 20: At the end of evening twilight, Mars is 1.3° above Tau Tauri and 4° to the lower right of Iota Tauri (m=4.6), next star to mark Mars’ course through the starry background.
April 21: At the end of evening twilight, Mars is 2° to the upper left of Tau Tauri and 3.5° to the lower right of Iota Tauri.
April 22: At the end of evening twilight, Mars is 3° to the lower right of Iota Tauri.
April 23:At the end of evening twilight, Mars is 2.7° to the right of Iota Tauri and nearly 10° from Zeta Tauri, the southern horn of Taurus.
April 24: At the end of evening twilight, Mars is 2.3° to the upper right of Iota Tauri and over 9° to the lower right of Zeta Tauri. If you have a good western horizon and you can still view the “V” of Taurus, although it is low in the west-northwest, notice that Mars is above it for the next few evenings. This evening Mars is over 9° to the upper right of Aldebaran.
April 25: At the end of evening twilight, Mars, nearly 24° up in the west-northwest, is 2.2° to the upper right of Iota Tauri and over 8° to the lower right of Zeta Tauri.
April 26: At the end of evening twilight, Mars is 2.3° to the upper right of Iota Tauri and 8° to the lower right of Zeta Tauri.
April 27: At the end of evening twilight, Mars is 2.6° to the upper right of Iota Tauri and over 7° to the lower right of Zeta Tauri.
April 28: At the end of evening twilight, Mars is 2.7° to the upper right of Iota Tauri and about 7° to the lower right of Zeta Tauri.
April 29: At the end of evening twilight, Mars is 3.4° above Iota Tauri and over 6° to the lower right of Zeta Tauri.
April 30: At the end of evening twilight, Mars, nearly 16° up in the west-northwest, is 3.9° above Iota Tauri and about 6° to the lower right of Zeta Tauri.

Astronomy, Sky Watching March 17, 2019March 17, 2019

2019, March 17: Mars Approaches the Pleiades

2019, March 17: Mars is about 10 degrees below the Pleiades.

Mars, in eastern Aries, is nearly starting its March through Taurus. Mars is the lone planet in the evening sky. This evening, with a bright sky from a very gibbous moon, Mars is nearly 10 degrees below the Pleiades star cluster. It passes the Pleiades later in the month. With a binocular, investigate the two star clusters — Pleiades and Hyades — and track Mars as it moves against the distant star field.

Astronomy, Sky Watching March 17, 2019April 1, 2019

2019, April 1: Venus and Crescent Moon

After passing Jupiter and Saturn late in March, the thin waning crescent moon appears near Venus on April 1. Locate a clear east-southeast horizon and look about 45 minutes before sunrise. This is during mid-twilight when the sky is brightening, but brilliant Venus is easily found. It is low in the sky, only 4° up in the sky, Venus is nearly 9° to the left of the waning crescent moon that is only 14% illuminated and just a few days before the moon reaches its New phase.

More about the morning planets:

Astronomy, Sky Watching March 17, 2019March 29, 2019

2019, March 26-29: Moon Glides Past Morning Planets Jupiter and Saturn

During late March, the moon glides past morning planets Jupiter and Saturn. The chart above shows the scene about 45 minutes before sunrise. Check your newspaper, television weather, or Internet source for the time of your local sunrise. These observations are not time sensitive because the moon and planets are higher in the sky than earlier in the year.

Step outside before sunrise and look south. Bright Jupiter is there about one-third of the way up in the sky. Saturn is about 25° to the lower left of Jupiter. Here’s what to look for:

March 26: This morning, the waning gibbous moon that is 68% illuminated is nearly 9° to the upper right of bright Jupiter
March 27: This morning. the nearly last quarter moon that is nearly 60% illuminated is over 4° to the left of Jupiter. Notice the distance that the moon moved from yesterday. With a binocular notice that the day-night line (terminator) on the moon is slightly convex – bowed outward.
March 28: At the beginning of morning twilight, the thick crescent moon that is 48% illuminated, 19° up in the south-southeast, is 9° to the right of Saturn. This morning the terminator is slightly concave – bowed in.
March 29: This morning, the moon that is 38% illuminated, 14° up in the southeast, is about 3° to the lower left of Saturn. Notice the amount the moon phase shrank during these mornings.

Look for the moon and Venus on April 1.

More about measurements. Degrees (°) are used in astronomy to measure separation of celestial objects and sizes of objects as they appear to us, not their real sizes, their apparent sizes. One-half degree is the apparent size of the moon. The next time you see the moon in the sky, extend your arm and then your pointer finger. The tip of the finger, with the finger nail, covers the moon. Your fist extended toward the sky covers about 10°. So, on March 26, the distance between the moon and Jupiter is about the distance across your fist. The next morning about three knuckles is the distance between the moon and Jupiter.