Tag: astronomy

Astronomy, Sky Watching

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.
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Astronomy, Sky Watching

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

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

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

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.

More about the morning planets:

 

Astronomy, Sky Watching

2019, April 13-20: Venus and Mercury in Morning Sky

Venus and Mercury appear near each other on mid-April.  There is no conjunction as Mercury does not pass Venus.  Mercury moves faster and, typically, its motion causes the two to pass each other.  During this event, the two planets do not pass each other but they move within 5° of each other.  This event is know as a quasi-conjunction.

Mercury is in a very unfavorable apparition to observe. It appears very low in the east at Civil Twilight, about 30 minutes before sunrise, when the sun is 6° below the horizon. During this appearance this speedy planet does not rise before Nautical Twilight – which occurs about an hour before sunrise; so Mercury visible in a very bright sky, near the horizon. At its greatest elongation, it is only 4° in altitude.  Find a clear horizon and use a binocular.  First locate Venus then look through your binocular to locate this elusive planet.

The Venus-Mercury gaps:

April 13: 4.5°
April 14: 4.4°
April 15: 4.4°
April 16: 4.3°
April 17: 4.3°
April 18: 4.3°
April 19: 4.4°
April 20: 4.5°

On these mornings, it’s possible to see four planets in the morning sky — Mercury, Venus, Jupiter, Saturn — although a binocular may be needed to locate Saturn.  The Ringed Wonder is low in the southern sky,  less than one-third of the way up in the sky.  Jupiter is farther west, to the right of the south direction, at about the same height as Saturn above the horizon.

More about the morning planets:

Astronomy, Sky Watching

2019, March 11: Moon, Mars, and Winter Stars

This evening, the crescent moon (overexposed on the image, is about 7.5 degrees to the left of Mars.  Tomorrow evening the moon is between the Pleiades and the Hyades star clusters.  Take a look with a binocular.

The star clusters are considered part of Taurus.  The Pleiades resemble a tiny dipper.  Through a binocular you can see a dozen or so stars.  The Hyades are to the left of the Pleiades.  They make a “check mark” shape.  When Aldebaran is included, the patter resembles a letter “V,” the face of the Bull.  Aldebaran could be considered its fiery red eye.  Zeta Tauri and Elnath are considered to be the bull’s horns.

Watch Mars move closer to Pleiades as the month progresses.  It passes them late in the month.

In focus, the moon is 5.4 days old and displaying a crescent phase that is 25% illuminated.

The flagship of winter constellations is Orion, with its bright stars Betelgeuse and Rigel, appears in the southern sky during early evening hours.  With a binocular look below the three stars, Orion’s belt, toward Rigel.  The region has a hazy cloud, the Orion Nebula, where stars are forming.  Betelgeuse, along with Sirius, the Dog Star, and Procyon, the Little Dog Star, make an equilateral triangle known as the Winter Triangle.  Take a look at them through your binocular and you can see some interesting contrasts of star color.