Category: Sky Watching

Astronomy, Sky Watching

2019, May 17: Moon in Clasp of the Pincers

On Friday evening (May 17), look toward the southeast for a nearly full moon.  The moon appears between Zubenelgenubi and Zubeneschamali, the northern claw and the southern claw, respectively.  The stars are not overly bright, and the moon’s size is exaggerated in the image above.

Today the stars are the two brightest in Libra, the Scales.  This constellation is the only inanimate object in the zodiac, the constellations that the sun, moon, and planets appear to move through.

The two stars were once part of Scorpius, the Scorpion, that is now rising in the southeast below the moon.  The scorpion was divided into two constellations, but the two stars retained their original names.

So if you imagine that the scorpion is largely below the southeast horizon with its pincers up in the sky holding the moon on this evening.

Advertisements
Astronomy, Sky Watching

2019, May 15-16: Moon Passes Spica

Step outside as the sky darkens on Wed (May 15) and Thurs (May 26).  The moon appears to pass the bluish star Spica on the two evenings.  Spica is the brightest star in the constellation Virgo.

On May 15, the moon, 11.1 days past its New phase and 90% illuminated, appears 8° above Spica.

On the next evening, the moon, one day older and 92% illuminated, is over 11° to the left of Spica.

Across these two evenings you can see the moon’s eastward movement compared to the starry background.

We notice several changes in the moon:

  • Phase:  The illuminated portion of the moon changes slightly each night, dramatically across a week.
  • Daily Rising and Setting:  On a warm spring evening, notice the moon’s position, relative to nearby trees and houses, for an hour.  You see it get farther west during that time.  Like the sun, it rises in the eastern sky, sometimes southeast and sometimes northeast, and sets later somewhere in the west that mirrors its rising spot.
  • Daily eastward orbital motion:  Each day, the moon moves slightly to the east.  In about 27 days appears near Spica again, but its phase is not quite the same as on these two nights.
Astronomy, Sky Watching

2019: May 11-13: Moon and Leo in Evening Sky

Leo, the Lion, stands high in the southwest as the sky darkens in early to mid-May.  The shape is fairly easy to locate.  Six stars resemble a backwards question mark, also known as “The Sickle” for the farm implement.  A triangle trails farther east.  Regulus is the bottom star of the question mark and represents the lion’s heart.  Denebola marks the lion’s tail.  The celestial lion is majestically facing westward as we view its profile.  The moon moves through the region May 11-13, 2019.  Here’s what to look for:

  • May 11: The moon reaches its First Quarter phase at 8:12 p.m. CDT. One hour after sunset, the moon, 7.1 days past its New Phase and 50% illuminated, is high in the southwest, 8.9° to the right of Regulus.

The angular degree measurement is used in astronomy to determine the separations and sizes of objects.  Because objects have various actual sizes and distances from Earth, the degree is the way for us to communicate apparent sizes and apparent separations.  The full moon has an apparent diameter of about 1/2°.  The charts we use typically exaggerate the size of the moon, so the chart cannot be used for a scale with the moon.  The distance from Regulus to Denebola is about 24°.

  • May 12: One hour after sunset, the moon (8.1d, 62%) is 6.2° to the upper left of Regulus.
  • May 13: The moon is closest to Earth at 4:53 p.m. CDT. An hour after sunset, the moon (9.1d, 73%), nearly 60° up in the south, is 8.5° to the lower right of Denebola– the tail of Leo.
Astronomy, Sky Watching

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.

Astronomy, Sky Watching

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

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

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.