Planetarium

February 2016 Night Sky Calendar

 

 

 

February already!

Well, don't we say that every year. In fact, don't we actually say something similar at the beginning of each month and, well, all the time? (Have you ever heard anybody say, "Ah, May 23rd! It's about time!") Though the phrase "February already" may be hackneyed, we are still astonished that January has passed into the ages and we're confronted by a full-fledged February, replete with 29 blood-freezingly frigid days. Yes, in case you've forgotten, 2016 is a leap year, so we've added an extra day onto February. (See Feb 29th.) Also,

Of course, the planetary "alignment" remains the highlight of the night. Throughout February, we will see all five "naked eye" planets in the morning sky. By early March, however, we'll only see four as Mercury will have dived below the eastern horizon by then. For more information pertaining to these planets, please see the "Planet Watch" section at the end.

Winter Hexagon 

The Winter Hexagon   (South at 8:00 p.m at month's beginning.)

We mustn't forget about the gorgeous "Winter Hexagon" that is front and center by 8:00 p.m. Orion's fire opal star Betelgeuse defines the center. Enclosing it are some of the night sky's brightest stars. Taurus' bulls eye star, Aldebaran, is poised to the northwest. Capella, the goat star, defines the northern tip. Castor and Pollux, the alpha and beta stars within Gemini the twins, together mark a vertex toward the northeast. Then descend toward Procyon, the bright star in Canis Minor, the little dog before proceeding down further to Sirius, the brightest star in Canis Major (and the night sky). Then migrate west to Rigel, Orion's western knee star. An ascending line connecting Rigel to Aldebaran completes the hexagon shape.

 

 

 

MONDAY, FEBRUARY 1: LAST QUARTER MOON

A perfect time to mention that February is the only month during which a lunar phase cannot repeat. The moon's synodic period, defined as the time separating successive new moons, is about 29.5 days long. Even on leap years, February cannot be longer than 29 days. If the last quarter moon occurred on the 1st day of any other month, a last quarter moon would recur before the month ended, unless the last quarter moon happened every late on the 1st and it was a 30 day month.

TUESDAY, FEBRUARY 2: GROUND HOG'S DAY (CANDLEMAS)

Yes, Ground Hog's Day is an astronomical event. We refer to it as a "Cross Quarter Day," defined as a day mid way between a solstice and equinox or an equinox or solstice. Our calendar recognizes four such days. Groundhog's Day (Candlemas) is between the winter (December) solstice and the vernal (March) equinox. May Day (Beltane) on May 1 marks the mid point between the vernal (March) equinox and the summer (June) solstice. Lammas, on August 1, is the cross quarter day between the summer (June) solstice and the autumnal (September) equinox. Finally, Halloween/Samhain on October 31st is the cross quarter day between the autumnal (September) equinox and the winter (December) solstice.

WEDNESDAY, FEBRUARY 3: MOON 3.5 DEGREES N OF SATURN

Saturn lingers close to the waning crescent moon tonight. Both the moon and its planet companion will rise a couple hours after midnight. Though far from the night sky's brightest planet, Saturn is nevertheless easy to find, especially tonight when the moon hangs soul-like above it.

SATURDAY, FEBRUARY 6: MOON 4.3 DEGREES NORTH OF VENUS; MOON 3.8 DEGREES NORTH OF MERCURY (SILVER EVENT!!)

Two inferior planets and the crescent moon gathered in the pre-dawn sky. A truly gorgeous sight. One will have no trouble identifying the three bodies. Venus is far brighter than Mercury and much smaller than the moon. Though it looks like a thin crescent, the moon will also appear spherical because of Earth shine. (Earth's reflected light is cast on the moon's dark area which is then reflected back to us.)

SUNDAY, FEBRUARY 7: MERCURY AT GREATEST WESTERN ELONGATION

It is a bit confusing at first. When an inferior planets is at western elongation, it is visible in the eastern pre-dawn sky. When an inferior planet is at eastern elongation, it is visible in the western evening sky. This morning, Mercury reaches its greatest western elongation and will stray 25.5 degrees from the Sun.

MONDAY, FEBRUARY 8: NEW MOON

Beginning of lunation cycle 1152

SATURDAY, FEBRUARY 13: MERCURY 4.0 DEGREES E OF VENUS (GOLD EVENT!!!)

Gold events are those we deem to be the month's most spectacular. This morning, Hermes and Aphrodite veer close to one another. The beauty goddess will appear about 40 times brighter than the winged messenger. We'll see them both in the early morning! While this close approach won't be as impressive as August's Jupiter-Venus appulse, it will still be well worth a second glance.

MONDAY, FEBRUARY 15: FIRST QUARTER MOON

WEDNESDAY, FEBRUARY 17: SUN ENTERS AQUARIUS

The Sun ascends through the water bearer. After lingering low in Sagittarius and then climbing slightly in Capricornus, the Sun now begins a sharper upward curve toward the higher altitudes. Though it remains below the celestial equator, Sol is moving upwards and onwards. Each year the Sun appears to migrate through thirteen constellations comprising the "zodiac." These constellations are AQUARIUS THE WATER BEARER, Pisces the Fish, Aries the Ram, Taurus the Bull, Gemini the Twins, Cancer the Crab, Leo the Lion, Virgo the Maiden, Libra the Scales and Scorpius the Scorpion, Ophiuchus the Serpent Charmer, Sagittarius the Archer and Capricornus the Seagoat. The Sun enters Pisces the Fish on March 11.

SATURDAY, FEBRUARY 20: MOON 5.0 DEGREES SOUTH OF BEEHIVE STAR CLUSTER

Though quite bright, this gibbous moon won't wholly obscure the Beehive Star Cluster as it will appear to be a few degrees away from it. See both the cluster and the moon in the eastern evening sky.

MONDAY, FEBRUARY 22: FULL MOON

One should hardly be surprised to discover that February's full moon is often called the "Snow Moon." After all, in February the land is covered in shrouds of snow. February's full moon is also known as the "Hunger Moon," for game is scarce and ravenous night hunters would need that bright lunar illumination to find much needed prey. Today, we know that the full moon's reflection on the snowfields makes a winter's night luminous with a crystalline lustre. Perfect conditions for a walk, if one is inclined to wander outside to enjoy winter's unsounded deeps.

WEDNESDAY, FEBRUARY 24: MOON 1.6 DEGREES SSW OF JUPITER (BRONZE EVENT!)

As you might be able to tell, Jupiter is close to opposition. We know that Jupiter is near opposition because it veers close to the 'young' waning gibbous moon. ('Young' meaning that we're two days or fewer into the waning phase.) Behold both the moon and giant planet rising by 7 p.m. and remaining in the sky for the rest of the night.

SATURDAY, FEBRUARY 27: MARS AND URANUS IN HELIOCENTRIC OPPOSITION

Consider this one to be an 'academic' event. Mars and Uranus are on opposite sides of the sun, hence the term "heliocentric," or "sun centered." There is nothing to see here, but we wanted to mention it for the benefit of those who just can't get enough astronomy.

MONDAY, FEBRUARY 29: LEAP DAY

Calendar reckoning is hardly a straightforward matter. Each calendar year necessarily consists of an integer number of days, either 365 or 366. Earth's orbital period is not so constrained. Our planet requires about 365.2422 days to complete one circuit around the Sun. This horrid number doesn't even become an integer when expressed in seconds. Earth's year is a bit longer than 365 days, so every fourth year we have to add an extra day to account for this discrepancy. Now, if Earth's orbital period were precisely 365.25 days, then including this extra day every four years would be the only necessary correction. However, adding an extra day every four years eventually becomes problematic because then our civil year soon starts to surpass the actual year. In fact, this is precisely what happened centuries after Julius Caesar instituted his calendar reform in the 1st century BCE. The Julian calendar added an extra day every four years without exception. By the 16th century, the time when Pope Gregory XII introduced his own calendar reform, the vernal equinox (first day of spring) occurred around March 10th or 11th, instead of March 21st, the equinox date as recognized by the ecclesiastical authorities. In 1582, the church dispensed with the eleven days separating the actual and the calendric equinox. It also implemented what has since become known as the "Gregorian calendar reform." In this new system, a leap day is added every four years. However, a leap day is not added during century years (those equally divisible by 100) unless that century year is also equally divisible by 400. So, 1600 was a leap year; 1700, 1800 and 1900 were not. The year 2000 was also a leap year: only the second century leap year we've experienced since the Gregorian calendar was introduced. The next century leap year will be 2400.

 

 

PLANET WATCH

(For the first time, we've decided to designate every naked eye planet the "pick planet" as they are all simultaneously visible for the first time since 2005.)

NOTE: A subscriber suggested that we include the host constellation for each planet. An excellent suggestion! From now until the Daily Astronomer ends on the summer solstice 3190 AD (Yes, we peeked at the prophecy), we will include the host constellation for each planet.

MERCURY: The last of the five planets to appear in the morning sky. Mercury will remain visible all month, but will be easiest to observe during the first half of February, around the time when it reaches its greatest western elongation. VERDICT: See Mercury and at the same time you'll see all the pick planets!

(Host constellation: Mercury starts the month in Sagittarius the Archer and ends the month in Capricornus the Seagoat.)

VENUS: As always, Venus is the brightest of the five planets. Venus rises just before Mercury. Venus rises later each day and by the end of the month will rise during astronomical twilight. Venus will vanish by early April and won't return until the end of July. VERDICT: Two months from now, Venus will be on hiatus for the rest of the spring and the first half of summer. Behold this beautiful world when you can.

(Host constellation: Sagittarius the Archer)

MARS: Keep your eye on Mars. Although the red planet is dimmer than all the naked eye planets at month's beginning, it will dramatically increase in brightness throughout the next few months. By the time Mars reaches opposition on May 22, it will be sixteen times brighter than it is now! In fact, by late May, Mars will be about as bright as Jupiter, as the latter will be moving away from Earth and diminishing in brightness. When Mars is so brilliant, it truly stands out owing to its distinctive reddish color. Mars rises after midnight in February VERDICT: Mars might not be that impressive now, but, by Heavens, it will soon command your attention. Find it in the eastern early morning sky while you're admiring all the other planets. And, then, just wait for it to become a spring sky spectacle!

(Host constellation: Libra the Scales)

JUPITER: The first planet to appear! Jupiter is the only one of the naked eye planets that rises before midnight, It is the parade's grand marshal, to adopt a creative and original analogy that only 134,982 people have already used. Jupiter reaches opposition on March 8th, when it will be at its brightest and visible throughout the night. VERDICT: Even sky watchers who prefer to turn in before the witching hour will find it easy to find Jupiter. February and March are the best months to observe Jupiter. Although Jupiter will diminish in brightness after its opposition, it will remain on our evening sky until September!

(Host constellation: Virgo the Maiden)

SATURN: The sixth planet rises after Mars, but before Venus and Mercury. While Saturn will brighten as it trudges toward its June 3rd opposition, its brightness increase won't be as dramatic as Mars' Also, we'll keep Saturn in our sky until late autumn, so one will have ample opportunity to observe it. VERDICT: Saturn isn't going anywhere anytime soon. If you're up already in the early morning, seek it out in the eastern early morning sky. It won't be as dazzling as Venus or as colorful as Mars, but it will still be conspicuously bright.

(Host constellation: Sagittarius the Archer.)

PLANETS IN DESCENDING ORDER OF BRIGHTNESS

MONTH'S BEGINNING: VENUS - JUPITER - MERCURY - SATURN - MARS

MONTH'S END: VENUS - JUPITER - MERCURY - MARS - SATURN

PLANETS IN ORDER OF APPEARANCE

JUPITER MARS SATURN VENUS MERCURY