Star Calendar – February 2016

Star Calendar

February 2016

Star calendar Planets:

Moon appears on the 1st at Last Quarter and makes a little line segment with Mars and Zubenelgenubi of Libra (for binoculars) for early risers. After a similar highlight of Saturn/Antares on the 3rd will be a fetching scene on the 6th, between about 6:15 and 6:30 in the SE with a thin crescent Moon beside Venus, and a possibly visible Mercury below.

Mercury shines at zero magnitude (as bright as the brightest star of summer, Vega) but is fairly low throughout this excursion into the light of dawn. Greatest elongation coincides with a proximate Moon as mentioned above.

Venus spends February making a graceful, slow departure from her late prominence in the morning scene. By March 1st she will barely peak over the horizon when civil twilight is well underway. We may then wait until some evening in late July for her next showing.

Sun makes a circuit through the stars in about (!) 365.24219 days. The Julian leap-day-every-four-years scheme still leaves a sizable error of 3days 3hours per century. The Gregorian refinement, omitting leap-days on the centuries excepting those divisible by 400, leaves an error of 44minutes 38seconds per century – which falls much nearer the noise floor of the long-term variability of the length of day.

Mars is highlighted by the Moon at both the beginning and end of this month and is positioned for optimal viewing, high in the South, before dawn. He now moves steadily away from Zubenelgenubi and toward his namesake (anti-nym?) Antares. Although “Antares” means “the equal of Mars”, in reference to their similar color, actual encounters of Mars and Antares vary widely in their relative brightness. This time Mars will become markedly the brighter as they draw nearer. We can look forward to an April 25th clustering of Moon, Mars, Saturn and Antares.

Jupiter is now an all-night feature, noticeably retrograde, and approaches the point in the sky opposite the Sun – which is currently near Regulus and moving toward Jupiter one degree per day. When they are closest we call the planet in opposition; it is then nearest Earth, brightest, and at the mid-point of its backward motion.

Saturn lies bright between the stars Sabik, of Ophiuchus, and Antares of Scorpio. Saturn burns at a steady .5 magnitude this month while Mars brightens from .8 (dimmer) to .4 (brighter) during this month – so the pair trade places in planetary dominance during this month. Remember that in the magnitude scale less-is-more.

Caveat Lector! Sorry about the 10-minute-too-late error for the occultation in January, I don’t know how that happened. As always, “Reader Beware!”

Star Calendar Days:

1      Moon, Mars, Zubenelgenubi in a tight little line; S 5:-6:AM

          Sunrise/sunset in Spring Valley at 7:07/17:12 (10h5m daylight)

2      Traditional mid-winter day, Candlemas/Groundhog Day

3      Moon above Saturn, Antares; SSE 5:-6:AM

6      Moon, Venus, Mercury in a small triangle; low SE at 6:AM

          Mercury at greatest angle from Sun, 26 degrees, and as bright as Vega

7      Mars is 90 degrees from Sun (quadrature), analogous to Last Quarter Moon

11      Mean-time clocks furthest ahead of Sun for the year, ET= -14 ¼ minutes

13      Venus and Mercury most proximate for this appearance; low ESE 6:AM

15      Moon occults the nose of the Bull after sunset (not readily observable)

22      Moon sets as near to Earth’s shadow as is Aldebaran; W at 5:30 AM

          Full Snow Moon at 13:20 (1:20PM EST) passing just beneath Earth’s shadow

23      Moon rises beside Jupiter; E 7:PM

29      Moon above Mars; S at 5:30AM

          Sunrise/sunset in Spring Valley at 6:31/17:47 (11h16m daylight)