Star Calendar – September, 2015

Star Calendar

September 2015

Star Calendar Planets:

Moon will be waning as September opens and the ecliptic especially steep to the horizon in the morning. This circumstance will show especially thin and horizontal crescents on the 11/12th. New Moon begins the Hebrew new year (Rosh Hashanah) 5776 Anno Mundi. Moon’s ascending node currently lies where the Sun stands on the 24th, making this month an eclipse season. On the 13th the New Moon will be at an extreme apogee and its shadow will not reach the earth; a partial solar eclipse (for those near South Africa and the proximate part of Antarctica). However the Full and most perigee Moon of the 27–28th may well yield an especially dark lunar eclipse. A dark Moon is hard to see and is much more creepy than a red/yellow one; it looks like a giant stone hanging in the sky.

Mercury makes a large angle from the evening Sun on the 4th — but suffers from a shallow ecliptic. One may catch a peek around then, low in the west at 8PM. Mercury begins retrograde motion on the 17 and crosses the nearside of the Sun on the 30th.

Venus brightens to a maximum magnitude (for the year) of -4.8 on the 20th. She is receding from us and waxing in phase but is brightest while still crescent. The angular area Venus occupies in the sky diminishes as she recedes, that area being maximal on the 21st — when the waxing phase briefly overtakes the diminishing of receding distance.

Sun crosses the celestial equator on the 23rd, its center crossing at 4:21AM. The day of equinox is still 3 minutes longer than night though, a 12-hour-night waits for the 25/26th. Success in balancing eggs on their ends at equinox only indicates a greater patience and diligence in the attempt. There is no special gravity or balance-energy that day. Sorry.

Mars defers to Venus these mornings and passes (slightly dimmer than and) close to Regulus on the 25th, while bracketed by Venus above, Jupiter below.

Jupiter will be noticed emerging from his sunbath some fine morning this month, appearing below and much brighter than Regulus in the east. Weather and horizon permitting, look for it while scouting for old crescent Moons in the east at 6AM on the 11/12th.

Saturn is in the lower SW in the evening, and is the brightest celestial object in the vicinity. The Moon will be nearby on the 18th. Continue reading

Star Calendar – August 2015

Star Calendar

August 2015

Star Calendar Planets:

Moon will now be Full near the ends of the months for a while. This month will have two occasions of perigee occurring within 24 hours of syzygy; look for Spring Tide inundations on the 1st and 30th. New Moon is timed for ideal Perseid meteor viewing this year. I plan to look for them (from Breezy Hill, Springfield, VT) during the 80th “Stellafane” convention. RIP Carl Breuning (I’ll never forget viewing Mars with the 12” Porter Turret; sharp and clear through solid cloud-cover – this surprised us both!).

Mercury slips into the evening sky as Venus departs. On the 6th and 7th, in the glare of evening twilight, there is a close tussle with Jupiter and Regulus but we may hope for a better view on the 16th, to the right of a standing crescent Moon.

Venus takes a bow and swiftly crosses the nearside of the Sun this month. Look for a liaison with Mars, beginning as the Full Moon sets on the morning of the 29th with RA conjunction, but more pleasing to the eye in the first week of September.

Sun is halfway from solstice to equinox on the 1st; “Lammas” (Loaf-Mass) is a cross-quarter harvest festival.

Mars will creep into view for early risers during the middle of this month. Diehards might look to the left of the crescent Moon at 4-4:15 AM on the 13th. Mars will then appear in line with and below Gemini’s Pollux and Castor.

Jupiter takes a passage behind the Sun, conjunct on the 26th.

Saturn finishes a long retrograde period on the 2nd and is at quadrature (90 degrees from Sun) on the 21st. Saturn is now strictly an “evening star” as it sets before midnight and appears in the evening beyond culmination.

Pluto: the latest astronomical centerfold, and an intriguing one it is. The space-camera is traveling at truly meteoric speed. Consider: my 33-yr-old car has traveled about 400,000 miles, or just over 2 light-seconds (“to the Moon” – and nearly back); Pluto (near the Teapot) is about 5½ light-hours away, or 9,900 times that distance. Continue reading

Star Calendar – July, 2015

Star Calendar

July 2015

Star Calendar Planets:

Moon is Full at both ends of this month; but most comely when a companion young crescent around the 18th.

Mercury slips behind the Sun on the 23rd. Our next chance to see Mercury may come August 16th, beside a crescent Moon.

Venus now approaches us in earnest and her disk is greatly increasing in size. At the same time she is showing us less of her disk as she wanes in phase. The visible (lighted) part of Venus covers the greatest angular area of our sky as she sets on the 9th, but she continues to brighten to a maximum on the 12th. Venus and Jupiter make the closest of three encounters on the 1st, separated by only 4/10 degree as the evening darkens. Their second (RA)* conjunction is less sensational at 6 degrees on the 31st, and the third will come on October 26th – that being a morning apparition.

Sun has appeared for half the number of days for our calendar year at noon on the 1st, but does not progress halfway round the ecliptic until the next day. The discrepancy may seem odd at first but makes sense when we consider that its progress is most rapid when nearer than average (Fall to Spring) and tardier when farther away (Spring to Fall). If the calendar year were to begin at spring equinox instead, we would be halfway through the calendar on Sept 19th, but the Sun would take another 5 days to reach halfway along the ecliptic. Put another way, the time between equinoxes are 186 ½ and 178 ¾ days respectively; between solstices 181 ¾ and 183 ½. The Sun does NOT run like clockwork!

Mars is on summer vacation.

Jupiter, encouraged by a kiss from Venus, continues his quest for Regulus. The evenings of the 17th, 18th and 19th offer especially picturesque arrangements of Crescent Moon, Crescent Venus, Jupiter and Regulus; don’t miss them.

Saturn culminates (is highest, in the south, at about 9:PM) just as it gets dark this month and shines now at the same brilliance as the brightest of our summer stars, Vega. Vega is to be seen then in the east, to the left of Saturn.

*RA, R.A. or Right Ascension refers to a sky coordinate system based on the celestial equator divided into 24 sections. It is the component of distance along the equator to the left of the vernal equinoctal point and is given in units of hours, minutes and seconds where 0h is vernal equinox point. The other component is degrees Declination, which is the distance above or below the equator (+/- 90). For example, the summer solstice point is at 6h, +23.5 degrees. Conjunctions are usually (but not always) considered to be when the RA of two objects are the same.

 Star Calendar Days:

1      Sunrise/sunset in Spring Valley at 5:27/20:33 EDT (15h6m daylight)

          Halfway through AD 2015 at lunchtime

          Venus and Jupiter in nearest of triple conjunction, .4 degrees apart

          Full Thunder Moon 10:20PM

2      Sun opposite its Jan.1st position on the ecliptic

6      Sun most distant for the year, 3% farther than in January; moves most slowly

9      Venus illuminates largest area of sky

12      Moon near Aldebaran predawn in east

          Venus brightest for this appearance, -4.7 mag.

16      Moon, Venus and Regulus within smallest circle, West at 9:PM

17-19 Moon, Venus, Jupiter and Regulus gather each evening in West

22-23 Moon passes Spica, SW after 9: each evening

23      Venus stationary to stars, begins retrograde motion

          Mercury at superior conjunction, crosses behind Sun

25      Moon approaches Saturn (from the right) SSW after 9:PM

26      Moon above Antares, Saturn to right, S – SSW after 9:PM

31      Sunrise/sunset in Spring Valley at 5:51/20:14 EDT (14h23m daylight)

          Full Hay Moon 6:43AM

          Venus and Jupiter are conjunct (same R.A.) again, 6 degrees apart