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.

Occultations are, astronomically, the obscuring of a celestial object by something else (eclipses are one form) and there is an opportunity to see a good one this month in the wee hours of the 4/5th. The bright edge of the Moon will cover Aldebaran just as the two rise. This is predicted to occur at 11:55PM in Spring Valley (write me for times at other locations) but will probably be too low to see. But wait! Regulus re-emerges from the dark upper limb of the Moon just around 12:39AM, and higher in the sky. It is really neat to see a bright star suddenly wink on.

Star Calendar Days:

1    Sunrise/sunset in Spring Valley at 6:23/19:29 EDT (13h06m daylight). Equation of time is zero for time zone center
2    Venus and Mars next to each other the next few mornings, in east at 5:45AM
4    Mercury at greatest angle from Sun for this appearance, very low west at 8PM
4-5  Moon occults Aldebaran 23:55, reappears 00:40, in east. Anticipate and be patient, times are approximate!
5    Venus stationary to stars, resumes direct (leftwards) motion
10    Mars, Moon and Venus make it worth rising at 5:45AM to look east
11-12    Very thin crescent Moons introduce Jupiter to the morning, east, 5:45-6:AM
13    Rosh Hashanah at sunset, begins year 5776 A.M. Partial solar eclipse, around South Africa
14    Moon most distant for the year
15    Moon above Spica (to left) and Mercury (very low to right) in west at 7:25PM
17    Mercury is stationary to retrograde (rightwards to stars) motion
18    Antares, Saturn and Moon in a line, SW at 8PM
20    Venus is brightest for the year
21    Venus is largest (angular area) for the year
23    Equinox at 4:21AM, center of Sun crosses to south of celestial equator. Sunrise/sunset in Spring Valley at 6:49/18:52 EDT (12h03m daylight)
25-26    Sunset/Sunrise in Spring Valley at 18:48/6:48 EDT (12h ‘twixt daylights)
27-28    Full Dark Moon is in deep eclipse just after extreme perigee. Totality from 10:10 ’til 11:24PM
30    Sunrise/sunset in Spring Valley at 6:52/18:40 EDT (11h48m daylight). Mercury crosses in front of  the Sun (inferior conjunction)


Tagged , , , , , , , , , , . Bookmark the permalink.

About pbdavis

Paul Davis is a former resident of the Threefold Community. He has been a teacher of Celestial Navigation, a Planetarium lecturer, and offered evening Astronomy classes at Sunbridge some years ago. He is now living in New Hampshire.