Home | Library | Directory | Employment | Site Index | Contact Us

Community Learning Center Home
Planetarium Home
Video on the Dome
Quick Information
Current Headlines
Reservation Request

David Mayeux
Planetarium Director
(505) 566 - 3361



Current Astronomy "Headlines"

Last Quarter September 05

New Moon September 13

First Quarter September 21

Full Moon September 27

Listed below are notable astronomical events coming up for the month of
September 2015:

Naked-Eye Planets

Mercury is in the evening sky at the start of September in the constellation Virgo. On the evening of the 3rd, Mercury comes to its closest to greatest eastern elongation at about 27 degrees separation from the Sun! Unfortunately, most of this angular separation is closer to parallel to the horizon, than it is to perpendicular – in other words, Mercury’s apparent distance from the Sun in the sky doesn’t translate to very much height above the horizon, so it may still be somewhat of a challenge to spot Mercury after sunset, unless you have a decently flat horizon in the west. Mercury doesn’t keep that separation for long! For the rest of the month Mercury descends ever more rapidly into the glare of sunset until inferior conjunction on the last day of the month.

Venus rises at a little after 5 a.m. in the constellation Cancer, roughly 10 degrees SSE of the planet Mars at the beginning of September. The waning crescent Moon makes a delightful pairing with Venus on the morning of the 10th. Venus crosses over into the constellation Leo on the 24th of the month and by the 30th is rising at about 3:45 a.m. as a prominent “morning star!”

At the beginning of September, Mars rises at about 4:45 a.m. in the constellation Cancer, about 10 degrees NNW of the much brighter planet Venus. Mars forms a line with the waning crescent Moon and Venus on the morning of the 10th of the month. Thereafter, Mars rises slightly earlier in the morning for the rest of the month, and rises at slightly before 4:30 a.m. by month’s end.

Jupiter is deep in the pre-dawn solar glare at the beginning of September, just having come to solar conjunction at the end of last month in the constellation Leo. By about the last third of the month, Jupiter finally begins rising early enough to be seen before the light of dawn hides its light. By the end of the month, Jupiter rises right at 5 a.m.

Saturn begins September modestly high in the SW in the constellation Libra, just a couple of degrees west of the stars of the head of Scorpius the scorpion. On the evening of the 18th, the waxing crescent Moon passes only about 3 degrees away from the Ringed Planet for a nice celestial meeting between solar system objects! All month long, Saturn has been resuming normal, westward annual motion with respect to the stars and ends the month setting at the edge of Libra slightly after 9:30 p.m.

Telescopic Planets

Uranus rises in the constellation Pisces all month long at a little after 9:20 p.m. The nearly Full Moon bypasses closest on 9/28, and at the end of the month rises a little after 7:20 p.m. Opposition is next month! It is possible to observe Uranus through binoculars or telescopes as a pale blue, steadily-shining “star” in binoculars, and a small telescope at moderate-to-high power (about 75x or more) will reveal its disc (magnitude 6.05, and 3.7 arc-seconds on 9/30).

Neptune is just hours past opposition on the 1st of the month in the constellation Aquarius, so during the entire month of September, Neptune will be up virtually all night long! The waning gibbous Moon bypasses closest on the night of 9/25. Neptune appears as a slightly deeper blue-hued “star” in binoculars than Uranus normally does, and also much less bright. A telescope will barely reveal a very small disc (magnitude 7.65, and 2.4 arc-seconds on 9/30) at high power (150x or more).

Dwarf Planets

Ceres is already above the horizon after sunset at the beginning of September in extreme SE Sagittarius, far from the Teapot asterism. Another way to describe its position is that it is just SW of the constellation Capricornus. The Moon makes its closest approach on the nights of 9/22 and 9/23, and it’s not particularly close – perhaps up to 15 degrees separation on either night. By month’s end, it is in modest retrograde motion in Sagittarius, nearly at meridian at about an hour after sunset. An observer will be able to view Ceres with a telescope (although a detailed star chart will be necessary to pinpoint its position), although far from glaringly, and even then Ceres’ disc is too small to be seen through any but the largest professional ground-based telescopes. Ceres should appear as a “dot” of a star, much like Pluto, only it will be visible with MUCH more modest viewing equipment! It is actually dimmer than Neptune is on 9/30 at magnitude 8.0.

Pluto is in the constellation Sagittarius for the month of September, and is nearly at meridian about an hour after sunset at the beginning of the month. The first quarter Moon makes its closest pass on the evening of 9/21, and Pluto finishes the month sat a little bit past meridian an hour after sunset. However, seeing it in a backyard telescope is another matter…! The icy dwarf planet is only visible as a very modest, slight “dot” of a star in a telescope of at least 8”-10” aperture. A very detailed star chart (as well as a great amount of patience and endurance!) is vitally necessary in order to spot it! Pluto glows feebly at magnitude 14.17.


Total Lunar Eclipse on the Evening of September 27!

On the night of September 27, Farmington will be treated to a total lunar eclipse immediately after sunset! The umbral, or deep-shadow, part of the eclipse will begin at 7:07 p.m. local time, when the leading edge of the darkest part of the Earth’s shadow will obscure the face of the Moon! At 8:11 p.m. all of the Moon will be in the Earth’s shadow, beginning the phase of totality. The Moon, however, will probably not be all dark - it will likely appear to be a reddish, or even orange, color! This has to do with the fact that the Earth’s atmosphere acts like an eyeglass lens and will bend light rays near the red end of the spectrum so that they project onto the Moon slightly! The midpoint of the eclipse will be at 8:48 p.m. and the Moon will begin to come out of the Earth’s shadow, ending totality, at 9:23 p.m.! The umbral eclipse will end at 10:27 p.m., when the trailing edge of the Earth’s shadow moves off the Moon’s surface.

The planetarium will hold a special telescopic observing session of part of the eclipse at the college in the courtyard behind the planetarium, which will begin at 8:00 p.m. and end at 9:30 p.m., weather permitting, of course. The planet Saturn will be visible to the naked eye, although very low over the western horizon at this time, and telescopic viewing of distant giant planets Uranus and Neptune may be possible! The event is free of charge and open to the public! If the weather is cloudy or rainy, however, the observing will have to be cancelled.

For more information, please call David Mayeux at 566-3361.





Meteor Showers - http://amsmeteors.org/showers.html

Viewable Comets - http://cometography.com/current_comets.html

Special events - http://www.skyandtelescope.com/observing/highlights



San Juan College, 2002.

All Rights Reserved.


4601 College Boulevard  Farmington, New Mexico  87402   505-326-3311


SJC Home  Library  Directory   Employment  Site Index  Contact Us