Lower California Weather & Climate, Spaceflight News and Casual Astronomy

New Earth(s) in the Neighborhood  (see comment 75)                                 Morning Crescent Moons                                                                                 State of the Solar System  (see comments 49 & 51)                                

By: LowerCal, 4:00 PM GMT on September 22, 2010


moon phases

• Very bright & golden Mercury very low east before sunrise
• Brilliant white Venus SW after sunset, sets WSW at dusk
• Bright & reddish Mars low WSW at dusk, sets WSW mid-evening
• Brilliant off-white Jupiter low ESE at dusk with dim (use binoculars) blueish-green Uranus just above, setting west at dawn
• Brilliant & blueish star Sirius rises ESE early morning, SSE at dawn

Directions and times are for the northern subtropics and vary somewhat for other latitudes.

Scroll past the links below to find special events for current and future dates.
Scroll farther to find past events.

***** Links *****

Today - SpaceWeather.com
also EarthSky,
365 Days of Astronomy
& Bad Astronomy | Discover Magazine
This Week - SkyandTelescope.com - This Week's Sky at a Glance
also Jack Horkheimer - Star Gazer, Current Scripts
& This Week In Space on YouTube
This Month - SkyandTelescope.com - Sky Tour Podcasts
also HubbleSite - Tonight's Sky: Your guide to constellations, deep sky objects, planets, and events
Anytime - Stellarium (free planetarium for your computer)
also Sky & Telescope Interactive Sky Chart (online planetarium)

Visible Satellites:
Simplest - Satellite Flybys by SpaceweatherPhone.com
More satellites and more info - Heavens-Above.com.

Spaceflight Now - Worldwide Launch Schedule,
Vandenberg AFB Launch Schedule &
Wallops Flight Facility Launch Webcast & Blog
Reentries - Center for Orbital and Reentry Debris Studies - Upcoming & Recent Reentries

Live Aurora Cams:
Kiruna, Sweden,
Sodankyla, Finland &
Yellowknife, Canada (click on CONNECT AURORAMAX LIVE)

Most events described below can be viewed with your eyes alone.
Occasionally simple binoculars will improve the view and that will be noted.

***** Current & Future Events *****

◑ Last (or Third) Quarter Moon

Exact at
October 1
0352 GMT
September 30
11:52pm EDT
8:52pm PDT.

Rises near midnight and sets near noon. Morning crescent moons for a week after. Each one thinner and closer to the eastern horizon.

Image from: Australian Cooperative Research Centre for Renewable Energy

The gravitational pull of the Moon accounts for about 2/3 of the influence on Earth's tides with the Sun accounting for the remaining 1/3. On this date the gravitational pull of the Moon and Sun are at right angles resulting in weaker tides - lower highs, higher lows and slower flows. (Due to the huge mass and volume of the ocean's water the tidal effect lags behind the phases of the Moon. The delay can be as long as three days at some times and places.)

Also see The Moon And Tides.

Events earlier than those listed below will be found in previous blog entries.

***** Past Events *****

Lunar Apogee (Greek apo, away from + Greek Gaia, Earth)

Image credit: Pearson Scott Foresman

Exact at
September 21
0804 GMT
4:04am EDT
1:04am PDT.

The Moon is at its farthest distance in its non circular orbit around Earth. The Moon is about 12% farther than at its closest distance (perigee - Greek peri, near + Greek Gaia, Earth) and the Moon's gravitational influence on Earth and its oceans is about 20% less (due to the inverse square law).

How to Balance an Egg on End (On Any Day)

Equinox Day

Image credit: Przemyslaw "Blueshade" Idzkiewicz & NASA

The September equinox occurs
September 23 at exactly
0309 GMT
September 22 at exactly
11:09pm EDT
8:09pm PDT.

At that moment the Sun will pass directly over the Equator on its way to the Southern Hemisphere. Everywhere on Earth the Sun rises directly east and sets directly west, the length of days will be equal, the length of nights will be equal and the length of day will nearly equal (Latin equi-) night (Latin -noct).

After this date nights will be longer than days in the Northern Hemisphere and vice versa in the Southern Hemisphere. It marks the beginning of autumn for the Northern Hemisphere and the beginning of spring in Southern Hemisphere

Satellite Outages

One effect of equinoctial periods is the temporary disruption of communications satellites. For all geostationary satellites, there are a few days near the equinox when the sun goes directly behind the satellite relative to Earth (ie, within the beamwidth of the groundstation antenna) for a short period each day. The Sun's immense power and broad radiation spectrum overload the Earth station's reception circuits with noise and, depending on antenna size and other factors, temporarily disrupt or degrade the circuit. The duration of those effects varies but can range from a few minutes to an hour. (For a given frequency band, a larger antenna has a narrower beamwidth, hence experience shorter duration "Sun outage" windows).
Cultural Aspects of the Equinox

Moon Rides with Jupiter and Uranus

September 22
This night the Moon will travel with the brilliant off-white planet Jupiter. The dim blueish-green planet Uranus is currently positioned about 1° from Jupiter and is visible in binoculars. (See comment 6.)

Harvest Moon

Image credit: Sky & Telescope

September 23 & Several Following Evenings
The Harvest Moon is the full Moon nearest to the date of the September equinox. This year the full moon follows the equinox by a little over one day six hours.

From Hunter's moon - Wikipedia, the free encyclopedia:
In general, the moon rises about 50 minutes later each day, as it moves in orbit around Earth. All full moons rise around the time of sunset. The Harvest Moon and Hunter's Moon are special because—as seen from the northern hemisphere—the time of moonrise on successive evenings is shorter than usual. The moon rises approximately 30 minutes later, from one night to the next, as seen from about 40 degrees N. latitude, for several evenings around the full Hunter's or Harvest Moons.

Thus there is no long period of darkness between sunset and moonrise, around the time of these full moons. In times past, this feature of these autumn moons was said to help hunters tracking their prey (or, in the case of the Harvest Moon, farmers working in the fields). They could continue tracking their prey (or bringing in their crops) by moonlight even when the sun had gone down. Hence the name Hunter's (or Harvest) Moon.

The reason for the shorter-than-usual rising time between successive moonrises around the time of the Harvest and Hunter's Moon is that the orbit of the Moon makes a narrow angle with respect to the horizon in the evening in autumn, leading the Moon to higher positions in the sky each successive day.

○ Full Moon

WunderPhoto: Moonrise over Washington, D.C. by mcqdc Wednesday August 25, 2010

Exact at
September 23
0917 GMT
5:17am EST
2:17am PST.

Rises near sunset and sets near sunrise. At those times the Moon may seem huge (the Moon illusion) and unusually colored. The yellow/orange/red appearance of the Moon at the horizon is at least partly for the same reason the sky appears blue!

Image from: Australian Cooperative Research Centre for Renewable Energy

The gravitational pull of the Moon accounts for about 2/3 of the influence on Earth's tides with the Sun accounting for the remaining 1/3. On this date the gravitational pull of the Moon and Sun are aligned resulting in stronger tides - higher highs, lower lows and faster flows. (Due to the huge mass and volume of the ocean's water the tidal effect lags behind the phases of the Moon. The delay can be as long as three days at some times and places.)

Also see The Moon And Tides.

Return from ISS (International Space Station) of Expedition 24

Mission: ISS Expedition 24 return
Spacecraft: Soyuz TMA-18

September 24
5:34am MSD (Moscow Summer Time)
0134 GMT
September 23
9:34pm EDT
6:34pm PDT.

September 25
6:02am MSD (Moscow Summer Time)
0202 GMT
September 24
10:02pm EDT
7:02pm PDT.

September 24
8:03am MSD (Moscow Summer Time)
0403 GMT
12:03am EDT
September 23
9:03pm PDT.

September 25
8:32am MSD (Moscow Summer Time)
0432 GMT
12:32am EDT
September 24
9:32pm PDT.

September 24
9:56am AQTT (Aqtobe Time, local time)
0456 GMT
12:56am EDT
September 23
9:56pm PDT.

September 25
10:21am AQTT (Aqtobe Time, local time)
0521 GMT
1:21am EDT
September 24
10:21pm PDT.

The last three crew members of ISS Expedition 24 will return to Earth.

Live updates and video are at
Spaceflight Now | Space Station Report | Mission Status Center.

There will be live coverage on NASA TV. Check the NASA TV Schedule for times.

Vandenberg Minotaur IV Launch

Photo credit: Joe Davila

Mission: Space Based Space Surveillance (SBSS) "pathfinder" satellite
Launch Vehicle: Minotaur IV
Launch from Vandenberg AFB, California
September 26
0441-0455 GMT
12:41-12:55am EDT
September 25
9:41-9:55pm PDT (local time).

Launch status updates are at
Spaceflight Now | Tracking Station | Worldwide launch schedule.

More details may appear on a launch blog at
Spaceflight Now | Minotaur Launch Report | Mission Status Center
as the launch date nears.

More details on the mission can be found at
Orbital Sciences Corp. - Minotaur IV/SBSS.

A live webcast begins about 30 minutes before launch.

Moon Passes (Over) the Seven Sisters (and won't return until 2023)

September 28, Early Morning
This morning the Moon will pass near the Pleiades star cluster (The Seven Sisters). Six or seven of the stars in this cluster can be seen with the naked eye. Many more can be seen through simple binoculars.

For parts of the southern South Atlantic Ocean and southernmost South America the Moon will pass over some of the stars in the Pleiades cluster.

The Moon won't hide any of the Pleiades again anywhere on Earth until 2023.

Maps and time tables for the disappearance & reappearance of the brightest stars at some cities can be found here with a DATE-TIME of "31 Aug 10". The star names can be found in the chart below.

Image credit: NASA, ESA and AURA/Caltech

Moon Rides the Bull

September 28, Late Evening through Dawn
This mornning the Moon will appear to the left of the bright and orange star Aldeberan. Alderberan is the brightest star and glaring right eye of the constellation Taurus the Bull. With binoculars you can easily see the "V" shaped pattern of stars that forms the rest of the face of the bull. This collection of stars is known as the Hyades star cluster. In the image below Aldeberan is the brightest star and the "V" shaped pattern is tipped to left.

Hyades Star Cluster

Image credit: Zbigniew Kawalec

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Updated: 2:05 AM GMT on October 02, 2010


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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