Astronomy News for the Month of September 2017

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For amateur radio operators and scanner enthusiasts, when in the Denver metro area, please join the Colorado Astronomy Net on the Rocky Mountain Radio League's 146.94 MHz and 449.825 MHz repeaters. The RMRL 146.94 repeater is also linked with the WB0WDF Cripple Creek 447.400 MHz repeater and Allstar nodes 28298, 28299 and 29436. We are also linked via Echolink, links are k0jsc-r and canoncty. More information on the WB0WDF repeater links and Allstar nodes and Echolinks can be found at The net meets on Tuesday nights at 7 P.M. Mountain Time (US).

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In this Newsletter...

Background screen credits: NGC5775
Imaged March 21/22, 2001
using the 16" Kitt Peak Visitors Center telescope
as part of the Kitt Peak Advanced Observing Program.

"Neptune's atmosphere displayed wispy clouds and a raging dark storm when Voyager 2 flew past in August 1989. In typical amateur scopes, the distant world shows a small, blue-gray disk."

The Month At-A-Glance
A calendar displaying the daily astronomical events.

07 day moon

The Moon



Moon/Planet Pairs

For reference: The Full Moon subtends an angle of ~0.5°.

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The Planets & Dwarf Planets

Planetary Reports generated by "TheSky" software. These reports provide predicted data for the planets for the first of each month for the current year. The rise and set times for the Sun and the Moon for each day of the month as well as meteor shower radiants are also included in the reports. These reports have been optimized for the Denver, Colorado location, however, the times will be approximate for other locations on Earth.

(All times are local unless otherwise noted.)

Planetary Highlights for September

September evenings are prime for observing the gas giants, Jupiter, Saturn, Uranus and Neptune. Neptune reaches its best visibility for the year. September mornings are best for viewing the inner planets, Mercury, Venus and Mars. As with Neptune, Mercury also reaches its best visibility for the year this month. Meteor shower activity slows down this month and Comet PANSTARRS makes a U-turn passing just south of the Pleiades. The Earth reaches the Autumnal Equinox.


Is stationary on the 4th. Mercury is at greatest western elongation (18° west of the Sun) on the 12th. Mercury rises at 5:46 a.m. on the 1st and about 6:26 a.m. by month's end. Look for Mercury about 30 minutes before sunrise in the east. Mercury will be best viewed during the second and third weeks of the month. Mercury moves from the constellation of Leo into Virgo this month shining at magnitude -0.7 on the 15th.


Rises at 3:49 a.m. on the 1st and about 4:54 a.m. by month's end. Look for Venus shining brightly in the early morning hours before sunrise. Venus moves from the constellation of Cancer into Leo shining at magnitude -3.9.


Autumnal equinox occurs at 4:02 a.m. EDT on the 22nd.


Is finally visible again in the morning sky. Mars rises at 5:29 a.m. on the 1st and about 5:07 a.m. by month's end. Mars is visible low on the eastern horizon and is best viewed during the latter part of the month. Mars is in the constellation of Leo shining at magnitude 1.8.


Sets at 9:15 p.m. on the 1st and about 7:32 p.m. by month's end. Jupiter is visible low in the evening sky soon after sunset, and appears to descend even lower by the end of the month. Jupiter is in the constellation of Virgo shining at magnitude -1.7.


Sets at 12:25 a.m. on the 1st and about 10:27 p.m. by month's end. Saturn is easily spotted soon after sunset towards the southwest. Saturn is in the constellation of Ophiuchus shining at magnitude 0.5.


Rises at 9:22 p.m. on the 1st and about 7:22 p.m. by month's end. Uranus is best viewed in the evening and early morning skies after midnight. Uranus is in the constellation of Pisces shining at magnitude 5.7.


Reaches opposition on the 5th (rising as the Sun sets). Neptune rises at 7:35 p.m. on the 1st and about 5:35 p.m. by month's end. Neptune is at its best for the year and is visible all night long. Neptune is in the constellation of Aquarius shining at magnitude 7.8.

Dwarf Planets


Rises at 3:23 a.m. on the 1st and about 2:16 a.m. by month's end. Ceres is best viewed at least an hour or so before sunrise to the southeast. Ceres moves from the constellation of Gemini into Cancer shining at magnitude 8.9.


Sets at 2:16 a.m. on the 1st and about 12:17 a.m. by month's end. Pluto is visible in the late evening but is best viewed when it is highest in the sky toward the south-southwest. Pluto is in the constellation of Sagittarius shining at magnitude 14.2.

As always, good luck at spotting Neptune, Ceres and Pluto, a large telescope and dark skies will be needed.

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Astronomical Events

Meteor Showers

  • The Alpha Aurigids - This shower's duration seems to persist from August 25 to September 6. Maximum occurs on September 1. The annual maximum hourly rate may be as high as 9, but outbursts of over 30 occurred in 1935, 1986, and 1994, and observers recorded up to 130 meteors per hour in 2007.

  • The Epsilon Perseids meteor shower is a relatively new meteor shower which can be observed from September 4 to the September 14. The Epsilon Perseids peaks on the night of the September 9, morning of September 10. Observers may expect to see up to 5 or 6 meteors per hour during the peak.

    Meteor Shower Radiant Report

    For more information about Meteor Showers, visit Gary Kronk's Meteor Showers Online web page.

    Meteor Scatter (or Meteor burst communications) - "is a radio propagation mode that exploits the ionized trails of meteors during atmospheric entry to establish brief communications paths between radio stations up to 2,250 kilometres (1,400 mi) apart." Tune your shortwave or your HF amateur radio to 54.310 MHz SSB and see if you can hear any pings.

  • Comets

  • Comet PANSTARRS (C/2015 ER61) is still in the constellation of Taurus the Bull this month. PANSTARRS makes a U-turn around the 11th passing south of the Pleiades by the end of the month, heading west. Comet PANSTARRS shines around 10th magnitude this month.

  • For information, orbital elements and ephemerides on observable comets, visit the Observable Comets page from the Harvard-Smithsonian Center for Astrophysics.

    For more information about Comets, visit Gary Kronk's webpage.

  • Eclipses

    Solar Eclipses

  • No solar eclipse activity this month.

    Lunar Eclipses

  • No lunar eclipse activity this month.
  • Observational Opportunities

  • Enjoy Jupiter, Saturn, Uranus and Neptune in the evening skies after sunset.
  • Look for Mercury, Venus and Mars in the morning skies before sunrise.
  • Try to spot Comets PANSTARRS in Taurus.

  • Asteroids

    (From west to east)
    • Florence passes nearest to Earth on the 1st, passing through the constellations of Delphinus and Cygnus during the first week of September.
    • Julia is at opposition on the 8th in the constellation of Pegusus.
    • Iris is in the constellation of Aries.
    • Pallas is in the constellation of Eridanus.

    • Information about the Minor Planets can be found at the Minor Planet Observer website.

    IOTA Logo

  • Information on various occultations can be found by clicking the IOTA logo.
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    Subscriber Gallery

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    Member Meteor Sightings

    This is a new section where I will post meteor, fireball, etc sightings that have been published on the American Meteor Society's web site. I want to make this an active section of the web pages and newsletter and would like to publish the links to member sightings. If you have any published sightings, please provide me with the links and I will post them here for all to enjoy.

    Event ID Date/Time Location Observer Link
    3587-2015 2015-11-22 17:38 MST CO Kevin S 3587aw
    3829-2015 2015-12-05 18:06 MST Highlands Ranch, CO Burness A 3829a
    3871-2015 2015-11-13 01:55 MST CO Charles N 3871a

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    Planetary/Lunar Exploration Missions

    (Excerpts from recent JPL mission updates)
    JPL Latest News
    The Latest from Space

    JPL Latest News

    Apply to Be a NASA Solar System Ambassador
    August 31, 2017

    Full Article & Images

    "Could you be one of them? If you want to share your passion of space with the public, being a NASA Solar System Ambassador is the perfect platform to do so.

    The annual Solar System Ambassadors application period begins on Sept. 1 and ends on Sept. 30. Chosen applicants will begin a one-year, renewable term on Jan. 1, 2018."

    "Read the latest news and discoveries from JPL's dozens of active space missions exploring Earth, the solar system and worlds beyond. "

    Past, Present, Future and Proposed JPL Missions -

    For special JPL programs and presentations in your area visit the JPL Solar System Ambassador web site at

    Juno - August 30, 2017
    Juno Scientists Prepare for Seventh Science Pass of Jupiter

    Full Article & Images

    "NASA's Juno spacecraft will make its seventh science flyby over Jupiter's mysterious cloud tops on Friday, Sept. 1, at 2:49 p.m. PDT (5:49 p.m. EDT and 21:49 UTC). At the time of perijove (defined as the point in Juno's orbit when it is closest to the planet's center), the spacecraft will be about 2,200 miles (3,500 kilometers) above the planet's cloud tops."

    NASA's JunoCam website can be visited at:

    More information on the Juno mission is available at:

    The public can follow the mission on Facebook and Twitter at:

    Cassini - August 29, 2017
    Saturn Plunge Nears for Cassini Spacecraft

    Full Article & Images

    NASA Previews Cassini's Grand Finale

    "NASA's Cassini spacecraft is 18 days from its mission-ending dive into the atmosphere of Saturn. Its fateful plunge on Sept. 15 is a foregone conclusion -- an April 22 gravitational kick from Saturn's moon Titan placed the two-and-a-half ton vehicle on its path for impending destruction. Yet several mission milestones have to occur over the coming two-plus weeks to prepare the vehicle for one last burst of trailblazing science…

    -- Sept. 9 -- Cassini will make the last of 22 passes between Saturn itself and its rings -- closest approach is 1,044 miles (1,680 kilometers) above the clouds tops.

    -- Sept. 11 -- Cassini will make a distant flyby of Saturn's largest moon, Titan. Even though the spacecraft will be at 73,974 miles (119,049 kilometers) away, the gravitational influence of the moon will slow down the spacecraft slightly as it speeds past. A few days later, instead of passing through the outermost fringes of Saturn's atmosphere, Cassini will dive in too deep to survive the friction and heating.

    -- Sept. 14 -- Cassini's imaging cameras take their last look around the Saturn system, sending back pictures of moons Titan and Enceladus, the hexagon-shaped jet stream around the planet's north pole, and features in the rings.

    -- Sept. 14 (5:45 p.m. EDT / 2:45 p.m. PDT) -- Cassini turns its antenna to point at Earth, begins a communications link that will continue until end of mission, and sends back its final images and other data collected along the way.

    -- Sept. 15 (4:37 a.m. EDT / 1:37 a.m. PDT) -- The "final plunge" begins. The spacecraft starts a 5-minute roll to position INMS for optimal sampling of the atmosphere, transmitting data in near real time from now to end of mission.

    -- Sept. 15 (7:53 a.m. EDT / 4:53 a.m. PDT) -- Cassini enters Saturn's atmosphere. Its thrusters fire at 10 percent of their capacity to maintain directional stability, enabling the spacecraft's high-gain antenna to remain pointed at Earth and allowing continued transmission of data.

    -- Sept. 15 (7:54 a.m. EDT / 4:54 a.m. PDT) -- Cassini's thrusters are at 100 percent of capacity. Atmospheric forces overwhelm the thrusters' capacity to maintain control of the spacecraft's orientation, and the high-gain antenna loses its lock on Earth. At this moment, expected to occur about 940 miles (1,510 kilometers) above Saturn's cloud tops, communication from the spacecraft will cease, and Cassini's mission of exploration will have concluded. The spacecraft will break up like a meteor moments later."

    Raw images are available at

    More information about Cassini is available at the following sites:

    Cassini Imaging Team - Archives from Dec. 2015 and earlier.

    New Horizons - August 17, 2017
    New Horizons Imaging and Spectroscopy Team Receives Prestigious SPIE George W. Goddard Award

    Full Article & Images

    "The multiorganizational team that brought the world its first close-up views of Pluto and its moons has received the 2017 George W. Goddard Award from SPIE, the international society for optics and photonics."

    New Horizons gallery

    Find New Horizons in the iTunes App Store here.

    For more information on the New Horizons mission - the first mission to the ninth planet - visit the New Horizons home page.

    Dawn - May 16, 2017
    Movie Shows Ceres at Opposition from Sun

    Full Article & Images

    "NASA's Dawn spacecraft successfully observed Ceres at opposition on April 29, taking images from a position exactly between the sun and Ceres' surface. Mission specialists had carefully maneuvered Dawn into a special orbit so that the spacecraft could view Occator Crater, which contains the brightest area of Ceres, from this new perspective.

    A new movie shows these opposition images, with contrast enhanced to highlight brightness differences. The bright spots of Occator stand out particularly well on an otherwise relatively bland surface. Dawn took these images from an altitude of about 12,000 miles (20,000 kilometers)." A gallery of images can be found online.

    For more information on the Dawn mission, visit the Dawn home page.


    The MESSENGER mission is officially ended but there is a lot to learn about the planet closest to our Sun. Visit the new, updated MESSENGER website:

    for resources, to learn, and to explore.

    (Click Link above for Full Article & Images)


    "After more than 10 years in operation, the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft impacted the surface of Mercury on April 30, 2015, at a speed of more than 3.91 kilometers per second (8,750 miles per hour), marking the end of operations for the hugely successful Mercury orbiter. At the MESSENGER Nears End of Operations media and public event, scientists and engineers discussed the mission's accomplishments, providing the top 10 scientific discoveries, as well as the technological innovations that grew out of the mission."

    The MESSENGER app is available for download from iTunes.

    For more information on the MESSENGER mission, visit the MESSENGER home page.

    Past, Present, Future and Proposed JPL Missions -

    Visit JPL's mission pages for current status.

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    Mars Missions

    Be A Martian

    Mars website mobile version is here!

    Mars on the Go! NASA Be A Martian Mobile App
    If you want the latest news as it happens, try our Be A Martian app.
    Download on Mobile Devices
    Android | iPhone | Windows Phone

    JMARS is an acronym that stands for Java Mission-planning and Analysis for Remote Sensing. It is a geospatial information system (GIS) developed by ASU's Mars Space Flight Facility to provide mission planning and data-analysis tools to NASA's orbiters, instrument team members, students of all ages, and the general public.

    Laboratory for Atmospheric and Space Physics

    "The Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder (CU) began in 1948, a decade before NASA. We are the world's only research institute to have sent instruments to all eight planets and Pluto. LASP is an affiliate of CU-Boulder AeroSpace Ventures, a collaboration among aerospace-related departments, institutes, centers, government labs, and industry partners."

    MAVEN - June 16, 2017
    1,000 Days in Orbit: MAVEN's Top 10 Discoveries at Mars

    Full Article & Images

    "On June 17, the MAVEN mission will celebrate 1,000 Earth days in orbit around the Red Planet. Since its launch in November 2013 and its orbit insertion in September 2014, MAVEN has been exploring the upper atmosphere of Mars. MAVEN is bringing insight to how the sun stripped Mars of most of its atmosphere, turning a planet once possibly habitable to microbial life into a barren desert world."

    Visit LASP and MAVEN for more information.

    Mars Science Laboratory - Curiosity - August 31, 2017
    Sol 1802: Stereo party

    Full Article & Images

    "Curiosity's drive on Sol 1801 brought us to an excellent location for some contact and remote science in today's 3-sol plan (setting up for a long Labor Day weekend). We'll kick off Sol 1802 with contact science (MAHLI + APXS) on the target called "Tyler," a region of Murray bedrock just in front of the rover."

    To follow the Mars Curiosity rover and NASA on Foursquare, visit: and

    For information about NASA's partnership with Foursquare, visit:

      Mars Rover Landing - Free for the Xbox 360 (requires Kinect)

      Visit the Mars Science Laboratory page.

    Mars Exploration Rover Mission (Spirit and Opportunity) - August 29, 2017

    SPIRIT UPDATE: Spirit Remains Silent at Troy - sols 2621-2627, May 18-24, 2011:

    "More than 1,300 commands were radiated to Spirit as part of the recovery effort in an attempt to elicit a response from the rover. No communication has been received from Spirit since Sol 2210 (March 22, 2010). The project concluded the Spirit recovery efforts on May 25, 2011. The remaining, pre-sequenced ultra-high frequency (UHF) relay passes scheduled for Spirit on board the Odyssey orbiter will complete on June 8, 2011.

    Total odometry is unchanged at 7,730.50 meters (4.80 miles)."

    OPPORTUNITY UPDATE: Opportunity Seeks Energy-Favorable Locations to Recharge its Solar Panels During Winter - sols 4828 - 4834, August 23, 2017 - August 29, 2017:

    "Opportunity is exploring "Perseverance Valley" on the west rim of Endeavour crater.

    Winter has constrained the energy levels on the rover, so the project has been exercising the strategy of driving the rover from one energy-favorable "lily pad" to the next. These lily pads are locations where the terrain is tilted sufficiently to the north to maximize the Sun illumination on the rover's solar panels. Even this is not enough and the rover has to spend some days recharging. During these "recharge" sols the rover sleeps throughout the day waking only for the morning Deep Space Network X-band session and the afternoon Ultra High Frequency relay pass.

    Opportunity drove on Sol 4831 (August 26, 2017), heading for an energy lily pad. While driving, the rover collected some mid-drive Panoramic Camera (Pancam) and Navigation Camera (Navcam) imaging. At the end of the drive, after traveling just over 82 feet (25 meters), the rover collected some more imagery. Unfortunately, due to side slip, the rover missed the lily pad by a few meters. After a couple of days of recharging, Opportunity drove a short distance of just over 13 feet (4 meters) to get onto that lily pad.

    The plan ahead is to collect more imagery from this location of the morphology (the shape) of Perseverance Valley, recharge some, and move on to the next lily pad.

    As of Sol 4834 (August 29, 2017), the solar array energy production was 279 watt-hours with an atmospheric opacity (Tau) of 0.608 and a solar array dust factor of 0.507.

    Total odometry is 27.97 miles (45.02 kilometers)."

    Landing sites

    Visit the Mars Exploration Rover page.

    Mars Reconnaissance Orbiter Mission - July 14, 2017
    For Moratorium on Sending Commands to Mars, Blame the Sun

    Full Article & Image

    "This month, movements of the planets will put Mars almost directly behind the sun, from Earth's perspective, causing curtailed communications between Earth and Mars.

    NASA will refrain from sending commands to America's three Mars orbiters and two Mars rovers during the period from July 22 to Aug. 1.

    "Out of caution, we won't talk to our Mars assets during that period because we expect significant degradation in the communication link, and we don't want to take a chance that one of our spacecraft would act on a corrupted command," said Chad Edwards, manager of the Mars Relay Network Office at NASA's Jet Propulsion Laboratory, Pasadena, California."

    All of the HiRISE images are archived here.

    More information about the MRO mission is available online.

    Mars Odyssey Orbiter -

    Pathfinder 360

    "Mars Pathfinder was launched December 4, 1996, and landed on Mars' Ares Vallis on July 4, 1997. The lander was NASA's first to bring a rover to explore the Red Planet. Together, they surveyed a world that may once have been wet and warm like Earth. Now you, too, can land on Mars and explore on your desktop, smartphone, tablet or 360 virtual reality (VR) viewer."

    Daily Mars Odyssey THEMIS Images
    Can be found at the Thermal Emission Imaging System (THEMIS) website.

    The Odyssey data are available through a new online access system established by the Planetary Data System.

    Visit the Mars Odyssey Mission page.

    Journey to Mars - August 28, 2017
    NASA's Next Mars Mission to Investigate Interior of Red Planet

    Full Article and Images

    "Preparation of NASA's next spacecraft to Mars, InSight, has ramped up this summer, on course for launch next May from Vandenberg Air Force Base in central California -- the first interplanetary launch in history from America's West Coast.

    Lockheed Martin Space Systems is assembling and testing the InSight spacecraft in a clean room facility near Denver. "Our team resumed system-level integration and test activities last month," said Stu Spath, spacecraft program manager at Lockheed Martin. "The lander is completed and instruments have been integrated onto it so that we can complete the final spacecraft testing including acoustics, instrument deployments and thermal balance tests."

    InSight is the first mission to focus on examining the deep interior of Mars. Information gathered will boost understanding of how all rocky planets formed, including Earth."

    Learn more about the InSight Mission.

    Mars Missions Status

    New Mars missions are being planned to include several new rover and sample collection missions. Check out the Mars Missions web page and the Mars Exploration page.

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    Astronomy Links and Other Space News

    (If you have a link you would like to recommend to our readers, please feel free to submit it.)

    Green Laser

    Colorado Astronomy Links

    Radio Astronomy Links

    Other Astronomy Links

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    Astronomical Lexicon

    Definitions of astronomical terms. Many of the astronomical terms used in this newsletter are defined here.

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    UT Logo

    Read the Universe Today Newsletter by clicking on the logo.

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    Acknowledgments and References

    Much of the information in this newsletter is from Astronomy® Magazine (Kalmbach Publishing), JPL mission status reports, the Internet, "Meteor Showers - A descriptive Catalog" by Gary W. Kronk, Sky & Telescope web pages, and other astronomical sources that I have stashed on my bookshelves.

    The author will accept any suggestions, constructive criticisms, and corrections. Please feel free to send me any new links or articles to share as well. I will try to accommodate any reasonable requests. Please feel free to send questions, comments, criticisms, or donations to the email address listed below. Enjoy!

    More Acknowledgements and References

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