Astronomy News for the Month of April 2017

    This news letter is provided as a service by
The International Association for Astronomical Studies
provides this newsletter as a service for interested persons worldwide.

Downloadable version of the newsletter in
PDF Format
(Right click and select "Save target as" to begin download.)
(Always check the PDF link above if the web page is not updated.
I always publish the PDF before I upload the web page.)
PDF updated 1st of every month!

Visit the Home Page of KIØAR

Subscribe to the
IAAS Monthly Astronomy Newsletter

(Email version)

Subscription notes below.

Web and email hosting by

TotalChoice Hosting

Locations of Site Visitors
Create your own visitor map!

An Open Invitation

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).

Interested in obtaining your Amateur Radio (Ham) License or your General Radio Operator's Licence (GROL)? Visit the South Metro VE Team website for more information. The South Metro VE Team provides test sessions on the 1st Saturday of each month at our new Eagle Street Facility, The City of Centennial, 7272 South Eagle Street, Centennial, Colorado 80112-4244 from 9am until 1pm.

The Colorado Astronomy Net is now on Facebook.
Please be sure to "Like" us!

 Excerpts from JPL mission updates are provided as a public service as part
of the JPL Solar System Ambassador/NASA Outreach program.

For special JPL programs and presentations in your area visit the JPL Solar System Ambassador website.
(Click on the logo to link to the JPL SSA homepage.)

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.

Solar Eclipse 2017
August 21, 2017
Links and Information

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

18 day moon

The Moon



Moon/Planet Pairs

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

Return to Top

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 April

"Mercury, Mars, and the Moon will delight evening observers in early April. The three create a fine prelude for the month’s "star" performer, Jupiter. The solar system's largest planet reaches peak visibility in April and remains visible throughout the night. As Jupiter dips low in the west before dawn, early risers can enjoy nice views of ringed Saturn in the south while brilliant Venus dominates the east." Astronomy Magazine, April 2017, p. 36.


Is at greatest eastern elongation (19° to the west of the Sun) on the 1st. Mercury is stationary on the 9th. Mercury is in inferior conjunction on the 20th. Look for Mercury in the west just after sunset during the first week of April. After that, Mercury will be a bit more difficult to spot until it swings into the morning sky during the last week of the month. Mercury sets at 9:03 p.m. on the 1st. Mercury rises at 5:24 a.m. on the 30th. Mercury moves from the constellation of Aries into Pisces this month shining at magnitude -0.2 on the 1st.


Is stationary on the 12th. Venus is at greatest brilliancy (magnitude -4.7) on the 29th. Venus rises at 5:44 a.m. on the 1st and about 4:17 a.m. by month's end. Look for Venus in the early morning towards the east before sunrise. Venus is in the constellation of Pisces shining at magnitude -4.7 on the 15th.




Sets at 10:15 p.m. on the 1st and about 10:03 p.m. by month's end. Look for Mars about 30 minutes or so after sunset to the west. Mars moves from the constellation of Aries into Taurus shining at magnitude 1.5.


Is at opposition on the 7th, rising as the Sun sets. On this day, Jupiter peaks at magnitude -2.5. Jupiter rises at 7:47 p.m. on the 1st and about 5:31 p.m. by month's end. Look for Jupiter in the evening to the east and follow Jupiter across the night sky into early morning to the west before sunrise. Jupiter is in the constellation of Virgo shining at magnitude -2.5.


Is stationary on the 6th. Saturn rises at 1:26 a.m. on the 1st and about 11:22 p.m. by month's end. Saturn is visible in the early morning sky before sunrise to the southeast. Saturn is in the constellation of Sagittarius shining at magnitude 0.3.


Is in conjunction with the Sun on the 14th. Uranus sets at 8:18 p.m. on the 1st and about 6:29 p.m. by month's end. Uranus is lost in the evening and morning twilight glow this month and is not visible this month. Uranus is in the constellation of Pisces shining at magnitude 5.9.


Neptune will be returning to the morning skies at the end of the month but will only be several degrees above the eastern horizon in the dawn twilight and difficult to spot. Neptune is in the constellation of Aquarius shining at magnitude 7.9.

Dwarf Planets


Sets at 11:20 p.m. on the 1st and about 10:23 p.m. by month's end. Ceres is visible in the early evening this month. Ceres moves from the constellation of Aries into Taurus shining at magnitude 9.0.


Is stationary on the 20th. Pluto rises at 2:54 a.m. on the 1st and about 12:56 a.m. by month's end. Pluto is visible in the early morning skies before sunrise. 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.

Return to Top

Astronomical Events

Meteor Showers

  • The Lyrids [meteor showers] are typically visible between April 16 and 25. Maximum occurs during April 21-22. Although the maximum rate is about 10, there have been instances during the last 200 years when rates were near or over 100 per hour. The average magnitude of the meteors is near 2.4 and the speed is described as rapid. About 15% of the meteors leave persistent trains.

    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 41P/Tuttle-Giacobini-Kresak could possibly reach 5th magnitude this month as it passes through the constellation of Draco the Dragon between Ursa Major and Ursa Minor. For northern observers, this region of sky is visible all night long. Comet 41 passes closest to Earth on the 1st and closest to the Sun on the 13th. However, predictions about comet brightness can be "should I say it?" unpredictable :). Conservative predictions are around 8th magnitude and optimistic predictions are around 5th magnitude. Use binoculars to find the comet and then if you are under dark skies, try to see if you can spot Comet 41 with your unaided eyes. The best views will be during the first week in the morning skies before dawn and during the last two weeks of the month in the evening skies when the Moon is not present.

  • Comet Johnson (C/2015 V2) is in the constellation of Hercules north of Corona Borealis.
  • Comet PANSTARRS (C/2015 ER61) passes from the constellation of Capricornus east through Aquarius.

  • 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

  • Observe Mercury and Mars in the early evening after sunset.
  • Enjoy Jupiter all night long.
  • Look for Saturn morning skies before sunrise.
  • Try to spot Comet 41P/Tuttle-Giacobini-Kresak in Draco.
  • Try to spot some of the Lyrid meteors after mid-month.

  • Asteroids

    (From west to east)
    • Vesta is in the constellation of Gemini.
    • Irene, Psyche and Amphitrite are in the constellation of Leo.

    • 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.
  • Return to Top

    Subscriber Gallery

    Return to Top

    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

    Return to Top

    Planetary/Lunar Exploration Missions

    (Excerpts from recent JPL mission updates)
    JPL Latest News - March 27, 2017
    NASA Selects Mission to Study Churning Chaos in Milky Way and Beyond

    Full Article & Images

    "NASA has selected a science mission that will measure emissions from the interstellar medium, which is the cosmic material found between stars. This data will help scientists determine the life cycle of interstellar gas in our Milky Way galaxy, witness the formation and destruction of star-forming clouds, and understand the dynamics and gas flow in the vicinity of the center of our galaxy.

    The Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO) mission, led by principal investigator of the University of Arizona, Christopher Walker, will fly an Ultralong-Duration Balloon (ULDB) carrying a telescope with carbon, oxygen and nitrogen emission line detectors. This unique combination of data will provide the spectral and spatial resolution information needed for Walker and his team to untangle the complexities of the interstellar medium, and map out large sections of the plane of our Milky Way galaxy and the nearby galaxy known as the Large Magellanic Cloud."

    JPL Latest News

    Juno - March 24, 2017
    NASA's Juno Spacecraft Completes Fifth Jupiter Flyby

    Full Article & Images

    "Updated March 27, 2017 at 1:45 p.m. PDT NASA's Juno mission accomplished a close flyby of Jupiter on Monday, March 27, successfully completing its fourth science orbit.

    All of Juno's science instruments and the spacecraft's JunoCam were operating during the flyby, collecting data that is now being returned to Earth. Juno's next close flyby of Jupiter will occur on May 19, 2017.

    NASA's Juno spacecraft will make its fifth flyby over Jupiter's mysterious cloud tops on Monday, March 27, at 1:52 a.m. PDT (4:52 a.m. EDT, 8:52 UTC).

    At the time of closest approach (called perijove), Juno will be about 2,700 miles (4,400 kilometers) above the planet's cloud tops, traveling at a speed of about 129,000 miles per hour (57.8 kilometers per second) relative to the gas-giant planet. All of Juno's eight science instruments will be on and collecting data during the flyby."

    Juno has successfully orbited Jupiter four times since arriving at the giant planet, with the most recent orbit completed on Feb. 2. Its next close flyby of Jupiter will be March 27."

    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 - March 28, 2017
    Space Ace

    Full Article & Images

    "NASA space scientists and engineers speak in an often bewildering shorthand slang of acronyms to describe complicated jobs, procedures and machines. "NAV" refers to teams of spacecraft navigators. "OTMs" are orbital trim maneuvers to help refine a spacecraft's path. Even NASA is short for National Aeronautics and Space Administration.

    Then there's the Ace: the engineer who monitors and communicates with the spacecraft in real time during big mission events and routine maneuvers.

    It's one of the few jobs that isn't part of NASA's acronym soup. Ace simply means ace, as in a person who excels at their job or the highest value playing card in the deck."

    The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA's Science Mission Directorate in Washington.

    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 - March 23, 2017
    Blue Rays: New Horizons' High-Res Farewell to Pluto

    Full Article & Images

    "This is the highest-resolution color departure shot of Pluto's receding crescent from NASA's New Horizons spacecraft, taken when the spacecraft was 120,000 miles (200,000 kilometers) away from Pluto. Shown in approximate true color, the picture was constructed from a mosaic of six black-and-white images from the Long Range Reconnaissance Imager (LORRI), with color added from a lower resolution Ralph/Multispectral Visible Imaging Camera (MVIC) color image, all acquired between 15:20 and 15:45 UT -- about 3.5 hours after closest approach to Pluto -- on July 14, 2015. The resolution of the LORRI images is about 0.6 miles (1 kilometer) per pixel; the sun illuminates the scene from the other side of Pluto and somewhat toward the top of this image."

    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 - March 22, 2017
    Ice in Ceres' Shadowed Craters Linked to Tilt History

    Full Article & Images

    "Dwarf planet Ceres may be hundreds of millions of miles from Jupiter, and even farther from Saturn, but the tremendous influence of gravity from these gas giants has an appreciable effect on Ceres' orientation. In a new study, researchers from NASA's Dawn mission calculate that the axial tilt of Ceres -- the angle at which it spins as it journeys around the sun -- varies widely over the course of about 24,500 years. Astronomers consider this to be a surprisingly short period of time for such dramatic deviations." 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.

    Pack Your Backpack

    Calling all explorers! Tour JPL with our new Virtual Field Trip site. Stops include Mission Control and the Rover Lab. Your guided tour starts when you select a "face" that will be yours throughout the visit. Cool space images and souvenirs are all included in your visit.

    Past, Present, Future and Proposed JPL Missions -

    Visit JPL's mission pages for current status.

    Return to Top

    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 - March 30, 2017
    MAVEN Reveals Most of Mars' Atmosphere Was Lost to Space

    Full Article & Images

    "Solar wind and radiation are responsible for stripping the Martian atmosphere, transforming Mars from a planet that could have supported life billions of years ago into a frigid desert world, according to new results from NASA's MAVEN spacecraft.

    "We've determined that most of the gas ever present in the Mars atmosphere has been lost to space," said Bruce Jakosky, MAVEN principal investigator from the University of Colorado in Boulder. The team made this determination from the latest results, which reveal that about 65 percent of the argon that was ever in the atmosphere has been lost to space. Jakosky is lead author of a paper on this research to be published in Science on Friday, March 31."

    Visit LASP and MAVEN for more information.

    Mars Science Laboratory - Curiosity - March 28, 2017
    Curiosity Mission Updates
    Sol 1651: Scoop #1 at Ogunquit Beach

    Full Article & Images

    "Sol 1650 activities completed as expected, so it's time to start scooping. Today's plan is focused on acquiring Scoop #1 and dropping off a portion of the sample to SAM. This is the first of four intended scoops at this location, aimed at sampling different grain sizes and their composition. The plan begins with a Mastcam mosaic of "Kennebago Divide" to document some possible layering exposed by the wheel scuff on the right side of the workspace. We'll also take several Mastcam images for change detection to monitor active sand movement. Then the arm backbone starts by retracting the arm and a vibe to clean APXS. After that we'll take a few MAHLI documentation images of the "Flanders Bay" and Scoop #1 locations (prior to scooping), and a very close-up image of the "Avery Peak" ripple crest. Next up, we'll acquire Scoop #1! The sample will be sieved, and the fine-grained portion (<150 microns) will be delivered to SAM. These are all very power intensive activities so there wasn't much room for other science today, but tomorrow's plan should accommodate more activities and context observations. In the meantime, sitting on "Ogunquit Beach" is providing a pretty great view."

    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 (requires Kinect)

      Visit the Mars Science Laboratory page.

    Mars Exploration Rover Mission (Spirit and Opportunity) - March 21, 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: The Dust Storm West of Opportunity is Starting to Abate - sols 4672-4677, March 16, 2017-March 21, 2017:

    "Opportunity is just outside the rim of Endeavour Crater, heading to the gully, named 'Perseverance Valley.'

    The large regional dust storm to the west of the rover's site has started to abate, although there is still a lot of dust in the atmosphere and rover energy levels are affected.

    On Sol 4672 (March 16, 2017), Opportunity drove over 141 feet (43 meters) to the south. Owning to the elevated atmospheric dust, the next sol had to be a recharge sol for the rover to restore charge in the batteries. The tight energy constraints persisted through the 3-sol weekend plan for the rover with only the first sol active with remote sensing and the last two sols used for recharging the batteries. Subsequently, a subtlety in the ground tool power modeling shed some light on the restricted power levels. The ground tool was not properly accounting for the rover's quiet time instead thinking the rover was active and consuming more energy than it really was. This has now been corrected in the tool.

    On Sol 4677 (March 21, 2017), Opportunity drove again to the south covering over 62 feet (19 meters) with the usual post-drive Panoramic Camera (Pancam) and Navigation Camera (Navcam) panoramas. The plan ahead is more driving and remote sensing as Opportunity heads towards 'Perseverance Valley.'

    As of Sol 4677 (March 21, 2017), the solar array energy production was 423 watt-hours with an atmospheric opacity (Tau) of 1.181 and a solar array dust factor of 0.615.

    Total odometry is 27.48 miles (44.23 kilometers)."

    Landing sites

    Visit the Mars Exploration Rover page.

    Mars Reconnaissance Orbiter Mission - March 09, 2017
    NASA Mars Orbiter Tracks Back-to-Back Regional Storms

    Full Article & Image

    "A regional dust storm currently swelling on Mars follows unusually closely on one that blossomed less than two weeks earlier and is now dissipating, as seen in daily global weather monitoring by NASA's Mars Reconnaissance Orbiter.

    Images from the orbiter's wide-angle Mars Color Imager (MARCI) show each storm growing in the Acidalia area of northern Mars, then blowing southward and exploding to sizes bigger than the United States after reaching the southern hemisphere.

    That development path is a common pattern for generating regional dust storms during spring and summer in Mars' southern hemisphere, where it is now mid-summer."

    All of the HiRISE images are archived here.

    More information about the MRO mission is available online.

    Mars Odyssey Orbiter - January 04, 2017
    NASA Mars Odyssey Orbiter Resumes Full Operations

    Full Article and Images

    UPDATED Jan. 4, 2017, at 2 p.m. PST
    NASA's Mars Odyssey spacecraft has resumed full service following recovery after entering a safe standby mode on Dec. 26, 2016.

    The orbiter resumed communication relay assistance to Mars rovers on Dec. 30, 2016. Science observations of Mars by instruments on Odyssey resumed on Jan. 3, 2017, with its Thermal Emission Imaging System, and on the next day with its High Energy Neutral Spectrometer and the Neutron Spectrometer."

    Video - What might it look like if you were walking around on Mars?

    See the Mars As Art Gallery

    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 - September 02, 2016
    InSight - Revealing the Heart of Mars
    NASA Approves 2018 Launch of Mars InSight Mission

    "InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) is a NASA Discovery Program mission that will place a single geophysical lander on Mars to study its deep interior.

    NASA is moving forward with a spring 2018 launch of its InSight mission to study the deep interior of Mars, following final approval this week by the agency's Science Mission Directorate."

    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.

    Return to Top

    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

    Return to Top

    Astronomical Lexicon

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

    Return to Top

    UT Logo

    Read the Universe Today Newsletter by clicking on the logo.

    Return to Top

    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

    Return to Top

    Subscription Information

    Return to Top

    ScienceandNature HomePage

    Return to Top


    Keep looking UP!
    73 from KIØAR

    Return to Top

    Free Web Counters

    Home of KIØAR
    created by Burness F. Ansell, III,
    Email me
    IAAS - COO, Director of Aerospace Technologies
    JPL Solar System Ambassador, Colorado
    last modified: April 01, 2017