Image: Sky map, Mercury, Venus, crescent moon
Starry Night Software
At sunrise on Thursday Aug. 16, Mercury and Venus are both as far from the sun in the sky as they can get. The crescent moon will help you to find Mercury.
By Starry Night Education
updated 8/15/2012 8:20:17 PM ET 2012-08-16T00:20:17

Both Mercury and Venus travel in orbits closer to the sun than we do on Earth. As a result we always need to look towards the sun to see them, and the planets never wander far from our nearest star as viewed from Earth.

As the brightest object in the sky after the sun and moon, Venus is hard to miss. Ever since Venus transited the sun on June 5, it has been shining like a brilliant beacon in our morning sky. It will continue to be a “morning star” until the end of the year.

Mercury is smaller, fainter, and closer to the sun, so is much harder to see. Many skywatchers go through their entire lives without ever seeing this elusive planet. Thursday morning, Aug. 16, is one of the rare opportunities when you can catch a glimpse of Mercury.

Two things make this possible. First, Mercury is at its greatest distance from the sun. Secondly, it will be close to the thin crescent moon, which will provide a guideline to lead you to it.

  1. Space news from NBCNews.com
    1. KARE
      Teen's space mission fueled by social media

      Science editor Alan Boyle's blog: "Astronaut Abby" is at the controls of a social-media machine that is launching the 15-year-old from Minnesota to Kazakhstan this month for the liftoff of the International Space Station's next crew.

    2. Buzz Aldrin's vision for journey to Mars
    3. Giant black hole may be cooking up meals
    4. Watch a 'ring of fire' solar eclipse online

In the sky map accompanying this guide, the time has been set to sunrise, but if you actually wait until sunrise it will probably be too late to see Mercury. [Planets in August Night Sky (Sky Map Gallery)]

Because Mercury is a tiny speck of light in a brightening dawn sky, there is only a narrow window of opportunity to spot it. It must be high enough above the horizon to be above the haze that usually obscures our view at low altitudes, but it must also be spotted before the sky becomes flooded with light from the sun.

The best time is about an hour to half an hour before sunrise. Most planetarium software programs will tell you the exact time of sunrise at your location, which is what you need to pin down this time. Get the time of sunrise, subtract an hour, and start watching close to the horizon.

Binoculars are a valuable aid in spotting Mercury. Focus them carefully on the moon or Venus, and then carefully sweep back and forth along the horizon just to the right of where the sun will rise. Use Venus and the moon to narrow down your search area.

Once you spot Mercury in binoculars and get your bearings on the horizon, it becomes surprisingly easy to see with your naked eye.

This is also a rare opportunity to get a sense of the structure of the inner solar system. Mercury is at its maximum westward extension from the sun. By coincidence, Venus is also just a day past its maximum westward extension. Once you’ve spotted Mercury and Venus, and have a sense of where the sun lies just below the horizon, you have an exact picture of the orbits of these two planets around the sun. In particular, you can see how much closer Mercury orbits around the sun than does Venus.

If you have a telescope, take a look at these two planets. Because of the geometry of their being at greatest elongation, both are also close to the “half moon” phase, 50 percent illuminated by the sun. In a telescope you will see that Venus is three times larger than Mercury: 24 arcseconds in diameter as opposed to 8 arcseconds.

If you miss Mercury Thursday morning, you will still have a chance to see it over the next few days, but it will be harder to find because the moon will have moved on, and will no longer serve as a guide.

Editor's note: If you snap an amazing photo Venus or Mercury that you'd like to share for a possible story or image gallery, send images and comments (including name and location) to managing editor Tariq Malik at tmalik@space.com.

This article was provided to SPACE.com by Starry Night Education, the leader in space science curriculum solutions. Follow Starry Night on Twitter @StarryNightEdu.

© 2013 Space.com. All rights reserved. More from Space.com.

Photos: Month in Space: January 2014

loading photos...
  1. Southern stargazing

    Stars, galaxies and nebulas dot the skies over the European Southern Observatory's La Silla Paranal Observatory in Chile, in a picture released on Jan. 7. This image also shows three of the four movable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: They reveal details that would otherwise be visible only through a telescope as large as the distance between them. (Y. Beletsky / ESO) Back to slideshow navigation
  2. A balloon's view

    Cameras captured the Grandville High School RoboDawgs' balloon floating through Earth's upper atmosphere during its ascent on Dec. 28, 2013. The Grandville RoboDawgs’ first winter balloon launch reached an estimated altitude of 130,000 feet, or about 25 miles, according to coaches Mike Evele and Doug Hepfer. It skyrocketed past the team’s previous 100,000-feet record set in June. The RoboDawgs started with just one robotics team in 1998, but they've grown to support more than 30 teams at public schools in Grandville, Mich. (Kyle Moroney / AP) Back to slideshow navigation
  3. Spacemen at work

    Russian cosmonauts Oleg Kotov, right, and Sergey Ryazanskiy perform maintenance on the International Space Station on Jan. 27. During the six-hour, eight-minute spacewalk, Kotov and Ryazanskiy completed the installation of a pair of high-fidelity cameras that experienced connectivity issues during a Dec. 27 spacewalk. The cosmonauts also retrieved scientific gear outside the station's Russian segment. (NASA) Back to slideshow navigation
  4. Special delivery

    The International Space Station's Canadian-built robotic arm moves toward Orbital Sciences Corp.'s Cygnus autonomous cargo craft as it approaches the station for a Jan. 12 delivery. The mountains below are the southwestern Alps. (NASA) Back to slideshow navigation
  5. Accidental art

    A piece of art? A time-lapse photo? A flickering light show? At first glance, this image looks nothing like the images we're used to seeing from the Hubble Space Telescope. But it's a genuine Hubble frame that was released on Jan. 27. Hubble's team suspects that the telescope's Fine Guidance System locked onto a bad guide star, potentially a double star or binary. This caused an error in the tracking system, resulting in a remarkable picture of brightly colored stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288. (NASA / ESA) Back to slideshow navigation
  6. Supersonic test flight

    A camera looking back over Virgin Galactic's SpaceShipTwo's fuselage shows the rocket burn with a Mojave Desert vista in the background during a test flight of the rocket plane on Jan. 10. Cameras were mounted on the exterior of SpaceShipTwo as well as its carrier airplane, WhiteKnightTwo, to monitor the rocket engine's performance. The test was aimed at setting the stage for honest-to-goodness flights into outer space later this year, and eventual commercial space tours.

    More about SpaceShipTwo on PhotoBlog (Virgin Galactic) Back to slideshow navigation
  7. Red lagoon

    The VLT Survey Telescope at the European Southern Observatory's Paranal Observatory in Chile captured this richly detailed new image of the Lagoon Nebula, released on Jan. 22. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of 11 public surveys of the sky now in progress using ESO telescopes. (ESO/VPHAS team) Back to slideshow navigation
  8. Fire on the mountain

    This image provided by NASA shows a satellite view of smoke from the Colby Fire, taken by the Multi-angle Imaging SpectroRadiometer aboard NASA's Terra spacecraft as it passed over Southern California on Jan. 16. The fire burned more than 1,863 acres and forced the evacuation of 3,700 people. (NASA via AP) Back to slideshow navigation
  9. Where stars are born

    An image captured by NASA's Spitzer Space Telescope shows the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This false-color infrared view, released on Jan. 15, spans about 40 light-years across the region. The brightest portion of the nebula is centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But Spitzer also can detect stars still in the process of formation, seen here in red hues. (NASA / JPL-Caltech) Back to slideshow navigation
  10. Cygnus takes flight

    Orbital Sciences Corp.'s Antares rocket rises from NASA's Wallops Flight Facility on Wallops Island, Va, on Jan. 9. The rocket sent Orbital's Cygnus cargo capsule on its first official resupply mission to the International Space Station. (Chris Perry / NASA) Back to slideshow navigation
  11. A long, long time ago...

    This long-exposure picture from the Hubble Space Telescope, released Jan. 8, is the deepest image ever made of any cluster of galaxies. The cluster known as Abell 2744 appears in the foreground. It contains several hundred galaxies as they looked 3.5 billion years ago. Abell 2744 acts as a gravitational lens to warp space, brightening and magnifying images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang. (NASA / NASA via AFP - Getty Images) Back to slideshow navigation
  12. Frosty halo

    Sun dogs are bright spots that appear in the sky around the sun when light is refracted through ice crystals in the atmosphere. These sun dogs appeared on Jan. 5 amid brutally cold temperatures along Highway 83, north of Bismarck, N.D. The temperature was about 22 degrees below zero Fahrenheit, with a 50-below-zero wind chill.

    Slideshow: The Year in Space (Brian Peterson / The Bismarck Tribune via AP) Back to slideshow navigation
  1. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  2. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  3. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  4. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

Discuss:

Discussion comments

,

Most active discussions

  1. votes comments
  2. votes comments
  3. votes comments
  4. votes comments