Curious about Curiosity?

Curiosity is scheduled to land on Mars on August 6, 2012.  Live coverage is available online beginning August 5, 2012, 10:30pm PDT.  The rover’s mission is to learn whether Mars ever has or is still able to support microbial life.

The rover Opportunity is in its ninth year!  Spirit and Opportunity landed on Mars in 2004 and found evidence of a past wet environment.  Opportunity has exceeded all expectations by continuing beyond its original several month mission.

One of the challenges rovers face on Mars is just getting there.  Entry and landing must occur within six minutes, within which time the spacecraft must slow down from 12,000 mph to zero.



Ursa Major (The Great Bear)

Ursa Major, the Great Bear, is the third largest constellation in the night sky.  It contains the most famous asterism, “The Big Dipper.”  An asterism is a group of stars within a constellation that are notable in and of themselves, but do not complete the constellation.

Ursa Minor, the Little Bear, or Little Dipper, contains the North Star, Polaris.  Both constellations are found among the North Circumpolar stars.

If you are viewing from the northern hemisphere, try to find both constellations in your night sky on an evening with exceptionally good visibility.  On any evening when at least some stars are visible, try to find the asterism, the Big Dipper.  Enjoy!!  

Castor and Pollux

Constellation Gemini

Two of the brightest stars in the evening sky are found in the constellation Gemini:  Pollux, visible as a bright orange star and Castor, a smaller, more distant cluster of stars.  Although Castor is labeled alpha Geminorum (α gem) and Pollux labeled beta Geminorum (β gem), it is actually Pollux, the red giant, that is the brightest of the two with a magnitude of 1.16.  Castor’s magnitude is 1.58.

A star’s brightness can be measured in several ways.  Magnitude is one way to measure brightness. This system was devised by the ancient Greeks, who arranged the stars into six groups based on their visible brightness.   The system was later refined in the 19th century rather than abandoned and includes groups ranging from negative numbers to higher positive numbers, inclusive of zero.  A lower magnitude indicates a brighter star.  For example, the sun’s magnitude is -26.74.  Vega’s magnitude is 0.03

The groups are referred to as the 1st magnitude, 2nd magnitude, 3rd magnitude and so on. Each magnitude is approximately 2.512 times greater than the next.  A star of first magnitude is 2.512 times greater than a star of 2nd magnitude.  A star of first magnitude is (2.512-squared) times greater than a star of 3rd magnitude.  A star of first magnitude is (2.512-cubed) times greater than a star of 4th magnitude and so on.  Note that the difference between magnitudes, (2-1=1, 3-1=2, 4-1=3 and so on) is the power to which you raise 2.512.

Referred to as the Twins in Greek mythology, their mother was Leda and they had different fathers.  Castor was mortal, unlike Pollux, and when Castor died, the two were united in the sky at Pollux’s request to his father, the god Zeus.  Castor’s father, King Tyndarus of Sparta, was mortal.  According to myth, they also had a sister, Helena, whose capture later in life led to the Trojan wars.  Although the twins were born out of misery and deceit, their love for one another was strong and pure.

* Of note, one of the most prominent meteor showers, the geminids, radiates from this constellation and can be viewed December through January.

Finding the constellation Gemini in the evening sky is easy to do, at least finding the two brightest stars is relatively easy. However, it can be difficult to locate the other stars in the constellation without a telescope and very clear conditions.  Gemini is located between Cancer, Auriga and Canis Minor. Refer to the Solar System Scope to find the constellation. (See also blog post dated March 9, 2012).

The Pleiades Star Cluster

Observed and noted throughout the centuries, Pleiades is a group of very brights stars located outside of our solar system, of which over a dozen can be seen during maximum viewing without the aid of a telescope.  Under moderate viewing conditions anywhere from six to nine can be seen.  Modern technology has detected over 500 stars belonging to this star cluster. It’s technical name is Messier 45 (M45).

Pleiades has been mentioned in numerous historical writings, including notable works by Homer: the Iliad  (about 750 BC) and the Odyssey (about 720 BC). Pleiades has also been mentioned in two books of the Bible: Job (about 750 BC) and Amos (about 1,000 BC although there are differing scholarly views on the date that Amos was written).  The exact locations in the Bible are: Job 9:7-9, Job 38:31-33, and Amos 5:8.

The Pleiades has also been named “The Seven Sisters,” a reference to the Greek mythology surrounding the seven daughters of Atlas and Pleione. In Japanese the Pleiades are known as Subaru, for which the automobile was named.

The seven sisters are Maia, Electra, Taygete, Alcyone, Celaeno, Sterope (Asterope) and Merope.  Below is a map of the nine most visible stars within the star cluster Pleiades, named after the Greek Mythology surrounding the Seven Sisters:

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The Pleiades are visible above and to the right of the Constellation Orion, just beyond the Constellation Taurus. Follow the line of Orion’s belt, the three stars in the middle of the constellation, upward to a sideways “V” shape of Taurus (this “V” shape forms the head of the bull). Just beyond, following the same line, is the Pleiades star cluster.  About 6 will be visible under ordinary viewing circumstances and up to 9 on a very clear, dark night sky, either with binoculars, a low power telescope or star gazing. For more general directions (with charts, photos and maps) and also a telescope setting see e-How. For general directions with information also about the Constellation Taurus, see EarthSky.  For more scientific information on the Pleiades see Messier Catalog entry for Pleiades/M45 and also Seven Gibson’s website, which is affiliated with the National Astronomy and Ionosphere Center.


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More about Jupiter and Venus

Jupiter and the recent Juno and earlier Voyager Missions

Jupiter is the largest planet in the solar system.  One of its notable features is the Great Red Spot.  Another is its four large moons and other smaller moons, almost as if it is its own solar system.  Read more here from NASA about Jupiter and its four large moons, Io, Gannymead, Europa and Callisto, also known as the Galilean satellites.

Here is a picture, not to scale, of Jupiter and its four largest moons.  Below it is a picture of the Great Red Spot using false colors. Both the Great Red Spot and the montage of Jupiter and its four largest moons were assembled from photographs taken by Voyager I in 1979, collected at NASA’s Photo Gallery.

NASA’s Juno mission began in August, 2011 and is scheduled to conclude in 2016.  Juno’s mission is to learn more about the early history of our solar system.


Venus is shrouded in clouds, but not the water-vapor clouds of the Earth. Venus has clouds that are made of sulfuric acid. These clouds permanently shroud Venus’ volcanic surface.

Here is an ultraviolet photograph of Venus taken in 1995 by the Hubble Space Telescope.  Below it are five surface views of Venus taken during the Magellan mission (1989-1994).  Both photos can be found at NASA’s Photo Gallery. For more information on the five globes, see the caption provided by NASA Photo Gallery.

When viewing Jupiter and Venus in the evening sky, Jupiter is the brightest of the two – a magnificent duo!  See 3/9/12 post for the Solar System Scope and information on how to use it to find Jupiter, Venus and the nearby Constellation Orion in your night sky.

Mars and the Constellation Leo

Mars is one of several observable planets in the night sky. The reddish planet shines brightly adjacent to the constellation Leo. Take a look at your Planisphere or the online Solar System Scope to find the location and time that Mars and the constellation Leo are visible on a clear night in your night sky. See 3/9/12 post below for a suggestion on how to best use the Solar System Scope.

The Constellation Leo

This photo was obtained from a scientific blog on 3/21/12, where you will also find other information about the constellation, its stars and deep sky objects.

An asterism, a recognizable shape found within a constellation, exists in Leo: the Sickle. The sickle in Leo is one of the most famous star patterns found in springtime, forming the head and mane of the lion.  Alpha Leo, called Regulus, sits at the base of the Sickle, the heart of the lion, and is the brightest star in Leo. You will also be able to easily find beta Leo, another bright star called Denebola that is the tail of the lion.

The Planet Mars

Here is an image from the Viking 1 mission (1975-1981).

For more information on the Viking 1 and 2 missions visit NASA’s website on the Viking Missions.

Here is an image from 1999. Four views of the planet with caption provided.

Other Mars photos and information you might enjoy:

Photo Source: The photos above are found on NASA’s Photo Gallery webpage for Mars.

Star Charts, Planispheres and something new…

Here’s a fun find. Try out an online Solar System Scope! 

On the left you will see a series of icons:

  1. The top two pertain to your cursor.
  2. The middle button is called “View Selection.”  Select the telescope view. 
  3. The last two buttons are “Settings” and a portal that is under construction.
  4. Under “Settings” you have Planets and Moons, Stars and Constellations, Earth Observatory, Time Settings and a Reset button.  Select Earth Observatory. Then select the City that is closest to you.  You may also wish to check Time Settings. Your current time zone and hour may be pre-selected. If not, you can reset it.  For fun, try out the different settings under Planets and Moons, and Stars and Constellations.  These settings will give you the amount of information you wish to have viewable when using the scope and can be set and reset as you like.

Now you are ready to use the Solar System Scope!

  • For a first look at the sky find Orion, Jupiter and Venus!  Determine when any one or all three are viewable in your night sky. Note that when viewing Jupiter and Venus, near Orion, Venus is the biggest and the brightest in the evening sky. Enjoy!
“What a great addition to your existing star map or Planisphere!”