Week of May 5, 2014

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, May 5.  All times are given as local St. Louis time (Central Daylight Time).  For definitions of terminology used in the night sky update, click the highlighted text.

Information updated weekly or as needed.

Join us for our next star party, Friday, June 6, 2014 held in association with the St. Louis Astronomical Society. For details, see the information at the bottom of this page.

The Sun and the Moon

Sunrise is at 5:59 a.m. on Monday, May 5 and sunset is at 7:57 p.m. providing us with nearly 14 hours of daylight.  Even after sunset, the light from the Sun will still illuminate our sky for about one hour and 30 minutes.  This period of time is called twilight, which ends around 9:39 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 12:58 p.m. this week. 

Moonrise for Monday, May 5 occurs at 11:18 a.m.  Moonset will occur at 1:18 a.m. on the following day.  On Monday the 5th the Moon will be exhibiting a waxing crescent phase with roughly 37% of the lunar disk illuminated.  First quarter moon will occur on the evening of May 6.    

International Space Station (ISS) Observing

There are no visible ISS passes this week.  The next visible pass of ISS from St. Louis will be on Tuesday May 13, 2014.  There are a number of visible passes of Tiangong 1 this week.  The best occur on the mornings of May 7, 9 and 12.  Use the table below to learn about these passes.

Catch Tiangong 1 flying over St. Louis in the morning hours starting Monday, May 5. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

07 May

 1.9

04:19:15

31

NW

04:20:08

41

N

04:22:57

10

ENE

09 May

 2.1

05:14:09

10

WNW

05:16:58

41

N

05:19:47

10

E

12 May

 0.8

05:02:06

10

WNW

05:05:03

83

SSW

05:07:59

10

ESE

Magnitude (Mag): The Measure of brightness for a celestial object.  The lower the value is, the brighter the object will be.

Altitude (Alt):  The angle of a celestial object measured upwards from the observer’s horizon.

Azimuth (Az):  The direction of a celestial object, measured clockwise from an observer’s location with north being 0°, east being 90°, south being 180° and west being 270°.

For information about ISS flyovers and other visible satellites, visit www.heavens-above.com

Detailed information regarding all unmanned exploration of our universe, missions past, present, and planned, can be found at Jet Propulsion Laboratories:

http://www.jpl.nasa.gov/

The Planets Visible Without A Telescope

Venus

Venus is now well within its current morning apparition. It rises around 4:21 a.m. becoming easily visible by 5:00 a.m.  For those awake at this time you will see Venus in the southeast and Saturn southwest.  This planetary display nicely represents the path that the planets, Sun and Moon follow.  This path is called the ecliptic.  Take a look at Venus through a telescope and you will see it is phased much like the Moon.  Venus is currently exhibiting a gibbous phase with roughly 60% of the Venusian disk illuminated.

Mars

Mars is now in the constellation Virgo and rises before the Sun sets.  For those awake around 9:00 p.m. look to the east and you will see a reddish-orange object high in the southeastern skies.  We have now passed by Mars in our orbit and will continue to move further away each day.  Views of the surface of Mars will be progressively more difficult as we move further away from Mars.  Take a look at the red planet now for it will be another 26 months before we get this opportunity again. 

Jupiter

Jupiter is now rising as the Sun is setting.  Look straight up roughly 30 minutes after sunset and you should see Jupiter shining brighter than any star in the sky.  As twilight fades you will see the bright stars Castor and Pollux just east of Jupiter.  Looking at these stars and then comparing them to Jupiter you will see that the stars are twinkling and Jupiter is not.  The twinkling you see is called scintillation which is a distortion of the stars light by Earth’s atmosphere.  Testing for scintillation is how you can distinguish stars from planets. 

Saturn

Saturn rises by 8:10 p.m. and will be an easy target by 9:00 p.m.  Saturn is currently in the constellation Libra.  It forms a nice triangle in the sky with Libra’s two brightest stars Zubenelgenubi and Zubeneschamali.  If you watch Saturn in relation to these two stars you will notice it is exhibiting retrograde motion.  This is caused as the Earth catches up with a planet and then passes it by.  During this we see the planet from changing angles making it appear to move westward and then eastward again.  This motion is more prevalent with planets closer to us such as Mars.  If you go outside once a week for the rest of the year and sketch where Saturn is in relation to Zubenelgenubi and Zubeneschamli you will see this retrograde motion.  As retrograde motion is occurring that also means we are approaching another opposition with Saturn.  This occurs on May 10th 2014.  As we approach this date Saturn will continue to get brighter in the sky. 

Constellation of the Month

Each month we will highlight one constellation and some of the objects that can be found within the boundaries of that constellation.  At the start of the month we will list only a few of these objects and each week we will add another to the list.  Some objects will be visible to the unaided eye and some may require a telescope.  Many of the objects listed will require a map of the sky to find or may require repeat observations to notice various properties.  Links to star charts and other information that will be useful in identifying the objects listed will be given at the end of each week’s section. 

This month we will change things up again and cover more than one constellation.  We tend to spend time with the big bright constellations as they are easy to find and offer up numerous objects to look for.  There are a number of smaller less frequented constellations that are worth finding but may not have enough to cover an entire month.  We will explore some of these constellations through the month of May.

The first constellation we will cover this month is Corvus the Raven.  According to Greek mythology Corvus was the raven that Apollo sent to collect the water of life.  On his journey Corvus found a fig tree and waited for the fruit to ripen.  Eventually Corvus made his way back to Apollo and explained his tardiness by claiming a water serpent delayed him.  As Apollo is seen as the god of truth and prophecy he knew Corvus was lying and threw Corvus, the goblet and the serpent in to the sky.  We see them every spring as the constellations Corvus, Crater and Hydra.

Corvus is a small constellation that contains only six bright stars visible in city skies.  These stars range in brightness from 2.5 to 4.3 magnitude.  All of these stars have Bayer designations with the brightest being Gamma Corvi.  To find Corvus first find the Big Dipper located in Ursa Major.  Follow the curve of the dipper’s handle down to the bright red star Arcturus in Bootes and then to the next brightest star Spica in Virgo.  Continuing to follow the curve will bring you to Corvus just below Spica.  Below you will find maps for Corvus and each of the constellations used to find Corvus.

http://www.iau.org/static/public/constellations/gif/CRV.gif

http://www.iau.org/static/public/constellations/gif/BOO.gif

http://www.iau.org/static/public/constellations/gif/VIR.gif

http://www.iau.org/static/public/constellations/gif/UMA.gif

The main object I will recommend looking for in Corvus is the third brightest star in the constellation named Algorab or Delta Corvi.  This is a bright B class yellow-white star that shines with a magnitude of 2.94 making it easily visible to the unaided eye.  With a small telescope and a pair of astronomical binoculars you can split Delta Corvi into two stars.  The pair of stars is separated by 650 AU and would take about 9400 years to orbit one another.  The secondary star, Algorab B, is a K-class star that will have an orange color and shines with a magnitude of 8.5.  At this magnitude you will need good viewing conditions to split the pair with binoculars.  This star is of interest as there is a high amount of infrared radiation associated with it.  This is indicative of a large cloud of dusty material associated with the star.  Stars from when dust and gas collapse until eventually there is enough temperature and pressure that hydrogen fusion begins.  The leftover material collapses into a disk surrounding the star.  This disk of material is what planets and other solar system objects form from.  Stars that have this disk of dusty material surrounding them have a high amount of infrared light present in their spectrum.  These young stars are called T Tauri stars and Algorab B is one of them.    

To find Algorab and its companion look for the cut diamond shape of Corvus.  The northernmost bright star in this shape is Algorab.  The pair of stars will be separated by 24.2 arc seconds and the fainter star will have a position angle of 218 degrees.

http://www.iau.org/static/public/constellations/gif/CRV.gif

Also of interest is the pair of galaxies known as the Antennae Galaxies.  The two galaxies that make up this pair are named NGC 4038 and NGC 4039.  These two galaxies are in the process of colliding and have distorted the shape of one another.  They have also induced immense gravitational waves in one another that sparked furious rates of star formation.  Areas that exhibit high rates of star formation glow the telltale pinkish color of ionized hydrogen.  Reference the Hubble article for detailed views of this process.  This merging of galaxies is a future look of what will happen in roughly 4 billion years when our galaxy the Milky Way and its largest neighbor the Andromeda galaxy collide. 

These two galaxies can be found about halfway between the two bright stars Gamma Corvi and Epsilon Corvi.  Unfortunately both galaxies are in the 11th magnitude range making them tough pull for telescopes under 8 inches in aperture.  For those that cannot observe these galaxies from their backyard you can always enjoy the Hubble views made available through the Hubble archives.  Below you will find a link to these archives.

http://heavens-above.com/passdetails.aspx?lat=38.627&lng=-90.1994&loc=St.+Louis&alt=141&tz=CST&satid=37820&mjd=56789.4201773727&type=V 

Our next Star Party will be held on Friday, June 6, 2014, from dusk until 10 p.m.

Weather permitting, the St. Louis Astronomical Society and the ScienceCenter will set up a number of telescopes outdoors and be on-hand to answer your questions.  Telescope viewing begins at 8:00 p.m.  Regardless of the weather on June 6, join us indoors in our planetarium theater for “The Sky Tonight”.  Showtime is at 7 p.m. 

This free, indoor star program will introduce you to the current night sky, the planets, and the seasonal constellations. Doors open 15 minutes before show time. Shows begins at 7 p.m. Sorry, no late admissions due to safety issues in the darkened theater.

The St. Louis Astronomical Society hosts the monthly Star Parties at the Science Center which are held on the first Friday of each month. Our Monthly Star Parties are open to the public and free of charge.  For more information about the St. Louis Astronomical Society visit their website at www.slasonline.org

Add new comment