Week of February 17, 2014

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, February 17.  All times are given as local St. Louis time (Central Standard 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, March 7, 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 6:49 a.m. on Monday, February 17 and sunset is at 5:41 p.m. providing us with roughly 11 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 7:10 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 12:15 p.m. this week.    

Moonrise for Monday, February 17 occurs at 8:34 p.m.  Moonset will occur at 8:24 a.m. on the following day.  On Monday the 10th the Moon will be exhibiting a waning gibbous phase with roughly 93% of the lunar disk illuminated.  Last quarter moon occurs on February 22.

International Space Station (ISS) Observing

The next visible passes of ISS over St. Louis are all evening passes.  The best passes are on the evenings of February 21 - 24.  Learn more about these passes and others this week in the table below.

Catch ISS flying over St. Louis in the evening hours starting Monday, February 17. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

19 Feb

-1.0

19:32:11

10

NNW

19:33:28

17

N

19:33:28

17

N

20 Feb

-1.3

18:43:36

10

NNW

18:45:50

17

NNE

18:46:47

15

NE

21 Feb

-2.1

19:30:45

10

NW

19:33:01

36

NNW

19:33:01

36

NNW

22 Feb

-2.3

18:41:59

10

NW

18:45:00

31

NNE

18:46:27

21

ENE

23 Feb

-2.7

19:29:32

10

WNW

19:32:47

52

SW

19:32:54

52

SSW

24 Feb

-3.4

18:40:29

10

NW

18:43:49

82

NE

18:46:35

14

SE

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 has started its next morning apparition. It rises around 4:22 a.m. becoming easily visible by 5:30 a.m.  For those awake at this time you will see Venus, Saturn and Mars stretching across the southern skies.  This planetary display nicely represents the path that the planets, Sun and Moon follow.  This path is called the ecliptic.

Mars

Mars is now in the constellation Virgo and will rise around 10:16 p.m. this week.  For those awake around 12:00 a.m. look to the east and you will see a reddish-orange object low in the eastern skies.  Mars will be seen earlier each week as we start to catch up with it in our orbit.  Mars will be close to us again in 2014 reaching opposition on April 8, 2014.  Fans of Mars rejoice it is back and on its way to another close approach.

Jupiter

Jupiter is now rising as the Sun is setting.  For those with a clear eastern horizon look east 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 north 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 is now out of the glare of the Sun.  It rises by 12:31 a.m. and will be an easy target by 1:35 a.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.

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. 

For February the constellation we will highlight is Auriga the Charioteer.  Auriga is the northern most constellation in the asterism known as the Winter Triangle.  The brightest star in Auriga is Capella which is the 6th brightest star in the sky.  This time of the year Auriga has already begun to rise once the Sun has set and will be visible shifting from east to west.  Look for a home plate shaped grouping of stars north of Orion.

One story in Greek myth had Auriga representing Erichthoneus the lame son of Hephaestus and the Mother Earth.  It was believed the Erichthoneus invented the four horse chariot so he could get around easier.  Zeus admired Erichthoneus for his ingenuity and placed him in the heavens for eternity.    

The first object we will explore in Auriga is the open star cluster M37.  This is an open cluster that lies about 4,400 light years away containing roughly 500 stars that are about 300 million years old.  M37 has a Trumpler classification of I,1,r.  This is as good as it gets as this classification means M37 is a (I) bright detached globe of stars, (1) has numerous bright members and (r) has a rich field of stars. 

To find M37 look north of Orion for Auriga’s home plate shape of stars.  Once you can find this look between the two stars Beta Taurii and Theta Aurgae.  Grab a pair of binoculars and look about halfway between these two stars.  Just east of this midpoint you will see a faint cotton ball shaped source of light; this is M37.  Through a telescope you can start to resolve the 150 or so stars that are 12th magnitude or brighter.  With an age of 300 million years there are roughly 12 red giant stars in the cluster that have evolved off the their main sequence.  See if you can spot any of them

M37 is the brightest of a trio of star clusters that span across the southeast corner of Auriga.  The next few weeks we will cover the other two of the great open clusters in Auriga.  All three are great binocular targets.  For help finding M37 follow the link below.

http://iau.org/static/public/constellations/pdf/AUR.pdf

http://iau.org/static/public/constellations/gif/TAU.gif

http://messier.seds.org/m/m037.html

The object for the week of February 10 is the open cluster M36.  Like last week’s star cluster M37, M36 is an open star cluster that lies roughly 4,100 light years away.  It has 60 stars that are proven to be members of this cluster which have an age of 25 million years.  Unlike M37, M36 has no red giant stars.  At 6.3 magnitude M36 is an easy target in binoculars and small telescopes will be able resolve a few of the brightest members.    

To find M36 look north of Orion for Auriga’s home plate shape of stars.  Once you can find this look between the two stars Beta Taurii and Theta Aurgae.  M36 will be about half way between and just a little to the right of these two bright stars.  It will not be quite as obvious as last week’s star cluster but with a Trumpler classification of I,3,r it will still be an easy find.  Follow the links below to find out more about this star cluster.

http://iau.org/static/public/constellations/gif/AUR.gif

http://messier.seds.org/m/m036.html

The object for the week of February 17 is the open star cluster M38.  M38 is the last of three star clusters in Auriga that we will cover.  M38 lies at a distance of roughly 4,200 light years away and its stars are estimated to be about 220 million years old.  The brightest star in the cluster is a 7.9 magnitude yellow giant star that is about 900 times more luminous than the Sun.  This will be the toughest of the three to see as it has a Trumpler classification of II,2,r.  M38 has a visual magnitude of 7.4 making it an easy target for those with binoculars.  Instead of the fuzzy ball shape of light you see with M37 and M36 you will see what some say looks like the Greek letter Pi or some say it looks like an oblique cross. 

To find M38 look north of Orion for Auriga’s home plate shape of stars.  Once you can find this look between the two stars Beta Taurii and Capella.  Grab a pair of binoculars and look about halfway between these two bright stars.  Again you will see a few lines of stars that look like an oblique cross shape.  For more information about M38 follow the links below.

http://iau.org/static/public/constellations/gif/AUR.gif

http://iau.org/static/public/constellations/gif/TAU.gif

http://messier.seds.org/m/m038.html    

Our next Star Party will be held on Friday, March 7, 2014 from dusk until 10pm

Weather permitting, the St. Louis Astronomical Society and the Science Center will set up a number of telescopes outdoors and be on-hand to answer your questions.  Telescope viewing begins at 7:00 p.m.  Regardless of the weather on March 7, 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

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