Week of April 14, 2014

This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Monday, April 14.  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, May 2, 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 6:26 a.m. on Monday, April 14 and sunset is at 7:37 p.m. providing us with over 12 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 9:11 p.m. this week.  For those with a sun dial, solar transit or local noon occurs around 1:01 p.m. this week. 

Moonrise for Monday, April 14 occurs at 12:35 p.m.  Moonset will occur at 12:45 a.m. on the following day.  On Monday the 14th the Moon will be exhibiting a waxing gibbous phase with nearly 100% of the lunar disk illuminated.  Full moon for April occurs on Tuesday, April 15.  April’s full moon is known as the Full Pink Moon    

On Tuesday, April 15 the Moon will completely pass through the darkest part of Earth’s shadow.  This type of event is called a total lunar eclipse and it is the first of two for this year.  The eclipse begins for us on April 14th but totality occurs later in the early morning hours of April 15.  Totality begins at 2:07 a.m. on April 15 and will last about 78 minutes.  For more information about this eclipse and the others that occur this year visit

http://eclipse.gsfc.nasa.gov/OH/OH2014.html

International Space Station (ISS) Observing

The next visible passes of ISS over St. Louis are evening passes.  The best passes are on the evenings of April 18, 19 and 20.  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, April 14. 

Date

Mag

Starts

Max. altitude

Ends

Time

Alt.

Az.

Time

Alt.

Az.

Time

Alt.

Az.

14 Apr

-0.3

22:02:31

10

N

22:03:23

11

N

22:03:23

11

N

16 Apr

-0.7

22:00:04

10

NNW

22:01:35

16

N

22:01:35

16

N

17 Apr

-0.7

21:11:10

10

NNW

21:12:57

14

NNE

21:14:12

12

NE

17 Apr

 0.3

22:46:54

10

NW

22:47:03

11

NW

22:47:03

11

NW

18 Apr

-0.5

20:22:23

10

N

20:23:21

11

NNE

20:24:20

10

NNE

18 Apr

-1.3

21:57:44

10

NW

21:59:40

26

N

21:59:40

26

N

19 Apr

-1.5

21:08:38

10

NNW

21:11:22

23

NNE

21:12:16

20

NE

20 Apr

-1.0

20:19:35

10

NNW

20:21:48

17

NNE

20:24:01

10

ENE

20 Apr

-1.9

21:55:32

10

NW

21:57:43

38

NW

21:57:43

38

NW

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 4:42 a.m. becoming easily visible by 5:30 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.

Mars

Mars is now in the constellation Virgo and will rise around 6:31 p.m. this week becoming visble shortly after the Sun sets.  For those awake around 9:00 p.m. look to the east and you will see a reddish-orange object in the eastern skies.  On April 14 Mars will be at its closest to us until our next opposition in 2016.  On April 14 Mars will be roughly 57 million miles away.  During these close approaches between Earth and Mars is when you can see the surface of Mars through a telescope.  Take a look now while you can for it will be another 26 months before we get another opportunity.      

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 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 9:48 p.m. and will be an easy target by 11:00 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.

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. 

The constellation for the month of April is Camelopardalis.  This little known constellation is found in our circumpolar sky so it can be viewed throughout the entire year.  With such visibility it might seem odd that most have never heard of let alone seen this large northern constellation.  The brightest stars in Camelopardalis only reach 4th magnitude meaning that for city observers these stars may need a pair of binoculars to be seen.

Camelopardalis is considered a modern constellation having only been recognized for about 400 years.  It is usually referred to as the giraffe as its name means spotted camel.  It was introduced as a constellation in 1612 by Dutch astronomer and cartographer Petrus Plancius.  Along with this constellation he is responsible for helping map out constellations of the southern hemisphere and introducing a few other constellations still recognized today.

Owing to its dim nature Camelopardalis can be difficult to find particularly in light polluted skies.  The first thing to do is find the constellation Perseus and Auriga.  Camelopardalis is north of these two constellations.  Next find the bright star Capella in Auriga.  About 8 degrees north of Capella you will find the two brightest stars of Camelopardalis called Beta and Alpha Cam.  Unfortunately there is no distinct pattern that stands out in Camelopardalis so you will have to use the star chart below to find the rest of the constellation.  Camelopardalis is north of the constellations Draco, Ursa Major, Lynx, Auriga and Perseus.  Its western boundary is at Cassiopeia and its northern boundary is at Ursa Minor and Cepheus.  This will be a difficult constellation to find but it is worth the effort as it will be the source location for a new meteor shower that will peak this year on May 24.  As we approach this new and potentially amazing meteor shower I wanted to help prepare readers for this event by introducing them to the constellation that houses its radiant.  Before we cover the meteor shower I want to first take a tour of this often over looked constellation.

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

The first object we will explore in Camelopardalis is its brightest star Beta Camelopardalis.  Beta cam is a G-class yellow supergiant star that is in the process of evolving off of its main sequence into the red giant phase.  It has started to fuse the helium at its core which has allowed for its outer atmosphere to cool and begin expanding.  Beta Cam is at a point where it should begin to pulsate as a Cepheid variable but has yet to start the clockwork like pulsations.  At a distance of 1000 light years this giant star with a luminosity that is 3300 times that of the Sun only shines as a 4th magnitude star.  This is because of Beta Cam’s distance and the dimming caused by interstellar dust. 

Another strange feature of this star is it was observed to suddenly display a bright flash of light in 1967  This and the fact that Beta cam is an x-ray source indicates the star likely experiences magnetic upheaval much like our Sun.  It is possible that the bright flash seen by pilots in 1967 was caused by a magnetic reconnection event similar to a solar flare on the Sun.   

Beta Cam is also a multiple star system.  A small telescope and large binoculars will be able to resolve a fainter companion (B-component) that is separated by 83 arc seconds.  The primary yellow supergiant star shines at 4th magnitude and the fainter companion shines at 7.4 magnitude.  The fainter B-component is itself a double star.  Very little is known about the second star in the B-component system.

To find Beta Cam first locate the star Capella in the constellation Auriga.  From here scan about 8 degrees north until you find the next brightest star.  This will be Beta Cam.  This triple star system will be the easiest thing to find that we cover for this month’s constellation.  Due to dim nature of the Camelopardalis our ability to star hop will be tested.  Use the map below to find Beta Cam and start familiarizing yourself with the other stars of Camelopardalis.

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

The next object for the week of April 7 is the asterism known as Kemble’s Cascade.  Most of the objects we include in this section are cataloged objects that are normally some kind of star cluster, nebula or galaxy.  However there are some objects that are no more than a chance grouping or alignment of stars that stand out to observers and can be quite nice to look at.  One such asterism is known as Kemble’s Cascade.  This grouping of stars was discovered by an amateur astronomer named Lucian Kemble.  He was scanning Camelopardalis and noticed a string of stars that spanned about 2.5 degrees of sky.  It was later named in his honor and remains a popular target in the sparse constellation of Camelopardalis.

Kemble’s Cascade is a string of 20 stars, mostly 7th to 10th magnitude, which spans about 2.5 degrees.  The center of the string is accented with a 5th magnitude star.  The stars that make up Kemble’s Cascade are not related to each so what we see is just a chance alignment.  Following this cascade of stars to the southeast will bring us to an open star cluster called NGC 1502.  This cluster contains about 45 stars that will appear as a faint glow at the end of Kemble’s Cascade. 

To find Kemble’s Cascade start by locating Beta and Alpha Cam again.  From these two stars sweep about one binocular field to the west and you will see a line of stars that appear to cascade down from northwest to southeast.  This is Kemble’s Cascade.  Using the map linked below you will see a small curved grouping of four stars.  The eastern most of the four is set a little further off from the other three.  This fourth star is the bright 5th magnitude star in the middle of Kemble’s Cascade.    

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

There are loads of interesting objects like Kemble’s Cascade scattered throughout the sky.  Backyard astronomy is not always just about finding distant galaxies or scanning the skies trying to complete deep sky catalogs.  Sometimes a keen eye and an imagination will allow an observer to see other chance alignments of stars like Kemble’s Cascade.  Reading monthly astronomy magazines and searching out observing forums is a great way to learn about many things that will not be included in the official deep sky catalogs. 

The Object for the week of April 14 is the spiral galaxy NGC 2403.  This galaxy lies about 12 million light years away and shines with an apparent magnitude of 8.4.  At this magnitude NGC 2403 is visible in binoculars but it will be considerately more difficult to see than a star with the same magnitude.  Stars have all their light concentrated into a singular point in the sky.  Whereas galaxies and other deep sky objects have more surface area so their surface brightness appears dimmer.  This is why when we see them they are frequently described as faint and fuzzy objects. 

To find NGC 2403 start by locating the star Muscida.  This star represents the nose of Ursa Major.  From here start scanning about 12 degrees to the east of this at a slight upward angle.  About two binocular fields to the east you should be able to find the dim patch of light that is NGC 2403.  Use the maps linked below to help you find this neighboring galaxy.

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

http://www.iau.org/public/themes/constellations/#uma

Our next Star Party will be held on Friday, May 2, 2014, from dusk until 10 p.m.

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 8:00 p.m.  Regardless of the weather on May 2, 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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