Mornings Have Hang Ups!

   Northern Hemisphere winter in addition to chilly or cold mornings may sort of warm you, at least in your mind. If you are outside looking at the sky, over the eastern horizon is a large triangular shape of three bright stars. One star each from three different constellations. Deneb in Cygnus the Swan, Vega in Lyra the Harp, and Altair in Aquila the Eagle. This is the asterism (star pattern but not a constellation) the Summer Triangle. There, warmer now?!
   So if you are outside checking out the Summer Triangle, or perhaps Mars and nearby Antares and you have an optical aid like binoculars or a lower power wide-field eyepiece in your telescope aim them and your eyes toward the star Altair. In dark enough skies you can make out the stars making up Sagitta the Arrow a few degrees away from Altair.
   As Altair is rising and with binoculars move the field of view up to the left until the stars of Sagitta fill the field of view. This small constellation, yes a constellation, could be used as a sort of pointer stars to look a few degrees away for a small open star cluster, Brocchi’s Cluster, or more commonly known as the ‘Coathanger Cluster’.
   So if mornings with stars like this don’t warm you up then wait a few months of Earth revolution and these same stars will be showing up in the warmer evening skies of Northern Hemisphere summer and fall.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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Saturn at Solar Conjunction – 2019

   Monday January 13th the planet Saturn will have reached the astronomical coordinates that officially place it at solar conjunction. From our perspective the planet is behind the Sun, or on the opposite side of the Sun from the Earth.

   In reality it is not as much as Saturn moving behind the Sun as it is the Sun passing in front of Saturn – or so it seems. As a distant outer planet Saturn moves more slowly around the Sun than the Earth does. One year on Saturn is equal to 29.7 years (10,832 days) on Earth. So in one Earth day Saturn would travel how much of the 360o orbit around the Sun? That would amount to approximately 0.033o each day.

   The Sun, in its apparent motion along the ecliptic moves at the rate the Earth is moving which is 0.99o each day. So with the Sun’s apparent motion (0.99o/day) it quickly, relative to Saturn, passes Saturn while both are moving eastward. This animated graphic starts with Saturn and the Sun above the horizon a couple of hours after sunrise. The animation is set for 1-day intervals showing the Sun moving eastward away from Saturn. The sky is purposely left dark to show Saturn more easily.

   So with that in mind you could start watching for Saturn to reappear in the morning skies later next month.
   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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January Moon at Perigee

   Our Moon reaches perigee, (closest to Earth), for this orbit, on Monday January 13th. At that time the Moon will be at a distance of 28.69 Earth diameters, 227,396 miles (365,958 km) from the Earth.

   On the day of the perigee Moon the 19-day old waning gibbous Moon will be over the eastern horizon late in the evening.

   Does our Moon actually go around the Earth as this graphic shows? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*
   *Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.


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From a Crab to a Lion

   Over the next two evenings, January 11th and 12th, the waning gibbous Moon moves from near the Beehive Cluster, M-44, an open star cluster in Cancer the Crab to near the bright star Regulus in Leo the Lion. M-44, with an apparent magnitude of 3.50 in a dark sky without the Moon nearby is visible to the unaided eye and is easily seen with optical assistance like binoculars, or a low-power wide field eyepiece.


   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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The Moon and the Twins


   Thursday evening January 10th the 16-day old waning gibbous Moon will be about 6-7o from the star Pollux. Pollux is one of the two Gemini Twin stars.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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January Moon at Ascending Node

   Wednesday January 9th the 14.8-day old nearly full Moon rises between the legs of the Gemini Twins. The Moon will be about 14-15o to the west from the ‘Twin’ Stars Pollux and Gemini.

   As it is rising the Moon will be crossing the plane of the ecliptic moving north. This is known as the ascending node, one of two intersections the Moon’s orbital path has with the ecliptic. The ecliptic is actually the Earth’s orbit, and the Moon’s orbit is inclined about 6o from the ecliptic. So there are two node intersections, the ascending and descending nodes.

   Does our Moon actually go around the Earth as many graphics show? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*
*Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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Waxing Gibbous Moon Near Aldebaran

   Tuesday evening January 7th the 13-day old waxing gibbous Moon will be about 3-4o from the reddish star Aldebaran. Aldebaran is known as the ‘angry’ red eye of the constellation pattern Taurus the Bull.

    Aldebaran is located at one end of a v-shaped cluster of stars making up the face of the Bull. This group of stars are all part of an open star cluster known as the Hyades. They are one of two naked-eye visible open star clusters within the boundaries of the constellation. The other one is the little dipper-shaped group known as the Pleiades.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


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