Give Mom a Diamond

   About an hour after local sunset, on Mother’s Day May 12th, go outside and face south and look for the 8-day old waxing gibbous Moon to be near the star Regulus. Then look for the bluish-white colored star Spica.
   Spica, a star in Virgo the Harvest Maiden, marks the lower corner of an *asterism known as ‘the Diamond of Virgo’. To see the asterism look up to the left from Spica for the reddish star Arcturus in the kite-shaped constellation Bootes the Herdsman. Then look nearly straight up, the zenith, for the dimmest of the diamond stars, Cor Caroli in Canes Venatici, the Hunting Dogs. Then look down to the right for the star Denebola, the tail of Leo the Lion.
   Look toward the western horizon for a reddish star, actually the ‘Red Planet’ Mars.

*An asterism is a group of stars forming a recognizable pattern using stars within a constellation or by combining stars from more than one constellation. For example, the Big and Little Dipper are asterisms.

   
   
   

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A Planetary Line-Up, Plus the Moon

   For the next week or so the evening skies will be filled with planets and dwarf planets. With the right timing and a relatively flat horizon you might be able to see Venus just before it sets and Mars just after it rises. A caveat to this is that as each day passes Mars will rise earlier while Venus, each day, will be setting earlier. And with the exception of Ceres the dwarf planets are too dim to be seen with the naked eye.

   As this graphic shows, the planets are closer to the ecliptic than the dwarf planets due to differences in the respective inclinations. Inclination: Every object orbiting the Sun has an orbital path that is tilted or inclined from the Earth’s orbit – the ecliptic.

   The waxing gibbous Moon is roughly mid-way between the red star Antares in Scorpius the Scorpion and the planet Saturn.

   
   
   

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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Follow the Arc to Spica, or Jupiter

   There is an ‘old’ Astronomical saying, a sort of memory aid, for finding at least two constellations by way of their alpha, or brightest star in their respective constellation. In Bootes the Herdsman there is the orange-reddish star Arcturus, and in Virgo the Harvest Maiden the bluish-white star Spica. The saying – “follow the arc to Arcturus, then speed to Spica” is how you connect these two stars with the curve, or arc, in the handle of the Big Dipper. This is typically done during the Northern Hemisphere spring and summer season when Bootes and Virgo are in the evening skies. However during the late autumn and winter months in the Northern Hemisphere this memory aid works best in the early morning skies before the Sun rises.
   So despite the graphic showing the morning sky for December 8th you could go out any morning for the next few months and find the 7 stars making up the Big Dipper. Then look for the curved handle and follow the arc or curved handle toward Arcturus and then continue on to Spica, or for the time being, the planet Jupiter.

   
   
   

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.

Follow the Arc to the Moon

   Thursday evening March 24th the 16-day old waning gibbous Moon rises about an hour after local time for sunset. About 3o from the Moon is the blue-white star Spica in the left hand of Virgo the Harvest Maiden.

   This is also the time of year when some would look at the sky and say, “Follow the arc to Arcturus and then speed to Spica.” This sort of silly sounding phrase links the curved handle, the arc, of the Big Dipper with the reddish star Arcturus in Bootes the Herdsman, and the blue-white star Spica. The Moon, at times, is part of the lineup as it is this time.

   
   
   
   

Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

3 Pairs or A Tale of Two Tails

   For the past month or so Comet Catalina (C/2013 US 10) has been moving in a northeast direction across my morning skies. It has hovered at around 6th or 7th magnitude making it somewhat visible in binoculars and obviously visible with telescopes. Sadly with my meager photo equipment this comet has so far eluded my efforts. There are some spectacular pictures showing a comet with a greenish tinge and two tails. However that is not the point of this posting.
Bootes, Arcturus and the comet   Over the next several mornings the comet will pass by the reddish star Arcturus in the constellation Bootes the Herdsman. To many the star pattern for this constellation resembles a kite shape and Arcturus is at the bottom of the kite where the kite tail is attached. The animated graphic shows the comet in motion for December 31st and January 1st.
   The morning sky, in addition to the comet – Arcturus pair, also contains two other pairs, or conjunctions. Jupiter has the Moon for a one-day partner and further east toward the horizon is Mars and the bluish star Spica in Virgo.

   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

A Celestial 2 for 1

   Saturday evening May 2nd the waxing gibbous Moon will be within a few degrees from the bluish-white star Spica in the constellation Virgo the Maiden. Both will easily fit in the field of view of binoculars. And while you are looking at this part of the sky direct your view up to the left from Spica to find the reddish star Arcturus in the constellation Bootes the Herdsman. If you continue looking up to the left you will find the 3 stars making the curved handle of the Big Dipper asterism. If you reverse your viewing then you can do as this astronomical mnemonic suggests, “Follow the Arc to Arcturus, then speed to Spica.”

mars-saturn-helio-conj
    Also, on May 2nd the outer planets Mars and Saturn will be on opposite sides of the Sun in an arrangement known as heliocentric opposition.

   
   
   
   

Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Follow the Arc to a Pulsar!

   During Spring in the northern hemisphere, the seven bright stars that form the Big Dipper are easily seen high over the northern horizon. Located at the hindquarters of the Great Bear (Ursa Major), this asterism (group of stars) has long been used as a celestial guide by travelers. During the American Civil War, slaves memorized a song called “Follow the Drinking Gourd” that helped them locate the stars that would point their way to freedom. By walking in the direction of the ‘drinking gourd’ stars the escaping, freedom seeking slaves, would be following a northerly route taking them away from the slave states to the free states to the north, or to Canada.
   There is an ‘old’ Astronomical saying, a sort of memory aid, for finding at least two constellations by way of their alpha, or brightest star in their respective constellation. In Bootes the Herdsman there is the orange-reddish star Arcturus, and in Virgo the Harvest Maiden the bluish-white star Spica. The saying – “follow the arc to Arcturus, then speed to Spica” is how you connect these two stars with the curve, or arc, in the handle of the Big Dipper.
   Simply look toward the northeast to find the 7 stars making up the Big Dipper. Then look for the curved handle and follow the arc or curved handle toward Arcturus and then continue on to Spica. This is typically done during the Northern Hemisphere spring and summer season when Bootes and Virgo are in the evening skies.
   While you are looking toward this region of the sky, you can also investigate some of our neighboring solar systems.
   Scientists now believe that two sunlike stars in this region have at least one orbiting satellite each, and that a nearby pulsar could have up to three satellites. Just below the bowl of the Big Dipper lies 47 Ursa Majoris, a star with an orbiting object estimated to have two to three times the mass of Jupiter and a revolution rate of 1103 Earth days. Near the northern boundaries of Virgo, an object orbiting around 70 Virginis is estimated to have six to seven times the mass of Jupiter and a revolution rate of 117 Earth days. Although the objects themselves are too far away to be seen, the suns around which they orbit are visible to the naked eye.
   A third solar system you could direct your attention to is also within the boundaries of Virgo. Unlike the other two solar systems, the objects in this system orbit a pulsar, PSR 1257+12. A pulsar is a small, extremely dense, and rapidly rotating neutron star, a remnant of a massive star that has collapsed into itself following a supernova event. PSR 1257+ 12 gets its name from its celestial coordinates, 12 hours 57 minutes right ascension and 12o north declination. This pulsar is one of at least several known pulsars in our galaxy and this one has an estimated diameter of 16 km, and a mass that is one to two times that of our Sun.
pulsar   Pulsars earn their name from the radio waves they emit, which we receive in regular pulses. Pulsars emit radio waves as a narrow beam, much like the beam of light emitted from a lighthouse. Just as direct light from a lighthouse sweeps past a point regularly, so does the beam of radio waves emitted from a pulsar. PSR 1257+ 12 emits radio waves that reach the Earth with at an interval of 6.2 milliseconds. Because we receive pulsed radio waves from a pulsar as a result of its rotation, we know a pulsar’s pulse interval coincides with its period of rotation. This means that PSR 1257 + 12 rotates every 6.2 milliseconds!
kepler   Exo-solar systems and their planets have been detected through various methods with the greater majority of these exo-solar systems being discovered by the Kepler orbiting observatory. To date more than 1,000 objects have been confirmed as an exo-planet, with more than 4,600 objects waiting confirmation.
distant-worlds-cover   Download a series of monthly star maps and data pages. Each monthly star map shows the location of many of the stars we know or are reasonably certain that are stars with their own planets. Click here to download the “Where Are the Distant Worlds Star Maps”. (2-3 Mb PDF)

   
   
   
   
   
   
   
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Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.