Over the next several days (evenings) both inner planets, Mercury and Venus, are moving along their respective orbits approaching each planet’s eastern elongation. From the animated graphic you can see that the stars in the background, like the two ‘Twin Stars’ Pollux and Castor, are also moving but toward the western horizon. This is a regular motion of the stars caused by the Earth’s own orbit, revolution, around the Sun. As the Earth revolves the stars appear to move westward – a real motion not to be confused with the apparent motion of stars toward the west as the Earth rotates.
On the evening of June 25th Mercury will pass within about 5-6o from the star Pollux.
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.
Also Follow me and other great resources at Feedspot.
Northern hemisphere spring comes to an end and its summer begins on Thursday day June 21st at 10:08 UT (5:08 am CDT) when the Sun ‘reaches’ the celestial coordinates of 23.5o north declination and 6 hours right ascension. With respect to the Earth’s surface the Sun is described as over the Tropic of Cancer, 23.5o, north latitude of the Earth’s equator. At this same time according to 
Saturday June 9th two of the outer planets, Mars and Saturn, will be at the same heliocentric longitude of about 278o, and would be in what is called a heliocentric conjunction. Heliocentric (Sun-centered) coordinates uses an overhead view of the solar system with planet location given as degrees of heliocentric longitude. The heliocentric longitude is based on a view from the Sun and is given as the angle between a planet and the vernal equinox. The 
