This is the Dudley Observatory Skywatch Line for Wednesday, May 23rd, and Thursday, May 24th, written by Louis Suarato.
The 67% illuminated, waxing gibbous Moon rises at 2:09 p.m. in the constellation Virgo. Virgo is the second largest constellation in the sky, occupying 1,294 square degrees. Only Hydra is larger. It is most prominent in May, and can be seen in the evening sky from March through July. Virgo is the home to the Virgo cluster of galaxies. This cluster is part of a larger concentration of galaxies known as the Virgo Supercluster, of which our Milky Way and Andromeda are members. This cluster may contain as many as 2,000 galaxies. Charles Messier cataloged 11 objects within Virgo including elliptical galaxies M49, M59, M60, M84, M86, M87, M89; spiral galaxies M58, M61, M90, and M104. Virgo’s brightest star, Spica can be seen to the east of the Moon. Further east will be Jupiter in the constellation Libra. Wednesday night, Jupiter’s moon Io, and its shadow cross the face of the planet between 9:13 and 11:01. Io’s shadow transit ends at 11:23. While Jupiter is rising, Venus is setting in Gemini. Look for Saturn rising in the southeast, in Sagittarius, after 11 pm. Mars follows 50 minutes later in Capricornus. Mars continues to brighten as its distance to Earth closes. Mars not only has the tallest mountain in the solar system, but it also is home to the deepest valley.. At 13.7 miles high, about twice as high as Mount Everest, and 15 miles above the average surface level, Olympus Mons is the solar system’s highest peak. The martian canyon, Melas Chasma, is the deepest in the solar system. This canyon is 5.6 miles below the plateau above it. With the exception of the snowy white pole, martianfeatures are difficult to see through a telescope, but Sky Telescope has developed a Mars Profiler Tool that allows you to see which side of the planet is facing Earth at any given time. The tool also includes a map identify the features. You can access the Mars Profiler Tool here: http://wwwcdn.skyandtelescope.com/wp-content/plugins/observing-tools/mars_profiler/mars.html.