Skywatch Line for Monday, and Tuesday, March 9th and 10th, 2020

This is the Skywatch Line for Monday, and Tuesday, March 9th and 10th, written by Joe Slomka.

Now that Daylight Saving Time is in effect, the Sun sets at 6:55 PM and night falls at 8:29. Dawn begins at 5:41 AM and ends with the Sun rising at 7:15.

The Moon occupies Virgo on both nights. Monday’s Moon rises at 6:59 PM and sets at 8:08 AM, Tuesday. Monday’s Moon is officially “Full” in the afternoon and called the “Full Worm Moon.” Tuesday’s Moon rises at 8:17 PM and sets at 8:38 AM, Wednesday.

Venus is the brightest evening star. By Civil Twilight, it blazes with minus 4th magnitude, appears about 20 arc-seconds in size, appears about 59% illuminated and is 26° high; it sets at 10:49 PM. Much dimmer Uranus shares Aries with Venus but is fainter with 6th magnitude, smaller with 3 arc-seconds and is only about 2° away from Venus; it sets at 10:36 PM. Both should fit within a binocular view and a low power telescope’s eyepiece.

The eastern Dawn sky continues to show off the parade of bright planets in Sagittarius. Mars starts off rising at 4:23 AM, shining with 1st magnitude, almost 6 arc-seconds, 90% lit and 17° altitude. Jupiter follows by rising at 4:42 AM, glowing with minus 2nd magnitude and 16° high. Saturn brings up the rear by rising at 5:09 AM, shining with zero magnitude, 15 arc-seconds and 14° high. Jupiter lags Mars by 5°; Saturn lies 8° behind Jupiter. Mercury hugs the eastern horizon by rising at 6:23 AM in Capricornus, glowing with first magnitude, appearing about 10 arc-seconds, 25% illuminated, but about 2° above the horizon and may be hidden by the rising Sun’s glare; binoculars may help find this elusive planet. Finding three planets in such a close formation is a treat for the early riser at about 6:30 AM.

Since Jupiter and Saturn are visible simultaneously, comparisons are in order. Both are gas giants – planets composed mostly of gas. Jupiter is larger; Saturn is about a third of Jupiter’s mass. In telescopes, Jupiter’s colored bands signify very active weather systems; one storm, the Great Red Spot, has been continuously observed for centuries. Saturn’s weather appears more subdued, with occasional faint features. Saturn’s ring system is easily visible from Earth. Jupiter’s rings are observable only from space-borne telescopes. Both planets’ 120 moons account for most of the Solar System total. Four of Jupiter’s moons appear in binoculars, while Saturn’s satellites can only be spotted through a telescope. Jupiter’s moon Io is the most volcanically active moon in the Solar System, while Europa, Ganymede and Callisto may hide oceans beneath their icy surfaces. Saturn’s moons Enceladus and Titan are geologically active, which spurt ice fountains. Titan is the only moon to have an atmosphere; however, its atmosphere contains cold methane, rather than oxygen. Titan also has vast lakes of liquid methane on its surface.

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