Heads UP! for April 2018
Jupiter is a wonderful sight in a telescope at 44 arc seconds wide from mid-April through early June. In June, Jupiter will be highest in the prime time evening skies, while, now, it’s highest at midnight. But why wait for summer, with the late sunrises due to daylight time, it’s a great sight in the morning twilight.
Saturn and Mars pair up in that same morning sky. They are patiently waiting offstage for Jupiter to have its time in the spotlight. They start out April right next to each other, seemingly hovering over the teapot of Sagittarius. They make a wonderful contrast as they pair up in the morning sky around early in the month – one is reddish; one is yellowish. They drift apart as the month goes on. A plump Moon joins the planetary couple on the morning of the 7th for a nice photo op.
Panorama of morning sky with Saturn, Mars and Jupiter from late March. Canon XS on tripod 1/2 second exposures at f/2 and ISO400, 50mm lens.
Mars and Saturn start April at the same brightness, but Mars jumps a full magnitude brighter by the end of the month. In a telescope (of any kind) Mars still appears smaller than Saturn’s disk, even as Mars gets large enough by the end of the month for moderate-sized telescopes to see some details. Does Mars leave Saturn for a dwarf planet? Mars happens to pass Pluto’s neighborhood in the sky near the end of April. It’ll be nice to use Mars to point out Pluto’s location.
Mercury is in conjunction with the Sun on the 1st. Then it makes a weak swing into the morning sky; not very easy to see from the Northern Hemisphere. It’ll be easier to see online in the Solar and Heliospheric Observatory’s C3 camera view through the 6th (if they fix the problems with the website). Uranus’s conjunction with the Sun will be harder to see as it crosses the C3’s field from the 10th through the 27th.
Mercury yields the title of ‘closest planet to Earth’ to Mars at the end of April. Mars keeps the title until Venus becomes the closest in mid-September through the rest of 2018.
Venus continues to arch higher from the western horizon just after dark, setting hours after the Sun. At the far side of its orbit from Earth, in a telescope it looks as tiny as Mars and looks just slightly out of round at 90 percent lit. Even then, it’s still the brightest planet at magnitude minus 3.9.
At the end of the month, Aldebaran sinks down, passing upgoing Venus. Orion, to Venus’ left, looks to make a hasty departure from the evening skies. Perhaps he left his eveningwear behind and feels underdressed. Or, is his arm, upstretched from Betelgeuse, waving in distress as he sinks below the horizon?
Vesta is the brightest minor planet. It passes through magnitude plus 6 on its way to magnitude +5.3 at opposition in June. It’s hanging out about 10 degrees to the upper right of Saturn in our skies. We’ll need binoculars to see it well.
The Lyrid meteors peak during the afternoon on the 22nd. We have the chance to see up to a dozen Lyrids an hour near their peak, with the best numbers before dawn. Elevated numbers of Lyrids are visible on the mornings of the 21st and 23rd as well.
Overflights of the very bright International Space Station are visible most evenings through the 12th.
Tiangong 1 fell out of the sky on at 8:16pm ET on April 1st into the southern Pacific Ocean. The uncontrolled fall of China’s first space station was a great example of how slamming into even the few molecules of air per cubic meter of the Earth’s thermosphere at 18,000 miles per hour saps the orbital energy of satellites.