I’m late getting Heads UP! out. I was so taken by the Venus/Pleiades conjunction and the morning planet show, I focused on writing about those events early in the month and seeing them for myself. Also, there’s this virus thing that’s been a bit distracting.
On April 7th, the April Full Moon is the closest of the year, with perigee only eight hours before Full Moon. According to NASA’s Scientific Visualization Studio’s Dial-a-Moon at https://svs.gsfc.nasa.gov/4768, April’s Full Moon is 216 miles closer than March’s. Once again, watch out for higher than normal tides around the date of the Full Moon.
Venus Goes Bowling
Did you see Venus bowling along the edge of the dipper-shaped Pleiades cluster on the 3rd, just missing a strike? Photographers were challenged to capture the almost eight-magnitude difference between the sublime setting of young stars with a planet over 600 times brighter (and four billion years older).
It was wonderful in binoculars for us human viewers.
Later in April, the Moon lines up with Venus on the 26th, hanging out above the rapidly sinking Hyades and Pleiades clusters. This is a sight worth finding a clear western horizon to view.
Venus Comes In for Her Close-up
Aim a telescope at Venus anytime this month and note its waning phase. The second planet from the Sun has its greatest illuminated extent on the 27th, coming around the corner toward Earth, blazing at magnitude -4.7 despite doing its impression of a crescent Moon. See for yourself if it’s a good impression! You might find sunglasses or sky-darkening filters helpful to find Venus in daylight. (Careful! Hide the Sun out of view!) A bright sky or good filters will help detect the crescent shape. Venus’ angular distance from the Sun sharply decreases from 45 degrees to 30 in April.
Jupiter and Saturn give Mars the slip in the morning sky, taking off toward the south-southeast. Our Moon joins the planet party in the wee hours at mid-month for wonderful photo-ops from the 14th through 16th.
Use Jupiter as a Pointer
Jupiter is at quadrature, getting sideways with the Earth. Shadows of Jupiter’s moons are furthest from where we see the moons, making the Jupiter-scene look very three dimensional.
Use Jupiter as a pointer to Pluto! From now through mid-April, Jupiter and Pluto will appear less than two degrees (but 17 magnitudes) apart. They are closest on the 9th at a half-degree apart. The New Horizons spacecraft is to the upper right in Sagittarius’ ‘teaspoon’.
This is a good time to compare the diameters of Mars, Saturn and Jupiter in a telescope. Jupiter appears six times wider than Mars, and Saturn half as wide as Jupiter (not counting the rings).
Mercury: Playing Hard to Find
Mercury will stay low in the morning twilight. At 15 degrees from the Sun and brightness increasing through magnitude -1, Mercury should be easy to find. But it’s in the southern part of the ecliptic and at its maximum distance south of the ecliptic, so it about as hard to find for northern hemispheric observers as it gets.
The very minor Lyrids meteor shower peaks on the morning of the 22nd. Lyrids are mostly faint meteors, totaling less than 20 per hour at its peak. It’s a dark night due to little moonlight, so you might notice some glowing grains left over from Comet Thatcher (C/1861 G1), a comet with a period of over 200 years.
A big rock 52768 (1998 OR2) will pass 1.4 million miles from Earth on the 29th. It’s about two miles wide. 1998 OR2 will be visible low in the evening sky in Hydra at magnitude +10 or 11. It will continue to loop through the inner solar system, passing across Earth’s orbit every 3 2/3 years.
Some big snowballs are swooping through the inner solar system. Comet C/2019 Y4 (ATLAS) is reported to be brightening through 9th magnitude in Camelopardis. It has the potential to be viewable with the unaided eye in late May, but it will be very close to the Sun then. It’s following the orbit of the Great Comet of 1844/5 and might be a chip off that block.
C/2019 Y1 (ATLAS) is in Andromeda, where it may peak at 9th magnitude. C/2017 T2 (PANSTARRS) floats into Camelopardis from Cassiopeia. It may peak at magnitude 8. It’s further from the Sun than the Earth, so it stays well out of the solar glare.
A sunspot was seen on the Sun last month. Okay, there were more, but we remain in the sunspot minimum with many days without visible sunspots. Statistical models predict sunspot numbers should increase in 2020, but data used for some dynamical models aren’t promising increasing solar spottiness soon. Aurora are still being seen. Chinks in the Earth’s magnetic armor occasionally let streams of energetic particles into our upper atmosphere to light up far northern (and southern) skies.
Overflights of the International Space Station
Uranus might be visible moving against the background stars in the Solar & Heliospheric Observatory’s field of view when passing through conjunction with the Sun on the 26th. Mercury passes Uranus on April 30th/1st of May on its way toward solar conjunction on the far side of the Sun in May.