The change and constancy of April skies – Longmont Times-Call

One truism of the natural world is that the more things change, the more they stay the same. April nights are no exception.

March’s abundance of planetary conjunctions continues uninterrupted into April’s early mornings. Of course, these formations take time to gather and crystalize, allowing for weeks and months of subtle shifts and variations on the theme. Although the dates and times below represent the peaks of the celestial events, the sky remains ablaze with the dazzling and colorful worlds beforehand and afterward during the month’s overnight hours.

There are few sights in the solar system as accessible and irresistible to the eyes as the arrangements of visible planets into remarkable patterns. This month has no fewer than five conjunctions to admire, some better than others. No optical enhancements necessary.

Both Saturn and Mars rise above the southeastern horizon about 4:30 am April 5, quickly followed by Venus, so all three will be in prime position by 5:30 am The ringed gas giant and the Red Planet, at nearly identical brightness of magnitudes +0.9 and +1.0 respectively, get to within one full moon’s width of one another and easily fit into a small telescope’s field of view at moderate magnification. Observe Saturn’s rings with the copper-orange campfire spark of Mars’s disk glowing just 0.4 degrees below it. Venus blazes to the lower left nearby.

The most dramatic conjunction of the year begins about one hour before daybreak April 18 after Jupiter clears the horizon at 5 am Look east-southeast to find, from the right, Saturn on high followed by Mars, Venus and Jupiter. The planets appear uniformly spaced apart about 11 degrees — give or take one half of one degree — with the exception of Mars and Saturn’s separation of 9 degrees. Witness in breathless silence the 32-degree upward trajectory of the four most imposing naked eye planets regally stretched over the horizon in grand splendor.

Neptune is here, too, technically giving us a quintuple conjunction. At magnitude +7.95, 30 times the Earth’s distance from the sun, located behind Jupiter and awash in the pre-dawn twilight, the gas giant will be for all intents and purposes impossible to see.

Keep in mind that Venus, shining brilliantly at magnitude ˗4.2, dominates the pre-sunrise mornings most of the year until mid-October when it becomes a rather diminished evening star through the New Year.

Mercury and Uranus, too, have their own conjunction on April 17. As a challenge, you could attempt to observe the pair separated by 2.0 degrees very low above the west-northwest horizon just after sunset. However, trying to find magnitude +5.86 Uranus, submerged in evening twilight and barely visible even under the best circumstances, may be more trouble than it’s worth even with a large telescope.

Finally, the two brightest planets Venus and Jupiter cap off months of conjunctions as they rise together at 4:20 am April 30. The goddess of love and the king of the gods are a mere ½ degree apart, with Venus dazzling six times brighter than Jupiter.

After the abundance of exceptional March and April conjunctions, the year sees just a few more, none of which are particularly worthy of note. This brings to mind another truism of nature: All things must pass.

At the end of the month, Mercury, the closest planet to the sun, reaches greatest western elongation — farthest position left of the sun from Earth’s perspective — in the evening April 29. It has seven elongations in 2022, and this is the best one . Many skywatchers have never seen this speedy sphere, so look for it on its paramount viewing dates from mid-April until the first week of May.

The magnitude +0.3 orb reaches its highest possible altitude and is visible 14 degrees above the west-northwestern horizon at the end of civil twilight at 8:23 pm when the sun is 6 degrees below the horizon. What’s more, Mercury remains in the sky a few minutes into astronomical twilight when the sun is 18 degrees below the horizon and night has officially fallen, making it easier to find.

Note that you can see Mercury get to within 1½ degrees of Alcyone, the brightest star in the Pleiades. Use binoculars for best views.

The constellations, though constantly changing over vast time scales, remain immutable for all practical purposes throughout one’s lifetime. Go to https://www.timescall.com/2021/03/27/skywatchers-guide-the-lion-and-the-bear-rule-the-night/ to visit constellations Leo and Ursa Major.

The moon is full at 12:55 pm April 16 and is called the Full Pink Moon, a reference to the ground phlox early spring flowers.

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