Thursday, April 16, 2020

The Venus Show

One thing is for certain - the disruption of our routines thanks to the COVID-19 virus outbreak has created a vacuum. Binge-watching has taken center stage for a lot of America, but if you step outside you'll find another show streaming through the evening twilight. Venus has been dazzling, high above the horizon like a super intense LED. Even the average person out for their stroll around the neighborhood notices this gem in the western sky.

Our sister planet returned to the evening twilight last fall. I recall catching sight of her in early November heading south on I-81 in Virginia on our way to NC, anchoring a wonderful Zodiacal alignment of Venus-Jupiter-Saturn. Slowly but steadily since then, like a diver ascending the ladder to the high dive platform, Venus has been gaining altitude from the Sun's glare.

Venus and crescent Moon Thanksgiving evening 2019


This evening apparition has been particularly auspicious, hitting a trifecta + one of favorable celestial mechanics. First, for us spring brings the angle of the ecliptic - that imaginary highway that the visible planets traverse - to its steepest angle with the horizon, reaching 73° on March 24th. This means that every degree that a planet lies from the Sun translates to maximum distance above our northern hemisphere horizon.

Next, that date of steepest ecliptic coincided with Venus reaching the point in its orbit where it forms a right angle alignment between itself, the Sun, and us - i.e., the greatest distance it can appear separated from our home star. The result of all this? Our brilliant neighbor began the evenings in late March a full 44° above the horizon, an inner-planet party animal that stayed up until close to midnight.

Another favorable aspect is that on March 20th the planet was at perihelion - the point in its orbit where it lies closest to the Sun. This contributes slightly to the planet's brightness so that when it hits that sweet spot between disk size and phase on April 28th it achieves an eye-catching maximum brilliance of -4.4 magnitude. While it may not be visually apparent that Venus is reaching an incremental notch above its normal brilliance it is as good as it gets (but don't tell the press less we start a "Super Venus!" meme). 

Perhaps the pièce de résistance of this apparition was Venus making a call upon the Pleiades, passing through their midst on April 3rd. While not rare (it happens every 8 years due to celestial mechanics returning Venus to roughly the same spot) it is one of the most lovely and photogenic conjunctions around. I have (somewhere) a shot of a similar alignment some 24 years ago taken on film. This time around I used the digital magic of taking 200+ shots with my 200mm lens and stacking them to produce a nice souvenir of the occasion (star spikes courtesy of Photoshop).

M45 and Venus on Apr 2, 2020
 
But wait - there's more! Like that diver perched high above on the platform our sister planet is preparing to swan dive into the glare of the Sun. Once we reach dichotomy (half phase) Venus becomes a more interesting target for amateur astronomers with even a modest scope. We enter a period where the size and apparent phase alter week by week and then day by day as we approach the June 3rd inferior conjunction date. If you have never tried to spot Venus in the daytime you'll have a great opportunity on April 26th using the Moon as your guide as it slides roughly 5° south of the planet. It also is a great time to see how soon you can pick out the phase using only binoculars or capture it using only your telephoto lens.

Remember, you don't have to practice social distancing with your old friends in the night sky - let them infect you with their beauty and mystery!