Earth Day Includes Earth Night

As Earth Day celebrates 50 years in 2020, embrace earth night, too, for half of all life occurs from sunset to sunrise. Stargazers will find celestial highlights before and after daylight hours on April 22. A new moon occurs that night (10:25 pm EDT), so natural moonlight will not interfere with the observing.

Lyrid Meteor Shower

In the opening hours of April 22, the Lyrid meteor shower peaks. Meteor showers are generally better after midnight because the observer is looking out the "front window" of earth as our orb plows through a debris trail left by a previous comet. It's like seeing snowflakes in the headlight of a moving car at night; less snow is seen out the back window.

As its name suggests, the Lyrid meteors of April 22 will appear to radiate from the constellation Lyra. While the celestial display is best before morning twilight (front window), frankly, more people will likely be up in the hours of the night after sunset. Lyra is anchored by the bright star Vega--one of the three prominent stars making up the Summer Triangle. That appearance alone is refreshing, as these stars are a harbinger of warmer months.

The star Vega is about 20 degrees above the northeast horizon just after midnight, shown below. Observers should look high to the northeast as the night begins, and slowly scan high and further south and west as the hours progress. If April 21-22 is cloudy, look for meteors the nights on either side of the peak. An interactive meteor shower sky map shows the position of the radiant in the night sky above your selected city.

Corona Rising

With the presence of coronavirus, which derives its name from the shape of the virus, rising just before Lyra is the constellation Corona Borealis. Its name means northern crown, the crown Dionysus gave to Ariadne. One appellation for the bright central star of the crown is Gemma, as in the gem of the crown. Other cultures have deemed this prominent hemisphere of seven stars to be different objects, but you'll realize the crown is apt once you see it in person.

So get out and see it in person. Corona Borealis is between the bright yellow star Arcturus ("from the handle of the Big Dipper, arc to Arcturus") in the constellation Bootes and the brilliant star Vega in Lyra. It conveniently sits in the path of meteors that appear to emanate out from Lyra.

Image: Lyrid meteors radiating outward from the constellation Lyra may pass through Corona Borealis.

Morning Planets

In the morning twilight of Earth Day, a few planetary cousins are aligned along the ecliptic. Prominent among them is brilliant (mag -2.3) Jupiter dominating the southeast horizon, with yellowish Saturn and reddish Mars being equally matched in brightness at magnitudes +0.6 and +0.5 respectively. Consider this a preview of what will delight people in December 2020, when Saturn and Jupiter appear so close together during conjunction that they can be seen in a single eyepiece. Though nearby in the sky, Pluto is too faint and Neptune is too close to the murky horizon to be readily observed.

Earth's Twin on Earth Night

As the sun sets on Earth Day, the spectacle continues. From the red horizon, shift your focus up and left to the prominent "star" that is visible even against the blue twilight sky. The dominant object is actually the planet Venus, sometimes dubbed earth's twin for it is comparable in size, mass, composition, and orbit. However, similarities end there, as its thicker atmosphere is extremely hot and caustic. It has no oceans and rotates backward compared to the other planets.

Venus is illustrative regarding global warming and climate change. A runaway greenhouse effect exists, in which sunlight is absorbed by the surface, just as on earth. However, high levels of carbon dioxide prevent infrared energy radiated from the ground from escaping back into space. Instead, the energy is trapped in the atmosphere and temperatures increase.

Back on earth, a similar situation occurs in which the increase in carbon dioxide raises the global temperature, yielding changes in the overall climate. Humans have certainly contributed to the woe with our significant contribution to the natural level of greenhouse gases. For this reason, Earth Day encourages us all to re-commit to lessening vastly our consumption of carbon-based fuels.

Stargazing in the Era of Coronavirus

One fortunate aspect of stargazing is that it can be done as a solitary or as a small group activity. If you choose to observe with others, follow CDC guidelines for general public hygiene. Then consider common sense items specific to stargazing, especially around telescopes. For example...

  • Only the telescope owner should handle it during setup and take down.

  • Allow only the owner of a telescope to make adjustments to its orientation. It's not yours to touch.

  • Do not grab the eyepiece that is sticking out like a stalk. It's not a handle anyway.

  • Do not grab the focuser knob, especially with bare hands. Ask the owner for assistance.

  • Approach the eyepiece slowly. Do not allow your eyeball to contact the surface of the eyepiece. People sometimes ask if telescopes are better with or without eyeglasses. This may be the time to practice observing with eyeglasses.

  • Take advantage of touch-free projections of the sun by day or digital imaging of celestial objects by night.

  • Don't talk if your face is near the eyepiece when you can accidentally expel moisture upon the equipment.

  • When necessary, wipe the eyepiece with a 70% alcohol solution and rinse with distilled water between users and wait for it to dry. Note that isopropyl alcohol is an eye irritant, so flush well.

  • Do not share or pass around a laser pointer, planisphere, or other equipment.

  • Keep a distance of 6 feet between people in line to observe through a telescope.

  • Have liberal placement of and encourage use of disinfectant wipes and hand sanitizer.

  • If you have to cough or sneeze, first remove yourself quickly from around the telescope and people.

  • Provide outreach material and alternative viewing opportunities that support social distancing.

  • Post written protocols or announce them repeatedly at telescope viewing sites.

If you are hosting an event or simply want to display astronomy-friendly instructions for anywhere else, you can print and post these handwashing and handshaking recommendations shared by John French of the Abrams Planetarium in East Lansing, MI.

Stargazing is a joy that amateur astronomers are eager to share. Earth Day--and night--are opportunities to advocate for earth, for astronomy, and for dark skies. Spread the word, not the virus.

[Added 2020 March 21: Watch Betelgeuse brighten from a historic low before Orion disappears for the season.]

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