Jared May: What's up January 19 - January 26, 2021

Ohio weather is leaning in favor of stargazers this week. Several clear or partially clear nights are coming up, so make sure you know where your binoculars and telescopes are.

Sunset this week is nearing 5:40 PM and nighttime temperatures, with wind-chill, aren’t a stranger to the mid-teens. If you take a scope out under the stars be sure to let your stargazing equipment thermally equilibrate with outside temperatures for at least 30 minutes before use.

This week will give us the first quarter moon, a celestial trio between the moon, Mars, and Uranus, Mercury at its greatest eastern elongation, and the Dog Star.

On Wednesday evening look in the Eastern skies to see the washed-out first quarter moon on the rise. As the sun sets, and the sky gets darker, the half-moon’s light will slowly dominate the night sky. First quarter is an excellent time to view the moon with a telescope or binoculars since there is lots of contrast along the terminator (Where the light meets the dark on the face). Many companies sell moon filters for telescopes and binoculars that are fairly cheap and really help with viewing the moon. These filters are basically sunglasses that simply reduce the amount of light getting through and since the moon is so bright, these filters help save your night vision.

Image of the First Quarter Moon, by Jared May

While you are observing the moon Wednesday night, scan your binoculars or telescope just 5° degrees “above” of the moon (more north) to see a celestial body trio – Uranus and Mars will both be neighbors to the moon. Uranus shines a faint magnitude 5.76 so binoculars will work best in a dark location and Mars shines a bright magnitude 0.22 (remember that the magnitude scale is reverse such that fainter objects have a more positive magnitude).

The Moon and Mars help guide you to Uranus (no joke!).

On Saturday, peer low into the WSW skies between 6 and 6:45 PM to see Mercury at its greatest eastern elongation. This is the day that Mercury will be above the horizon for the longest since the greatest eastern elongation is just a point where Mercury appears to be at its furthest distance away from the sun. Binoculars and telescopes both will do a great job of showing this inner planet, but it is a very small planet so don’t expect to see any details of the planet’s surface.

After sunset, look for Mercury in the twilight. This is the best week for a while to view the elusive planet.

Almost exactly an hour after sunset this time of year, turn your attention eastward to see the Dog Star a.k.a. Siruis. This star is part of the constellation Canis Major (Latin for “The Greater Dog” – hence the star’s nickname) and is the seventh brightest natural object in the sky behind the sun, moon, Venus, Jupiter, Mars, and Mercury - Sirius shines at magnitude -1.46. This bright star sits just 8.6 light-years away from Earth (very close in terms of cosmic scale), and is 25.4 times as luminous as our sun and these combined make it the brightest star in the sky. This “dog star”, is actually not alone in the sky, it is part of a binary system and its accompanying star is a much fainter white dwarf. These two dance around each other once every 50 years. This is a perfect naked-eye object but looks equally impressive through binoculars and telescopes.

Sirius, the brightest star in the night sky, is easy to find at this time of year.

The forecast shows potential for several nights this week to be clear or have gaps in the clouds – the weather this time of year is hardly ever that nice. Be sure to take full advantage of this rare opportunity and explore the sea of stars and the treasures found in the night sky. This week lookout for the first quarter moon, the celestial trio, the inner planet Mercury, and the unmissable Dog Star.

Clear Skies!