What's Up: May 27 - June 3

We are inching closer and closer to summer and the daytime temperatures reflect that – sitting in the 80s and 90s this week. After the sun sets, the air begins to cool but still hangs on to some of the daytime heat. The lowest nighttime temperatures will be in the mid-60s, which is the perfect temperature for stargazing. On top of that, despite Ohio weather being highly unpredictable (but generally cloudy), most of this week will yield clear nights!

Sunset this week is around 8:50 PM. Be ready with all your stargazing gear about an hour later for when the skies are truly dark. Be on the lookout this week for a Mars-Jupiter conjunction, some solar eclipses on Jupiter, the new moon and young crescent, and twins in the sky.

All throughout the week if you are awake between the hours of 3:30 AM and 6 AM, you have a good chance of seeing Jupiter. This gas giant is the third brightest object in the night sky (behind the moon and Venus) so it should be easy to spot in the eastern skies before sunrise. A careful eye will reveal a red star very near to Jupiter – this is Mars. A pair of binoculars or a low-power telescope will likely show both planets within the same field of view. These two objects will be around 0.75° apart.

Jupiter and Mars pass close by one another in the morning sky.

Speaking of Jupiter, did you know that we can see solar eclipses happen on that planet as well as earth? Okay, that isn’t an entirely fair question, because while we can experience the blackout of the sun here on earth during a solar eclipse, we can only see the shadow cast by the eclipsing body on Jupiter. If you’re up watching the Mars-Jupiter conjunction, grab a higher-power telescope on May 29th and watch Jupiter between 3:20 AM and 5:50 AM. You will see the diffuse shadow of Ganymede (one of the four Galilean moons of Jupiter) passing over Jupiter’s southern hemisphere. If you have a camera attached to a telescope this can make an interesting timelapse!

At certain times, we can regularly spot, well… spots on Jupiter. These are the shadows of Jupiter’s four large moons which frequently are cast upon the planet.

An almost solar eclipse on Monday morning (not visible, but cool nonetheless.)

Monday, May 30th, marks the day of the new moon. If you somehow could look at the sun and moon simultaneously at 7:30 AM on Monday, without damaging your eyes, this is what you would see.



Notice how close the moon is to the sun. This is due to its slightly tiled orbit relative to the earth-sun orbital plane by 5°. Solar eclipses on earth happen when the moon during its new moon phase crosses that 0° point in the plane (image of off-axis moon and earth from:

https://moon.nasa.gov/moon-in-motion/overview/ ). As the week goes on, you will notice an extremely thin crescent poking up over the western skies only visible for an hour or so before setting.

A diagram showing why there’s not a solar eclipse every month. Sometimes the moon appears “above” or “below” the sun in the sky..

While spotting this crescent moon shortly after sunset, also be on the lookout for twins in the sunset sky. More specifically, try spotting the bright starts of Pollux and Castor. According to Greek and Roman mythology, Castor and Pollux were twin half-brothers (more technically caused by heteropaternal superfecundation) and their neighboring constellations (in Gemini) look almost identical. Castor the star is actually a collection of a whopping six stars that sit 50 light-years away that are so close they appear as one. Pollux the star is a colder (cold in terms of stellar temperatures – its surface temperature is still 7650°F) orange giant that sits 34 light-years away and is the nearest giant star to earth.

The Gemini Twins, Castor and Pollux are setting int the west.

Get outside and enjoy the plethora of warm and clear nights coming up. Invite friends over or enjoy the solitude of your backyard to explore the cosmos at varying depths. Your naked eye will reveal all but two planets and thousands of stars or a telescope will reveal all the planets, clusters, galaxies, and upward of a million stars. With your eyes, binoculars, and telescopes, try spotting a planetary conjunction, eclipses on Jupiter, a thin crescent moon, and Castor and Pollux.

Clear Skies!