The forecast this week looks rather cloudy, but there might be some hope for clear nights closer to next weekend. Sunset is around 5:30 PM so be ready for dark skies and stargazing by 6:30 PM. During the sunset hours the temperature will be in the mid-30s and the windchill about ten degrees colder – so make sure to wear your warmest coats and protect your skin from potential frostbite.

This week be on the lookout for an early-morning planetary meetup, the waning gibbous moon, and the brightest star in the sky.

In the moments before sunrise, between 6:45 AM and 7:30 AM, look low in the eastern sky. The first object you’ll likely notice is Venus, the brightest object in the sky (behind the moon and sun). “Below” Venus will be Mercury and Mars separated by only a few degrees. As the week progresses the two planets will slowly appear to drift further apart. A pair of binoculars is perfect for viewing Venus, but a telescope is more suited for viewing Mercury and Mars.

In related news, the tiny helicopter on Mars, Ingenuity, that was attached to the Perseverance rover that landed on Mars in 2020, had its final flight this week. This tiny 4 lb autonomous helicopter completed 72 flights with a cumulative in-air time of over two hours. It covered a total distance of nearly 11 miles. Ingenuity has paved the way for future powered-flight vehicles on Mars and other bodies in the solar system. In addition to being a technology demonstration platform, the helicopter was equipped with two cameras that helped with terrain mapping for current and future rover and sample-return missions to Mars. [GIF credit: NASA/JPL-Caltech/ASU/MSSS.]

A short video showing Ingenuity’s first test flight in the thin air of Mars as seen from the nearby Perseverance rover.

An hour or more following sunset, the eastern skies will begin to glow from the light of the waning gibbous moon. Luckily sunset and dark skies occur early in the evenings, so there will still be several hours of darkness before the lunar glow washes out some of the stars. A set of binoculars or a telescope are great options for viewing the moon, especially when equipped with a lunar filter, which is basically a set of sunglasses for your telescope/binoculars (the moon is surprisingly bright when magnified).

In the southeast sky, somewhat “below” the famous Orion constellation, try spotting Sirius, the brightest star in the sky (excluding the sun). Sirius shines at magnitude -1.5, or about 25 times brighter than the stars that comprise the Big Dipper. The magnitude scale is a bit odd in that lower numbers are brighter, hence the negative number. The 0.0 magnitude is referenced to Vega, another bright and easily recognizable star. The equation, for those who are interested, for the apparent magnitude and brightness of a star (or planet) goes as

Where m2 and m1 are the apparent magnitudes of object one and two respectively and B2 and B1 are the brightnesses of object 2 and 1 respectively. If you know the apparent magnitude and absolute magnitude of a star, there is a different equation you can use to calculate how far away the object is!

Despite a pessimistic forecast, there is some chance for partially clear skies through the week, especially heading into next weekend. Hopefully, the experience of sitting out under a crystal-clear night sky full of celestial wonders outweighs the nipping cold. Stay warm and be on the lookout for Venus, a Mercury-Mars meetup (while thinking about the Martian helicopter, Ingenuity), a glowing gibbous moon, and the brightest star, Sirius.

Clear Skies!

What's Up: January 28- Feb 4, 2024 by Jared May