Astro Bob: Jupiter-moon/BlueWalker 3 mash-up stalks the skies – Reuters

DULUTH – Clouds blocked Saturday’s moonrise here, so I couldn’t see Jupiter and the Harvest Moon cresting the horizon together. I hope you had better luck. Luckily, 15 minutes later, they both shared a narrow slit of clear sky and provided an alluring sight. We may curse clouds for hiding our favorite cosmic trinkets, but they add so much to a moonlit scene.

In one day, the moon moves about 13° to the east. On Sunday evening (September 11), it follows under and behind Jupiter.

Contribution / Stellarium

On Sunday evening September 11, the moon will rise about 20 minutes later and shine bottom and left of the mighty planet, providing a spectacular demonstration of the distance traveled eastward in 24 hours. I hope you will watch. The moon’s next planetary play date is set for September 16-17, when it glides alongside Mars. I like these routine but special visits. They add spice and anticipation to a night of stargazing.

Launch of the BlueWalker 3 satellite

On September 10, SpaceX launched another batch of 34 Starlink satellites into orbit along with an all-new craft built by

AST SpaceMobile

, the BlueWalker 3. Considered the largest commercial satellite ever made, this 1.5-ton monster, shaped like a giant computer chip, is 693 square feet (64 square meters) in area. It is mounted in the folded space in a much smaller package; in the next few days it will unfold to the size of a squash court.

Blue Walker 3
This is the BlueWalker 3, a prototype satellite that will deploy in a vast array of antennas. The rear face of the array is lined with solar cells to power the system.

Contribution / AST SpaceMobile

BlueWalker 3 is a prototype satellite with numerous sub-antenna modules that will connect directly to regular smartphones to provide high-speed 4G coverage virtually anywhere on Earth. Think of it as a raft in orbit of cellphone towers.

Before it becomes fully operational, engineers will perform tests to demonstrate that the technology works in low Earth orbit in coordination with ground infrastructure. Testing locations include the company’s home state of Texas, as well as Hawaii and AST’s cellular partners in Europe, Japan, South America, Africa and Asia.


Now on to the potential bad news, at least when it comes to astronomy and skywatching. Assuming all goes according to plan, the company will work with SpaceX and possibly other vendors to launch about 110 much larger satellites called BlueBirds into orbit to establish a full network by 2024.

While this number pales in comparison to the current (and projected) number of Starlinks, the BlueBirds will be considerably larger and therefore likely MUCH brighter, greatly increasing the number of bright satellites tracking the night sky. Some observers expect them to become the second brightest objects after the International Space Station.

BlueWalker 3 in orbit
In this artist’s impression, we see BlueWalker 3 in orbit. The network will circle the Earth approximately every 90 minutes.

Contributed / Nokia, AST SpaceMobile

Everyone, from amateurs like you and me to professional astronomers, are worried about the impact. Will their light compromise our vision of faint cosmic objects? What about the aesthetic experience of a night sky with minimal human interference? That’s not all. There are 30,000 new next-generation Starlink satellites awaiting FCC approval that can also carry antennas for cellphone connectivity. While these birds are only 269 ​​square feet (25 square meters) in diameter, there’s a whole lot more!

Tony Mallama

, who worked on the Hubble Space Telescope, is interested in the brightness of BlueWalker 3 and BlueBirds and asks for your help in monitoring their brightness. Once BlueWalker 3 rolls out, I’ll post when and where you can see it, along with a list of stars you can use to compare and estimate its brightness. You send me your luminosity estimates, and I’ll pass them on to Mallama. OK? Good.

Stay tuned for an update!

About Hannah Schaeffer

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