Sightings of SpaceX’s Starlink satellites spark awe — and astronomical angst

SpaceX’s unorthodox card-dealing launch of 60 Starlink broadband satellites has led to into an unusual viewing opportunity for skywatchers — and an occasion to wonder about the impact of such mega-constellations on the natural night sky.

A video captured by satellite-watcher Marco Langbroek in the Netherlands sums up the awe. “I could not help shouting ‘OAAAAAH!!!!’ he wrote on his SatTrackCam Leiden blog. “Here is the video I shot, be prepared to be mind-blown!”:

It didn’t take long for Langbroek and other skywatchers to work out the coordinates for the long train of satellites, and to plug those coordinates into online satellite-pass calculators such as CalSky. On Twitter, David Dickinson, author of “The Universe Today Ultimate Guide to Viewing the Cosmos,” started doling out location-specific sighting predictions based on the Orbitron satellite-tracking program.

CalSky automatically picks up your coordinates for satellite sightings, but for those in the Seattle area, the best time to look for the Starlink train passing by tonight is likely to be in the range of 10:50 to 11:10 p.m. PT, going from southwest to northeast. That’s a liberal stretch of time that accounts for a range of locations (say, Port Townsend vs. North Bend), plus uncertainties in the orbital estimates.

There are other passes overnight at around 12:30, 3:50 and 5:20 a.m. PT. The brightness of the satellites is a question mark. Some say they can be seen with the naked eye, while others advise scanning with binoculars. A lot depends on how the satellites pick up the glint of the sun after dusk or before dawn. Tonight Langbroek reported that the satellite train wasn’t as bright as it was the night before.

Speaking of brightness, astronomers and SpaceX fans have already begun the debate over the prospect of having thousands of broadband-beaming satellites in low Earth orbit. The 60 satellites launched this week merely represent the beginning of a campaign aimed at launching as many as 11,000 such spacecraft. And that’s just for SpaceX’s Starlink system. Thousands more could go into orbit for the constellations being contemplated by OneWeb, Telesat, LeoSat Enterprises and Amazon’s Project Kuiper.

Last year, Rocket Lab came in for some grief from astronomers for sending up its “mirror-ball” Humanity Star satellite for a few months of twinkle time in the night sky. This week’s Starlink spectacle renewed the discussion over potential interference with astronomical observations. Even SpaceX CEO Elon Musk joined in:

In any case, the Starlink satellites shouldn’t be bunched up for long. SpaceX’s plan calls for each satellite to raise its orbit from the deployment altitude of 440 kilometers (273 miles) to the operational altitude of 550 kilometers (342 miles). That happens on a timed basis, every 90 minutes. The idea is that as each satellite raises its orbit, it lags behind the rest of the chain.

Within just a few days, the tightly spaced “train” will turn into a dispersed chain that girdles the globe. And once that happens, chances are that skywatchers and sky-worriers alike will turn their attention to the next batch of Starlink satellites.

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