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Enlarge image | West after sunset, an ordinary Saturday early June. In 2019, we can see Mars in this part of the sky. Some observers worry that Starlink satellites – because of their number – interfere with astronomy. See the table below. Graph via Guy Ottewell's blog.
Originally posted on Guy Ottewell's blog. Reprinted here with permission.
Editor's note: Skywatch observers were amazed last weekend to see a "train" of SpaceX Starlink satellites cross the night sky. Many wanted to see them. Soon, however, we began hearing rumors from seasoned observers about what will happen to our skies if SpaceX materializes its deployment plan for some 12,000 of these satellites. SpaceX plans to put about 720 satellites in orbit in 2019. Nobody knows for sure how bright the satellites will be once fully deployed and in their final orbit. This post by astronomer Guy Ottewell is one of the many articles we saw this week, expressing the concerns of lovers of the night sky on Earth.
The map above shows the evening sky for Saturday, June 1, 2019.
Mars, traveling north of the northernmost part of the ecliptic, was at its greatest declination north (over 24 ° C) on May 16. But it is still falling in the evening sky to pass behind the sun on September 2nd. moving in the opposite direction, came from behind the sun on May 21st and will be furthest away on June 23rd.
The moon is well below the horizon yet. It will be new on June 3, passing in front of the sun. The sky will be dark if there are neither clouds nor light pollution.
However, the graph below shows what this sky might look like after Elon Musk's SpaceX and nine other companies launched their commercial satellite 'constellations'. [Editor’s note: We hear the satellites will be moved to a higher orbit, making them too dim for the eye to see, except perhaps for the occasional flare when sunlight strikes them just so. Still … will they all be at the same high orbit? Will any of them be visible to the eye? Even if they can’t be seen with the eye alone, will they ruin astrophotos? Will they interfere with observations of professional astronomers? Many questions remain.]
Enlarge image | This view is purely imaginary. It's the Saturday night sky (same map as above), with several "trains" Starlink satellites. We do not yet know how bright the Starlink satellites will be, when the 12,000 of them will be deployed and installed in their final orbits. Even if they are not visible to the eye, will they interfere with astronomy, by their number? Graph via Guy Ottewell's blog.
The first 60 Musk Starlink satellites were launched in space on May 30th.
They were 280 miles and crossed horizon in about five minutes. Their eventual height will be 450 km (240 miles), so they will be less bright, but above the horizon longer and in the sun longer. They will be visible for three or four hours after sunset and before sunrise, which means that in the summer they will be visible all night long.
There will be a first set of 1,584 of these satellites, and possibly 12,000. They must be used for Internet communication. In addition to SpaceX, nine other companies are working on this "global space internet".
Astronomers, cited in an article by The Guardian, were "surprised". One of them said:
Everyone is surprised at how brilliant they are.
They had known:
… dismayed as they began to calculate the potentially dramatic impact on people's opinions on the cosmos.
They could be expected to have calculated early and soon enough the additional light added to the sky and the sky zone blocked for the telescopes.
Here's how the first "train" of Starlinks appeared as he was crossing Holland.
SpaceX Starlink objects will train on May 24, 2019, from Marco Langbroek to Vimeo.
Will our vision of the universe by our children be masked by these "constellations" of artificial satellites?
There is some analogy with the constellation, or procession, or the trail of ants of people that we now see on Mount Everest. This photo of a few days ago gave me a shock:
Crowd of hikers climbing the summit of Mount Everest. Image via the blog of Nirmal Sherpa / AP / Guy Ottewell.
Where is Sirius? Where is the long outdoor learning to know the starry sky? Where is the epic of progressive victory at the world summit?
Bottom line: Reflections on the possible damage to the night sky caused by SpaceX Starlink satellites. SpaceX would have been of service to the world of astronomy if it had calculated the effect of satellites on the night sky in advance and clearly communicated this effect.
More: SpaceX satellites could blur the night sky, warn astronomers. Of The Guardian
Read more: Will Elon Musk's Starlink satellites harm astronomy? Here is what we know. Of National Geographic
There are very good details about the Starlink mission in this article from NASASpaceflight.com
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