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Comment by DoingIsLearning | Hacker News Reader

"...that said, we’ll make sure Starlink has no material effect on discoveries in astronomy. We care a great deal about science." Elon Musk

A long exposure of Comet NEOWISE by Photographer Daniel Lopez: https://imgur.com/a/rDI1Onn

N.B. The white streaks are Starlink constellation passthrough trajectories

Starlink currently has 597 orbiting satellites they plan for more than 12k to be deployed. Amazon just got an approval for their own constellation of another 3k low orbiting satellites. Facebook and Alibaba will probably join this trend.

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That NEOWISE photo was 17 photos deliberately stacked to emphasise the problem rather than minimise it, so it's not really a fair datapoint. Astrophotograhy stacking software will generally remove items that don't appear in all photos in the stack rather than retain them (previous discussion on the topic: https://news.ycombinator.com/item?id=23926699). That said, I love taking photos of the night sky myself and had some Starlink satellites affect a single exposure photo of mine recently, so it is a real issue - just not quite as crazy as it looks from that photo.

> it is a real issue - just not quite as crazy as it looks from that photo

Aren't they planning to add a bunch more satellites?

Yes, but they're also trying to darken them so later launches should end up significantly less problematic than the initial ones[0]. I'm not trying to defend them here (in fact I'm quite annoyed from a photography perspective) but appreciate there's two sides to the story and they're at least trying to minimise the problem.

[0] https://www.theverge.com/2020/3/24/21190273/spacex-starlink-...

Since the ephemerides of all starlink satellites are known, shouldn't it be possible to program these into the camera and not expose the sensor when a satellite is overhead? Makes it more complicated of course but this can let everyone win

This image was pretty thoroughly panned as being either ignorant or malicious - there’s as much light coming off planes in the sky, yet astronomers don’t complain about that. That’s not to say the satellite aren’t irritating, but astronomers have mitigation mechanisms.

SpaceX doing well is also a net good thing, because it’s getting cheaper to put the telescopes in orbit, which is where we really want them to be. Earth’s surface has light pollution from cities, planes and drones; is dark enough for astronomy only a fraction of the time; and has constant occlusion from birds and bees.

> there’s as much light coming off planes in the sky

If you live right outside of an international airport, maybe, but there are areas where this is not true at all. Observatories are strategically built to be far away from such light pollution. StarLink encircles the globe, and there is no way to build around it.

Do the satellites in the photo have the new shades on them? I'd be interested to know how much the situation has improved with the improved anti-reflection.

Do they plan to retrofit the coating on the +500 deployed?

Are there regulations that prevent future constellations from Amazon or Facebook, or any other giant, to implement albedo reduction on their constellations?

Those won't be up forever. They're all in a decaying orbit. They will get replaced in about 5 years.

As has been stated many, many times, the satellites are in very low orbit and naturally degrade over time to burn up in the atmosphere. The ones in the first batches that do not have a shade will only be up for a few years (5 at most).

The visor satellites are supposed to be invisible to the naked eye. They're still orbit raising, so we don't have results yet.

A non-reflective coating on the satellites will not stop them from blocking the light from astronomical objects.

The concern astronomers raised was blooming caused by oversaturating their sensors, not blockage.

The photographer has admitted that he used stacking to create the image.

But isn’t stacking used for astro-photography all the time?

Yes. The same tool can be used to either remove or emphasize streaks.

Yes, it absolutely is.

Once we can colonize Mars and set up astronomy observatories on Mars, Starlink satellites orbiting Earth won't get in the way of astronomy discoveries.

The starlink satellites orbiting Mars might!

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