3 ms·
It's the other way around. It's possible to escape light pollution by moving away from electrified areas, whereas satellite streak ruins observations in every p
by sreevisakh 6y ago
It's the other way around. It's possible to escape light pollution by moving away from electrified areas, whereas satellite streak ruins observations in every part of the world. Besides, the streaks are not really localized in the image. Its glow reportedly extends up to 15 arc seconds. That's a very large area for a carefully exposed array.
- 0-_-0 6y agoI meant light pollution affects the entire image, while a streak affects only part of it, which you can just remove. A 30 arcsec stripe on an (apparently average) 20 arcmin detector is 2.5% of the total area, so it's not a very large area. Overall, 20000 satellites at any given time cover 20kπ15acsec² of sky area, which is 0.0005% of total sky area, and over 1 second (assuming a satellite speed of 3.6 arcmin per second) it's 0.02424% of the sky, so roughly 1.45% of the surface area of a 1 minute exposure would have to be thrown out. This assumes that satellite streaks don't overlap, with overlap it would be less.
- sreevisakh 6y agoThe problem is with the exposure. 1min exposures are common in astrophotography, but astronomers are complaining about the types that need night-long exposure - ones that try to study cosmology, stellar composition etc. Many observations (like SDSS) are also large field observations that observe many objects simultaneously. Even a single streak can ruin an entire exposure. The odds just grow considerably.
- fingerlocks 6y agoIn digital photography, an exposure of N seconds can be produced from the sum of N/K shorter exposures at K seconds. This is more of a nuisance than a devastating blow.