How bad are satellite megaconstellations for astronomy? • Hacker News Board

Re: How bad are satellite megaconstellations for astronomy?

#131

Post by thayne » Fri, May 10, 2024, 4:40 AM UTC

dheera wrote: post #81

StellarScience wrote: post #42

There certainly is a real concern for astronomers, but the photo illustrations used in the article are selected to make things seem worse than they really are. They're wide field of view, long-duration exposures. That used to be the way astronomers imaged space, with film systems a century ago. But these days astronomical telescopes tend to have much narrower fields of view (like tiny soda straws peering into one par…

> the photo illustrations used in the article are selected to make things seem worse than they really are Exactly. I do a LOT of astrophotography and satellite trails are actually very easy to get rid of. Even the stupidest, most naive outlier rejection techniques, such as taking a stack of tracked images, finding their mean and standard deviation, throwing out any data points outside of 2 standard deviations, and th…

Taking pretty pictures, and collecting scientific data are very different.

If a satellite is anywhere close to your target object in a frame you are using for photometry (measuring the amount of light), the frame is ruined, because it adds noise.

Re: How bad are satellite megaconstellations for astronomy?

#132

Post by serial_dev » Fri, May 10, 2024, 4:40 AM UTC

thayne wrote: post #130

StellarScience wrote: post #42

There certainly is a real concern for astronomers, but the photo illustrations used in the article are selected to make things seem worse than they really are. They're wide field of view, long-duration exposures. That used to be the way astronomers imaged space, with film systems a century ago. But these days astronomical telescopes tend to have much narrower fields of view (like tiny soda straws peering into one par…

If you are looking for short period events, losing a single frame can mean losing critical data. > Or they can just use that information for better scheduling: wait a minute or two to image a particular spot, so there won't be satellites in the field of view. Which means more time and effort, and ultimately money needs to be spent on scheduling observations to avoid the thousands of these satellites. And sometimes it…

> What if a GRB happens

Yeah, what if? I mean, you probably missed the GRB, sure, but apart from that, you'll be fine and you can wait for the next one, or find a data from somewhere else.

Re: How bad are satellite megaconstellations for astronomy?

#133

Post by philwelch » Fri, May 10, 2024, 4:41 AM UTC

willy_k wrote: post #120

pfdietz wrote: post #91

Earlier quoted context omitted.

Ultimately it becomes so cheap we'll be able to put workers up there to assemble and maintain the telescopes, just like on Earth. We might see telescopes in telescope farms near a small station for the workers. It might even be possible to send workers out to the Sun-Earth L2 point to maintain telescopes there.

For what it’s worth, people have already fixed telescopes in space (ISS astronauts operating on Hubble).

Shuttle astronauts. ISS and Hubble are in very different orbits.

Re: How bad are satellite megaconstellations for astronomy?

#134

Post by whoopdedo » Fri, May 10, 2024, 4:41 AM UTC

StellarScience wrote: post #42

There certainly is a real concern for astronomers, but the photo illustrations used in the article are selected to make things seem worse than they really are. They're wide field of view, long-duration exposures. That used to be the way astronomers imaged space, with film systems a century ago. But these days astronomical telescopes tend to have much narrower fields of view (like tiny soda straws peering into one par…

> these days some of the best astronomy is performed by telescopes in space, so astronomy overall benefits by having easier access to space.

Public access satellites. The FCC requires broadcast licensees to demonstrate that they're acting "in the public interest". Should private rocket launches have to give a minimum amount of their payload to research and non-profit purposes?

Re: How bad are satellite megaconstellations for astronomy?

#135

Post by willy_k » Fri, May 10, 2024, 4:49 AM UTC

philwelch wrote: post #133

willy_k wrote: post #120

Earlier quoted context omitted.

For what it’s worth, people have already fixed telescopes in space (ISS astronauts operating on Hubble).

Shuttle astronauts. ISS and Hubble are in very different orbits.

Totally, I mixed up my spacewalk associations, thanks.

Re: How bad are satellite megaconstellations for astronomy?

#136

Post by ThrowawayTestr » Fri, May 10, 2024, 4:49 AM UTC

p_j_w wrote: post #96

delichon wrote: post #32

Earlier quoted context omitted.

Don't Chandra, Webb and Hubble, et. al. sufficiently prove the usefulness?

The cost of getting those into space is a relatively small part of the overall cost. The amount of cost benefit one of these telescopes would see just to the cost reductions gained specifically because of Starlink are insignificant.

> The cost of getting those into space is a relatively small part of the overall cost.

Are you sure about that?

Re: How bad are satellite megaconstellations for astronomy?

#137

Post by sitkack » Fri, May 10, 2024, 5:06 AM UTC

StellarScience wrote: post #42

There certainly is a real concern for astronomers, but the photo illustrations used in the article are selected to make things seem worse than they really are. They're wide field of view, long-duration exposures. That used to be the way astronomers imaged space, with film systems a century ago. But these days astronomical telescopes tend to have much narrower fields of view (like tiny soda straws peering into one par…

You ignore the entirety of the LSST which will take more image data in its first year than all of humanity.

It is wide field, and these constellations cannot just be stacked out.

You think you are more informed than you are.

Re: How bad are satellite megaconstellations for astronomy?

#138

Post by sitkack » Fri, May 10, 2024, 5:06 AM UTC

StellarScience wrote: post #42

There certainly is a real concern for astronomers, but the photo illustrations used in the article are selected to make things seem worse than they really are. They're wide field of view, long-duration exposures. That used to be the way astronomers imaged space, with film systems a century ago. But these days astronomical telescopes tend to have much narrower fields of view (like tiny soda straws peering into one par…

You ignore the entirety of the LSST which will take more image data in its first year than all of humanity.

It is wide field, and these constellations cannot just be stacked out.

You think you are more informed than you are.

Re: How bad are satellite megaconstellations for astronomy?

#139

Post by alethiophile » Fri, May 10, 2024, 5:17 AM UTC

p_j_w wrote: post #96

delichon wrote: post #32

Earlier quoted context omitted.

Don't Chandra, Webb and Hubble, et. al. sufficiently prove the usefulness?

The cost of getting those into space is a relatively small part of the overall cost. The amount of cost benefit one of these telescopes would see just to the cost reductions gained specifically because of Starlink are insignificant.

The cost of launch is small-ish compared to the total program cost, but the limitations on launch condition the engineering requirements in ways that inflate the engineering costs. JWST had to be built as an insane on-orbit autonomous origami project because its mirror couldn't fit in a fairing unfolded. Repeat for ten thousand other decisions that are made in order to optimize weight or volume.

If you can launch a hundred tons to orbit for $5M, you can just make a huge dumb cheap telescope and throw a dozen of them up there. Quantity covers a multitude of sins.

Re: How bad are satellite megaconstellations for astronomy?

#140

Post by labcomputer » Fri, May 10, 2024, 5:27 AM UTC

whoopdedo wrote: post #134

StellarScience wrote: post #42

There certainly is a real concern for astronomers, but the photo illustrations used in the article are selected to make things seem worse than they really are. They're wide field of view, long-duration exposures. That used to be the way astronomers imaged space, with film systems a century ago. But these days astronomical telescopes tend to have much narrower fields of view (like tiny soda straws peering into one par…

> these days some of the best astronomy is performed by telescopes in space, so astronomy overall benefits by having easier access to space. Public access satellites. The FCC requires broadcast licensees to demonstrate that they're acting "in the public interest". Should private rocket launches have to give a minimum amount of their payload to research and non-profit purposes?

Sure, why not? A Hubble-sized telescope is only about 12 tons, which is only about 70% the mass of what a Falcon 9 can deliver to low earth orbit, and SpaceX does that 100x per year (it's only May and they've launched 47 so far this year). For reference, Spitzer is 1 ton and Chandra is 6 tons.

The elephant in the room is that launching one Hubble per year to a Hubble-like orbit only uses about 1% of SpaceX's current annual demonstrated launch capacity, and the actual reason people are upset has little to do with the actual impact on astronomy and more do with wanting to punish a certain CEO. One new space telescope every year would completely revolutionize the field, yet he'd barely notice. Better think of something else.