6 ms·

Guide stars found as Euclid's navigation fine tuned

70 points by raattgift 3y ago

greggsy 3y ago
This makes me wonder, do extra-solar space probes need to adjust their star charts to account for a change in their related location, or is the change negligible?
- icegreentea2 3y ago
  If you knew you were going extra-solar, you would want to pick guide stars with minimal/immeasurable parallax over the scale traveled. A naive worst case scenario would be not negligible. For example, Proxima Centuri has a measured stellar parallax (from Earth - so across a 2AU distance) of ~0.8 arcseconds. We were able to measure that parallex from the ground by the mid 19th century. Abusing small angle approximations, that implies that each ~arcsecond of shift you encounter could potentially mislocate you by ~2AU...
  - dylan604 3y ago
    close enough for horseshoes, on a cosmological scale. pretty much a ringer!
- wolfram74 3y ago
  As others have noted, depends on which stars you're using as reference points. We've done some interesting long-distance parallax stuff at the demo scale, new horizons took some pictures last year to that effect. https://www.nasa.gov/solar-system/nasas-new-horizons-conducts-the-first-interstellar-parallax-experiment/ https://www.nasa.gov/solar-system/nasas-new-horizons-conduct...
- dylan604 3y ago
  Have you ever seen the 3D views of where stars in the constellations are in relation to each other? These kinds of videos are something that I think really helps esoteric concepts become much more widely understood, and I'm constantly jealous of them from the position of going to school vs "back then" when I was in school. Here's Orion: https://www.youtube.com/watch?v=lD-5ZOipE48 https://www.youtube.com/watch?v=lD-5ZOipE48
Y_Y 3y ago
"We'll fix it in the first patch" Programming for astronomy is famously difficult, since you're always pushing the boundaries one way or another. That said the problem domain is fairly well specified and (as the article shows) usually well models. Mr. Feynman going to Washington showed what treating astro like office software can do, but it's a shame when an expensive project gets a fleshwound from something predictable. See also: what JAXA launched and x-ray satellite that couldn't stop spinning, or that notorious kerfuffle converting pounds-force-hogsheads into metric that sent a very expensive item off into oblivion.
- cratermoon 3y ago
  I've noted, unscientifically, space flight problems are now largely about software bugs. Rarely is the hardware the root cause, with notable exceptions like the first SpaceX Starship flight. That tracks for me, as software "engineering" is a long way from any other engineering discipline, including aerospace. > that notorious kerfuffle converting pounds-force-hogsheads into metric that sent a very expensive item off into oblivion. I feel compelled to chime in here and point out there was far more at fault than a units conversion error. “A critical flaw was a program management grown too confident and too careless, even to the point of missing opportunities to avoid the disaster.” https://spectrum.ieee.org/why-the-mars-probe-went-off-course https://spectrum.ieee.org/why-the-mars-probe-went-off-course Look at program management in the aerospace industry and you'll see software treated as an afterthought, or poorly managed and tested. It seems developing space-worthy software is still largely a work in progress.
  - pests 3y ago
    I saw a quote on here awhile back. Not sure from where or who said it originally. It was exactly what you realized. We would have intergalactic space travel and von neumann probes by now if it wasn't for software. Materials science, energy production, construction - all solved problems. We just don't have the computer engineering skills to make it all work. I think this also touches on another thing I've always felt about software engineering - we are not a professional field. I have seen programmers complain about having to read the documentation for their tools or that they have to go fix 100 instances of some issue. Contrast this to an engineer on a skyscraper for example - you would never hear "you cant expect me to go re-torque all 1000 bolts! its not my fault the spec sheet put that information 3/4ths into the manual. i didnt get that far!" - but this is exactly how I've seen people treat computer engineering.
yardshop 3y ago
> Loopy star trails show the effect of Euclid's Fine Guidance Sensor intermittently losing its guide stars https://www.esa.int/ESA_Multimedia/Images/2023/10/Loopy_star_trails_show_the_effect_of_Euclid_s_Fine_Guidance_Sensor_intermittently_losing_its_guide_stars https://www.esa.int/ESA_Multimedia/Images/2023/10/Loopy_star... Now that's some beautiful Glitch Art!
- dylan604 3y ago
  You can achieve similar on terra firma. Go way out to the boonies away from city light pollution. You'll be in nature with all of the critters that entails, but hopefully the flying types. Set up your camera to frame just the night sky. Set it for long exposure focused at infinity. Place a dim light source near the camera but out of frame. Black lights work wonderfully well. As the night progresses, all sorts of flying insects will swarm your camera rig at random heights. As they fly around during the exposure, you'll end up with a very similar look.
  - dotancohen 3y ago
    In the fine article, all the trails have identical paths.
    - dylan604 3y ago
      i said "similar". besides, mine cost pennies compared to what the image in TFA cost. you get what you pay for. or, set up the same rig minus the light, and then give the rig a shake while the shutter is open. much less random in the streaks.
  - yardshop 3y ago
    I like your idea, I could do it right in my front yard, but what I like about the image in the article is the very nice proportions and exact repetitions of the curves and even the little dove-head figure, and the fact that it was entirely unintentional. Added bonus that it cost millions and millions and involved over the top equipment and time and distance!
kwentine 3y ago
> It arrived smoothly at Lagrange point 2, focussed its telescope mirror and captured its first mesmerising test images. It soon became clear, however, that the mission was experiencing some hiccups. Did anyone else wonder if Advent of Code had begun early this year ? ;)
bloopernova 3y ago
What a wonderful sci-fi headline. "Guide Stars Found as Euclid's Navigation Fine Tuned" (I included it here in case the headline is changed)

70 points by raattgift 3y ago

This makes me wonder, do extra-solar space probes need to adjust their star charts to account for a change in their related location, or is the change negligible?

icegreentea2 3y ago
If you knew you were going extra-solar, you would want to pick guide stars with minimal/immeasurable parallax over the scale traveled. A naive worst case scenario would be not negligible. For example, Proxima Centuri has a measured stellar parallax (from Earth - so across a 2AU distance) of ~0.8 arcseconds. We were able to measure that parallex from the ground by the mid 19th century. Abusing small angle approximations, that implies that each ~arcsecond of shift you encounter could potentially mislocate you by ~2AU...
- dylan604 3y ago
  close enough for horseshoes, on a cosmological scale. pretty much a ringer!
wolfram74 3y ago
As others have noted, depends on which stars you're using as reference points. We've done some interesting long-distance parallax stuff at the demo scale, new horizons took some pictures last year to that effect. https://www.nasa.gov/solar-system/nasas-new-horizons-conducts-the-first-interstellar-parallax-experiment/ https://www.nasa.gov/solar-system/nasas-new-horizons-conduct...
dylan604 3y ago
Have you ever seen the 3D views of where stars in the constellations are in relation to each other? These kinds of videos are something that I think really helps esoteric concepts become much more widely understood, and I'm constantly jealous of them from the position of going to school vs "back then" when I was in school. Here's Orion: https://www.youtube.com/watch?v=lD-5ZOipE48 https://www.youtube.com/watch?v=lD-5ZOipE48

Y_Y 3y ago

"We'll fix it in the first patch" Programming for astronomy is famously difficult, since you're always pushing the boundaries one way or another. That said the problem domain is fairly well specified and (as the article shows) usually well models. Mr. Feynman going to Washington showed what treating astro like office software can do, but it's a shame when an expensive project gets a fleshwound from something predictable. See also: what JAXA launched and x-ray satellite that couldn't stop spinning, or that notorious kerfuffle converting pounds-force-hogsheads into metric that sent a very expensive item off into oblivion.

cratermoon 3y ago
I've noted, unscientifically, space flight problems are now largely about software bugs. Rarely is the hardware the root cause, with notable exceptions like the first SpaceX Starship flight. That tracks for me, as software "engineering" is a long way from any other engineering discipline, including aerospace. > that notorious kerfuffle converting pounds-force-hogsheads into metric that sent a very expensive item off into oblivion. I feel compelled to chime in here and point out there was far more at fault than a units conversion error. “A critical flaw was a program management grown too confident and too careless, even to the point of missing opportunities to avoid the disaster.” https://spectrum.ieee.org/why-the-mars-probe-went-off-course https://spectrum.ieee.org/why-the-mars-probe-went-off-course Look at program management in the aerospace industry and you'll see software treated as an afterthought, or poorly managed and tested. It seems developing space-worthy software is still largely a work in progress.
- pests 3y ago
  I saw a quote on here awhile back. Not sure from where or who said it originally. It was exactly what you realized. We would have intergalactic space travel and von neumann probes by now if it wasn't for software. Materials science, energy production, construction - all solved problems. We just don't have the computer engineering skills to make it all work. I think this also touches on another thing I've always felt about software engineering - we are not a professional field. I have seen programmers complain about having to read the documentation for their tools or that they have to go fix 100 instances of some issue. Contrast this to an engineer on a skyscraper for example - you would never hear "you cant expect me to go re-torque all 1000 bolts! its not my fault the spec sheet put that information 3/4ths into the manual. i didnt get that far!" - but this is exactly how I've seen people treat computer engineering.

yardshop 3y ago

> Loopy star trails show the effect of Euclid's Fine Guidance Sensor intermittently losing its guide stars https://www.esa.int/ESA_Multimedia/Images/2023/10/Loopy_star_trails_show_the_effect_of_Euclid_s_Fine_Guidance_Sensor_intermittently_losing_its_guide_stars https://www.esa.int/ESA_Multimedia/Images/2023/10/Loopy_star... Now that's some beautiful Glitch Art!

dylan604 3y ago
You can achieve similar on terra firma. Go way out to the boonies away from city light pollution. You'll be in nature with all of the critters that entails, but hopefully the flying types. Set up your camera to frame just the night sky. Set it for long exposure focused at infinity. Place a dim light source near the camera but out of frame. Black lights work wonderfully well. As the night progresses, all sorts of flying insects will swarm your camera rig at random heights. As they fly around during the exposure, you'll end up with a very similar look.
- dotancohen 3y ago
  In the fine article, all the trails have identical paths.
  - dylan604 3y ago
    i said "similar". besides, mine cost pennies compared to what the image in TFA cost. you get what you pay for. or, set up the same rig minus the light, and then give the rig a shake while the shutter is open. much less random in the streaks.
- yardshop 3y ago
  I like your idea, I could do it right in my front yard, but what I like about the image in the article is the very nice proportions and exact repetitions of the curves and even the little dove-head figure, and the fact that it was entirely unintentional. Added bonus that it cost millions and millions and involved over the top equipment and time and distance!

kwentine 3y ago

> It arrived smoothly at Lagrange point 2, focussed its telescope mirror and captured its first mesmerising test images. It soon became clear, however, that the mission was experiencing some hiccups. Did anyone else wonder if Advent of Code had begun early this year ? ;)

bloopernova 3y ago

What a wonderful sci-fi headline. "Guide Stars Found as Euclid's Navigation Fine Tuned" (I included it here in case the headline is changed)