4 ms·

Have you ever looked at the moon while driving? It stays in the same position relative to the car, if the car is not turning. Plane on autopilot + camera stea

Have you ever looked at the moon while driving? It stays in the same position relative to the car, if the car is not turning. Plane on autopilot + camera steadied by plane body + fisheye lens (which he was using) makes this very believable. EDIT: not to mention, we are all hurtling around the Earth at around 1,000 miles per hour AS WE SPEAK. If that doesn't produce trails (it doesn't, see my math below), a few extra hundred MPH in a plane doesn't change jack squat.

dperfect 12y ago
Sorry, I still don't believe it. Even with a fisheye lens and an incredibly stable aircraft, you're still going to see trails. If you don't believe me, I invite you to try it. EDIT: I assume all the downvoters can provide us with links to their libraries of long-exposure, night aerial photography without using gyros?
- colanderman 12y ago
  See my edit. The only trails you will see are due to the rotation of the earth; not the movement of the plane. EDIT: MATH: Assume the horizontal FOV is ~90 degrees (conservative according to Wikipedia). 30 (time) seconds around the Earth is (90/360)/(24x60x60/30) = 1/720 of that field. Meaning, you'd need a 720 px image to even see one PIXEL of blur due to the rotation of the Earth. The additional velocity of the plane contributes MUCH LESS than this; hence it is not visible.
  - dperfect 12y ago
    Running some rough numbers: If a 10mm lens can capture ~120° angle of view, then the image at 1024 px (low quality) represents 0.117° per pixel. In the 30s exposure, there is < 3 px represented by many stars, so that's 0.351° of tolerance. How often have you flown in an airplane with less than 1/3 of a degree of drift on any axis over 30 seconds? Yes, I'm quite familiar with the rotation of the earth and its effects on long exposures (I do some astrophotography myself). I'm not referring to that here, but rather to the normal instability of an airplane. EDIT: I'm not just referring to pitch, but also to roll, yaw and vibration.
    - colanderman 12y ago
      Seeing as 1/3 degree drift in a plane traveling 700 MPH translates into nearly 300 feet of elevation gain/loss; and that the seat-back altimeter readouts on commercial airlines I've flown in never seem to deviate more than 10 feet from the set altitude, I'm gonna guess every auto-piloted flight I've been on drifts less than that. Not to mention that these are not the first pictures of stars this guy has taken from a plane: http://www.pbase.com/flying_dutchman/image/155755548 http://www.pbase.com/flying_dutchman/image/155755548
      - dperfect 12y ago
        Alright, you've convinced me. To be fair, most of this guy's other night aerial photos either have shorter exposure times or exhibit some obvious trails in the stars (even the one you posted shows considerably more streaking in the stars). Taken out of context, the few photos included in this post did seem more suspicious, but it looks like a combination of very good/stable conditions and a lack of resolution to notice more streaking.
        nitrogen 12y ago
        I thought it was worth letting you know that I upvoted this comment for conceding the debate when presented with evidence. This is a commendable skill, one which many of us lack, and which all of us occasionally forget to exercise.
        TeMPOraL 12y ago
        Yes, I also upvoted that comment and the one he made before. This is how a debate should look like - both sides present their reasoning using (however rough) numbers and facts, and settle on the result evidence suggests. Thank you for reminding us how adults should talk, and - if you forgive going meta - thanks @nitrogen for reminding us to remind this ourselves :).
        SiVal 12y ago
- ScottBurson 12y ago
  Skepticism is mandatory on HN, except when it's forbidden.
  - sgt101 12y ago
    People have taken to down voting things that they don't agree with, it's sad because it stops debate and contrary opinions. Down vote trolls, down vote personal attacks, down vote propaganda - sure.
    - Curmudgel 12y ago
      > People have taken to down voting things that they don't agree with, it's sad because it stops debate and contrary opinions. Downvoting to express disagreement was explicitly sanctioned by pg back in February 2008. https://news.ycombinator.com/item?id=117171 https://news.ycombinator.com/item?id=117171

dperfect 12y ago

Sorry, I still don't believe it. Even with a fisheye lens and an incredibly stable aircraft, you're still going to see trails. If you don't believe me, I invite you to try it. EDIT: I assume all the downvoters can provide us with links to their libraries of long-exposure, night aerial photography without using gyros?

colanderman 12y ago
See my edit. The only trails you will see are due to the rotation of the earth; not the movement of the plane. EDIT: MATH: Assume the horizontal FOV is ~90 degrees (conservative according to Wikipedia). 30 (time) seconds around the Earth is (90/360)/(24x60x60/30) = 1/720 of that field. Meaning, you'd need a 720 px image to even see one PIXEL of blur due to the rotation of the Earth. The additional velocity of the plane contributes MUCH LESS than this; hence it is not visible.
- dperfect 12y ago
  Running some rough numbers: If a 10mm lens can capture ~120° angle of view, then the image at 1024 px (low quality) represents 0.117° per pixel. In the 30s exposure, there is < 3 px represented by many stars, so that's 0.351° of tolerance. How often have you flown in an airplane with less than 1/3 of a degree of drift on any axis over 30 seconds? Yes, I'm quite familiar with the rotation of the earth and its effects on long exposures (I do some astrophotography myself). I'm not referring to that here, but rather to the normal instability of an airplane. EDIT: I'm not just referring to pitch, but also to roll, yaw and vibration.
  - colanderman 12y ago
    Seeing as 1/3 degree drift in a plane traveling 700 MPH translates into nearly 300 feet of elevation gain/loss; and that the seat-back altimeter readouts on commercial airlines I've flown in never seem to deviate more than 10 feet from the set altitude, I'm gonna guess every auto-piloted flight I've been on drifts less than that. Not to mention that these are not the first pictures of stars this guy has taken from a plane: http://www.pbase.com/flying_dutchman/image/155755548 http://www.pbase.com/flying_dutchman/image/155755548
    - dperfect 12y ago
      Alright, you've convinced me. To be fair, most of this guy's other night aerial photos either have shorter exposure times or exhibit some obvious trails in the stars (even the one you posted shows considerably more streaking in the stars). Taken out of context, the few photos included in this post did seem more suspicious, but it looks like a combination of very good/stable conditions and a lack of resolution to notice more streaking.
      - nitrogen 12y ago
        I thought it was worth letting you know that I upvoted this comment for conceding the debate when presented with evidence. This is a commendable skill, one which many of us lack, and which all of us occasionally forget to exercise.
        TeMPOraL 12y ago
        Yes, I also upvoted that comment and the one he made before. This is how a debate should look like - both sides present their reasoning using (however rough) numbers and facts, and settle on the result evidence suggests. Thank you for reminding us how adults should talk, and - if you forgive going meta - thanks @nitrogen for reminding us to remind this ourselves :).
        SiVal 12y ago
ScottBurson 12y ago
Skepticism is mandatory on HN, except when it's forbidden.
- sgt101 12y ago
  People have taken to down voting things that they don't agree with, it's sad because it stops debate and contrary opinions. Down vote trolls, down vote personal attacks, down vote propaganda - sure.
  - Curmudgel 12y ago
    > People have taken to down voting things that they don't agree with, it's sad because it stops debate and contrary opinions. Downvoting to express disagreement was explicitly sanctioned by pg back in February 2008. https://news.ycombinator.com/item?id=117171 https://news.ycombinator.com/item?id=117171