Asteroid Zoo Talk

objets that appear in only 1 frame

  • sisifolibre by sisifolibre

    We must mark like asteroids objects that appear in only 1 frame?

    i have found some examples like this one that in the third frame appear two objets left down

    Posted

  • sisifolibre by sisifolibre

    http://talk.asteroidzoo.org/#/subjects/AAZ0001chp

    another one: frame 4, up left

    Posted

  • Emili_Sancha by Emili_Sancha

    How do yo know is an asteroid in only one frame?

    Posted

  • crystallubinsky by crystallubinsky

    If it appears in only one frame, and in that one very clear, are you marking the randoms as artifacts instead of asteroids? At first I was ignoring them due to lack of evidence of motion - but.... idk

    Posted

  • Emili_Sancha by Emili_Sancha

    an asteroid is a moving object...if it is very clear maybe is a star...two frames are the minimun.

    Posted

  • krezdorn by krezdorn

    However it could be that it is in frame "5..6..and 7", which we do not have. I have seen several of these very clear "one frame" dots. These do not look like artifacts as I currently understand them to be (from the online guide and help file), which look just like those that have been in multiple frames. Perhaps future and better explanations on the website here will help us. Until then however, without further frames I would say it's hard to say if it is or is not...but I would hate to mark it as an artifact, given it's "sharpness" (not a blur of pixels) Of course, unless it's possible that a light source (photon) can just appear in the darkness of space on the CCD detector, like ET turning on and off their interstellar flashlight to mess with us - LoL 😉

    Posted

  • sisifolibre by sisifolibre

    thank you very much krezdorn, you have expressed very good the motives of my question... and a good response

    in the future i mark this objets like artifacts, waiting for a better explication 😉

    Posted

  • scibuff by scibuff

    These are just hot pixels caused by cosmic rays hitting the CCD chip during exposure (it is fairly common). You can actually tell by how "sharp" and rather small (1-2pixel) the objects are. All real objects stars / asteroid (unless saturated) have very much the same apparent size - called Full Width Half Max = FWHM - http://en.wikipedia.org/wiki/Full_width_at_half_maximum

    Unless you see the object on at least three images of the four (or five), you should NOT be marking it as an asteroid e.g. two cosmic rays can strike the CCD so that it appears as a motion of a single object across two frame. Theoretically, the same could happen with 3 or 4 cosmic rays but it is statistically quite unlikely.

    Posted

  • sisifolibre by sisifolibre

    ok, perfect explanation, I hope this artifact joins the tutorial or guide in whith a little more detail because I see more people with the same question

    Posted

  • dudrea by dudrea

    Thank's also. I've marked last one as asteroid in error. Now I know !

    Posted

  • Dr.Asteroid by Dr.Asteroid scientist, admin

    This an issue. While it certainly possible for an asteroid to show up in only one frame of a given set, I would say that it needs to be at least 3 out of the 4 for us to be able to report to the minor planet center. The frames are chopped to ensure enough overlap that for any reasonable asteroid speed, it should be present in some set (even if this particular set of frames on has one appearance). So even if it looks really good but is only two frames - don't worry. It'll show up in another set of images.

    Posted

  • Del_Congdon by Del_Congdon

    bump

    Posted