First attempt at ISS streaking by

Discussion in 'Astrophotography' started by Djarum, Jun 2, 2015.

  1. Djarum

    Djarum Super Moderator

    Dec 15, 2009
    Huntsville, AL, USA
    Jason
    First attempt at ISS streaking by. This was actually a much wider shot, but my house was overexposed from the street lights.

    I find it interesting that the stars trail, but the ISS does not.

    full.
     
  2. Carbonman

    Carbonman Mu-43 All-Pro

    Jul 10, 2014
    Vancouver BC
    Graham
    The stars trail because they have continuous output, so show up as streaks from Earth's rotation. The ISS has short pulses of output and change of position relative to the stars, so can't generate streaks. Very neat shot - it would be interesting if you could borrow (or piggyback on) a motorized star tracker from a local astronomy club.
     
  3. Djarum

    Djarum Super Moderator

    Dec 15, 2009
    Huntsville, AL, USA
    Jason
    We were visited by the ISS again last night. The first image is a little bright because it was still dusk and the ISS was coming out of the WSW.

    Here, the ISS streaks right next to Jupiter in the sky.


    full.


    Over a neighbors house, heading NE.


    full.
     
  4. Wolfeye

    Wolfeye Mu-43 Regular

    64
    Mar 20, 2015
    Iowa
    I misread the title and thought I'd see nude extremist muslims... :)
     
    • Funny Funny x 1
  5. DeeJayK

    DeeJayK Mu-43 Hall of Famer

    Feb 8, 2011
    Pacific Northwest, USA
    Keith
    These are nice attempts, Jason. I like the third one best as including the house adds a sense of context. I'm curious as to what focal length these are shot at and how long the exposures were.

    Also, as to your question of why the stars trail, but the ISS doesn't, maybe I'm missing something, but the ISS is trailing, in fact much more dramatically than the stars. In fact, that's basically the intent of the shot.
     
  6. Djarum

    Djarum Super Moderator

    Dec 15, 2009
    Huntsville, AL, USA
    Jason
    DeeJay,

    The shots from Saturday night were at 24mm, cropped. 40s Exposure. Last nights shots were 60s at 30mm. The first image is slightly cropped. Second one uncropped.

    The stars "streak" or move in the frame because the earth is moving. LEO such as the ISS circle the earth at some inclination angle. I think the ISS rotates around at 51 degrees or something like that. Its moving at thousands of miles an hour. For instance, last night, from rise to set, it only took the ISS 5 minutes to pass.

    Since I was looking South I was expecting some lateral movement of the ISS since its not quite a geostationary orbit and does exibit some lateral movement as it rotates around the earth. Its just so small and the ISS moves so fast that I guess the camera can't capture it.

    http://www.nlsa.com/images/gallery/large/gallery1.gif
     
  7. DeeJayK

    DeeJayK Mu-43 Hall of Famer

    Feb 8, 2011
    Pacific Northwest, USA
    Keith
    I think I understand what you're saying w/r/t the streaking, but how would you expect the earth's rotation to effect the trail of the ISS? I imagine that if the satellite were moving more slowly this would show up as a sort of "bending" or curvature of the light trail.