1. Mick West

    Mick West Administrator Staff Member

    DSCN5041-aw.

    This was a very lucky shot. I did not know the plane was there and it was only in front of the sun for about six seconds. Note also the two sunspots above and below the trail.

    Nikon P900 @ 2000mm
    Date Time Original: May 19, 2017, 7:47:19 PM (PDT, so 02:47AM May 20th UTC)
    Approximate photo location: 38.63°, -121°

    It presents an interesting geolocation opportunity for identifying the plane, due to the precisely known location the the sun at any time.
     

    Attached Files:

    Last edited: May 25, 2017
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  2. Mick West

    Mick West Administrator Staff Member

    We can use SunCalc to see what direction the plane would be in at that precise time.
    http://suncalc.net/#/38.63,-121,8/2017.05.19/19:47
    20170520-084921-9wbpn.

    Then overlay this on a FlightRadar24 playback to see what planes are in that direction.
    https://www.flightradar24.com/2017-05-20/02:47/12x/VRD353/d71c242
    20170520-085241-etzjg.

    Overlaid:
    20170520-085315-uepfz.

    It looks like the Virgin Plane is the best bet. Its tricky though, as there's three planes heading south (VX353 @36,750 descending, UA5523 @33,700 descending, and UA1170 @29,700 descending). And playback is inconsistent in positioning them. The above playback is labeled 02:47, but if I do it again at 02:48 I get the planes earlier in their tracks.

    20170520-085829-6t4ap.
     
    Last edited: May 20, 2017
  3. Mick West

    Mick West Administrator Staff Member

    Closeups of the plane, which appeared in two shots four seconds apart

    7:47:15
    20170520-090400-1m2yb.


    7:47:19
    20170520-090441-1pf56.

    Both images overlaid. Handheld, so the sun is in different position and I've lined them up. Not sure how much the sun moves in 4 seconds
    Both Overlay.
     
  4. Trailspotter

    Trailspotter Senior Member

    You can download the KML tracks of these planes and play them on Google Earth to see which one goes across the Sun if seen from the camera location.
     
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  5. Mick West

    Mick West Administrator Staff Member

    Can we ID the plane from the profile? All three planes are pretty similar. But I'd go for the A320 (Virgin) based on this:
    20170520-093204-wxrej.
     
  6. Trailspotter

    Trailspotter Senior Member

    These airframes are of different lengths. Can you derive the length of the plane with a sufficient accuracy from its angular dimensions and the known distances to each plane?
     
  7. Mick West

    Mick West Administrator Staff Member

    Winner! Only the Virgin plane goes across the sun.
    20170520-094659-qcupm.

    20170520-094744-t6ope.

    Viewed from my precise location (atmosphere turned off, to make the sun glare less)
    ScreenFlow.
     
    Last edited: May 20, 2017
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  8. Mick West

    Mick West Administrator Staff Member

    Approximately, for full zoom it's
    Size = distance * 0.01737 * pixels / image width
    (See: https://www.metabunk.org/calculatin...in-a-p900-photo-when-distance-is-known.t8146/ )
    20170520-102127-pfynh.
    Using the distance to the Virgin track
    467,000 feet * 0.01737 * 63 / 4608 = 111 feet.

    A320 = 122 feet
    ERJ-175 = 104 feet
    757-200 = 155 feet

    So you could eliminate the 757
     
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