International Space Station (ISS)

Solar Disk Transit Video (33x slow-motion)

Technical Details:

Place:  Observatory Hubelmatt Luzerne, Switzerland (8°18’23’’ E, 47°02’17’’ N, 487 m)

Time:   August 16,  2003           12:17:51.6 MESZ

High speed video camera (Photron-ultima 512) in focal plane of solar telescope (refractor with 150 mm diameter and 3'600 mm focal length, grey filter 1/1’000x). Video with 1’000 fps, each with 1/36'500 sec exposure time. North is up – the transit was from right to left towards East, at a distance of 473 km from the observatory with a speed of nearly 8 km/sec. This picture is a composite of 11 video frames with an interval of 15 ms – ISS moves 120 m between 2 frames. 

© Roland Stalder, Astronomical Society Lucerne, Switzerland

Transit alert for event:

        name: ISS SonneMond Hubelmatt
    latitude: 47.0381 N
   longitude: 8.3064 E
   elevation: 1597 ft
alert radius: 10 mi
   time zone: 2.0
  last alert: 11 Aug 2003 | 5:21:50

During the current reporting period:
  minimum sun transit distance: 1.1 mi
  minimum moon transit distance: 13.7 mi

A - transit type (sun or moon)
B - travel distance (miles)
C - date
D - time
E - elevation angle of the ISS
F - azimuth angle of the ISS (positive = east from north; negative = west from north)
G - range (miles)
H - elevation corrected latitude for observing the transit
I -     "         "     longitude
J - how far (miles) can I be from the centerline?
K - is space station sunlit?
L - sun elevation angle
M - sun/moon separation angle

A B----- C----- D-------  E--- F-----  G--  H------ I-------- J---- K L---- M----
s    7.3 16 Aug 12:17:50  53.5  148.8  295  46.9973    8.1644   1.6
s    2.8 16 Aug 12:17:51  53.5  148.9  295  47.0322    8.2475   1.6
s    1.1              51.56                 47.0516    8.2941   1.6
s    2.3 16 Aug 12:17:52  53.5  149.1  295  47.0669    8.3307   1.6
s    6.7 16 Aug 12:17:53  53.5  149.2  295  47.1016    8.4140   1.6
s   11.3 16 Aug 12:17:54  53.5  149.4  295  47.1363    8.4975   1.6

Editorial comments (by Tom Fly)

I attempted to analyze Roland's composite photo, in order to estimate the prediction error.  In the process, I generated the graphic below.  Roland commented that he isn't certain that "up" was exactly north, so in fact this graphic (and hence the error estimated from it) may not exactly right.  Nonetheless, I think it's instructive for illustrating the amount of magnification Roland used.

Given the small field-of-view, Roland's video was amazingly well centered.  Also, the camera he used had only 2 seconds of digital "film" at the recording rate of 1000 frames per second, so his "window of opportunity" was quite narrow!

I look forward to seeing if this was a matter of beginner's luck, or if he can repeat the performance with a lunar transit  :-)