ISS transit over Saturn (APOD) image

From: Jon . via Seesat-l <seesat-l_at_satobs.org>
Date: Sun, 24 Jan 2016 20:50:18 +0100
Hello all;

Seeing the last messages on the list I've thought I'ts interesting to show
a conversation that some astrofriends and I had last days about this
"photo".

The following information was made and compiled by Dani Caxete, Fernando
Cabrerizo, Manu Arregi and myself.

Name of the author: Julian Wessel.

The APOD image was released the 2016 jan. 22:
http://apod.nasa.gov/apod/ap160122.html
The video is available here: https://www.youtube.com/watch?v=OV7iGt0AH_U
The blog post of the author:
http://jwastronomy.com/news/ISS-transit-in-front-of-Saturn
The equipment (setup): http://jwastronomy.com/me/equipment

Transit data:

Date: 2016/01/15
Time (taken from the video): 07:34:32.000 UTC (Real time of transit:
07:34:21:569 UTC)
Place: 51.826903, 7.431114, 57m (WGS84), +-100 meters.

Celestial coordinates:
-Saturn at transit time: RA 16h45'17", DEC 20º41'02" (J2000)
-Saturn's angular size: aprox: 15.5"

ISS data:
-Celestial coordinates at transit time: RA 16h44'41", DEC -20º37'51.8"
(J2000)
-Obs-ISS distance: 1145.302Km
-Mag. of ISS: +1.3 (V),30x20m
-ISS's size: 05.4" (based on mcnames archive, by Mike McCants).



Part one: ISS's trajectroy respect Saturn.

Please see the following capture:
https://dl.dropboxusercontent.com/u/32266013/iss1.PNG

This capture shows that taking the (practically) exact place showed on the
video taken from calsky.com, the ISS passes a bit higger than Saturn, about
1min 29 arcseconds from the center of Saturn. This can be seen on the video
released by the author on Stellarium's simulation. The image of the ISS is
not at scale but the ball represents the real size of Saturn despite the
rings.

See this second image:
https://dl.dropboxusercontent.com/u/32266013/iss3.PNG

This image shows all orbits published by the USPACECOM between the 13th and
16 of january. The marked one is expected to be the one of the calsky
prediction, of 1.3 days old.
Even if observer would be placed just in the middle of the transit line (of
about 30 meters wide), a 0.0 days old orbit released at about the transit
time indicates that it would be slightly off-track, inside Saturn but not
at center:

https://dl.dropboxusercontent.com/u/32266013/iss4.PNG

That does not make impossible to be true, but yes that would be extremely
"lucky".

As those days ISS's orbit is updated up to 4-5 times per day its easy to
think that accuracy of those elsets is enough good for reach that
conclusion.



Part two: ISS and Saturn's size:

As mentioned above, there is a mis-match between the size of Saturn and ISS.
ISS's size in this case is expected to be of 05'4" of arc, vs 36.5" of size
of Saturn. The ISS would be significatly smaller than Saturn, and in the
image is about of the same size. The size of Saturn was taken from
Stellarium, and the size of the ISS is taken by file mcnames, using
Heavensat for computing it.



Part three: Illumination of the ISS and Saturn:

The transit is taken about 4 minutes before local sunrise, and the Sun's
elevation is af about 0.4 degrees. It's impossible to obtain a so-dark
image with so many colours, specially of the ISS that is on movement.

Dani Caxete has noticed also that the illumination of the ISS is incorrect,
based of the rings of Saturn and a simulation of Stellarium plus putting
over the image:

https://dl.dropboxusercontent.com/u/32266013/dani1.jpg

As can be seen on this image the sun is in the other direction, that means
that the ISS should be illuminated in its other side, and also that the
solar panels should be pointing to the Sun.
That points that this ISS image was taken at dusk, not at dawn, when its
suposed to be taken.



Part four: The ISS looks to be copied and pasted:

This has been demonstrated by Fernando Cabrerizo.
Fernando showed us that the marked frame looks to be copy-pasted:

https://dl.dropboxusercontent.com/u/32266013/fernando1.PNG

Using advanced photo-edition software in subtraction mode using as
reference the marked frame shower in the previous image the ISS dessapears
in a perfect black over Saturn:

https://dl.dropboxusercontent.com/u/32266013/fernando2.PNG

All "frames" looks to be very similar, and for be like that the author
should had a never watched seeing in astronomy.

Fernando demostrated us that using the differential show mode with the
first frame compared with the rest, and taking some care because the image
was compressed in .jpg format one of the frames looks to be exactly the
same, and it dissapears in a perfect black colour:

https://dl.dropboxusercontent.com/u/32266013/fernando3.PNG

Here in GIF format, that points all frames to be practically identical:

https://dl.dropboxusercontent.com/u/32266013/fernando4.gif



Part five: Different distances between ISS shots.

Fernando used all the pre-transit frames for make the average of distance
between ISS shots. This image plots the first ISS frame and expands it at
same distance. There is an obvious distance mis-match, specially in the
frame that ISS transits Saturn:

https://dl.dropboxusercontent.com/u/32266013/fernando5.PNG

This was commented to the author of the photo, and he said that was because
a delay of the computer.



Part six: Conclusion.

All points explained above gives no chance to think that this photo is real.
Know what Julian Wessel really made is not easy. My theory is that he took
a photo of Saturn and a shot of some frames of the ISS in a high elevation
dusk pass and then pasted them together.
Anyway its clear that does not accomplish APOD's rules.


Sorry if this message does not comply Seesat-L's rules.



Jon.

​​
-- 
Jon, COSPAR 6242, 42.9453, -2.82839, 623m, Bitoriano, Basque Country.
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Received on Sun Jan 24 2016 - 13:51:07 UTC

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