QUOTE (Bjorn Jonsson @ Aug 11 2015, 12:25 AM)
Regarding NH's trajectory, if I remember correctly the flyby didn't occur at exactly the planned time (off by some seconds but well within the required accuracy) and this makes it more tricky to use the metadata to accurately determine the viewing geometry (especially in the hi-res images) until an updated trajectory (SPICE kernels) becomes avvailable.
At first I tried to use the data from
http://ssd.jpl.nasa.gov/horizons.cgi#top2457218.000000000 = A.D. 2015-Jul-14 12:00:00.0000 (CT)
NH:
r[km] 1.197739374505814E+09 -4.443897760753548E+09 -1.747680731829689E+09
v[km/s] 5.534336802447741E+00 -1.252001712778965E+01 -4.846832563458260E+00
Pluto:
1.197726655664916E+09 -4.443893298780707E+09 -1.747673432906277E+09
5.379986303470789E+00 8.159673817708096E-01 -1.389030301906091E+00
Charon:
1.197712275411875E+09 -4.443906278626040E+09 -1.747670469452485E+09
5.388459229072444E+00 8.566266433864180E-01 -1.169827709122328E+00
but I found that the position of NH was displaced approximately 120 seconds, so I used the least squares method (with using distances to Pluto, Charon, Nix and Hydra up to 2,000,000 km) to made a correction of 3D position (about 1,665 kilometers) and velocity vector (about 11.6 m/s) so that the simulated distances become coincide to metadata with an error of about 0.1 km.
r0_NH {1.1977391023383e9, -4.44389934311302e9, -1.74768117382772e9}
v0_NH {5.53196172582933, -12.51701129448342, -4.85774060000822}
For the calculation of rotation of Pluto and Charon, I used data from
http://link.springer.com/article/10.1007%2Fs10569-010-9320-4North pole: alpha0=132°.993, delta0=-6°.163, turn: W=237°.305+56°.3625225d
Click to view attachmentbut turn does not coincide with data from
http://ssd.jpl.nasa.gov/horizons.cgi#topso I use turn W=304°.155524+56°.3625225d and changed GM=873.22336378 km^3/s^2 for Pluto (instead 872.4 km^3/s^2).
As a result I got the following location of Charon relative Pluto:
Click to view attachmentSo if we take the Charon position as the origin point on Pluto, the ambiguity is not more than 0.1 degrees in latitude and 0.01 degrees in longitude. While for the purposes of mapping accuracy it is sufficient.
QUOTE (scalbers @ Aug 11 2015, 02:16 AM)
Interesting in that I had also noticed a North-South in my map compared with the official one near Tombaugh Regio. If we have the lat/lon subpoints readily available for the images (and if they are accurate) we can perhaps check and refine the maps better.
The main ambiguity is in position of Pluto center in frames. The given in metadata values are too bad, so I adjust it manually.
Only selfconsistent automatic map generation procedure can give accurate parameters...
Now I generate grids for all available LORRI frames. To better quality size is doubled to 2048x2048. Steps are 1,5,10 and 30 degrees.
For example:
Click to view attachmentYou can get grids in folder "Grids" from
ftp://gionov:NG@46.45.15.20/_Data/_LORRI/The source images placed in "Source", simulated images in "Simulate".