deltack requires iterative application for edge cases with poor pointing and small targets.
This is an external support board issue.
It is likely that deltack will require a redesign to fix this issue.
Hello, I'm trying to do a simple deltack on images from the New Horizons Jupiter Encounter.
I run lor_0030677639_0x630_sci_1.fit through lorri2isis, do an editlab to swtich TargetName to Io, and then do a spiceinit attach=yes. However, when I try and deltack, I get this:
deltack fr= Io_deltack.cub samp1= 437 line1= 191 lat1= -5.249 lon1= 216.651
starting iteration 1
Degrees of Freedom: 0
Deltack Bundle has converged
Generating report files
Group = "Iteration1: Final"
Sigma0 = nan
Observations = 2
Constrained_Point_Parameters = 3
Constrained_Image_Parameters = 0
Unknown_Parameters = 5
Degrees_of_Freedom = 0
Rejected_Measures = 0
Converged = TRUE
TotalElapsedTime = 5.41e-04
ERROR Unable to update camera pointing for [Io_deltack.cub].
ERROR An unknown NAIF error has been encountered. The short explanation provided by NAIF is [SPICE(NOTAROTATION)]. The Naif error is [Input matrix was not a rotation.].
I hope the SPICE error is more instructive for you than it is for me. The intent is to move the pointing only by about 9 pixels.
In this particular case, Io was only a few pixels across, and that motion of 9 pixels was 'off the disk' of where SPICE thought Io was. I was told by a colleague (Schenk who heard it from Tammy) that deltack only works when the 'motion' is within the disk of the planet that SPICE is knows about. So to deltack your way more than a planetary radius requires several applications of deltack, moving about 2/3 of the disk each time.
So the solution requires me to iteratively apply deltack, when I'd just like to do it in one go.