NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Will anyone ever find Shackleton's lost ship?
From: Peter Monta
Date: 2022 Feb 09, 20:01 +0000
From: Peter Monta
Date: 2022 Feb 09, 20:01 +0000
It may not make much difference to your (interesting) analysis, but I wonder about the proper motions. Hipparcos has reference epoch 1991.25, which is pretty far removed from 1915 and would tend to amplify astrometric errors from extrapolation.
Would photographic plates from near 1915 be competitive astrometrically with backpropagated Hipparcos or Gaia? I think many of the early plate surveys have been scanned. On the downside, these stars are likely bright, and the photographic images may not be that great (saturated). Also, the surveys of the photographic era covered the southern hemisphere much less well.
I think the early Gaia releases used Hipparcos proper motions precisely because the Gaia time-baseline was still small (only one or two years) and Hipparcos could still usefully constrain the solution. But now, with more observation time, Gaia is fully self-sufficient. Maybe this means Gaia would offer lower uncertainty than Hipparcos for your application.
Cheers,
Peter
