after Andrew has thoroughly overhauled Celestia's stars by implementing
** the new Reduction of the raw Hipparcos data
** Floor van Leeuwen, 2007 'Hipparcos, the New Reduction of the Raw Data'
** Astrophysics & Space Science Library #350.
** available at http://cdsarc.u-strasbg.fr/viz-bin/Cat?I/311
with much improved parallaxes (distances), my binary orbit data need to be revisited as well, since --for consistency-- the barycenter distances, RA, Dec and the primary's spectral classes are typically taken from
Celestia's stars.txt merged with revised.stc.
Moreover, Andrew made use of the 'Modify' statement in his new 'revised.stc' file, which my visualbins.pl and spectbins.pl Perl scripts in SVN do not yet understand. Since I found some time in the train during my past days of travelling, here are my adapted Perl scripts along with the resulting improved binary orbit data files.
Everything you need for testing is contained in this archive (~2.5 MB):
+++++++++++++++++++++++
http://www.celestiaproject.net/~t00fri/images/binaries_rev.zip
+++++++++++++++++++++++
(my modified Perl scripts, along with the current stars.txt, revised.stc from SVN (r 4643), all input data files and the modified output files, visualbins.stc and spectbins.stc).
If you have Perl along with the Math::libm module installed, you can easily run the Perl scripts yourself, just by typing their names (visualbins.pl or spectbins.pl) at the console prompt.
The generated data files visualbins.stc and spectbins.stc go into Celestia's data/ directory, as usual.
The Perl scripts first of all merge all modifications from revised.stc with the stars from stars.txt and save the result in memory. Then the published data
for 163 visual binaries from
S. Soederhjelm, Astronomy and Astrophysics, v.341, p.121-140 (1999)
(http://adsabs.harvard.edu/cgi-bin/nph-b ... .341..121S)
and for 39 spectroscopic binaries from
D. Pourbaix, Astron. Astrophys. Suppl. Ser. 145, 2000, 215-222
(http://www.edpsciences.org/journal/inde ... s9259.html)
, respectively, are read in and the distances compared with the improved ones from Andrew's new analysis. There are only the following few binary star systems, where there is a more than 10% disagreement of the published binary distances with Andrew's new analysis. Here is the direct output from my Perl scripts:
visualbins.stc:
---------------
Distance mismatch of 10.5236890878469 % with (revised) stars.txt for HIP 47479
Distance mismatch of 12.1248879450477 % with (revised) stars.txt for HIP 60129
Distance mismatch of 17.7512706376436 % with (revised) stars.txt for HIP 87655
Distance mismatch of 10.4594762802037 % with (revised) stars.txt for HIP 20347
Distance mismatch of 18.645348178515 % with (revised) stars.txt for HIP 20916
Distance mismatch of 10.4700427605474 % with (revised) stars.txt for HIP 113996
spectbins.stc
--------------
Distance mismatch of 46.6639357764932 % with (revised) stars.txt for HIP 10644
Distance mismatch of 15.9196185748745 % with (revised) stars.txt for HIP 96683
Distance mismatch of 22.9161641972114 % with (revised) stars.txt for HIP 99473
Distance mismatch of 12.4605212777792 % with (revised) stars.txt for HIP 108917
Distance mismatch of 16.7844770348707 % with (revised) stars.txt for HIP 114576
Note the 46% discrepancy for the HIP 10644 (Del Tri) distance, about which we had plenty of discussion previously! I hope, Andrew has also made sure that his HIP 10644 distance is indeed better than the one published by D. Pourbaix
. For reasons of internal consistency, I have decided to give preference to Andrew's new distances over the published barycenter distances from the above two binary orbit papers in ALL cases. Analogously, I replaced the RA, DEC coordinates of the barycenter by the ones from Andrew throughout. So part of the Del Tri issues should now be resolved...
+++++++++++++++++++++++++
As I frequently wrote, I ONLY believe results of an (involved) analysis after I have seen DIRECT tests of it's results in comparison with solid measurements. This also applies to my own results, of course
. Indeed, so far, direct observational tests of my Celestia binaries were still lacking (in public ).+++++++++++++++++++++++++
So let me present two (out of many) here:
70 Oph
-------------
Note that the shown data include almost 100 years of precision orbit measurements (black dots)!
Astrometric measurements of visual double stars are done with a telescope, by precisely observing in the course of time the 'position angle' of the secondary starting from North towards East and the apparent primary-secondary distance in the skyplane. Here is a nice diagram from
http://www.asahi-net.or.jp/~zs3t-tk/index.htm
containing the precise definitions of these to crucial experimental quantities for binary systems.
The corresponding predictions from Celestia (using my 70 Oph parameters from visualbins.stc not the ones from Grant in nearstars.stc!), I have extracted as follows:
I positioned the observer very close to Earth, activated the equatorial grid, turned it around by 180 degrees to have North pointing towards the observer's "feet" in accordance with the above diagram. Then I zoomed into the 70 Oph system (SHIFT + mouse left) such that the primary-secondary distance spans a fair fraction of the screen. Next without ever changing the zoom scale again, I entered the following times, where mostly the secondary is expected to align almost in parallel to one of the grid axes:
11/1887, 10/1898, 2/1905, 11/1931, 3/1961.
Each time, I made a screen shot of the changing 70 Oph configuration. Then I used GIMP to prepare a semi-transparent overlay of the 5 color-inverted screenshots with the primary always centered. Finally I performed ONE (and only one) rescaling of the image with the 70 Oph measurements wrto the overlay results from Celestia, to match the two drawing scales.
Here is the result, demonstrating beautiful consistency with my entire binary orbit implementation. The red dots (secondary) are from Celestia. The fat black dot is the primary.
Procyon CMi
--------------------
Same procedure, perfect consistency once again:
Let me ephasize the quite different inclination of this projected orbit as compared to that of 70 Oph!
Note that Grant's nearstars.stc file is still lacking the adaptation to Andrew's new analysis.
We should discuss how to proceed with the redoubled visual/spectroscopic binaries in nearstars.stc! Besides....it would be good to compare the quality of agreement of Grant's parameters (differing somewhat from mine) with direct observations as I exemplified above! Then we can tell, which data sets are more accurate...
I'll wait for some time to get your feedback. Then I shall commit my modifications to SVN.
Fridger
