#293 Support HJD

Aaron Price

When the user is loading data for a star, allow them the option to load the HJD instead of the JD data. Most stars don't have HJD records, but some do. And those that do usually have a reason for it (ultra short periods, for example). So a checkbox on the data load page that says "HJD or JD (default)" or something like that should work.


  • David Benn

    David Benn - 2011-10-31
    • priority: 2 --> 8
  • David Benn

    David Benn - 2012-06-23

    It seems that there are 2 distinct scenarios here:

    1. Loading already-converted HJD (vs JD) values from a data source.
    2. Adjusting a set of JD-only data to HJD.

    For the first case, no computation is required. For the second case, computation is required and in particular, we need as input, the RA/Dec of the object whose observation times we are adjusting. The rest can be computed, e.g. Sun's RA/Dec for a given JD.

  • Sara Beck

    Sara Beck - 2012-08-06

    In the "AAVSO Extended format" there is a switch in the header information called "#DATE" which specifies whether the reported times are in JD or HJD. If HJD is specified, then the observations should be plotted as they are in HJD. If the user subsequently loads data from the AID (see tracker #3519136) those observations will need to be converted to HJD to match.

    Matthew says that the conversion algorithm isn't too hard and he will help us with it, David.

  • David Benn

    David Benn - 2012-08-07

    Comment from Sara in email Aug 7 2012: "For HJD files, they can be plotted exactly as JD ones would be. The only thing you should have to change is the X axis title which should say Time (HJD) to avoid confusion."

  • David Benn

    David Benn - 2012-08-19

    Perl HJD example code from Matt T

  • David Benn

    David Benn - 2013-01-20

    Implemented in http://vstar.svn.sourceforge.net/viewvc/vstar?view=revision&revision=946

    This currently uses B1950 RA/Dec from VSX since that's what hjd.pl used (and was converted to Java).

    The Landolt paper [2] below, and chapter 24 could be used as the basis for J2000 coords and HJD conversion.

  • David Benn

    David Benn - 2013-01-20
    • status: open --> closed-fixed

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