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increase displayed resolution of altitude and azimuth in ephemerides

Originally from ticket #7531.

I would like to generate ephemerides of altitude and azimuth of specific stars and the moon that require better that one decimal place accuracy (e.g. 236.0°) for a plot of relative orientation compared to vertical. Three decimal place accuracy is preferred (e.g. 236.052°). However, the ephemeris generator only records altitude and azimuth to one decimal. Can this be changed to three decimal place accuracy? If not, is there a way to convert from right ascension and declination (which are recorded in the ephemerides to greater accuracy) to altitude and azimuth?


  • 0
    Dave Whipps

    You can convert from RA/Dec to Alt/Az manually, but it's a tedious process. Unfortunately having only one decimal place precision in the Ephemeris Generator was a design decision (perhaps not well thought out) and there's no way for you (the user) to change it.

    One place that you do get much better precision is in the "Info" pane (on the left) when you choose and object and select "Show Info...". Alt/Az are shown to 3 decimal places here.

    If there are specific times / objects you're after, you can (manually) set Starry Night up to that time/location and view these more precise values for each object. Again, this is a bit tedious if you're after a lot of values, but manageable if you're interested in precision at a few, key times.

    We'll look into fixing that in a future version. Sorry.

  • 0
    Susan Thorson

    Thank you. Unfortunately, I will be generating many graphs each with 
    hundreds of data points for a book on the star motions that allowed the 
    Magi (spoken about in the Bible, book of Matthew) to find the Christ Child. 
    The graphs have quantum breaks as the decimal changes one unit. I can 
    work around this. Though once I understand the equations to convert from 
    RA/Dec to Alt/Az, I can convert these equations to a spreadsheet to 
    automate. Is there a reference you would suggest for these equations? 
    When you have a update that has more precision, I will update the my 

    Appreciate the response,

    Murray Thorson

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