Monday, November 10, 2008

solar system objects by RA positions

I did up a new chart for the position of solar system objects by Right Ascension (RA). This is for 2009.

Once again I used Excel to produce the graph. But I did a few things a bit different this time, compared to last year.
  • Downloaded more granular data from USNO, every 7 days instead of 14. Hell, now that I think of it, I could go daily. Excel can handle it. More granularity gives smoother curves.
  • I created "dummy" or duplicate columns in the data set to handle the "loops" for Mercury and Mars. That was the inspired moment, the muses looking down on my brain. I don't know why I didn't figure that out last year. While it requires some manual intervention, it is an elegant trick to get another curve in the graph.
  • I let Excel interpolate values for the midnight line calculations. That said, I forgot to note the midnight line style in the legend...
  • Used a funky background fill pattern within the Plot Area, so to be a little more realistic. That said, it's too bad multiple dark and light regions could not be specified.
  • Having used the fill, now I'm forced to use JPEG as the image file format. I had to crank up the quality to reduce the lossy data dumping. And that in turn increased the file size.
  • Remembered to save the chart design in Excel under the User Defined. Should be able to build this much faster next year.

And if you want the Excel file, let me know...

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