Almanac and Celestial Navigation Calculator

[Sean C]

I have added the option to the sky chart to display all 1,535 stars in the basic FK5 catalogue (see screenshot, below). As with the navigational stars, corrections for proper motion have been included. There is a check-box below the chart to show or hide them. These will not be selectable in the almanac or sight reduction calculator. But if you hover your mouse over them, the calculated azimuth and altitude will be displayed. So, they can be used for navigation in a pinch ... you'll just have to plot the LOPs manually. Maybe I will change this in the future.

I have also tweaked the map alignment. Waypoints shouldn't be plotted off the edge of the map anymore [mostly], and the waypoints, DR and fix should be plotted a bit more accurately. (Although at this scale I admit it's hard to see the difference.)

As always, the new version is available in the downloads section. Cheers!

v 0.3.3 - 2021, Nov 7

• Added the option to the sky chart to display all 1,535 stars in the basic FK5 catalogue. (This increased the size of the spreadsheet from 2.5MB to 3.7MB.)
• Tip: You can hover your mouse over any star to see its calculated azimuth and altitude.
• Fixed a bug causing the almanac date and time to change when using the data series or rise/set calculators. (Almanac date and time will still change when using the sight reduction tab.)
• Improved map alignment. Waypoints and DR/Fix will now be plotted more accurately.
• Minor formatting changes.

[Sean C]

New version available in the downloads section:

v 0.3.4 - 2022, Oct 24
· Added day of the week calculation on Almanac tab.
· Added the option to display the celestial equator and ecliptic to the sky chart.
· Added the ability to increment time on the Almanac tab.
· Updated the delta-T values.
· Moved the "Auto-Fill" button for the date of celestial sights and added an arrow to hopefully clarify the button's purpose.

[Sean C]

New version available in the downloads section:


v 0.3.5 - 2023, September 10
· Fixed a very old bug causing the LMST/LAST to exceed 24h.

v 0.3.6 - 2024, October 9
· Updated Delta-T values and extended the predictions to 2035.
· Corrected an error in the Delta-T tables which caused all BC years to be off by one year. The error resulted in a very minor mis-calculation of the position of all celestial bodies, most notably: the Moon.
· Updated the text above the Almanac output fields and printable list to indicate whether the year is BC or AD. This text will now also show the Julian calendar year for BC years. (I.e. it will not display a year "zero".)
· Fixed a bug which caused the times of rise, set & transit of the Moon to be calculated incorrectly under certain circumstances.