Sean C
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Posts
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Sean C's Achievements
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New version available at my website: https://www.cooknavigation.com: 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.
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I have added the option to the sky chart to display all 1,535 stars from 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 at my website. Cheers! v 0.3.3 - 2021, Nov 7 Added the option to the sky chart to display all 1,535 stars from 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.
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Apologies, but I just found a bug ... of course. And it's a bug I thought I had already squashed. Maybe I'll get it right this time ... :o [Link] v 0.3.2 - 2021, Nov 2 Fixed a bug [again] causing the spreadsheet to display incorrect values for the equation of time under certain circumstances.
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New version available at my website. v 0.3.1 - 2021, Oct 31 Added rise, set, transit and twilight calculator. Increased precision of azimuths on the printable list to 0.1°. Added button to Data Series calculator to get the date and time from the Almanac. Added ecliptic longitude of Sun, Moon and planets to the Data Series calculator to facilitate determination of the times of equinoxes, conjunctions, etc. Corrected a minor error in the calculation of Ha of the LL of the Moon and Sun at extremely low altitudes. Added PA correction to the Sun. Updated delta-T table. Extended visibility chart to -5°. Minor formatting changes.
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If you can tell me what the format is, I might be able to do it. Shouldn't be hard, really.
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Sure. In fact, you can get 26,000 of them now ... from the same place I did: Pareto Software, LLC That's just the free database. There are paid options for up to 4.2 million cities! Cheers!
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New version available at my website. v 0.2.8 - 2021, Feb 28 Increased the number of decimals of azimuth included in the data series to a ridiculous precision. Fixed a bug causing the spreadsheet to display wildly inaccurate values for the equation of time under certain circumstances.
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There are numerous great apps for Android that will help with that: Sextant Stars, Google Sky Map, Nightshift (great app for astronomy) just to name a few. I think you can also get Stellarium on mobile. I don't use Apple products, so I can't advise on that. Stellarium for desktop is an outstanding program, and it's free. My spreadsheet does give some information which would be interesting to amateur astronomers. But I wouldn't recommend it to anyone who isn't somewhat familiar with all of the concepts involved. I have a Travel Scope 80 from Celestron (in addition to all my sextants, transits and other toys). That's what I used to take the 'blue Moon' picture (blue filter also from Celestron) which is the background of the homepage of my website. I want to get an Omni XLT 120 ... but everyone is sold out at the moment. Oh, well ... Cheers! Sean C
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New version at my website. beta v 0.2.7 Bug fixes/changes: Fixed a bug causing the intercept "away/toward" cell for sight #10 to remain empty Updated the cities database from ~15,500 cities to Pareto's current [free] offering: 26,570 cities (+ the two suggested cities) And here's an animation I made showing "Xerxes' Eclipse" on Oct. 2nd, 480 BC:
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New version posted at my website. Changes: v 0.2.6 Added printable bodies list Reformatted notes on "Precession and Stars" tab
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New version is available at my new website: https://www.cooknavigation.com
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Here is a new version: Bug fixes/changes: Fixed a bug causing the data series tab to display incorrect distances to some stars. By request: Added Hiva Oa and Nuku Hiva, Fr. Polynesia to the city database. Added unit indicators to the data series table headers. Clarified the note about stellar magnitudes. Added some credits to the "Instructions" tab. Zipped spreadsheet. Unzipped spreadsheet. And here is another example of the type of things you can do with the data series calculator: This chart of the recent conjunction of Jupiter and Saturn was made using the formula: acos(sin(dec.1) · sin(dec.2) + cos(dec.1) · cos(dec.2) · cos(GHA1 - GHA2 )) Hint: To convert a Julian Date to an Excel date, simply subtract 2415018.5 from the JD and format it as a date and/or time. Note, however, that Excel itself does not recognize dates before January 1st, 1900.
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Just found a new bug: the data series calculator gives incorrect distances for stars. :mad: That will be fixed in the next version.
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Bug fixes/changes: Fixed a long forgotten bug causing DRs to be calculated incorrectly when crossing the IDL. Fixed the bug causing the "Send to Log" button to overwrite manual entries. Added a "Data Series" tab which calculates data for a specified period and interval. Created a new bug by doing the above. (See "Instructions" tab.) Added a bar below the sky chart which indicates day/twilights/night. Added notes about stellar positions/magnitudes on the "Instructions" tab. Updated my contact email address. Please do not send mail to the previously listed one. Thank you. Link to the zipped spreadsheet. Link to the unzipped spreadsheet. All older links will now be broken. Current list of features: Perpetual almanac which lists basic data necessary for celestial navigation Sky chart showing traditional nav bodies above the horizon Data series calculator for comparison/analysis DR and sight reduction calculator Position log Great circle route calculator including internal database of ~15,500 cities worldwide Internal delta-T values for dates between 500 BC and AD 2030 Custom delta-T value fields for dates outside the above range - or whenever Only 2MB The new data series calculator can be used to make charts like the following for data comparison or analysis: Some stats: Total Sheets: 18 Cells with data: 180,868 Tables: 4 Formulas: 8,373 Charts: 2 Macros: 26 Days I've been working on it so far: 237 I will probably only post new versions at SubSim and NavList from now on ... unless someone really wants me to keep posting them here. You should always be able to find the latest version at one of the above sites.
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Bug fixes/changes: Fixed the bug preventing the sight reduction cells from clearing correctly ... I think. Delta-T values are now interpolated for dates between table entries. This will have the most noticeable effect on really old dates which cannot be completely trusted anyway. :confused: Added a note about compatibility issues. We're just not right for each other. (LibreOffice, not you - you're cool.) Discovered the "Application.ScreenUpdating" VBA object. The spreadsheet generally runs more smoothly after a liberal application to the macros (as you do). Added a nifty sky chart showing the positions of all visible traditional navigational bodies for the currently selected time and location which isn't quite what I intended, but looks pretty cool nonetheless. Link to new version. I still want to add Sunrise/set/twilight times. And maybe even some other calculators such as "Time Sights" and "Lunars". We'll see ... Enjoy! Sean C.