Almanac and Celestial Navigation Calculator

[GrowleyMonster]

Thanks for posting this sad news and putting a face on a company that I have done business with on several occasions. Hopefully the company has enough momentum to keep providing the same level of service and same varied and high quality product line that this strange, landlocked ocean navigation supply company has become known for in the past several decades.

[SeanPatrick]

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.

[Midnight Son]

Thank you for all the work you are doing.
Best wishes.

[SeanPatrick]

Thank you!

[surazo]

I'm one of the sailor's that to which maintain the tradition of the sextant .Unfortunately I can't open your spreadsheet because It has eliminated from dropbox .Could you send another link please .Thanks

[surazo]

Thanks .I can downloads without VPN .Regards and great work ,Congrats

[Bycrick]

Actually, I found the combination of the sextant with a computer quite the best of both worlds. First long passage, I used an old Radio Shack computer with a home brew Basic program. The computer saved an immense amount of work and mistakes. Then as things got really wet, first the computer, then the HO229, then the HO249 all went away. Finished the trip with the sextant and HO211 from the back of Bowditch.

[GrowleyMonster]

Originally Posted by surazo

I'm one of the sailor's that to which maintain the tradition of the sextant .Unfortunately I can't open your spreadsheet because It has eliminated from dropbox .Could you send another link please .Thanks

FWIW, despite the disclaimer, I was able to open it with LIbre Office on my Ubuntu laptop. Seems to work okay but I didn't give it an exhaustive test or anything.

[SeanPatrick]

Originally Posted by GrowleyMonster

FWIW, despite the disclaimer, I was able to open it with LIbre Office on my Ubuntu laptop. Seems to work okay but I didn't give it an exhaustive test or anything.

Yes, it seems most of it will function correctly on other platforms. But some of the features don't work even on some versions of Excel itself. For example, I tried opening it on a machine at work and the printable list of bodies was all error messages. It seems the "filter()" formula I used is exclusive to newer versions and not backwards compatible.

In order to save myself the headache of figuring out exactly what won't work on each and every platform, I just went with the blanket statement that it "can't be guaranteed" to work on anything else. But hey, if it works well enough, then great!

I was thinking about making another version just for Libre Office. (I do have it installed on my PC.) Maybe it's time I got to work on that. We'll see. I had also planned on turning it into a mobile app, but I'm not sure if I will ever get around to that.

Thanks for the heads up! And thank you all for the kind words and for trying it out!

[SeanPatrick]

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 ... [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.

[surazo]

Thanks Sean

[SeanPatrick]

Originally Posted by surazo

Thanks Sean

You are very welcome!

[SeanPatrick]

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.

[Bowdrie]

Originally Posted by GrowleyMonster

I knew a guy who kept his old Loran C long after the stations were shut down. Why? Because he could use the Great Circle computation ability of the obsolete Loran to calculate his Zn and Hc by entering declination and GHA as a waypoint and his AP as another, and subtracting the resulting miles as minutes of arc from 90, All because he understood the celestial triangle and how it fits in to the world and universe around him. And this depth of understanding came from a dedicated study of Navigation. Cool? I think so. Some navi-phobes I am sure will disagree.

That was a great idea!
I did something on a smaller scale; Kept a Magnavox Sat-Nav on board for years after the system shut down.
It already had speed and course inputs, you could manually enter your estimated set/drift, (or not,) and it would keep a running DR for you.
I liked that Sat-Nav and found it quite accurate, (of course this was when GPS was in its 1st generation,) once, while sitting at anchor, I was in a place where I could take a round of bearings of known objects shown on the chart.
Plotting those bearings I KNEW where I was, and the Sat-Nav was actually closer than either of the 2 handheld GPS units.

Originally Posted by A.Sailor

Amazing work! I wish I could use it!
...it would be rather hard while far from the sea.

You might enjoy the stories of how the British drove a stake at the low tide of the tip of India and proceeded to march North, spreading out and mapping the entire country using sextants and transits, hauling huge degree wheels up on towers.
They poured mercury from a flask into a dish to make an horizon.

Sorry for thread drift,, I prefer HO 211, and made/printed up my own worksheets for it.
The HP 41 has a Nav-Pak in it, but the 41 has failed.
I wrote simple programs into the HP 48SX, but alas, it has gone down too.
But now I have no "need" to do any celestial work, but after recently observing the moon coming up on Jupiter and passing it I was intrigued by the idea of Lunar Distance.

[SeanPatrick]

Originally Posted by Bowdrie

But now I have no "need" to do any celestial work, but after recently observing the moon coming up on Jupiter and passing it I was intrigued by the idea of Lunar Distance.

Frank Reed has a great lunars page with information and tools for shooting lunars. My personal favorite is his easy lunars page, which describes how to do all of the math on a handheld calculator.

I also like the Stark Tables. But I think that once you get used to it, the calculator method is faster. Of course, Frank's online calculator is the quickest and easiest way.

Cheers!


PS
My original intent was to include a lunars calculator in my spreadsheet. I still plan on adding it one day when I have the time.