I'd like to start with one question in particular, because I think it is the best question I've gotten so far:
Originally Posted by gerson
My answer is: It isn't. Stellarium is an awesome program and I use it all the time. But AFAIK, Stellarium won't do all the things that my spreadsheet does. Nor will my sheet do what Stellarium does. And you are correct that there are a lot of other almanac programs out there. Some of my favorites are: Teacup Navigation
by Roger Farley, AstroNav
by NavSoft, Navigational Algorithms
by Andres Ruiz González (also on mobile) and MICA
by the USNO. Some of those are free, some aren't - but I think they are all well worth the price
. So ... why mine?
Maybe a little background would help: My absolute favorite almanac program of all time was ICE - the USNO's Interactive Computer Ephemeris
. It ran on DOS and was geared mainly toward navigation
, with (IIRC) a little extra astronomy stuff. Well, ICE has long since been replaced by MICA and another program (the name of which escapes me at the moment). Now, I can still run ICE today using DOSBOX or similar, but the delta-T values are so far off that it is just not worth it. Hence the inclusion of a user-editable delta-T tab in my spreadsheet.
My next favorite program is MICA, and it still outputs accurate data today. Unfortunately, the one and only vendor of the program (Willmann Bell
) has closed. Hopefully a new vendor will be found soon. Besides that, MICA is sort of the opposite of ICE in that it seems mainly geared toward general astronomy, with navigation
taking a back seat. It is incredibly powerful, but not my ideal. And all of the other programs are great, too. But I always think I would like to see things done a little differently. So ... I made my own. Eventually I plan to turn it into an app (I'm learning
how to do that now) and maybe a PC program too ... a command line program.
Bottom line is: there is absolutely no reason not to use Stellarium (unless it really does have errors in some proper motions as has been discussed on NavList)
or any other program or method - as long as you like it. There is also no reason you cannot use them all. Except the USNO website (another great resource) which is down for an indeterminate amount of time.
Tell you what: if you are not completely satisfied with my spreadsheet, I will give you a full refund!
Seriously, though: thank you for giving me the chance to explain a little about my motivation.
Originally Posted by double u
I always found the idea of combining a traditional, "handicraft"-type of skill like celestial with computers
I do too. It always feels like cheating to me (like grantmc said) in this context ... or almost even (dare I say) pointless. (And I'm not being flippant.) The idea being that you're planning to use celestial when all the electronics
. I have shelves upon shelves of navigation books
. I even have a 1781 printing of the Tables Requisite. However, sometimes I want to reduce a round of sights quickly, or maybe go back over a bunch of old sights, or even just use the incredible computing power available to play around and see what time the Sun set in Timbuktu ... in 1502.
But there's also another thing to consider: celestial as a backup. Frank Reed has made an app which instantly allows you to check if your GPS is inaccurate
for whatever reason. All you need is a sextant
, his app and maybe a dodgy GPS
signal. Or you could just use it to practice your sextant
technique, it's great for that, too. That's another thing: tools like this are great for learning and checking to see if you're doing it right.
Anyway, point is: there are some good reasons for it. But I still haul out
the tables from time to time.
Originally Posted by Smokeys Kitchen
Wondering if the updated version(s) will be on the same link? Haven't looked at the link yet - but will there be a note regarding the versions?
Unfortunately no, not for the time being. I apologize. I will work
on a better delivery
method. I do plan on setting up a web page soon with other resources.
Originally Posted by Russ
Great Spread Sheets
but how do I download to actually USE it.
Sorry not enough of a computer geek
Russ [et al.]
Apologies. Please see my previous post.
Originally Posted by SaltyMetals
From the little that i remember from 30 years ago i notice one of your screenshots is for details of the moon but surely it should be "lower limb" ?
I'm not sure where you saw that, but it is entirely possible. There are in fact times when you need to use the upper limb. Certain arrangements of the celestial bodies, cloud covering the lower limb, doing a backsight, etc. These conditions are admittedly the exception, though.
Originally Posted by StoneCrab
It may not be in the near future, who knows? With the USNO site down and Willmann Bell closing their doors, I wonder. But, as Apollo366 mentioned: there are some great long-term almanacs available. I highly recommend this one:
Long Term Almanac 2000-2050: For the Sun and Selected Stars with Concise Sight Reduction Tables, 2nd Edition
Originally Posted by Apollo366
Hi Sean, I just tried using the Great Circle calculator and you don't have Hiva Oa or Nuka Hiva, Fr Polynesia in the data base.
As these are the two most common destinations leaving Balboa
for the So Pacific, can you include them or show me how to add them please?
I haven't looked, but are all the other common Coconut Milk Run destinations included?
Done. The data was copied almost verbatim from Pareto, so I don't know what all cities are in there. I just checked a few to see if it all worked. It's trivial (for me) to add new ones. The sheet is [supposed to be
] hidden and locked because I didn't really anticipate adding to it much. Maybe I'll unlock and unhide it in a future version, IDK.
Originally Posted by hzcruiser
I tried the beta 0.24 it with "Numbers" and "Open Office" on a Mac M1. Numbers could open it and seems to work, OO crashes on every attempt.
Yeah ............ I'm not too happy about the fact that LibreOffice and Numbers can simply bypass the password protection I carefully put in place to keep anyone from copying months of my hard work. But the blame for that rests squarely on Microsoft's shoulders and no one else's.
Thank you for testing it, though!
Originally Posted by Invictus69
Until some years ago I have been occasionally using Starpath Perpetual Almanac (www.starpath.com
), mostly for double checking the GPS chartplotter
Curious if someone can share experiences or comparison between the two.
I haven't tried Starpath's so I don't know. But I do know they are a great school
, so I imagine whatever they are using is at least as good as my spreadsheet.
Anyway, I hope that answered some questions. If I missed any, please let me know. I will try to answer as many future questions as I can, too.