Digital sextant

[Steve Laume]

Well this seems interesting. For all you traditionalists or doomsdayers how does this fit into the scheme of things. Celestial navigation racing categories?

http://www.kdigitalsextant.com/dsspec.h ... xk_Cqbafww

This certainly blurs the lines, Steve.

[wikakaru]

Interesting. There have been electronic sight reduction calculators for many decades, but putting the chronometer, a DR calculator, and a sight reduction calculator together with a sextant is something I haven't seen before. It makes sense that someone would eventually do this, though the market has got to be really small.

If you look carefully in the "Sighting Process" page (http://www.kdigitalsextant.com/dsprocess.html) they show getting a lat/lon fix using only the lower limb of the sun and upper limb of the sun taken a few seconds apart. I have no idea how that would work. I can understand getting a fix using two different celestial bodies, or using one body (i.e. the sun) in mid-morning and mid-afternoon and then advancing the earlier LOP, but how does two nearly simultaneous shots of the sun, even if they are of opposite limbs, give you a fix?

I assume that the sextant's computer would be susceptible to a lightning strike that could fry any other electronic navigation equipment, so you'd still need a nautical almanac and sight reduction tables anyway.

I guess if you are the kind of traditionalist who scoffs at using an electronic calculator to do your sights, then you will scoff at this, too.

Still, as I said, interesting. Thanks for posting.

Smooth sailing,

Jim

[John Stone]

Oh good grief. Once again we have taken something simple and robust and added unnecessary complication to it and made it less reliable. I guess we just can’t help ourselves. So you can mark me down as not interested in another gizmo that only serves to move us further away from using our brains.

Celestial is just not that difficult. I find turning the pages of the almanac and sight reduction tables fun and rewarding. The math is basic—adding and subtracting only. Sure, you have to buy a new almanac every year. The sight reduction tables for HO 229 are good forever. The tables for HO 249 (my method of choice) are good for 5 years.

https://farreachvoyages.net/2019/05/21/ ... beginning/

https://farreachvoyages.net/2019/05/27/ ... tar-shots/

There are inexpensive ways to learn celestial. It took me a couple days of reading and making practice shots to develop base line skills—accuracy within a mile. You can learn the basics from someone that already knows how in just a few hours. I taught all the steps to a fellow sailor in the Virgin Islands in about two hours. He was amazed that was all there was to it.

To be honest, most people are never going to learn celestial. GPS is so accurate and so easy the lazy parts of our brains, and the expense of learning celestial, will prove insurmountable. That’s not a crime. Learning new skills should not be annoying or aggravating. But for those interested in it, I can assure you it is very rewarding. Even if you never employ it, just learning the steps is eye opening.

[Pembquist]

I think it falls into the uncanny valley. It has convenience features but isn't really built around the user. What I mean is that a sextant that say has a built in chronometer that can save the time of sighting without taking your eye off the sextant seems like a basic nice feature. This isn't that. A compact machine that uses the miniature accelerometers optics and computing power of a smart phone to deliver the the ability to autonomously perform celestial navigation with an inuitive easy to use interface at a reasonable price would seem like a good backup/error check to gps/satnav. This isn't that either. It isn't clear why the computer is mounted to the sextant in this case but maybe I am missing something.

[BernieA]

I find it interesting that a digital sextant has even been created. I am not an open ocean sailor, but I have learned celestial navigation, dead reckoning, etc. simply because I want to know how to do it. I use GPS as I sail in the Salish Sea, but have the skills now to do so without it. My feeling about manual means of navigation is that they are a backup when modern technology fails. The idea of a sextant with digital technology added on makes it less capable as a backup to electronic failures. In a lightening strike, will its electronics survive? I've worked in telecommunications for 46 years and if there's one thing I learned, its not to completely trust the reliability of electronic systems. I guess I'm something of a luddite.

Bernie
CD 28 S/V Pinafore
Sequim WA

[mgphl52]

... if there's one thing I learned, its not to completely trust the reliability of electronic systems.

No, You are not a luddite! I have a neighbor who constantly tells me how the "electronics are going to kill us all!!"
Of course, he also knows I spent over 45 years as a programmer before I finally retired...
But back on the subject, I cannot imagine adding that much "pure crap" to a proper piece of navigational equipment.
Then again, look at the source country.
If you just want to make the simple math & table look up easier, surely you can download the tables to your phone which, as long as you have battery life on the phone, can be accessed anywhere.

[Steve Laume]

I put this up to see how it would be relieved. Not very well so far. I find it interesting that people don't like the idea of electronics mounted on the sextant but would rely on their phones or a calculator to do the sight reductions.

I am going to stick with my multiple GPS units for instant and continuous fixes. If lighting strikes are a major concern then keep one of your back up devices in a metal box or the oven.

I am still curious about how this thing would fit into celestial navigation, racing classes. If you are already allowed to use atomic clocks or watches and sight reduction calculators then how different is this?

We have come a long way, Steve.

[ghockaday]

I use a GPS, very useful when learning a new area to sail. Not to keep from getting lost but to get an estimate of water depth. Navigation aids are a long way apart and when you can go quickly from 40 feet to 4 feet in depth you may not have time to tack away.

Now if I ocean sailed I would definitely like to learn how to use a sextant without a bunch of electronic stuff. It kind of defeats the purpose of something so basic. Use one or the other or use as a backup but don't try to make it something its not. I don't see the point.

It's like using a telescope (also amature astronomer), if you depend on the computer on a telescope to find what you are looking for, you don't learn the sky.

Just my opinion, other's may vary, Dennis

[John Stone]

I put this up to see how it would be relieved. Not very well so far. I find it interesting that people don't like the idea of electronics mounted on the sextant but would rely on their phones or a calculator to do the sight reductions.

I am going to stick with my multiple GPS units for instant and continuous fixes. If lighting strikes are a major concern then keep one of your back up devices in a metal box or the oven.

I am still curious about how this thing would fit into celestial navigation, racing classes. If you are already allowed to use atomic clocks or watches and sight reduction calculators then how different is this?

We have come a long way, Steve.

Thanks for posting this Steve. It’s sailing related and it actually is interesting despite my negative diatribe. You can determine the time by “lunars” so you don’t have to have a clock for latitude. I’ve never done one. I think it’s pretty difficult even for very skilled celestial navigators, which I am not...yet. We all appreciate how accurate time transformed celestial nav from some guess work to a real fix. Who knows how many tens of thousands of lives it saved. I wouldn’t want to attempt a difficult landfall running down a line of latitude....

If it were my choice, philosophically, there would be no electronic computers allowed in celestial racing classes. You should submit your worksheets to the navigation committees-all the stubby pencil work that supports your calculations. While I stand by my remarks celestial is not difficult, I admit there is plenty of opportunity to make a math error, especially if you are tired...though the error will be quite obvious as it is almost always very large. The discipline and concentration required to make accurate fixes even when you are tired is part of the test for capable navigators. To me, manual computing is a big part of how we keep the skills alive. But, I imagine it creates a huge burden on the racing committee to verify it. And if racing allows electronic computation how is this digital sextant that much different. So, you asked a fair question. I don’t know. I guess that’s for the racing community to figure out. It has zero bearing on my choices.

I don’t carry electronic tables. Paper all the way. Not because I’m a purest (I have a hand held GPS and I have used inavx) but because it’s rewarding. The thrill can’t be duplicated electronically.

But, I will offer this after rereading Steve’s initial post and reconsidering the questions he asked. So after diving into the digital sextant literature...I appreciate some folks like clever electronics. They find using them fun and enjoyable. The user still has to located the heavenly body and make an accurate shot. That’s the hardest part anyway.

Sounds like a clever device though needlessly complex. But, who am I to judge what folks enjoy using. It would be interesting to use it and see it work. But I don’t think anything can replace my Plath sextant, paper almanac, sight reduction tables, and polar diagrams. That’s just me.

[John Ring]

...I am still curious about how this thing would fit into celestial navigation, racing classes. If you are already allowed to use atomic clocks or watches and sight reduction calculators then how different is this?...

That's a great point Steve.

Aside from the GGR where the whole race is celestial, there aren't many races with a Celestial class, just the Marion-Bermuda I believe. I'm sure this navigational atrocity will be DOA in the GGR, and I'm pretty sure it will be banned from Marion-Bermuda too.

It's really hard to verify a celestial boat's achievement when all they have to show for supporting paperwork is a bunch of digital plots on a scientific calculator. Based on this I'm thinking there is a fair chance calculators may be banned too, even when a traditional sextant is used. These devices run contrary to the tradition, and the spirit, of celestial navigation. There's nothing like a stack of damp/wrinkled/coffee stained, traditional sight reduction sheets to confirm authentic achievement in celestial navigation.

John Ring
CD36 Tiara

[Carl Thunberg]

I don't see this taking off in the sailing market for the reasons cited. I see a lot of potential in Naval or cargo vessels as a defense against a cyber attack that could take out GPS navigation, even temporarily. Plus, the Navy has a lot of money. We sailors are a drop in the bucket, financially.

[tartansailor]

I support all the aspersions cast at the advertized "gizmo" above.
Now I'm definately not the sharpest knife in the drawer; in fact
it took me four years of study before the Northern New Jersey Power Squadron
awarded me the grade of "Navigator" in 1993.
Guess what! I forgot it all. The emphasis was on the "Nautical Almanac Site Reduction Method.
but also included was HO 229. I have the 6 copies. as well as Ageton. John Stone is into the "Air Almanac.
That's interesting. The Invatation is open to any fellow Cape Dory sailor sailing through the Delaware Bay.
rest, respite, Dark and Stormys, who might like to take sites together.
Dick