What sextant ?

Lew Decker

Member III
:esad::esad::esad:

Whoops. I remember that I paid $340 for my Tamaya, and that included the 7X scope. I just punched up the current offerings. All I can say is, "Dang!"

Since celestial navigation via sextant has been reduced to hobby status, you could use any type that falls into a decent price range. People have circumnavigated with the Davis instruments, so...

I also know of at least one cruising boat that made it out to Hawaii by following jet contrails. Hmmm. Maybe that's an old sailing myth?

I actually sailed to Tortola from St. Pete on a delivery and took exactly one star sight. True story. There were a lot of contrails.:egrin:
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
"Sky and Sextant" is indeed easy to understand. (Relatively speaking...)
It has been on my bookshelf for many years. When you want even more reasons to have a sextant handy, read his other book "Shoreline and Sextant".

I may never need/ to utilize this technology for my local sailing, but his books are accessible and understandable even for duffers like me.

Loren
(sailing 90 miles inland from the ocean.)
 

bgary

Advanced Beginner
Blogs Author
Dusting off an old thread.

I feel like relearning celestial. No particular reason other than a combination of long winter nights and the recognition that it was an interesting discipline.

I have my trusty old sextant, I have my HO-229, I ordered a 2020 almanac from Amazon, I figure I can use my GPS-sync'd watch as a chronometer. I might even go completely old-school and dig out my "star-finder" although the "stellarium" app on my phone is pretty amazing.

Given that it's been more than 20 years since I did my last sight reduction, I gotta believe the craft has evolved. Anyone have a favorite self-teaching book (I was once a fan of Blewitt's book, but open to suggestions.), a favorite sight-reduction form, or other hot tips?

Bruce
 
Last edited:

Joliba

Contributing Member
Dusting off an old thread.

I feel like relearning celestial. No particular reason other than a combination of long winter nights and the recognition that it was an interesting discipline.

I have my trusty old sextant, I have my HO-229, I ordered a 2020 almanac from Amazon, I figure I can use my GPS-sync'd watch as a chronometer. I might even go completely old-school and dig out my "star-finder" although the "stellarium" app on my phone is pretty amazing.

Given that it's been more than 20 years since I did my last sight reduction, I gotta believe the craft has evolved. Anyone have a favorite self-teaching book (I was once a fan of Blewitt's book, but open to suggestions.), a favorite sight-reduction form, or other hot tips?

Bruce
Bruce,
I know that you wrote this a few months ago. But I just noticed it. I used my Heath sextant, which I still have, to navigate across the Caribbean and South Pacific in 1976-7. I have pulled it out to play with a few times since then. I learned to navigate from Dr. Frances Wright. Her book, Celestial Navigation is a short, very good way to refresh your techniques. If you want to try something more “high tech” the iOS app, Star Pilot, though pricy, has all you need to quickly reduce any celestial sight without need for tables or almanacs. It even picks out possible stars for sight planning. I hope to try a few sextant sights this summer myself.
Mike Jacker
 

Teranodon

Member III
I have a sextant but do not use it any more. It is very hard to use on a boat, and I would say that it would be pointless to take it up without intending to devote months to the project. That said, the learning process can be great fun, if one tries to actually understand the principles of celestial navigation, rather than just using the tables in a cookbook way. One of the fun things that one learns is spherical geometry, which is pretty mindblowing.

I cannot possibly worry about a failure of the GPS system. Short of nuclear war or a complicated terrorist attack, it just ain't going to happen. Anyone who is concerned nonetheless should get a multi-system receiver that picks up the Russian satellites. Then there is the European Galileo, and the Chinese are launching one too. I have GPS in my chartplotter and an additional Garmin handheld (these are mounted on the pedestal and work off my house battery), plus two old Garmin ETrex units that live in the nav desk, plus my iPhone, plus I sail in the San Juan/Gulf Islands, where I can see where I'm going...
 

Joliba

Contributing Member
Sometimes I’ll use both the sextant and the GPS... just to check the accuracy of the GPS;)
Funny but the GPS is sometimes off by 50NM...Hmmm?:rolleyes:
 

toddster

Curator of Broken Parts
Blogs Author
Odd... I have that stuff spread out all over the dining room table.
...It has been there for a month or two. I delve into a few problems when I need to procrastinate on something in the office.
The apps are neat, but it seems like the whole point is to be independent of anything electronic. It would also be neat to be independent of many pounds of reference books. When I'm done with this book, will delve into one of the one-volume methods. But on the other hand, it's getting to be outdoor fun season...
I'd say the only conceivable scenario to really need it is some local event that takes out all electronics and/or charging sources on the boat. Or posing for a facebook picture.
I've got a Davis Mk25 that I got for cheap on eBay - just trying to get a reproducible value for sextant error shows how fuzzy it is - but probably good enough to find a reasonably sized island.

BTW: Over the winter I read a few sailing books from the early 20th century, and it seemed as if suddenly discovering that one was a few hundred miles from the plotted track, due to silly math errors, was a regular occurrence, even on commercial ships.
 

Tin Kicker

Member III
I cannot possibly worry about a failure of the GPS system. Short of nuclear war or a complicated terrorist attack, it just ain't going to happen. Anyone who is concerned nonetheless should get a multi-system receiver that picks up the Russian satellites. Then there is the European Galileo, and the Chinese are launching one too. I have GPS in my chartplotter and an additional Garmin handheld (these are mounted on the pedestal and work off my house battery), plus two old Garmin ETrex units that live in the nav desk, plus my iPhone, plus I sail in the San Juan/Gulf Islands, where I can see where I'm going...
Ummm- Solar flares are a great equalizer, can, and have, knocked out GPS for periods of time; we just happen to be at a quiescent period in time as shown in the chart below. I know with some of the very best commercial airline and military GPS we periodically have problems in aviation because solar flares come in waves. It's the X's and some M's that interrupt GPS.

We should see an increase before long because well - it'd just fit for being 2020. ;)

 
Top