The Bowditch (Celestial Navigation thread--cont)

beasly

beasly

Well-Known Member
Has arrived.

I am humbled.

Much more on this over the years, for it will be years--

First impressons.

It weighs close to 10 lbs.

It is an important part of American history--a working part of it. It has been on sailing ships since 1802 and then on through WWII.

Bowditch died in 1838 and he is still relevant today--I will be using it.

Think Far/AIM--then make it all AIM at nearly 900 pages. Then, consider the technical content in the AIM and kick the standards up by a factor of 2 or 3 in some parts.

It is Maritime based--but any Pilot will find it interesting.

btw, The co-efficient of compressibility of seawater is 0.000046 pr bar under standard conditions.


Browsing Section 4 on Celestial Navigation I learned there is such a thing as a "Celestial Horizon". Basically, it is a spherical coordinate system, but the position and orientation of the earth within this thing is NOT Earth centric. there is an adventure right there.

In summary, if you care about Navigation, you owe it to yourself to investigate this book.

Amazon also had the 50'th anniversary edition of "Star Maps" for less than 10 bucks.

It is organized by month, so this month, it is "September Sky Map" . I haven't used it yet and am a bit leery about it as it is "optimized" for the 40'th parallel--i.e. Philadelphia PA where it was originally published.

That said, it makes sense! The maps look like a Maltese Cross and the words are printed so that you can orient yourself N,S,E,W and read the words without having to re-orient yourself. For example--let the top of this post be North--well you are reading the words just fine. Now, turn your monitor on its side to E,W or South and you cannot read the words. This book fixes that. So, you turn N,S, E or W and you can do pilotage.

I have it in my car and will be using it as I get the chance.

I am not sure if it is "out of date". I am thinking that "like a stopped watch is correct twice a day" I lucked out on this.

Goal number 1--identify the North Star.

In summary, "The Bowditch" is a serious work. Give it a browse if you have the chance.

Cheers.
 
Did not know seawater was compressible *at all*. Kewl to know. How is it relevent to navigation, (in cliff note form of course!)
 
My trick for finding the north star is pretty simple so I can probably describe it to you with some luck.

Find the big dipper. Draw a line through the two outer stars that form the edge of the dipper, and are perpendicular to the handle (the spoon part). This line points to the north star.
 
The Bowditch is one of the best reference books

Bowditch's, The American Practical Navigator, is an almanac. The reader will find all kinds of information in there. Not all is significant to purely navigational purposes.

However, knowing say, the density of the waters one transits, they can deduce the currents and effects of winds of that area. File this under Nice To Know.

That is not to say there isn't a boatload of Need To Know information in the book.

BTW: The US Hydrologic Office owns the copyright of what is commonly referred to as "Bowditch" (the book). You'll find the "H.O. Tables" in the back which aid the navigator in deducing his position. These tables change year to year, therefore the book is published as a new edition annually.
 
Finding Polaris in the night sky.
 

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beasly said:
Has arrived.

I am humbled.

Much more on this over the years, for it will be years--

First impressons.

It weighs close to 10 lbs.

It is an important part of American history--a working part of it. It has been on sailing ships since 1802 and then on through WWII.

Bowditch died in 1838 and he is still relevant today--I will be using it.

Think Far/AIM--then make it all AIM at nearly 900 pages. Then, consider the technical content in the AIM and kick the standards up by a factor of 2 or 3 in some parts.

It is Maritime based--but any Pilot will find it interesting.

btw, The co-efficient of compressibility of seawater is 0.000046 pr bar under standard conditions.


Browsing Section 4 on Celestial Navigation I learned there is such a thing as a "Celestial Horizon". Basically, it is a spherical coordinate system, but the position and orientation of the earth within this thing is NOT Earth centric. there is an adventure right there.

In summary, if you care about Navigation, you owe it to yourself to investigate this book.

Amazon also had the 50'th anniversary edition of "Star Maps" for less than 10 bucks.

It is organized by month, so this month, it is "September Sky Map" . I haven't used it yet and am a bit leery about it as it is "optimized" for the 40'th parallel--i.e. Philadelphia PA where it was originally published.

That said, it makes sense! The maps look like a Maltese Cross and the words are printed so that you can orient yourself N,S,E,W and read the words without having to re-orient yourself. For example--let the top of this post be North--well you are reading the words just fine. Now, turn your monitor on its side to E,W or South and you cannot read the words. This book fixes that. So, you turn N,S, E or W and you can do pilotage.

I have it in my car and will be using it as I get the chance.

I am not sure if it is "out of date". I am thinking that "like a stopped watch is correct twice a day" I lucked out on this.

Goal number 1--identify the North Star.

In summary, "The Bowditch" is a serious work. Give it a browse if you have the chance.

Cheers.
Click to expand...



Sounds like something I would be into!
 
Hmm, I'm reading: The Most Powerful Idea in the World

Which is all about the revolution due to the steam engine. I think figuring out Celestial Navigation might be my next great read.

Trying to get a job flying UAS. You never know when being able to navigate by the stars will come in handy over the ocean.
 
If you really want to give your mind a thorough scrubbing, read through the history of trigonometry. Start with Apollonius of Perga's "Conic Sections" (and, uhm, get a guide), which was pretty much the genesis of meaningfully "post-arithmetic" math. The amount of brainpower that went in to astronomy up to the Renaissance is staggering and humbling. Strike that. HUMILIATING.
 
beasly said:
In summary, "The Bowditch" is a serious work. Give it a browse if you have the chance.
Click to expand...

For those who are interested in looking before buying - the whole book from the original source.

http://www.nga.mil/NGAPortal/MSI.portal?_nfpb=true&_pageLabel=msi_portal_page_62

Under the Menu Options - choose American Practical Navigator (the long name for Bowditch.)

This link also is the source for the Sight Reduction Tables from the Air and Nautical Almanacs which are used to compute your fixes after taking your observations or shots.
 
To be honest, I like the fact thatvto make celestial navigation work you assume that that you the observer are at the centre of the universe and that everything revolves around you!
 
Jwscud said:
To be honest, I like the fact thatvto make celestial navigation work you assume that that you the observer are at the centre of the universe and that everything revolves around you!
Click to expand...

I appreciate the spirit but it's not the case and hasn't been for a number of centuries.
 
Beasly, a couple of others that I have in my library that I have enjoyed:

  • Duttons Nautical Navigation (the big one as opposed to the smaller nav and piloting book)
  • A Star to Steer Her By
  • Practical Celestial Navigation (A great work book)
  • The Sextant Handbook (a nice reference)
 
Re: The Bowditch is one of the best reference books

RICHARD5 said:
Bowditch's, The American Practical Navigator, is an almanac. The reader will find all kinds of information in there. Not all is significant to purely navigational purposes.

However, knowing say, the density of the waters one transits, they can deduce the currents and effects of winds of that area. File this under Nice To Know.

That is not to say there isn't a boatload of Need To Know information in the book.

BTW: The US Hydrologic Office owns the copyright of what is commonly referred to as "Bowditch" (the book). You'll find the "H.O. Tables" in the back which aid the navigator in deducing his position. These tables change year to year, therefore the book is published as a new edition annually.
Click to expand...


There is also a lot of "cool to know" stuff--for example, like Wx trends from West to East, so currents in the oceans have patterns. I did not know that. They also have some pics of estimating wind speed from ocean surface conditions.Besides the pics being seriously cool, that is a good thing to know.

Cheers.
 
Acadia said:
Beasly, a couple of others that I have in my library that I have enjoyed:

  • Duttons Nautical Navigation (the big one as opposed to the smaller nav and piloting book)
  • A Star to Steer Her By
  • Practical Celestial Navigation (A great work book)
  • The Sextant Handbook (a nice reference)
Click to expand...


Hi Acadia,

Thank you, but first things first. Like Hienlien's rabbit recipe--"first, catch a rabbit"

I woke up at 3:30 EST this A.M and took the Bee-Line to Cocoa beach with my Sky Maps For Beginners with the intent of identifying 1 thing on the chart.


FAIL!

Galaxy 1 Beasly 0

Think first-solo pilot hopelessly lost.


:mad:

:bandit:



As is my wont, I did not follow directions.The sky Maps For Beginners says shows the sky at specific times for the beginning, middle and end of September.
It is all the same view, but the sky "lags" the sun. For the same picture, you have to be there at later times as the month goes by.

Also, I am not sure my Sky Maps for Beginners is the right tool to use. It is dated for the nineties, and I was "hoping" that things would be cyclic so that Amazon would ship me something that would work today. Caveat Emptor, I suppose, but that said, I am going to investigate real "Manly Man" Sky Charts!


To be honest, part of me is saying--How come I don't have this on my E6B?

Wouldn't that be cool! We have the wiz-wheel on the E6B and the sky is "round" so we should be able to flip the wind calculation wheel and pull up a sky chart, then tune it for position and time and have that night's sky for any place on Earth. (or, I could have my head up my ass--I would guess the latter)


Finally, It is a LOT OF FUN to have something new to think about in aviation. Yes, the Bowditch is made for mariner's but there is a lot of overlap.

I have the privilege of having a new goal--


  • learn all the constellations in the sky
  • be able to name all the stars in them.
  • know their trends over time and seasons
  • be as familiar with the sky as I am with my local VFR chart
  • Correlate directions to stars.

I think that will give me the basis to start thinking about Celestial Nav.


As an aviator, think about that. You have lost everything--say you had to ditch in the desert or something and you have to lead your crew to civilization.

To me, that is a basic responsibility of being a good aviator.


Cheers.
 
If anybody could recommend a "real" sky chart, please do.


What I am looking for is the ability at anytime of the year, any month, any time to know where to look to identify a constellation.

Once I get that, I will look for the dipper and then Polaris.

I am really angry I could not identify a single freaking thing in the sky.

thx


:beer:
 
ProudPilot said:
Hmm, I'm reading: The Most Powerful Idea in the World

Which is all about the revolution due to the steam engine. I think figuring out Celestial Navigation might be my next great read.

Trying to get a job flying UAS. You never know when beingable to navigate by the stars will come in handy over the ocean.
Click to expand...


Fwiw, I read that "following contrails" is a good strategy as well.

That said, say your are in a small twin, over the ocean at night.


You have no internal lights (should not happen given proper prep--spare batteries, redundant light sources--but this time it fails).


You have control of the A.C but have lost positional awareness.

Which way?

:dunno:


Gonna get that fixed.
 
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