What does decent celestial navigation freeware on Android ac

[Raymond Spruance III]

Do you know anything about celestial navigation?

What's important in the software?
http://opencpn.org/ocpn/node/143

Other than sighting Polaris' angle from the horizon, and noting that the sun
rises in the east and sets in the west, I have never had a need for
celestial navigation software on Android.

However, I want to test out celestial navigation, on a lark mostly, but more
to learn how it's done (in case I ever need it in an emergency) and to show
a high school math teacher how its done so she can use it to make trig more
interesting to her students.

Looking up celestial navigation software, I find plenty of payware:
https://play.google.com/store/apps/details?id=com.vikrant
https://play.google.com/store/apps/details?id=com.navimatics.app.celnav
https://play.google.com/store/apps/details?id=com.polyglotz.starstruck
http://appcrawlr.com/android/observation-of-celestial-body
etc.

But it's standard policy to never buy the payware until you've exhausted the
freeware, if for no other reason than you *know* exactly what you need the
payware to do if/when the freeware fails. (99% of the time or more, the
freeware does what you need, at least on Android.)

Looking up the freeware celestial navigation software, I find:
https://play.google.com/store/apps/details?id=com.AstroNavigation
https://play.google.com/store/apps/details?id=com.Sightreduction
https://play.google.com/store/apps/details?id=com.checkmyrest.celestialnavigator

All I ask in this thread are the basic questions anyone new to celestial
navigation would ask:
a. What freeware is the best one to try out first?
b. What are the minimum required features of that freeware

 

[Raymond Spruance III]

On Sun, 27 Nov 2016 10:09:46 -0800, Jeff Liebermann wrote:

You're unlikely to have a working Android device available in an
emergency.

You're right Jeff, but one nice thing about knowledge is that you have
*that* always with you, even in an emergency.

So, one goal, always, is to *learn* how to do celestial navigation, where,
in a pinch, you can approximate given the experience gained using the
battery operated tools.

At best, a WWV/WWVB receiver, reasonable accurate clock,
and HO229 sight reduction tables or this years nautical almanac.

Really on the accurate clock? C'mon. I'll bet a five-dollar digital watch
has better accuracy than all the navigators had in the age of exploration.

If
you're going to impress a math teacher, then *YOU* get to do the
required math, not the computah.

Yes. Indeed. But I would like the help of the instruments and the
calculations, since, half of math is just intuition on how to do it (which
is gained by being right before, when you have more tools available).

The only thing the computah does is
replace the tables and save you from the pain of interpolation.

Fine with me.

You
still have to do 3 other sextant sight corrections (index error, dip,
altitude correction).

Can a plastic protractor substitute for a sextant for our purposes?
(i.e., it's more the process than the accuracy that I'm after.)

You can download HO229 or the nautical almanac from:
http://thenauticalalmanac.com

Egads. 250 pages. For 2016 only! Another 250 pages for 2017.
Plus 180 Megabytes of celestial stuff.

Wow. There's a *lot* of learning that needs to be accomplished.
I thought it was just a sighting of about 60 stars!

There are plenty of instructional videos on YouTube under "how to use
a sextant" and such. Most deal with a noon sight, which is where you
start.

Ah, Jeff. Thanks for letting me know where you sight. Seems to me a "noon
sighting" is easy. stick a twig in the ground, mark when the shadow switches
from west to east, and bingo. That's noon at your longitude when compared
with GMT, and, voila!

I guess a noon longitude is as simple, using a rough estimate of the angle
from the horizon to the sun. Bingo. Latitude.

Since you're likely to be doing this on land, instead of at
sea, you'll need an artificial horizon for your sextant.
http://www.davisnet.com/product/artificial-horizon/

Interesting. A $32 artificial horizon. Who knew that's needed?

Seems to me a bubble meter should work as well. Right?
Can't the phone bubble meter work for an artificial horizon?

Anyway, you are correct these are land sightings.
In mountains. Santa Cruz mountains.

The rest is RTFM, arithmetic, and practice. Once you've mastered the
noon sight, try using the moon or stars. If you want a lesson in
reality, find a suitable sailboat, wrap one arm around the mast, and
then try taking a series of noon sights.

Thanks for the suggestion of starting with a noon sight, and then a moon
sight (must be a sailor's rhyme there somewhere). And yes, I get seasick,
so, I'm intimately familiar with the reality of the motion of the ocean (I
give Captain William Bligh a lot of credit for what he done did).

a. What freeware is the best one to try out first?

The free Nautical Almanac. It's in PDF form so you can display it on
a laptop, eBook reader, or whatever while you do the math by hand.

Very interesting that this PDF is all that is needed (along with a sextant
and an artificial horizon, both of which should be phone tools if you ask
me).
2017: https://thenauticalalmanac.com/2017%20Nautical%20Almanac.pdf
2016: https://thenauticalalmanac.com/2016%20Nautical%20Almanac.pdf

b. What are the minimum required features of that freeware

Ummm... that it's free? If you want to learn navigation, you're going
to need to learn about celestial mechanics, navigational conventions,
a fair number of new terms, and what happens when you're in a
different part of the planet.

For now, Jeff, I'm gonna be at around 35 to 40 degrees North and about 120
to 122 degrees West. After I get good at that, I can work on the other
angles.

You could learn those from a computah
program that offers a tutorial, but I believe these are best learned
with paper and pen. Once you're proficient with the process, then you
can use the computer to allegedly save you some time.

Thanks for the advice. What would be nice is learning how to do dead
reckoning with the phone as the artificial horizon and sextant and a few
well-known start (e.g., Polaris) as the frame of reference.

 

[Harkung Vorbestellung]

On Sun, 27 Nov 2016 18:54:08 -0000 (UTC), Raymond Spruance III wrote:

> Can a plastic protractor substitute for a sextant for our purposes?

Here are PDF almanacs:
http://thenauticalalmanac.com

Tools needed should all be on Android for free:
a. sextant (tutorial https://www.youtube.com/watch?v=qsErtrttJsY)
b. artificial horizon (tutorial https://www.youtube.com/watch?v=B5Ud9iPW-yk)
c. almanac (tutorial https://www.youtube.com/watch?v=p6znyx0gjb4

For example:
A. Android Sextant App by Talltree Software:
https://play.google.com/store/apps/details?id=com.sharpitor.nightsky20

B. Aircraft Horizon Free by Sensorworks
https://play.google.com/store/apps/details?id=com.sensorworks.aircrafthorizon_free

C. Google Sky Map:
https://play.google.com/store/apps/details?id=com.google.android.stardroid

 

[Allodoxaphobia]

On Sun, 27 Nov 2016 16:01:33 +0000 (UTC), Raymond Spruance III wrote:
> Do you know anything about celestial navigation?

<--- big snip -->

All I ask in this thread are the basic questions anyone new to
celestial > navigation would ask:

And you _just had_ to cross-post this to sci.electronics.repair ... why?

 

[James Mick]

MJC wrote:

But explorers, by definition, don't need to know exactly where they are
because they don't have accurate charts anyway! Not to mention a lot of
them came to grief...

The early explorers used plenty of charts and tables though!

Peter Hakel has made many spreadsheets for Celnav that are useful.
http://www.navigation-spreadsheets.com/navigation_triangles.html

A perfect Sun sight reduction spreadsheet can be obtained here.
http://backbearing.com/excel.html

Erik Deman has all of the Nautical Almanac information on his site.
http://www.siranah.de/

You can get HO 249 Volumes 1, 2 and 3 here;
https://www.celestaire.com/pubs/category/3-pub-249.html

Fair winds and clear skies.

 

[Robert Bannon]

On 27 Nov Allodoxaphobia scrit:

> And you _just had_ to cross-post this to sci.electronics.repair

Too bad it wasn't cross posted to the windows ng.
They could use this information below.

1. TeaCup http://www.teacupnavigation.net/CN.html
2. StarCalc http://www.relex.ru/~zalex/main.htm
3. SeaClear http://www.sping.com/seaclear/

1. Teacup Navigation has free celestial software and a free book in PDF
format for downloading. The book teaches the concepts and techniques of
celestial navigation, some interesting history, and computational methods
using a simple pocket scientific calculator. The book also has condensed
tables and work sheets for when you have no calculators available. It also
shows how to build your own navigational tools. The free comprehensive
celestial navigation software is for the Windows operating system. It will
run in Ubuntu (Linux) when "Wine" software is also installed. The same is
true for a Mac when the Mac version of Wine is used. The Teacup Navigation
site is at http://www.teacupnavigation.net/CN.html

2. StarCalc is a free program that will bring a planetarium onto your
computer monitor. The program is a creation of Alexander E. Zavalishin, a
Russian, and is provided at no charge. This program will show a picture of
the sky at any time of the day or night from any location in the world at
any time. The program provides an alternative to the "Star Finder" plastic
circular slide rule used in the JN and N courses. Using the program, you can
print a copy of the sky showing the bodies that you intend to "shoot". The
graphic provided by StarCalc gives a clear diagram of where the celestial
targets of opportunity are located and the hassle of plotting solar system
objects is eliminated. The StarCalc program can be downloaded from:
http://www.relex.ru/~zalex/main.htm

3. SeaClear is a freeware navigation program for Windows NT 4.0, 2000 or
95/98/ME which, when connected to a GPS (or other unit capable of
transmitting NMEA position data), will display the vessel on a chart, with
the current position, speed and direction. New charts are loaded as needed.
The track may be saved to a file for later reviewing, and log book entries
may be manually and automatically entered. An unlimited number of routes and
waypoints may be created and used to assist in the navigation. The screen
area for charts is maximized with most functions accessed with the right
mouse button. Zooming is provided with support for IntelliMouse wheel. The
program may be downloaded from: http://www.sping.com/seaclear/

 

[Jeff Liebermann]

On Sun, 27 Nov 2016 16:01:33 +0000 (UTC), Raymond Spruance III
<spruancerayIII@example.com> wrote:

>Do you know anything about celestial navigation?

Yep.

I want to test out celestial navigation, on a lark mostly, but more
to learn how it's done (in case I ever need it in an emergency) and to show
a high school math teacher how its done so she can use it to make trig more
interesting to her students.

You're unlikely to have a working Android device available in an
emergency. At best, a WWV/WWVB receiver, reasonable accurate clock,
and HO229 sight reduction tables or this years nautical almanac. If
you're going to impress a math teacher, then *YOU* get to do the
required math, not the computah. The only thing the computah does is
replace the tables and save you from the pain of interpolation. You
still have to do 3 other sextant sight corrections (index error, dip,
altitude correction). You can download HO229 or the nautical almanac
from:
<http://thenauticalalmanac.com>

There are plenty of instructional videos on YouTube under "how to use
a sextant" and such. Most deal with a noon sight, which is where you
start. Since you're likely to be doing this on land, instead of at
sea, you'll need an artificial horizon for your sextant.
<http://www.davisnet.com/product/artificial-horizon/>

The rest is RTFM, arithmetic, and practice. Once you've mastered the
noon sight, try using the moon or stars. If you want a lesson in
reality, find a suitable sailboat, wrap one arm around the mast, and
then try taking a series of noon sights.

All I ask in this thread are the basic questions anyone new to celestial
navigation would ask:
a. What freeware is the best one to try out first?

The free Nautical Almanac. It's in PDF form so you can display it on
a laptop, eBook reader, or whatever while you do the math by hand.

>b. What are the minimum required features of that freeware

Ummm... that it's free? If you want to learn navigation, you're going
to need to learn about celestial mechanics, navigational conventions,
a fair number of new terms, and what happens when you're in a
different part of the planet. You could learn those from a computah
program that offers a tutorial, but I believe these are best learned
with paper and pen. Once you're proficient with the process, then you
can use the computer to allegedly save you some time.

Good luck and have fun.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[MJC]

In article <o1fa4f$fg3$1@news.mixmin.net>, spruancerayIII@example.com
says...

Really on the accurate clock? C'mon. I'll bet a five-dollar digital watch
has better accuracy than all the navigators had in the age of exploration.

But explorers, by definition, don't need to know exactly where they are
because they don't have accurate charts anyway! Not to mention a lot of
them came to grief...

Mike.

 

[Jeff Liebermann]

On Sun, 27 Nov 2016 18:54:08 -0000 (UTC), Raymond Spruance III
<spruancerayIII@example.com> wrote:

On Sun, 27 Nov 2016 10:09:46 -0800, Jeff Liebermann wrote:

You're unlikely to have a working Android device available in an
emergency.

You're right Jeff, but one nice thing about knowledge is that you have
*that* always with you, even in an emergency.

I'm not sure what manner of emergency would require knowing your exact
location using a sextant, but I would guess(tm) that it's either
nautical or aeronautical. Somehow, I don't see you tramping around
the woods with a sextant. If you're on land, can see some landmarks,
and have a map, you don't need a sextant. Therefore, unless you're
planning to go sailing or flying, a sextant isn't going to be much
help, even with an Android phone (which has a GPS receiver).

So, one goal, always, is to *learn* how to do celestial navigation, where,
in a pinch, you can approximate given the experience gained using the
battery operated tools.

Ok, a hybrid approach. I'm more of a purist, but that's fine. As I
mumbled, all that an Android app buys you is a laundry list of boxes
to fill with numbers, a scratch pad, and if the program is really
good, a sanity check.

At best, a WWV/WWVB receiver, reasonable accurate clock,
and HO229 sight reduction tables or this years nautical almanac.

Really on the accurate clock? C'mon. I'll bet a five-dollar digital watch
has better accuracy than all the navigators had in the age of exploration.

I'll take the bet. First, you only need an accurate clock if you want
to obtain your latitude. Longitude can be done with just a noon
sight. Latitude requires a clock.

Find yourself a copy of "Longitude: The True Story of a Lone Genius
Who Solved the Greatest Scientific Problem of His Time"
<https://en.wikipedia.org/wiki/Longitude_(book)>
There are also some YouTube videos on the topic of Longitude:
<https://www.youtube.com/watch?v=ecrf8KhVcyo> (3hrs)
<https://www.youtube.com/watch?v=NENPdT4LASw> (54 min Nova version)
There's quite a bit there on how navigation was done in the 18th
century including the accuracy of the various John Harrison clocks.

"John Harrison's 'longitude' clock sets new record - 300 years on"
<http://www.independent.co.uk/news/science/john-harrisons-longitude-clock-sets-new-record-300-years-on-10187304.html>
One second in 100 days (on land). The target value for an acceptable
clock was 1 minute in 50 days.

I don't want to get into a rant on the accuracy of todays digital
watches. Everything is dependent on the stability of the tuning for
crystal, with is far from temperature stable. I just dug out the
specs for a random Casio wristwatch. About +/-12 sec per month at
room temp and who knows over a reasonable temperature range. I'm sure
someone has done some testing, but I'm late for a free lunch, so you
get to Google for the numbers.

Can a plastic protractor substitute for a sextant for our purposes?
(i.e., it's more the process than the accuracy that I'm after.)

No, unless you're only interested in knowing which state you're in.
Also, the optics one a sextant are designed to protect your eyes.
Prior to the sextant, the use of a cross staff required staring at the
sun, a really bad idea.

You can download HO229 or the nautical almanac from:
http://thenauticalalmanac.com

Egads. 250 pages. For 2016 only! Another 250 pages for 2017.
Plus 180 Megabytes of celestial stuff.

You're not expected to read it cover to cover. On the average, you'll
use 3 or 4 pages at a time. However, for every sighting, all 3 or 4
pages are different.

Wow. There's a *lot* of learning that needs to be accomplished.
I thought it was just a sighting of about 60 stars!

Stop complaining and start reading.

Since you're likely to be doing this on land, instead of at
sea, you'll need an artificial horizon for your sextant.
http://www.davisnet.com/product/artificial-horizon/

Interesting. A $32 artificial horizon. Who knew that's needed?

You can build your own:
<https://thenauticalalmanac.com/Artificial%20Horizon.html>

Seems to me a bubble meter should work as well. Right?
Can't the phone bubble meter work for an artificial horizon?

Neither is accurate. Bolting a bubble level onto the sextant is that
way its done on aeronautical sextants as the sloshing of the liquid in
the larger reflection type artificial horizon doesn't work well on a
vibrating airplane.

Thanks for the suggestion of starting with a noon sight, and then a moon
sight

The moon is tricky. It moves quite rapidly across the field of vision
and is therefore difficult to get an accurate measurement.

Thanks for the advice. What would be nice is learning how to do dead
reckoning with the phone as the artificial horizon and sextant and a few
well-known start (e.g., Polaris) as the frame of reference.

I can tell this is not going to be a classical lesson in navigation.
No, you can't borrow any of my sextants.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Raymond Spruance III]

On Sun, 27 Nov 2016 17:27:31 -0800, Jeff Liebermann wrote:

Sigh. No brain today. That should be Latitude can be done with a
noon sight while longitude requires a clock. Dyslexia induced by
schlepping a 150 lb drill press up about 40 stairs.

You had me scared, Jeff, when you flipped the coordinate system on me.

I'm currently reading this book, so hopefully I'll be slightly more
educumated when I next write back.
Celestial Navigation in a Teacup, by Rodger E. Farley
http://www.teacupnavigation.net/Celestial_Navigation_in_a_Teacup_v.pdf

The goal is to give the math teacher a lesson for her high school kids,
using freeware, where most are on iOS but some are on Android.

 

[Jeff Liebermann]

On Sun, 27 Nov 2016 14:40:54 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:

I'll take the bet. First, you only need an accurate clock if you want
to obtain your latitude. Longitude can be done with just a noon
sight. Latitude requires a clock.

Sigh. No brain today. That should be Latitude can be done with a
noon sight while longitude requires a clock. Dyslexia induced by
schlepping a 150 lb drill press up about 40 stairs.

I don't want to get into a rant on the accuracy of todays digital
watches. Everything is dependent on the stability of the tuning for
crystal, with is far from temperature stable. I just dug out the
specs for a random Casio wristwatch. About +/-12 sec per month at
room temp and who knows over a reasonable temperature range. I'm sure
someone has done some testing, but I'm late for a free lunch, so you
get to Google for the numbers.

For a common digital clock:
<https://en.wikipedia.org/wiki/Quartz_clock#Accuracy>
"...a typical quartz clock or wristwatch will gain or
lose 15 seconds per 30 days (within a normal temperature
range of 5 °C/41 °F to 35 °C/95 °F) or less than a half
second clock drift per day when worn near the body."

or a marine chronometer:
<https://en.wikipedia.org/wiki/Marine_chronometer#Today>
"...even in wrist watches such as the Omega Marine Chronometer,
that are accurate to within 5 or 20 seconds per year."

Incidentally, be careful what you use for a clock. GPS time is
currently 17 seconds ahead of UTC (WWV/WWVB) time:
<http://www.leapsecond.com/java/gpsclock.htm>
For navigation, you want GMT, UTC or UT1 (all the same). Most GPS
receivers and smartphones correct for this, but not every smartphone
manufacturer got the memo:
<http://802.11junk.com/jeffl/crud/GPS-vs-UTC.jpg>
Best to check your smartphone:
60 nautical miles = 1 degree of latitude
1 nautical mile = 6076ft
60 NM/sec * 6076ft/NM / 3600 sec/deg= 101 ft/second
Therefore the 17 second difference between GMT and UTC will produce an
error of about 1,717 ft (about 1/4th nautical mile) in longitude at
the equator and lesser errors at higher latitudes.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[pfjw@aol.com]

On Sunday, November 27, 2016 at 11:01:40 AM UTC-5, Raymond Spruance III wrote:

Is trolling again under a different alias.

Please let this one stay a small thread!

Peter Wieck
Melrose Park, PA

 

[Jeff Liebermann]

On Mon, 28 Nov 2016 04:05:54 -0000 (UTC), Raymond Spruance III
<spruancerayIII@example.com> wrote:
>You had me scared, Jeff, when you flipped the coordinate system on me.

My proof reader and copy editor both missed my mistake.

I'm currently reading this book, so hopefully I'll be slightly more
educumated when I next write back.
Celestial Navigation in a Teacup, by Rodger E. Farley
http://www.teacupnavigation.net/Celestial_Navigation_in_a_Teacup_v.pdf

Looks quite good from a quick skim.

The book assumes a working knowledge of geometry and trigonometry
which might be suitable for a high skool level class. I think her
biggest problem will be adding about 30 navigational terms to the
students vocabulary. A navigation glossary might be useful. For
example:
<http://www.diy-wood-boat.com/Navigation_terms.html>

The goal is to give the math teacher a lesson for her high school kids,
using freeware, where most are on iOS but some are on Android.

Like I suggested. Lose the apps and computah programs initially.
Those can come later. Learn navigation with tables, paper, pen,
calculator, slide rule, etc. I don't know if they're going to be
plotting a course, but plotting sheets might be useful. Once you make
it past the geometry and basic concepts, the rest is just math.
However, my guess(tm) is that the teacher will become bogged down in
the terminology and geometry. Due to lack of time, she will not get
very far into practical navigation. At best probably a demonstration.

One problem is getting students a sextant for practice. Even the
cheapest plastic sextant (Davis 3) is $50. Make their own sextant,
octant, or quadrant?
<http://www.tecepe.com.br/nav/CDSextantProject.htm>
<http://www.science-teachers.com/space/north_star/HowtoMakeaSextant.doc>
<http://www.tecepe.com.br/nav/XTantProject.htm>
Make sure it has eye protection. I first learned navigation in a
class of about 25 aspiring nautical types. Most brought their own
sextants of varying quality. We took turns practicing sun sights with
everyone using those numbers. I would not expect a high skool student
to buy a sextant.

Good luck.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Whiskers]

On 2016-11-27, Raymond Spruance III <spruancerayIII@example.com> wrote:

On Sun, 27 Nov 2016 10:09:46 -0800, Jeff Liebermann wrote:

You're unlikely to have a working Android device available in an
emergency.

You're right Jeff, but one nice thing about knowledge is that you have
*that* always with you, even in an emergency.

So, one goal, always, is to *learn* how to do celestial navigation, where,
in a pinch, you can approximate given the experience gained using the
battery operated tools.


At best, a WWV/WWVB receiver, reasonable accurate clock,
and HO229 sight reduction tables or this years nautical almanac.

Really on the accurate clock? C'mon. I'll bet a five-dollar digital watch
has better accuracy than all the navigators had in the age of exploration.

Not many quartz watches qualify as 'chronometers' for navigation
purposes. Best practice on ships is to have more than one chronometer
on board, and know the 'rate' of each (ie how much it gains or loses
each day, usually established by an observatory), and have them wound up
and cared for by a designated officer and no-one else. These are used
to maintain the accuracy of the watches actually used for observations.

But in an emergency, yes, any reliable watch is better than nothing. As
long as the battery doesn't fail.

If
you're going to impress a math teacher, then *YOU* get to do the
required math, not the computah.

Yes. Indeed. But I would like the help of the instruments and the
calculations, since, half of math is just intuition on how to do it (which
is gained by being right before, when you have more tools available).

The only thing the computah does is
replace the tables and save you from the pain of interpolation.

Fine with me.

You
still have to do 3 other sextant sight corrections (index error, dip,
altitude correction).

Can a plastic protractor substitute for a sextant for our purposes?
(i.e., it's more the process than the accuracy that I'm after.)

Consider at least looking at information about the 'astrolabe'; also
later developments such as the 'quadrant' and 'back-staff' which
preceded the 'sextant', all of which are within the scope of
'handicraft' or 'model-makers' to make (albeit not as accurately as a
skilled instrument maker, but a lot cheaper!). I've even used a
cardboard astrolabe to get fairly accurate time and latitude
measurements. Once you've used an astrolabe, it's easier to grasp what
a modern sextant is doing.

As well as maths and so on, this brings in history and culture and
geography - and even literature (Chaucer wrote a little treatise on the
astrolabe to instruct his son).

You can download HO229 or the nautical almanac from:
http://thenauticalalmanac.com

Egads. 250 pages. For 2016 only! Another 250 pages for 2017.
Plus 180 Megabytes of celestial stuff.

Wow. There's a *lot* of learning that needs to be accomplished.
I thought it was just a sighting of about 60 stars!

There are plenty of instructional videos on YouTube under "how to use
a sextant" and such. Most deal with a noon sight, which is where you
start.

Ah, Jeff. Thanks for letting me know where you sight. Seems to me a "noon
sighting" is easy. stick a twig in the ground, mark when the shadow switches
from west to east, and bingo. That's noon at your longitude when compared
with GMT, and, voila!

I guess a noon longitude is as simple, using a rough estimate of the angle
from the horizon to the sun. Bingo. Latitude.

Since you're likely to be doing this on land, instead of at
sea, you'll need an artificial horizon for your sextant.
http://www.davisnet.com/product/artificial-horizon/

Interesting. A $32 artificial horizon. Who knew that's needed?

Seems to me a bubble meter should work as well. Right?
Can't the phone bubble meter work for an artificial horizon?

Anyway, you are correct these are land sightings.
In mountains. Santa Cruz mountains.

Any horizontal reflecting surface will do, eg a lake or strategically
placed bowl of water. The nifty gadget is convenient, not essential.

(Astrolabes and quadrants don't need any sort of horizon, they use
gravity to establish the vertical plane).

[...]

--
-- ^^^^^^^^^^
-- Whiskers
-- ~~~~~~~~~~

 

[Jeff Liebermann]

On Mon, 28 Nov 2016 18:49:20 +0000, Whiskers
<catwheezel@operamail.com> wrote:

Not many quartz watches qualify as 'chronometers' for navigation
purposes.

If it's certified by the COSC, then it's a chronometer:
<https://en.wikipedia.org/wiki/COSC>
Only a fairly small number of watches are certified.

The specs allow a mechanical clock a daily rate of
-4/+6 sec/day = 2.5 minutes/month = 30 min/year.

However, a crystal controlled clock is only allowed
+/-0.07 sec/day = 2.1 sec/month = 25.2 sec/year.

There are now better clocks that easily meet the COSC requirements:
<http://www.leapsecond.com/pages/atomic-bill/>
<https://www.kickstarter.com/projects/846511652/the-worlds-first-true-atomic-wristwatch-the-cesium>
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[The Real Bev]

On 11/28/2016 08:34 PM, Jeff Liebermann wrote:

On Mon, 28 Nov 2016 18:49:20 +0000, Whiskers
catwheezel@operamail.com> wrote:

Not many quartz watches qualify as 'chronometers' for navigation
purposes.

If it's certified by the COSC, then it's a chronometer:
https://en.wikipedia.org/wiki/COSC
Only a fairly small number of watches are certified.

The specs allow a mechanical clock a daily rate of
-4/+6 sec/day = 2.5 minutes/month = 30 min/year.

However, a crystal controlled clock is only allowed
+/-0.07 sec/day = 2.1 sec/month = 25.2 sec/year.

There are now better clocks that easily meet the COSC requirements:
http://www.leapsecond.com/pages/atomic-bill/
https://www.kickstarter.com/projects/846511652/the-worlds-first-true-atomic-wristwatch-the-cesium

In [possibly] 2008 we bought some Casio 'atomic' watches with solar
batteries at Costco for ~$25 each plus tax. The same watches are
generally available for >$100 now. Not only are they incredibly
accurate due to receiving nightly hits from the atomic clock in [I
believe] Boulder CO, the black plastic bands show no sign of wearing
out, unlike the bands on previous Casio digital watches I've had.

There's nothing quite like owning a truly accurate timepiece


--
Cheers, Bev
"The fact that windows is one of the most popular ways to
operate a computer means that evolution has made a general
fuckup and our race is doomed." -- Anon.

 

[lew]

On 2016-11-29, Jeff Liebermann <jeffl@cruzio.com> wrote:

On Mon, 28 Nov 2016 23:27:33 -0800, The Real Bev
bashley101@gmail.com> wrote:

In [possibly] 2008 we bought some Casio 'atomic' watches with solar
batteries at Costco for ~$25 each plus tax. The same watches are
generally available for >$100 now. Not only are they incredibly
accurate due to receiving nightly hits from the atomic clock in [I
believe] Boulder CO, the black plastic bands show no sign of wearing
out, unlike the bands on previous Casio digital watches I've had.
There's nothing quite like owning a truly accurate timepiece

The nightly updates can be a problem. Propagation from WWVB is rather
lousy during the daylight hours, and only improves on the left coast
around midnight.
http://tf.nist.gov/stations/wwvbcoverage.htm
http://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi
It's not lack of signal that causes problems. It's interference. It's
not uncommon for updates to fail if the watch is left in an RF noisy
location, such as next to an operating switching power supply.

Orientation is also a problem. Put the watch down with the tiny
loopstick pointed at WWVB and you get no signal even if propagation is
good. This is a lousy noisy signal with the end pointed at WWVB:
http://802.11junk.com/jeffl/WWVB%20test/end-pointed-at-WWVB.jpg
This is what a good signal looks like with the loopstick broadside to
WWVB:
http://802.11junk.com/jeffl/WWVB%20test/loopstick-perpendicular-to-WWVB.jpg
Even cross polarization will produce a lousy signal. This is a noisy
signal with the loopstick oriented vertically:
http://802.11junk.com/jeffl/WWVB%20test/loopstick-vertical.jpg

What the watch does without WWVB updates is a matter of conjecture. I
haven't done any testing nor could I find any online. Without the
updates from WWVB, it's probably no better than a common digital
watch. Even so, that's good enough for navigation, but for accuracy
it requires WWVB updates. (4 sec error = 1 nautical mile)

I had "atomic" wall clocks on battery as well as a bedroom clock
on ac. Worked very nice until the utility companies went with the
rf meters. Then the "atomic" clocks became drastically out of sync
& sometimes got reset to what look like an unknown timezone. Had even
tried replacement atomic wall clocks which had the same problems.

The Casio watch was nice until I had eye surgery after which I wasn't
able to see the time well without reading glasses. Have switched
to an analog faced timepiece with large numbers now.

 

[Carlos E.R.]

On 2016-11-29 08:27, The Real Bev wrote:

On 11/28/2016 08:34 PM, Jeff Liebermann wrote:
On Mon, 28 Nov 2016 18:49:20 +0000, Whiskers
wrote:

However, a crystal controlled clock is only allowed
+/-0.07 sec/day = 2.1 sec/month = 25.2 sec/year.

There are now better clocks that easily meet the COSC requirements:
http://www.leapsecond.com/pages/atomic-bill/
https://www.kickstarter.com/projects/846511652/the-worlds-first-true-atomic-wristwatch-the-cesium


In [possibly] 2008 we bought some Casio 'atomic' watches with solar
batteries at Costco for ~$25 each plus tax. The same watches are
generally available for >$100 now. Not only are they incredibly
accurate due to receiving nightly hits from the atomic clock in [I
believe] Boulder CO, the black plastic bands show no sign of wearing
out, unlike the bands on previous Casio digital watches I've had.

There's nothing quite like owning a truly accurate timepiece

But it is not a "truly accurate timepiece", in the sense that it is not
autonomous. It needs a sync signal from outside.

And I hope it is well built... I have a wall clock that syncs every
night (about 3 AM) from a radio signal from Germany, I think. The rest
of the day it runs autonomously.

https://en.wikipedia.org/wiki/Radio_clock

However, sometimes there is some problem and it is 15 hours off sync.
Depending on the model, it can manage to sync the next day, or never. I
can not really trust it.

--
Cheers, Carlos.

 

[The Real Bev]

On 11/29/2016 09:07 AM, Carlos E.R. wrote:

On 2016-11-29 08:27, The Real Bev wrote:
On 11/28/2016 08:34 PM, Jeff Liebermann wrote:
On Mon, 28 Nov 2016 18:49:20 +0000, Whiskers
wrote:

However, a crystal controlled clock is only allowed
+/-0.07 sec/day = 2.1 sec/month = 25.2 sec/year.

There are now better clocks that easily meet the COSC requirements:
http://www.leapsecond.com/pages/atomic-bill/
https://www.kickstarter.com/projects/846511652/the-worlds-first-true-atomic-wristwatch-the-cesium

In [possibly] 2008 we bought some Casio 'atomic' watches with solar
batteries at Costco for ~$25 each plus tax. The same watches are
generally available for >$100 now. Not only are they incredibly
accurate due to receiving nightly hits from the atomic clock in [I
believe] Boulder CO, the black plastic bands show no sign of wearing
out, unlike the bands on previous Casio digital watches I've had.

There's nothing quite like owning a truly accurate timepiece

But it is not a "truly accurate timepiece", in the sense that it is not
autonomous. It needs a sync signal from outside.

I suspect that if Boulder stops sending sync signals the microsecond
accuracy of my watch will NOT be on my top-ten problem list

And I hope it is well built... I have a wall clock that syncs every
night (about 3 AM) from a radio signal from Germany, I think. The rest
of the day it runs autonomously.

https://en.wikipedia.org/wiki/Radio_clock

However, sometimes there is some problem and it is 15 hours off sync.
Depending on the model, it can manage to sync the next day, or never. I
can not really trust it.

Occasionally it doesn't get an update, probably because I was moving
around during the syncing process -- I'm not a good sleeper.
Unfortunately, I have no way of judging the resulting inaccuracy.

--
Cheers, Bev
"I read about this syndrome called hypochondria in a
magazine. I think I've got it." -- DA

 

[Jeff Liebermann]

On Mon, 28 Nov 2016 23:27:33 -0800, The Real Bev
<bashley101@gmail.com> wrote:

2008 we bought some Casio 'atomic' watches with solar
batteries at Costco for ~$25 each plus tax. The same watches are
generally available for >$100 now. Not only are they incredibly
accurate due to receiving nightly hits from the atomic clock in [I
believe] Boulder CO, the black plastic bands show no sign of wearing
out, unlike the bands on previous Casio digital watches I've had.
There's nothing quite like owning a truly accurate timepiece

The nightly updates can be a problem. Propagation from WWVB is rather
lousy during the daylight hours, and only improves on the left coast
around midnight.
<http://tf.nist.gov/stations/wwvbcoverage.htm>
<http://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi>
It's not lack of signal that causes problems. It's interference. It's
not uncommon for updates to fail if the watch is left in an RF noisy
location, such as next to an operating switching power supply.

Orientation is also a problem. Put the watch down with the tiny
loopstick pointed at WWVB and you get no signal even if propagation is
good. This is a lousy noisy signal with the end pointed at WWVB:
<http://802.11junk.com/jeffl/WWVB%20test/end-pointed-at-WWVB.jpg>
This is what a good signal looks like with the loopstick broadside to
WWVB:
<http://802.11junk.com/jeffl/WWVB%20test/loopstick-perpendicular-to-WWVB.jpg>
Even cross polarization will produce a lousy signal. This is a noisy
signal with the loopstick oriented vertically:
<http://802.11junk.com/jeffl/WWVB%20test/loopstick-vertical.jpg>

What the watch does without WWVB updates is a matter of conjecture. I
haven't done any testing nor could I find any online. Without the
updates from WWVB, it's probably no better than a common digital
watch. Even so, that's good enough for navigation, but for accuracy
it requires WWVB updates. (4 sec error = 1 nautical mile)

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558