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Thread: How to get LHA and Ap longitude in Eastern longitudes
Post: RE: How to get LHA and Ap longitude in Eastern lon...
| PeterB,
Ok, that makes it perfectly clear. I see it's a very simple process. It's interesting that I have never seen any direct reference to either the Eastern or Western Ap λ adjustments other t... |
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P.Rutherford |
General Topics Here
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15 |
7,550 |
04-22-2023, 10:30 PM |
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Thread: How to get LHA and Ap longitude in Eastern longitudes
Post: RE: How to get LHA and Ap longitude in Eastern lon...
| Peter,
The final check (only really important for taking exams) is to confirm in either case that your resulting AP longitude is within 30.0' of longitude from your DR position, and if not to adjus... |
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P.Rutherford |
General Topics Here
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15 |
7,550 |
04-21-2023, 07:06 PM |
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Thread: How to get LHA and Ap longitude in Eastern longitudes
Post: RE: How to get LHA and Ap longitude in Eastern lon...
| PeterB,
Is the process the same for getting a good Ap λ in Western longitudes? That is- subtract the GHA minutes from 60? (and subtract 1° if there's over a 30 minute difference?)
Thanks,
P... |
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P.Rutherford |
General Topics Here
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15 |
7,550 |
04-18-2023, 07:21 PM |
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Thread: A Source of Confusion in Selecting an Assumed Position
Post: RE: A Source of Confusion in Selecting an Assumed ...
| Peter,
Your explanation(s) are most helpful. By providing the complex and simple way to get LHA, as you did, there's more clarity to the overall problem.
Have you ever tried the Doniol method?
... |
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P.Rutherford |
General Topics Here
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8 |
4,842 |
03-28-2023, 07:40 PM |
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Thread: A Source of Confusion in Selecting an Assumed Position
Post: RE: A Source of Confusion in Selecting an Assumed ...
| Peter,
The above is very useful but could you please give an example for Eastern longitudes that isn't for a the short cut method and gives an answer that provides the Ap longitude with minutes use... |
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P.Rutherford |
General Topics Here
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8 |
4,842 |
03-27-2023, 03:17 PM |
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Thread: Sextant mirrors re-silvering
Post: RE: Sextant mirrors re-silvering
| Steambum,
To answer you immediately, no, I don't know where or who to send it to. However, the maker of the sextant might be able to help you.
The index mirror on your sextant is a "first surf... |
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P.Rutherford |
General Topics Here
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2 |
2,225 |
01-31-2023, 12:17 AM |
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Thread: LHA in Eastern longitudes?
Post: RE: LHA in Eastern longitudes?
| I'd like to know why there's so much difficulty placed in determining LHA in Eastern longitudes when all you do is add the whole degrees and then add 1 degree to it? Chris Nolan's many excellent vide... |
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P.Rutherford |
General Topics Here
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5 |
4,070 |
11-30-2022, 01:20 AM |
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Thread: LHA in Eastern longitudes?
Post: RE: LHA in Eastern longitudes?
| Just my 2 cents, add the GHA and ApL whole degrees then add 1 degree. |
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P.Rutherford |
General Topics Here
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5 |
4,070 |
11-26-2022, 11:58 AM |
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Thread: Sextant - what are these bits for?
Post: RE: Sextant - what are these bits for?
| PeterB,
Wow! What an excellent explanation! And now I know why there are different colored filters and what the filter out.
Thank you,
Paul |
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P.Rutherford |
General Topics Here
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6 |
5,475 |
03-18-2022, 11:24 PM |
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Thread: Sun gone in hiding
Post: RE: Sun gone in hiding
| Pabrides,
Would you please describe what it's like to be in such a rainy situation? There are numerous and plenteous stories about such things. Like, having your house filled with water, knee dee... |
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P.Rutherford |
General Topics Here
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1 |
1,934 |
05-16-2021, 12:59 AM |
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Thread: Apparent time
Post: RE: Apparent time
| Rumata,
My thought is that the moment of LAN as observed in your sextant is correct but this must be qualified by the following;
- Sextants and ship movement combine to effect imprecise determin... |
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P.Rutherford |
General Topics Here
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3 |
3,247 |
02-05-2021, 02:51 PM |
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Thread: Haversine
Post: RE: Haversine
| Haversines have been very useful especially with the Doniol method. CelNav and Lou worked this stuff out a while back.
https://thenauticalalmanac.com/Forum/showthread.php?tid=65&highlight=doniol
... |
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P.Rutherford |
General Topics Here
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1 |
3,216 |
12-29-2020, 11:58 AM |
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Thread: Dead Reckoning
Post: RE: Dead Reckoning
| That is a good method but between the time the line pays out and goes taught could be a lot.
I was reading in a book, don't remember the title, but in the 1500's aboard ships certain crew members wer... |
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P.Rutherford |
General Topics Here
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3 |
3,680 |
12-29-2020, 11:47 AM |
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Thread: Great Voyages
Post: RE: Great Voyages
| Now that's very interesting and a good series of questions.
Recently I read, "Over the Edge of the World" by Laurence Bergreen. It's about Magellan's circumnavigation (he got murdered in the Phili... |
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P.Rutherford |
General Topics Here
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2 |
2,769 |
12-26-2020, 06:44 PM |
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Thread: Fake Weather....
Post: RE: Fake Weather....
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pabrides Wrote: (11-18-2018, 02:43 AM)
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We are all interested in weather - are we not??
So here is some news about fake weather.... read it a weep. However, I whole-heartedly disagree that glo... |
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P.Rutherford |
Marine Weather
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1 |
5,476 |
11-18-2018, 09:32 PM |
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Thread: Sextant in music- Thomas Dolby
Post: Sextant in music- Thomas Dolby
| Thomas Dolby wrote the song Oceanea which is a rather nice song.
In various portions of the video a sextant is shown.
Here's a link- https://www.youtube.com/watch?v=7STUTxwdC5A
Dolby was popular ma... |
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P.Rutherford |
Humor & Laughter
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0 |
2,177 |
08-16-2018, 12:38 AM |
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Thread: LONGITUDE
Post: RE: LONGITUDE
| In one part of his book, around the world, he speaks of using his sextant to take a lunar and then, just as calculated...the island appeared a few hours later.
Lunars would be the death of my inter... |
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P.Rutherford |
General Topics Here
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6 |
8,673 |
07-16-2018, 10:26 AM |
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Thread: Gunter and Bowditch
Post: RE: Gunter and Bowditch
| Fellas,
The survivorlibrary also has a very good section on astronomy;
http://www.survivorlibrary.com/index.php/8-category/9-library-astronomy
Most of the books in both sections (navigation and ast... |
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P.Rutherford |
General Topics Here
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6 |
12,213 |
06-12-2018, 12:29 PM |
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Thread: Our missing shipmate- John Fisher
Post: RE: Our missing shipmate- John Fisher
| Yes, he is a true shipmate! If he's not found, and it appears he wont be, I hope when he "hands in his log book" it's accepted as "well done" by The Great Commodore.
...."To them that go down to t... |
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P.Rutherford |
General Topics Here
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1 |
3,801 |
03-29-2018, 12:02 AM |
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Thread: Filters
Post: RE: Filters
| If you're familiar with this movie scene below you know it has nothing to do with sextant work. Let's just say it did.
"It 'twas.....sun...sights!"
https://s16-us2.ixquick.com/cgi-bin/se... |
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P.Rutherford |
General Topics Here
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6 |
9,328 |
03-15-2018, 07:54 PM |
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Thread: The Sun and Stars will be our guide...
Post: The Sun and Stars will be our guide...
| Bundaberg rum made many funny advertisements and since this forum is mostly about nautical things here's a good one-
https://www.youtube.com/watch?v=N5Kf7QPLsvs
I'm a member of a yacht club th... |
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P.Rutherford |
Humor & Laughter
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1 |
3,645 |
03-10-2018, 10:31 PM |
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Thread: Volvo Ocean race- cel nav?
Post: Volvo Ocean race- cel nav?
| I was just watching a video about the Volvo ocean race 2014-15 and at this link;
https://youtu.be/vpM12gPOte8?t=34m32s
...it shows a sailor using a sextant. I do not know what year they show in... |
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P.Rutherford |
General Topics Here
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1 |
4,348 |
10-14-2017, 12:27 AM |
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Thread: How to buy a sextant
Post: RE: How to buy a sextant
| James,
If it's any help, and these are just my ideas, a good way to start is not to buy a Davis Mark 15 "plastic" sextant. I have one and am tired of having to adjust the thing every few minutes. ... |
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P.Rutherford |
General Topics Here
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8 |
16,692 |
08-10-2017, 08:35 PM |
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Thread: Planning for twilight phenomena observation
Post: RE: Planning for twilight phenomena observation
| Gentlemen,
Perhaps for a refinement in determining longitude by, say, Sunset, you could use the Altitude Correction Tables- https://thenauticalalmanac.com/Altitude%20Correction%20Table.pdf
....u... |
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P.Rutherford |
The Sight Reduction process
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5 |
9,221 |
07-03-2017, 08:53 PM |
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Thread: Great Circle route difficulty
Post: RE: Great Circle route difficulty
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BigBill Wrote: (04-22-2017, 08:22 PM)
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I was brushing up on the procedure for figuring the great circle route, the one in the 50 year almanac by Kolbe and had some troubles. Maybe I was just tired... |
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P.Rutherford |
General Topics Here
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4 |
8,668 |
04-23-2017, 02:47 AM |
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Thread: Bad Map Might Be Why Earhart Didn't Reach Island
Post: Bad Map Might Be Why Earhart Didn't Reach Island
| Amelia Earhart and Fred Noonan disappeared into the Pacific ocean in 1937, 80 years ago, and there are still people trying to figure out what happened to them and why.
The story below, click on it,... |
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P.Rutherford |
General Topics Here
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0 |
3,074 |
04-13-2017, 09:06 PM |
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Thread: Fun day on the deck
Post: RE: Fun day on the deck
| Bigbill,
Do you use the recording drum on the A12? I know there is one but I've never known how they work.
Paul. |
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P.Rutherford |
General Topics Here
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4 |
7,473 |
04-04-2017, 11:23 AM |
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Thread: WindyTV.com
Post: WindyTV.com
| Here's a good site for graphical weather conditions.
WindyTV (https://www.windytv.com/)
It would make a great a screen saver too.
Paul |
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P.Rutherford |
Marine Weather
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0 |
3,288 |
03-30-2017, 01:15 AM |
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Thread: Limb to use- Upper or Lower?
Post: RE: Limb to use- Upper or Lower?
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P.Rutherford Wrote: (03-22-2017, 11:18 PM)
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BigBill Wrote: (03-22-2017, 09:33 PM)
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CarlosPindle Wrote: (03-21-2017, 10:06 PM)
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BigBill,
Have you tried placing it on the railing of your dec... |
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P.Rutherford |
The Sight Reduction process
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11 |
18,990 |
03-23-2017, 12:36 PM |
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Thread: Need 2017 Altitude Correction Tables
Post: Need 2017 Altitude Correction Tables
| Will someone please upload a copy of the 2017 Altitude Correction Tables?
I've been using the an old version of them- mostly for the Sun. There isn't much difference between years, it seems.
Pa... |
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P.Rutherford |
The Sight Reduction process
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2 |
5,304 |
03-22-2017, 11:40 PM |
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Thread: Beaufort scale
Post: RE: Beaufort scale
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Rdutton Wrote: (03-21-2017, 11:47 AM)
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Many are the words I've read where mariners say, "you have no idea of the tremendous power of the ocean and the wx until you get hit by it".
--
I've read th... |
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P.Rutherford |
Marine Weather
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4 |
9,362 |
03-22-2017, 11:21 PM |
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Thread: Limb to use- Upper or Lower?
Post: RE: Limb to use- Upper or Lower?
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BigBill Wrote: (03-22-2017, 09:33 PM)
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CarlosPindle Wrote: (03-21-2017, 10:06 PM)
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BigBill,
Have you tried placing it on the railing of your deck or directly over the deck's beam?
It's mes... |
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P.Rutherford |
The Sight Reduction process
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11 |
18,990 |
03-22-2017, 11:18 PM |
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Thread: GHA Aries Long term for years 2017-2025
Post: RE: GHA Aries Long term for years 2017-2025
| How is the month and year figure determined in "part a" ? |
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P.Rutherford |
GHA Aries Long term for years 2017-2025
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3 |
9,104 |
03-21-2017, 11:57 AM |
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Thread: Beaufort scale
Post: RE: Beaufort scale
| The video was perfect. How'd you like to be in a Beaufort 12?
Paul |
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P.Rutherford |
Marine Weather
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4 |
9,362 |
03-21-2017, 11:43 AM |
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Thread: Stellarium- finding stars
Post: RE: Stellarium- finding stars
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BigBill Wrote: (03-18-2017, 12:54 AM)
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Windows on my pc.
So far it's helped me identify a number of uncertain stars but the real treat was Venus, Mars and Jupiter which I had been struggling to i... |
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P.Rutherford |
General Topics Here
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11 |
19,609 |
03-18-2017, 12:19 PM |
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Thread: Bowditch 2017- The American Practical Navigator for you
Post: RE: Bowditch- The American Practical Navigator for...
| Good work. The NGIA's Bowditch site is messed up. The web page isn't secure.
Plus, their download was always a pain. They even have Chapter 30/31 incorrectly named in the file name. You ought ... |
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P.Rutherford |
Bowditch 2017- The American Practical Navigator
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1 |
5,414 |
03-04-2017, 03:06 AM |
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Thread: Lego Sextant
Post: Lego Sextant
|
Thought you would enjoy seeing a Lego mini-figure sailor with his sextant. And you thought the Bris mini-sextant is small. |
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P.Rutherford |
General Topics Here
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3 |
7,742 |
02-04-2017, 11:03 PM |
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Thread: Buy a sextant
Post: RE: Buy a sextant
| Douglas,
I've never seen a SNO-T up that close. It looks like a remarkably well made instrument.
Does the box sextant lend itself to marine navigation?
Do you have a Plath sextant by chance?... |
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P.Rutherford |
General Topics Here
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14 |
34,337 |
01-20-2017, 08:36 PM |
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Thread: Landfall procedure?
Post: RE: Landfall procedure?
| Fellas, a few weeks back I found this Air Force Landfall training procedure- see below.
In its basic form the Landfall procedure is simply following an LOP that passes through your destination on... |
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P.Rutherford |
General Topics Here
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10 |
16,210 |
06-03-2016, 02:05 PM |
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Thread: Mercury Transit of the Sun's disk May 9, 2016
Post: RE: Mercury Transit of the Sun's disk May 9
| I watched part of the transit this morning using my III-B. Mercury was a very tiny dot on the face of the Sun.
It gives one an idea of scale between the Sun and tiny Mercury! |
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P.Rutherford |
General Topics Here
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1 |
4,688 |
05-09-2016, 11:04 PM |
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Thread: Landfall procedure?
Post: Landfall procedure?
| I've been reading some old Air Force manuals which mention using the Landfall procedure as a safe means to arrive at your destination while flying.
Francis Chichester used it (maybe invented it) an... |
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P.Rutherford |
General Topics Here
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10 |
16,210 |
04-14-2016, 11:53 AM |
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Thread: What time is Spring, exactly?
Post: RE: What time is Spring, exactly?
| The Vernal equinox is on March 20, 2016 at UT 04:30:08.325
Date and time is based on UT/GMT.
Paul |
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P.Rutherford |
General Topics Here
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2 |
4,971 |
03-19-2016, 04:29 PM |
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Thread: Does anyone really shoot the Moon?
Post: RE: Does anyone really shoot the Moon?
| Have any of you done a "Lunar"?
It seems much more involved than I'd like to get. But, it was part of the art quite a while ago.
Noon-sights? Yes, they're part of our regular daily observation... |
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P.Rutherford |
The Sight Reduction process
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8 |
15,860 |
02-27-2016, 02:25 AM |
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Thread: Davis Mark 15 sextant- wanted
Post: Davis Mark 15 sextant- wanted
| Does anyone have a Davis Mark 15 sextant they want to sell?
Paul |
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P.Rutherford |
Equipment- Wanted or for Sale
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4 |
10,751 |
02-03-2016, 02:49 PM |
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Thread: CelNav again at USNA
Post: RE: CelNav again at USNA
| Surprise is right! I was doubtful that they would teach CelNav and the December issue of Ocean Navigator makes it apparent- they aren't.
CelNav familiarization only at USNA (http://www.oceannaviga... |
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P.Rutherford |
General Topics Here
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1 |
5,209 |
01-30-2016, 02:07 PM |
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Thread: Kindle- The Nautical Almanac
Post: Kindle- The Nautical Almanac
| Remember ebook readers? I've found that my old Kindle Wifi is perfect for putting The Nautical Almanac on. Since the file is a PDF zoom in is necessary. The advantage of using the Kindle (old clunk... |
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P.Rutherford |
General Topics Here
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0 |
3,635 |
01-07-2016, 11:36 PM |
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Thread: Fastest sight reduction you've done
Post: RE: Fastest sight reduction you've done
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EdCa Wrote: (12-18-2015, 02:37 PM)
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Like everything in celnav sight reduction takes time.
What's the fastest Sun sight reduction you have carried out?
Just the time from when you store the... |
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P.Rutherford |
The Sight Reduction process
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1 |
5,116 |
12-29-2015, 03:04 AM |
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Thread: Stellarium- finding stars
Post: RE: Stellarium- finding stars
| Stellarium has been a real help in figuring out stars that aren't too familiar. In Linux it's free but don't know if there's a cost for other OS.
Stellarium does cost when purchased for Android.
... |
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P.Rutherford |
General Topics Here
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11 |
19,609 |
12-23-2015, 04:11 AM |
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Thread: Problem using Moon Altitude Correction Table
Post: Problem using Moon Altitude Correction Table
| The far left hand column of the Moon Altitude Correction Tables has App. Alt. in it. Do I assume correctly that the column is for minutes of Ha?
Altitude Correction Tables for the Moon (http://the... |
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P.Rutherford |
The Sight Reduction process
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1 |
4,221 |
12-22-2015, 12:36 AM |
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Thread: Joshua Slocum- Around the World Alone
Post: RE: Joshua Slocum- Around the World Alone
| Slocum is a hero of mine. Fighting off savages in The Strait of Magellan and the Chilean coast. What a mariner!
It's speculated he got holed heading for the Caribbean by perhaps a steamship which... |
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P.Rutherford |
General Topics Here
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1 |
4,534 |
12-22-2015, 12:28 AM |
