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Doniol- Sight reduction

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Doniol- Sight reduction
LouisC Offline
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#1
01-13-2016, 02:23 AM
Anybody want to talk about their experience in doing a Doniol sight reduction?

Do you HAV your Haversine tables?

Louis
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Fred_B Offline
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#2
01-14-2016, 11:58 PM
Yes, I'm up for it. The haversine tables I got off the web somewhere last year. Bowditch 1972 vol. 2 has 'em also. You have to buy the 1972 edition now. Confound it.

Unless I'm in error the only problem with Doniol is that you're only obtaining Hc. Never figured out how to get Zn yet.

It certainly is one of those "no batteries required" method to get Hc.

Louis, do you know the formula to obtain a haversine of an angle like 45° ?
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LouisC Offline
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#3
01-16-2016, 02:35 AM
(01-14-2016, 11:58 PM)Fred_B Wrote: Yes, I'm up for it.  The haversine tables I got off the web somewhere last year.  Bowditch 1972 vol. 2 has 'em also.  You have to buy the 1972 edition now.  Confound it.

Unless I'm in error the only problem with Doniol is that you're only obtaining Hc.  Never figured out how to get Zn yet.

It certainly is one of those "no batteries required" method to get Hc.

Louis, do you know the formula to obtain a haversine of an angle like 45°  ?

Fred, the formula to get a haversine is;  haversine of x= [1- cos(x) / 2

That's to get the haversine of an angle (1- cosine(angle)) divided by 2

So, the haversine of 45° is .1464
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LouisC Offline
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#4
01-19-2016, 10:05 PM
I used Libreoffice Calc to make some haversine tables up to 179° 58'.  Beginning at 178° 37' the haversine figure goes to .9999 all the way up to 179° 59'

I'll post them here tomorrow.

Lou
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LouisC Offline
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#5
01-20-2016, 03:19 AM (This post was last modified: 01-20-2016, 03:25 AM by LouisC.)
Here are the haversine tables up to 179° 58'.

The decimal point was eliminated to save space on the pages.  Just assume there's a decimal point in front of each of the 4 digit numbers.

Only the haversine even degree minutes are calculated and you can estimate (interpolate) what an odd haversine minute would be.  It won't change the Hc result by much even if you don't interpolate.

I'm working on a Doniol sight reduction form along with CelNav57.


Attached Files
.pdf   Haversine 0 to 179° 58' degrees.pdf (Size: 70.17 KB / Downloads: 1,262)
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c_davidson Offline
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#6
02-02-2016, 01:18 PM
(01-20-2016, 03:19 AM)LouisC Wrote: Here are the haversine tables up to 179° 58'.


I'm working on a Doniol sight reduction form along with CelNav57.

Thanks Louis for the tables.

Is the Doniol form finished?

Clendon
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Fred_B Offline
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#7
02-03-2016, 05:16 PM
Speaking of "no batteries required", has anyone considered using a slide rule?

Fred
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LouisC Offline
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#8
02-03-2016, 05:20 PM
Slide rules are rather out of date but they don't require batteries!

What I like about them is you can see a variety of answers linearly, such as 25nm divided by 3kn.

I wish I had piles of them- you can make a fortune on ebay as they are going up in price.
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