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Old 16-12-2014, 20:00   #1
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GHA Aries long term Table?

2015 is coming....surely.

HO 249 Volume 1 page 340 has "Table 4- GHA Y for the years 2006 to 2014" which is a very compact way to determining GHA Y (Aries) for stars.

See here (page 339)

http://www.waypointamsterdam.com/Han...Pub249Vol1.pdf

I use it instead of carrying around the NA. (I can easily calculate Hc and Az using the Spherical Trig formulas so I can reduce the amount of paper on board).

But, that sheet will expire this year. Do you know of the same Table 4 for the coming years?

Or rather....do you know of quick, accurate way to determine GHA Aries?

Thanks
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Old 18-12-2014, 05:38   #2
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Re: GHA Aries long term Table?

A Long Term Almanac can be found here: http://www.amerisurv.com/PDF/LongTermAlmanac.pdf

I think there are also some PC-based almanacs lasting longer than 2015...
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Old 18-12-2014, 07:07   #3
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Re: GHA Aries long term Table?

That long term almanac, I think, is from Geof Kolbe's book.
While a nice idea there are too many steps involved, for me, and thus prone to error.

Celestaire has HO 249 2015 here (free pdf)

https://www.celestaire.com/pubs/category/3-pub-249.html

Table 4 is on page 340, 341 and extends out to 2019

Thanks for the effort.
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Old 18-12-2014, 07:28   #4
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Re: GHA Aries long term Table?

Here is a free digital almanach up to 2100 with daily pages (every hour) for sun, moon, planets and stars...
Bateaux autour du monde - Sail The World - L'Univers de la grande croisière en voilier - STW
(Headings in French though)
random example: Friday dec 18th 2020
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Old 18-12-2014, 07:38   #5
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Re: GHA Aries long term Table?

Thank you but it's French and Windows.
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Old 18-12-2014, 07:42   #6
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Re: GHA Aries long term Table?

Quote:
Originally Posted by PDA1 View Post
2015 is coming....surely.

....(I can easily calculate Hc and Az using the Spherical Trig formulas...

Thanks
Could you please provide details on how to calculate Hc and Az without the Nautical Almanac? Any online reference on how to do this??
Thanks
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Old 18-12-2014, 07:43   #7
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Re: GHA Aries long term Table?

I think this is what you want, but its a big download (171MB), but it is the complete Pub 249 Vol 1 Selected Stars Epoch 2015.
If it is too big for you to download, let me know and I can make a PDF print of the GHA Aries pages.
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Old 18-12-2014, 07:52   #8
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Re: GHA Aries long term Table?

Sorry, forgot the link
https://www.celestaire.com/pubs/category/3-pub-249.html
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Old 18-12-2014, 08:01   #9
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Re: GHA Aries long term Table?

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Originally Posted by Capt.Don View Post
Could you please provide details on how to calculate Hc and Az without the Nautical Almanac? Any online reference on how to do this??
Thanks
Note- I use a Casio fx-300ES Plus calculator (Walmart $10)
The "/" means "divide"

To determine Hc-

First, the formula

Hc = asin[sin(Declination)*sin(Latitude) + cos(Latitude)*cos(Declination)*cos(LHA)]

Example- AP Latitude= N41d Declination= N1d 21.1' LHA= 345d


Next, how I enter the formula into the Casio calculator


Sin-1(Sin(Ap Latitude) x Sin(Declination) + Cos(Ap Latitude) x Cos(Declination) x Cos(LHA)


Hc= 48d 06' (using the figures above)


When the heavily body's Declination is South enter the negative sign before it.


It takes about 15 seconds to enter and get the result. Much faster than using HO 229 or HO 249 but the same basic result.


To get Zn-


First, the formula

Z = acos[(sin(Declination) – sin(AP Latitude) x sin(Hc)) / (cos(AP Latitude) x cos(Hc))]

Example
- AP Latitude= N41d Declination= 1d 21.1' Hc= 48d 06'


Next, how I enter the formula into the Casio calculator


Cos-1((Sin(Declination) – Sin(AP Latitude) x Sin(Hc)) / (Cos(AP Latitude) x Cos(Hc)


Example answer= 157d 13' 31.23”


Another way to get Zn (casio again) without needing Hc.


tan-1((sin(LHA) / (cos(AP Latitude) x tan(Declination) – (sin(AP Latitude) x cos(LHA))


If LHA is greater than 180 it's treated as a negative quantity.
If the Azimith angle as calculated is negative, add 180 to it.



Get the Nautical Almanac from Navsoft.com downloads.


In truth, for Sun GHA I use HO249 Vol 3 TABLE 4. — GHA and Declination of the Sun for the Years 1981−2016  Argument “Orbit Time”


This table provides the means of getting GHA and Dec for the Sun. It's a little confusing to use...but cuts down on the amount of paper. And, I also have Navsoft's Almanac on a kindle.
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Old 18-12-2014, 08:03   #10
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Re: GHA Aries long term Table?

Quote:
Originally Posted by PDA1 View Post
Note- I use a Casio fx-300ES Plus calculator (Walmart $10)
The "/" means "divide"

To determine Hc-

First, the formula

Hc = asin[sin(Declination)*sin(Latitude) + cos(Latitude)*cos(Declination)*cos(LHA)]

Example- Latitude= N41d Declination= N1d 21.1' LHA= 345d


Next, how I enter the formula into the Casio calculator


Sin-1(Sin(Ap Latitude) x Sin(Declination) + Cos(Ap Latitude) x Cos(Declination) x Cos(LHA)


Hc= 48d 06' (using the figures above)


When the heavily body's Declination is South enter the negative sign before it.


It takes about 15 seconds to enter and get the result. Much faster than using HO 229 but the same basic result.


To get Zn-


First, the formula

Z = acos[(sin(Declination) – sin(Latitude) x sin(Hc))/(cos(Latitude) x cos(Hc))] Example- Latitude= N41d Declination= 1d 21.1' Hc= 48d 06'


Next, how I enter the formula into the Casio calculator


Cos-1((Sin(Declination) – Sin(AP Latitude) x Sin(Hc)) / (Cos(AP Latitude) x Cos(Hc)


Example answer= 157d 13' 31.23”


P { margin-bottom: 0.08in; }
Another way to get Zn (casio again)



tan-1((sin(LHA) / (cos(Present Latitude) x tan(Declination) – (sin(Present Latitude) x cos(LHA))



If LHA is greater than 180 it's treated as a negative quantity.
If the Azimith angle as calculated is negative, add 180 to it.



Get the Nautical Almanac from Navsoft.com downloads.


In truth, for Sun GHA I use HO249 Vol 3 TABLE 4. — GHA and Declination of the Sun for the Years 1981−2016  Argument “Orbit Time”


This table provides the means of getting GHA and Dec for the Sun. It's a little confusing t use...but cuts down on the amount of paper. And, also have Navsoft's Almanac on a kindle.
Thanks - I've always been curious about doing this with trig formulas!
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Old 18-12-2014, 08:14   #11
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Re: GHA Aries long term Table?

Quote:
Originally Posted by Capt.Don View Post
Thanks - I've always been curious about doing this with trig formulas!
Don, it really is pretty easy.

Often I use both methods of determining Hc & Zn- calculator and HO 249 for the Latitude I'm in.

It's alot easier to print out the HO 249 Latitude sheets you'll typically find yourself in than having the entire book.

In my case I'm in Latitudes N39, N40 and N41 so all I require is about 6 sheets double side printed.

I want to avoid using electronics as much as possible when doing Sextant work....including the calculator. But, as mentioned before they too are useful tools.

Also, HO 249 only covers up to Declinations of 29 degrees so you can't use that for many stars. I'm certainly not going to carry HO 229. Thus, using a calculator to get Hc and Zn for stars above that declination is necessary. So, again, you won't have lug around a lot of paper.
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Old 18-12-2014, 08:20   #12
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Re: GHA Aries long term Table?

If you feel really lazy you can get a Sun sight reduction spreadsheet from-

Excel Sight Reduction Spreadsheet for Astro Navigation.

That program is great!

I wish the sailor would write one for stars!
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