Real Navigation with SH4

[don1reed]

Your Antares example:
I get:

Hc: 7*32.1' - Ho: 7* 14.1' = Away 18.0 nm

Thats what I come up with using the Hc formula that was used to compile HO 229

Hc = arcsin [(sin L sin d) + (cos L cos d cos LHA)]

Z = [(sin d - sin L sin Hc) / (cos L cos Hc)]

Z = 145*, then Zn = 360* - Z = 215*

Legend:

L = Latitude
d = Declination
LHA = Local Hour Angle
Z = Azimuth Angle (measured E & W from 0-180*)
Zn = Azimuth (measured 0-360*)

[don1reed]

The answer to your question must be in the data you're using for GHA, SHA, and Aries.

Here's what I get:

Aries: for 03:17:01 = 287*04.1'
SHA: Antares = 113*31.7'
min/sec = 4* 15.9'
404*51.7' - 360*

GHA = 44* 51.7'
aLong = -5*(W)
LHA = 39* 51.7'

Dec = S26* 18.2'

[jmr]

Thanks for being patient with my, don1. :p I just realized the mistake I made when doing my calculations for Antares in my worksheet. It was another simple boneheaded arithmetic error when calculating d with my Hc.

[don1reed]

No problem, jmr.

This is worse than doing your own taxes...sometimes

[jmr]

Don, I'm curious, what's the longest you've gone without a sun/star shoot due to poor weather? In real life of course :}

[don1reed]

3 to 4 days. Even then you get a lil nervous about your DR position. Never had to navigate during any wartime conditions, however. (My maritime nav experience is all civilian.) Constantly proceeding from point A to B, whereas wartime sailors are sometimes ordered to patrol a "box" and that means they were/are at the mercy of the wx in their AO and can't punch out of their confinement and could be without celestial help for weeks.

Edit:

one thing I forgot...it's not that you cannot see any celestial bodies, in fact, you can see some stars occasionally, but they're either too low in the sky to be usable or they're unrecognizable. The sun, however, can be used...sort of, if you use center of mass of that hugh cotton, fuzzy mass on the other side of the clouds. When its really socked in--forgetaboutit.

cheers,

[6SJ7GT]

JMR,

Just a quick post to let you know I haven't forgotten about the '39 and '40 almanacs. I've been a little busy, mostly with the weather around here. We got 10+ inches of rain in less than a week, set the all time record for any month and we still have half a month to go. Gonna NEED a sub if this keeps up!

Your mathematical travails look similar to mine, about half the time I get a LOP that seems wrong, then go back and find a simple error and it works out.

Don's right, almost as bad as doing your taxes. (and we're doing this for fun?)

Cheers,
Mike

[Pisces]

Roger 6SJ7GT,

There's no sense in doing starcalcs when your deck is poored awash by rain.

*Whoop... Whoop* ... All hands, man the bucket brigade!.