If your chronometer is broken and time is unknown or you can't get a WWV or WWVH signal you're going to have a hard time determining Longitude.  Latitude can be obtained easily enough from the blessed noon-sight.  No time...no position fix.

Have any of you tried "the recovery of time" technique.  I think it requires a known position and the GHA deriving the Hc specific to the position.  Beyond that, I know nothing about.

Looking at Bowditch Chapter 26 Emergency Navigation

"Section 2612. Finding Longitude" (page 10) mentions something about determining meridian transit time and correcting the chronometer for same.  There has to be some explanation for this?

I hope.

Craig

Got the 2102-d star finder from Weems & Plath a few months ago and have been enjoying the ease and simplicity of it.

Previously, but still, I use the USNO's Navigation Star Chart;

USNO Navigational Star chart



The 2102-d makes identifying stars of doubtful position or when only a few stars can be seen at a certain azimuth and one is trying to figure out which star(s) it was.

The included directions mention the plotting of planets or the Sun but I am rather confused on how it's done.

Can anyone help out?

Have a nice weekend,

Craig

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 sextant and sit down to begin the paper work.

For me, it was about 1 minute 30 seconds.  A lot of time is eaten up in turning pages.

Ed

Pub. No. 229 is way too cumbersome to lug around so I solve for Hc and Zn using the respective formulae for them.

These are handy to carry- http://thenauticalalmanac.com/Formulas.html

and a lot lighter than books.

Messing around with the various formulae to determine Z led me to the one on the Formulas page.  Most of the others require too many conditions ("if, then") to arrive at a solution.

Would like to hear what others use or maybe a quicker method.

Fb

Standing on a beach on the East coast of the US is good practice for sights made while on the ocean. Except one big problem- SAND!!  It teaches you a new regard for keeping the sextant clean.

Has anyone here made sights over one of the Great Lakes?

Fred

When using an AH it seems the Lower Limb shots are the ones I usually make because I can add quicker than subtract when using the Altitude Correction Tables.  If the LL isn't available then the Upper is the only choice.

Do any of you shoot super-imposed?  If so, why do you use it?

FB.

The program, Stellarium, I've found to be helpful in figuring out the doubtful position of navigational stars.  Similar to the problem of, "I just shot a certain star but am not sure what its name is". So, Stellarium can be used to help identify a celestial body.

You can get it here;  Stellarium

2102-D is good too and so is the USNO's Navigation star chart

Carlos

Hello everyone,

The full sized UPS are ok but I like to use a small 8-1/2 x 11 sheet printed off or just making one using Bowditch method in Chapter 26- Emergency Navigation section 2603.  Very easy to make one.

Carlos P.

Hello all,

Got a series of good shots of Venus this morning at around UTC 11 and will be trying my first planet sight reduction.

In The Nautical Almanac, for Venus, there's a "v" correction.  I understand how it's to be obtained through the Increments and Corrections but do not know what the "v" stands for?

Good day,

Carl

It would be nice if Pub. No. 249 Vol. 1 could be compiled for the Sun too.  Man, you could do a sight reduction in a couple of minutes!

Clendon D.