vanjast,

it's fantastic to see your mod developing more and more !:up:

Do you have a source for a nautical star almanac from 1939-45 - with all the necessary data of major fix stars?

I wonder if its possible to get a position fix by method of shooting 3 stars "nautical triangle". I don't know how accurate SH3 models the position of all the stars from years 39-45, maybe you know more about this vanjast?

I've got a Navigation piece of software that I think, has all the star data in, from 3000BC to 3000AD. I'll get around to this as at a later stage, as I must still get the Longitude clock sorted out.

Considering that it's only a 6 year period, out of a 26,000 year cycle - I'm sure the triangulation method will work. I did a fix on Mintaka in Irion's belt from the southern hemisphere and this was accurate enough, so yes, the accuracy looks to be there. Naturally we must check the whole lot though.

On my first mission with this mod I managed to arrive at the northern tip of the Hebrides (I think it's called), the island chain that has Lewick in it.

I arrived about 4 hours before my calculated time, after been harassed 3x by a/c, leaving my course to sink a ship, 3 days of rain,sleet and snow, 2 days of mirror seas.

I left the Kristiaansand area and set course for the northern tip of Scotland. I arrived soon after noticing the depth beneath keel was reducing (land nearby), but did not have a clue where I was - I'm too early??

Looking through my scope ( I was running submerged during the daytime - after 3x a/c attacks), I could barely make out land in the mist and gale force winds. surfaced and turned north to 2 hours. then set course 270 for 6 hours. No land was encountered.

i had reached the right area, and I'm into the north atlantic from here...
First time for me, and I find myself developing methods for quick nav on the way.
:up:

Yea that was my asumption - i have tried to tickle with it, but can not get the Sixtant to be draggable...

Copying the menuxxxxx.dat entry directly over to the SH4 menuxxxx.dat does not cut it. - Im going to try looking at the stock clock that is draggable.

oops,
using the sextant and playing in higher resolution than 1024x768 is no good.
Tried to get a fix on polaris at ~59 deg Latitude, but it's way off. I can't even measure it - neither from horizon nor from zenit.

This is a side effect of the higher resolution, I'm playing in 1280x1024 (using well known higher resolution workaround).


oh well...

Many of us have tried to make draggable objects in SH3, similar in SH4 and none so far have worked. It's a problem at the moment.

The way I made the sextant scales was to make a single mission at positions 0, 10, 20...80 North (90 N sort of put you on top of the world/ice ans you sink ).

I'd line up the bottom of my screen with the horizon, Then, with Polaris in the horiztontal cebtre (x-axis), measure with a ruler (yup a normal school ruler) the distance to it. I'd then use these individual measurements to set the 10' scales and then scale the units between each 10'.
You can either do this yourself or send me your measurements and I'll make a sextant pic.

I suspect the scaling will be the same for 1024x768, where the screen height gives you 0-60 degrees. If Polaris is between 60 - 90, you move the POV (screen view)as high up as possible (so you're looking straight up) and start the process again from 60-90 N.
The 60' angle should now be at the bottom of your screen.

:up:

I have the same problem:cry:

Mikael

I'll create a higher res sextant, but I cannot test it on my screen.
Are you OK to check it out yourselves ?
:cool:

Yes please! No problems:up: .

Mikael

Okey Dokey.. I'll start with 1280x1024 res

Are there any other resolutions used. What I'll do it go with the resolutions, that are in SH4, but these will have to be individually tested by people with these screens.
Also the 1024x768.INI file input will probably have to be changed as well, regarding the height of the sextant image.

It'll take a few days as I have RL stuff to do.
:up:

thanks vanjast, will do some more tests in 1280x1024 and different angles on polaris. Trying to see how big the error is.

edit:
with 1280x1024 res I get these angles on polaris:

28° (at 20° lat - enabled marker to get real position)
36° (at 25° lat)
43° (at 30° lat)
49,5° (at 35° lat)
56,5° (at 40° lat)

stars around 58 - 64° elevation are not measurable. also looking upwards is no good reference, so you get additional errors when shooting stars at high elevations.

I wonder if this could be solved.

So what method are you guys using to fix longitude with this mod?

Rely good idea making a real sextant to put on the screen.

I think ill use a transparrent sheet and mark on that one. That can be lined up all along the buttom of the screen and up along one side giving high presicion for all placements.

This is how I did the original. Once you have that you use the ratios to mark off the scale on the image.

Say from..
1) 0-10 = 30mm
10-20 = 28mm
20-30 = 25mm
.
.
80-90 = 25mm

You totalise the mm (say 300)
your vertical resolution is 1024

0-10 scale will be marked at (30/300) x 1024 = 102.4 pixels high
So 10 marker is at 102(103)

Now the unit scales 1,2,3,...8,9 will be marked off at every 102.4/10 = 10.24 pixels

and so on up the scale..

I'll post a picture on this, as well, later.
:up:

I'm on a first serious mission and have used the GMT clock (lower right), with the almanac. It seems like the GMT clock might be locked onto your home base, instead of greenwich (I might have been mistaken first time) as I decided to do all my Longitude calcs on this basis.
My first plot was dead reckoning and ended up being 4 hours out, but he second time I decided to use the clock after 5 days on gale force winds and rain, I'd got a clear patch of sky, did a sextant reading and then later Longitude based on homebase time.

I found myself ~50km out on dead reckoning, but Longitude was spot on and located land a few hours later. I'll carry on testing this idea and come back later with results.

:up: