(REQ) for Cel Nav Scope

[don1reed]

For the Cel Nav enthusiast, is there a way to Mod the MaGui F or any Obs scope to have a movable (rotatable with mouse wheel or up/down cursor keys) vertical 0 to 90° angle indicator installed alongside the viewer lens as I've drawn on this snap?
http://img607.imageshack.us/img607/2217/obsscope.jpg (http://imageshack.us/photo/my-images/607/obsscope.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

You Moders are extraordinary in your magic. My thinking was to be able to see the angles of elevation rotate as the player scans up or down. It's my belief, this addition would allow the Navigation enthusiast to read celestial bodies' Altitudes, allowing for enhanced realism.

Edit: This would be an addition to the horizon compass card above the lens.

Thank you for all your endeavors.

[Hitman]

I can only think of two ways to do it:

The first one is unfortunately too complicated. It would involve editing the 3D model of the periscope head to put there a vertical degree scale, then edit the mask in the 2D view letting it show the scale on the side, as you proposed in your picture.

The second one is easier, but I can't tell for sure how it would work with celestial navigation. It would involve adding a 3rd zoom level to the scope with a very large aperture angle for the lense, and a 2D vertical degree scale (Draggable or that appears with a click). This would allow you to actually see at the same time horizon, sky and the degree scale to measure the angle subtended between horizon and stars. It would cause a sort of fish-eye view, but should work.

[don1reed]

I see your point, Hitman, but what I was thinking about is keeping it simpler with the current level of max zoom @ 6x as it currently is. Having the horizontal cross-hair at sea level at 0° then as the player rotates the view upward toward the celestial body, the degrees would increase until the lower-limb of sun/moon is reached, for example.
Another example for illustration, that comes readily to mind is: Observing the Sun at noon while on the Equator, the Sun should be at our Zenith and reading 90°.

If the zero line is slightly above or below the wet horizon, the player would figure in Index Correction (I.C.) error, as in real life.

IDK, I'm just spit-ballin' here.

[LemonA]

Give us an example how you get a position fix (error +- 10nm) from the celestial SH3 bodies if you can measure the SH3 stars with good accuracy.

[don1reed]

At present, LemonA, I don't know of an accurate system of measuring the in-game celestial dome; however, the Phython/Stellarium stand-alone navigation programs is a very accurate method; however, tedious to use. The Player must save/exit the game in order to auto-update the Sub's position in the My Documents/SH3 or SH4 files.

My thought about using the Observation scope as a stand-in sextant, was to hopefully improve upon that accuracy. If the moders could design a rotatable, vertical altitude gauge, capable of displaying 10ths of a degree between 0° and 90°, experimentation could reveal how accurate the in-game celestial dome really is.

Edit: If the Game's celestial dome is an accurate rendition, then standard cel nav procedures could be implemented, i.e.,calibrate I.C., measure the altitude of three or more objects with ITC (GMT),, using 1939-1945 almanacs and either HO 211, HO 249, or HO 229 tables for sight reduction. Or, for the mathematically inclined: Hc = asin [(sin Lat sin Dec) + (cos Lat cos Dec cos LHA)]...Z = acos [(sin Dec - sin Lat sin Hc) / (cos Lat cos Hc)]. Accuracy to within 5 nm should be adequate at minimum.

Frankly, using Cel Nav with SH3 / SH4 almost dictates the player use Time x 1.

Any thoughts?

[vanjast]

I made an obs-scope 'sextant' for SH4 some time ago - which you probably can convert to SH3. Have a look in the SH4 mods repository or in Maikes mod server. I've just been too lazy to convert this.. but maybe it's time!! :)
As far as I can see the Celestial dome is the same for SH3 and SH4. You'll just have to add another obs-scope zoom level in the Cameras.dat file and adjust this view scaling to match the 'sextant'.
The methods (and test missions) are all described in the SH4 RealNav mod.

Some guy has claimed a 100m accuracy using the 'sextant' and triangulation, but I'm not sure about this. I've managed to get approx 5nM at my best (after 1 week of shiet weather), but I was using non-stabilized scope option, so maybe with stabilized it might be achievable. Naturally with practise one's accuracy will improve - and also some people are 'naturals'.

[don1reed]

Tks Vanjast! Excellent work btw. Nicely done.

:oops: I'm embarrassed that I somehow missed your Mod.

[vanjast]

Thanks.. I seem to have a made a mistake here... I think I made the SH4 Obs Scope sextant but never published it.
I've looked through all my backup usb drives from years ago, but nothing ??
I used photoshop 7 to create the obs scope, what I'll do is post the SH4 dds file and a converted TGA file for SH3, and you can copy and paste freely.

Give me a few days to see if it really still exists, as I find the win-7 search function all but useless.
:)

[don1reed]

Berta Zeppelin

[makman94]

hello guys,

there is a problem that need to 'solve' for creating such scales and this is that there are no 'universal' scales becuase the viewports-angular angle values are NOT the same to all mods

@Don1reed: in MaGui F the scales that you see at the scope are representing,at x1,5 power, the degrees (each mark is one degree) and also are taking in account the screen's distrortion
[this distortion is from middle point(the point that scope's lines cross each other) to edges of viewport] so you can use these scales for your purpose

bye

[don1reed]

Howdy, markman94. Greatly enjoy your mods. Thanks for the input. Let me paraphrase... Are you saying:

No matter which mod the player is using, the Cross + point of the scope focus is the point of least distortion?

If so, then the obs-scope could be the likely candidate as a stand in sextant. Provided, of course, an accurate rotatable quadrant scale could be read between the wet horizon and zenith.

What do you think?

[vanjast]

If you look at that attached pic in Post 6, you'll see that allowances have been made for distortions - The gradations are not equal, and symmetrical about the centre point. :)

[don1reed]

Roger that, Vanjast. :up:

[vanjast]

Here's what I managed to find. I extracted the 'sextant' out of the SH4 images so that all you have to do is copy into the SH3 Obsscope.

I made a brief explanation on how I created and calibrated the sextant and view scalings.

https://dl-web.dropbox.com/get/SH3_Stuff/Sh3Sextant.zip?w=AABv_PSRBFtmAmKP1x9Z8SrZYU1uYxCa8 AxJ6FiG4N8RAA

:up:

[don1reed]

Here's a pic of the accuracy and results I usually get using Python/Stellarium programs. It's as good as it gets, but, as I've said, very tedious to use.

I've overlaid Grid AN41 onto Geocoordinates. When working off screen and on paper the constructions can become crowded as well as tedious. The scale is 1/10th inch = 1 nm of latitude, btw.

Hopefully, Vanjast, your mod will narrow us into the real thing. Thanks.

http://i77.photobucket.com/albums/j42/donhreed/scan0001.jpg (http://s77.photobucket.com/user/donhreed/media/scan0001.jpg.html)

Thanks again.

[_Seth_]

Good work, it`s a start :up:

[makman94]

If you look at that attached pic in Post 6, you'll see that allowances have been made for distortions - The gradations are not equal, and symmetrical about the centre point. :)

hello guys,

you don't understand me Vanjast ,i didn't say that your scale is wrong or that doesn't taking in acount the screen distortion.
i am saying that your scale is good for use ONLY at the scope that you used for building this scale. you definetely can't use this scale to every scope and eventually to MaGui F.
MaGui F's scopes are using different viewport values and different angular angle values and this is effecting the way that the degrees are rendering on screen.

@Don1reed: i don't know what you are running after you 'celestian' guys (i haven't study all these stuff about celestian navigation yet) but all i am saying to you is this: if you are running after to see how the degrees are rendering in MaGui scope's view then this is right in front of you : each mark is one degree (at x1,5 power). i mentioned that the distortion is allready concidered becuase i think that you need this feature for your porpouse.
the only limitation that i see is that you can't take a measurment if the star is more than 38 degrees above the horizon (becuase scope's fov is 38 degrees).
i can't understand this phrase that you said ''Provided, of course, an accurate rotatable quadrant scale could be read between the wet horizon and zenith''.

[don1reed]

@Markmen94:

I understand that each of the small marks @1.5 power = 1° in MaGui F :up:

I'll admit I was not aware of that until your post above. Thank you.

As you say it gives us a 38°, vertical, FOV.

In order to take a sight on a low declination body, < 38°, your Observation scope is perfect for the job.

However, you have created on both the attack and Obs scope a wonderful, Horizontal, rotatable degree scale, that slowly rotates as the player pans the horizon.

My question regarding the Obs scope is: Is it possible to create a vertical, rotatable scale on the right side of the viewport, that shows elevation as the player pans upward to show elevation in degrees?

If the player looks to the horizon, the + crosspoint should show baseline 0°, and as he/she pans upward in elevation, it should show 90° at Zenith.

Technical writing is difficult, I hope that made sense.

Edit: I realize if it's difficult to describe, it's surely just as difficult to accomplish. Cheers.

[vanjast]

In order to use a vertical scrolling angle indicator, like the horizontal bearing indicator, one would have to use an elevation variable similar to the deck gun range indicator in SH4.
This elevation variable, AFAIK is not available (exported) for use, which is why I thought HSie or TDW might have more joy in finding it.
This currently leaves no alternative other than creating an extra zoom level for the obsscope, to fit 60 degrees in the vertical.

Makman, you can add an extra scope zoom level to any scope and use this for the sextant. But it makes no sense using it on the attack scope.

[makman94]

@Markmen94:

I understand that each of the small marks @1.5 power = 1° in MaGui F :up:

I'll admit I was not aware of that until your post above. Thank you.

As you say it gives us a 38°, vertical, FOV.

In order to take a sight on a low declination body, < 38°, your Observation scope is perfect for the job.

However, you have created on both the attack and Obs scope a wonderful, Horizontal, rotatable degree scale, that slowly rotates as the player pans the horizon.

My question regarding the Obs scope is: Is it possible to create a vertical, rotatable scale on the right side of the viewport, that shows elevation as the player pans upward to show elevation in degrees?

If the player looks to the horizon, the + crosspoint should show baseline 0°, and as he/she pans upward in elevation, it should show 90° at Zenith.

Technical writing is difficult, I hope that made sense.

Edit: I realize if it's difficult to describe, it's surely just as difficult to accomplish. Cheers.

i see what you mean now Don1reed and i am afraid that is not possible to be done becuase the code is NOT written at sh3 and sh4. the sad thing is that this feature is one (of the many simulator) features that the devs 'killed' from the brilliant sh2 ui (best ui ever made).
have a look at sh2's scope (also is showing one more 'killing',the true bearings but this feature was possible to bring back at sh3.at MaGui ,it is the red pointer that you see at the small compass when you are at attack or obs or uzo pages):

http://imageshack.us/a/img132/5323/48446710.png

long time ago , i tried to add the fuction that you are interested by using the only liner dial that exists in sh3 (this is the pointer that shows the scope's level on water level scale) but i have no success.
as Vanjast says , this is possible ONLY by hacking the executables and the only ones around that are able for this are H.Sie , Stiebler or TDW


In order to use a vertical scrolling angle indicator, like the horizontal bearing indicator, one would have to use an elevation variable similar to the deck gun range indicator in SH4.
This elevation variable, AFAIK is not available (exported) for use, which is why I thought HSie or TDW might have more joy in finding it.
This currently leaves no alternative other than creating an extra zoom level for the obsscope, to fit 60 degrees in the vertical.

Makman, you can add an extra scope zoom level to any scope and use this for the sextant. But it makes no sense using it on the attack scope.

hi Vanjast ,
your idea about adding a zoom just exactly for this porpouse is not bad at all Vanjast! :up:
BUT ....there is always a 'BUT' at this game ... zooms are reducing fov (if fov at x1,5 is 38 deg then at x6 is 9,5 deg)
your idea may work if someone tries to add a < x1,5 power zoom.
for example a x0.75 zoom will give as (if it works) a 76 degrees fov at scope . have you try something like this ?

[don1reed]

I remember reading about the Kriegsmarine when survival evolution demanded they start using the snorkel, they also began working on a sextant scope, as it became too dangerous to surface long enough to take celestial readings with a hand held sextant. It was a very expensive project in both treasure and lives.

I thank you for taking the time to answer my request with honest insight.

bylandorsea
N38 x W90

[LemonA]

Here's a pic of the accuracy...

Thanks again.

"Real" course plotting of U-2, operating south of the Dutch Bank

http://img.xrmb2.net/images/876848.jpeg

I assume from your drawings you calculated the 3-star fix with a Nautical Almanac. Would be interesting to recheck your calculation with a celestial program but we dont know the exact time of observation and not the 3 observation heights of one position fix.

[don1reed]

Well done, LemonA. You have correctly plotted my course on an accurate chart. It demonstrates the close-out errors encountered due to set, drift, and lazy helmsman.

My tools:

Python
Stellarium
NAVIGATOR v 4.5.135 (www.tecepe.com.br/nav) personal copy.
TeacupCelestial v2.7 NETBOOK (free download: http://mysite.verizon.net/milkyway99/id1.html)

The use of these RL celnav tools makes for very slow and tedious game play (time compression X1).

What my request for an in-game accurate sextant revealed was the next step toward making the SH345 true simulations. It can run the full gambit of arcade game to a usable celnav teaching platform, depending on the player.

An accurate means of seeing a degree of altitude measured in 10ths would be wonderful and a great place to start. All we have to work with is division by "Sailor's Eye".

Markman94 , Vanjast , and many others have started the ball rolling in this regard, hopefully, they continue their labor of love.

I'm off to discover what results are attainable using their mod's Obs scopes. Markman94's Obs scope seems to, perhaps, work hand in glove with HO 249 since it is limited to low angle declinations. What say you?

[makman94]

i have some good (maybe) news for you guys !

the Vanjast's idea to add a specific zoom for this porpouse is working !
i tried yesterday a <x1 magnification and ...yea ...we have now a scope that can show us 90 degrees above horizon.

have a look at this pic (each bold mark of the celestian scale is 5 degrees):


http://imageshack.us/a/img826/4876/79040895.png

for example , looking to stars during night will look like this( due to the extreme distortion at this magnification ,you have to place the star exactly on the vertical line of celestian scale).at this example we are looking at a star being 53 degrees above horizon :

http://imageshack.us/a/img706/1475/73786151.png


a note : each mark is placed on this scale one by one by using the scope's elevation values and the horizon line. so ,in order this scale to be completed,it needs the same procedure to be repeated 45 times so if you think that this scale is worthing the effort i will complete it.

one question that still is not confirmed by devs or experts on these themes is this : are you sure that the star's positions on sky are properly modeled by the devs ? becuase if not, i am afraid that this is definetely the end of the road.

[don1reed]

:o <speechless> :up:

catches breath...

A great amount of experimentation is now needed, trial and error.

The soul of the scientific method, if you will.

You've given us a base camp two. Vanjast began it all with RealNav. We are now a step closer. T.H.A.N.K...Y.O.U.

-...-

Question:

Is the Center vertical scale still usable? And if so does the large marks now represent 1° and the small marks equal 12 minutes each?

The reason I ask is, every degree = 60 nm, every minute = 1 nm. The trick then becomes determining if a star is 53°00.0' or 53°25.0' in altitude. The 25 minute difference could put us 25 sea miles away from possible landfall.

In RL sailors could tolerate a 6 nm error in clear weather, because in most cases he could see that far from the bridge (Turm).

I don't want to get ahead of myself here, hopefully, I'm just providing a little background for some of the navigational problems.

Again, many thanks for looking into this.

[makman94]

Question:

Is the Center vertical scale still usable? And if so does the large marks now represent 1° and the small marks equal 12 minutes each?

yea , sure a lot of tests are needed but i think that you 'celestian' guys must start firstly by this : are the stars modeled in sh3's sky ? if not , anything we are talking here is ...useless.
once ,the above is confirmed i garantee that the scales you see are degrees

about your question :
both scales are showing degrees .the difference between the scales is that the 'bigger' one (left to the peri's vertical line) is showing the degrees (each mark is one degree) at x1,5 magnification .
the celestian scale (the one right to the peri's vertical line) is showing the degrees (each mini mark is one degree-haven't finished all these marks yet as i said at my previous post) at x0,5 magnification.this scale is for use ONLY AT x0,5 MAGNIFICATION.
don't mix the two scales becuase (although should have been the one devided by 3) ,due to the extreme distortion we have at the x0,5 magnifiction the scales are not matching . pay attention that you must place the star exactly on the vertical line of celestian scale for getting accurate degrees readings. you will understand why i am saying this when i send you the files for testing

[vanjast]

Makman, may I make a suggestion.. From my experienced with this, when one rotates the scope the stars follow a curved path, the lowest point of the curve being the centre of the scope (the vertical line). IOW rotation adds a vertical offset.

How about placing the 'sextant gradations' on the centre vertical line, but on the right hand side. This way you be guaranteed of consistent accuracy, and when triangulating as you'll also have an accurate bearing reading as well.

Just a thought.
:)

[don1reed]

Relative to the accuracy of the celestial dome in SH3/4, I'll defer to the data Vanjast has accumulated since the inception of his wonderful RelNav mod.

The testing I'm talking about is to determine the improvement in accuracy of your 90° scale vs. your "as currently is" 38°, 1.5x.

Although limited by 38° fov, it may prove to be the more accurate, due to wider spacing between the tick marks allowing for "sailor's eye" adjustment. (?)

Regarding the 1.5 power center scale....Roger, acknowledged.

[vanjast]

don1reed has a point as:

1 minute of arc gives you 1 Nautical mile (Nm)
1 degree accuracy would place you +- 30 Nm about your location, and with the horizon about 5nM away you could miss things.

This is why I went for the 60 degree vertical zoom magnification, as it's a workable compromise.

[makman94]

......
The reason I ask is, every degree = 60 nm, every minute = 1 nm. The trick then becomes determining if a star is 53°00.0' or 53°25.0' in altitude. The 25 minute difference could put us 25 sea miles away from possible landfall.
......
don1reed has a point as:

1 minute of arc gives you 1 Nautical mile (Nm)
1 degree accuracy would place you +- 30 Nm about your location, and with the horizon about 5nM away you could miss things.

This is why I went for the 60 degree vertical zoom magnification, as it's a workable compromise.

i see what you mean guys.as the scale is at this state , there is no way to make wider spacing between the tick marks of the scale becuase as you can see the scale is covering the (ok ..almost) diameter of scope.
the only ways to make wider the spacing between marks are:
1. to do as Vanjast suggests ,not to make a complete 0 to 90 sextant but a shorter one so here is your knowledge needed guys...till what degrees you think the sextant will be ok to be for your porpouses ? 0 to 60 , 0 to 70 or 0 to 80 degrees ?
or
2. move to the conning deck cameras and make the sextant there (becuase there we can take advantage of the full screen view.we can add the sextant at one of the binocular's zooms if we like,just an idea) there i have finished a complete sextant for you .what do you think about the spacing between the marks here (i haven't move the scale to center yet after the last info Vanjast gave us but i will do):

http://imageshack.us/a/img339/1862/45902614.png



Makman, may I make a suggestion.. From my experienced with this, when one rotates the scope the stars follow a curved path, the lowest point of the curve being the centre of the scope (the vertical line). IOW rotation adds a vertical offset.

How about placing the 'sextant gradations' on the centre vertical line, but on the right hand side. This way you be guaranteed of consistent accuracy, and when triangulating as you'll also have an accurate bearing reading as well.

Just a thought.
:)
....the curved paths of stars.....
that was my biggest headache Vanjast and i mean where the game's engine is taking measurments of degrees. at the following pic , i am showing you the hardcore degree scales as these are drawn by the game's engine. i assumed that there the game was counting the degrees and i just mirror this hardcore scale at the opposite side.(my goal was exactly to avoid this offset you are talking about from the curved path of stars)
BUT , your info is very nice news for me becuase i always wanted (and also like better) the scales to be at center lines .
so the correct time for taking a measurment is at position 2 ?in other words,the correct placing of scale is on the center ? are you sure about this ?

http://imageshack.us/a/img580/2946/78478599.png

[vanjast]

so the correct time for taking a measurment is at position 2 ?in other words,the correct placing of scale is on the center ? are you sure about this ?

Definitely.. as that draggable sextant in the SH3 RealNav mod had to be placed in the centre of the screen to be accurate - The same thing for the scope, as the wider FOV resulting from the zoom factor, creates a bigger curve.

One has to have a consistent reference point for consistent accuracy and the centre of the scope is perfect, as it also gives you a bearing reading which is needed for triangulation plotting. Naturally this forces you to make the gradations according to this centre position.

[don1reed]

Speaking as a "User" and not a designer, Vanjast's rendition of 0-60° allows more space between the tick marks, allowing a better judgement of decimal parts.

"Background note": The best made RL sextants are accurate +/- 10 seconds throughout the arc (-5° to +125°).

The only time it will get tricky is when the user is attempting readings on high altitude bodies while operating N of the Shetlands; but, even then, it's not a mission stopper. :up:

[makman94]

Definitely.. as that draggable sextant in the SH3 RealNav mod had to be placed in the centre of the screen to be accurate - The same thing for the scope, as the wider FOV resulting from the zoom factor, creates a bigger curve.

One has to have a consistent reference point for consistent accuracy and the centre of the scope is perfect, as it also gives you a bearing reading which is needed for triangulation plotting. Naturally this forces you to make the gradations according to this centre position.

Speaking as a "User" and not a designer, Vanjast's rendition of 0-60° allows more space between the tick marks, allowing a better judgement of decimal parts.

"Background note": The best made RL sextants are accurate +/- 10 seconds throughout the arc (-5° to +125°).

The only time it will get tricky is when the user is attempting readings on high altitude bodies while operating N of the Shetlands; but, even then, it's not a mission stopper. :up:

hello Vanjast and Don1reed,
thank you for the clarifications :up:
so, a scale till 60 degrees can be usefull in most of the cases ,is this that you are saying ? the scale till 60 degrees is showing at the folowing pic (still have to place some .5 marks ) . what do you think ?

http://imageshack.us/a/img138/6571/29010285.png

[don1reed]

Very Nice, markman94! :salute:

Watching you modders work is always a joy. You guys are truly the glue of Subsim.

[vanjast]

Perfect :)
You know what you could do.. Is add another (4th) zoom level with magnification 2x (or 5x, 10x) the sextant one. If one centres (vertical and horizontal) the object of observation.. and then turns on the more powerful magnification level, you should get an offset from the centre point that is measurable.

This offset would be the added/subtracted to the original reading to get a more accurate one. Something similar to how a vernier (and sextant) works on the smaller scales.

Now if the sky/star system is this accurate wrt to the map... one should be able to land a torp down Winstons' bath plug. :)

[don1reed]

@vanjast: check your PM.

Don

[vanjast]

Don.. the SH3 times are wrong with regard to RL.
The problem always has been that ship time and/or Greenwich times are messed up with loading saved games.

The Rise/Set times are usually fairly accurate (within the minute) at the equator, but the error increases as you approach the poles.
This might have something to do with the Mercator projection used for the world map.
What one has to work with is the pole star and the yet to be solved Greenwich (or Base) time.

I have mentioned that someone used triangulation instead of relying on time and Pole star, to get a Fix.
Maybe this is the way to go wrt navigation
:)

[don1reed]

I am currently running a test career out of Kiel, heading N then W out of the Skaggerak, across the North Sea, through the Fair Isle channel, using 60° test sextant, installed in the Attack scope with MaGui F @ 0.9 power, designed by makman94. Date/time: 6.9.1939, using three star fixes taken only from BMNT* and BENT*. So far, the accuracy is within 3 to 10 nm of actual fix.

I have been using the GMT indicated time minus 1 hour.

*BMNT = Before Morning Nautical Twilight
*BENT = Before Evening Nautical Twilight

I am also using the "NAVIGATOR" celnav program for sight reduction.

The method of checking if my fixes are accurate is by saving game, then going to My Documents/SH3/data/cfg/Careers/a/0/a.map

opening a.map going to the bottom of the file to [Waypoints] then separately dividing the two large numbers found behind Pt0 separated with a comma by 120000. Positive dividends = N lat E long. Negative dividends = S lat W long. I then compare these results with those derived by sextant. So far, so good.

I'll keep you informed of my results if you're interested.

[don1reed]

My experiment and experience with the IN-GAME celestial dome, Time, & celestial navigation has failed. But, that's not to say it's a lost cause. I feel certain that within our lifetimes, a programming prodegy will arrive upon the scene and salvage SH3's chart and Time discrepancies. In the mean time, I'll content myself with the lure of CelNav for SH3 with stand alone programs such as Python and Stellarium.

Poseidon has willed that I retreat from this effort for now, but not without leaving an offering for fellow mariners of like interests:
Here is free download with built-in almanac and emphemeris data for Navigation in a TeaCup:

http://mysite.verizon.net/milkyway99/id1.html

A giant Thanks to every Modder in search of HOMOTO.

cheers,

[LemonA]

I am currently running a test career out of Kiel, heading N then W out of the Skaggerak, across the North Sea, through the Fair Isle channel, using 60° test sextant, installed in the Attack scope with MaGui F @ 0.9 power, designed by makman94. Date/time: 6.9.1939, using three star fixes taken only from BMNT* and BENT*. So far, the accuracy is within 3 to 10 nm of actual fix.
...


how can you check your results with the Teacupcelestial navigation program when you do not know the T-Delta value for the data 6.9.1939?
Which t-delta values do you use for 1939ish dates?

[don1reed]

Howdy LemonA

That test ran terribly afoul as soon as I turned onto course 270° upon entering the Skaggerak. But even before that, while proceeding N through the Kattagat from Kiel, to make it work, I had to subtract -1 hour from SH3's displayed GMT time. And things went to the deep six, the longer I kept at it.

The Time in conjunction with the celestial dome in SH3 IS NOT CORRECT Full Stop.

The F5 Chart in SH3 IS NOT CORRECT either. It's simply eye candy for the game mechanics to work. Simple navigation problems, i.e., Speed = Distance / Time, do not work in conjunction with the "chart" as in RL.

By, T-Delta, I'm presuming you mean the difference in UT and TT, (Universal Time vs. Terrestrial Time)? If so, then UT (GMT) is the time that is always on display in the game. When placing the cursor over the displayed time, the TT (Local time) will then be displayed.

The Clocks in SH3, BTW, do not show seconds, and as you and other navigators know, seconds are ESSENTIAL in celnav. The way we've gotten around this oversight by the Devs is to start a hand-held stopwatch just as the perceived minutes change. I play in X1 time compression, anything faster, would, naturally throw my system into the 'head'. But, lacking a hand-held stopwatch, you can obviously use SH3's internal stopwatch and use any time compression you desire. Starting and stopping for fixed-wire speed evaluations caused me to go to an external time piece.

As far as using mods to make the UBoat icon disappear while you attempt to navigate in game, I believe, is putting the horse before the cart. Until certain game functions are repaired it's futile to use a useless chart to guess where you are. Only enemy Destroyers know where I am. :haha:

[vanjast]

The pole star (Polaris) is accurate in the SH3 dome wrt to Latitude. The problem has always been the GMT and Ship Time.

Ship Time has been correctly simmed as you pass the Hourly (Longitude) midpoint (so to speak). If you don't know your ship times and methods.. you'll get this wrong.

The problem with Longitude(GMT) and Ship Time comes with the game Reloads - AFAIR they end up being the same time ???

Sunrise/Set times are fairly close to the USNOs almanac according to the 1939-45 time period (within the minute at equator, but losing it at the Higher/Lower Latitudes)
I would say the the game times are calculated at the equator (try a test mission there).. without consideration of latitude.

[don1reed]

Wilco, vanjast. I'll give it a try.

As I mentioned in an earlier post and/or PM, the celestial canopy may be tilted as well, where the ground point of various stars and their inherent circles of equal altitudes are distorted into elliptic ovals instead. This distortion would also cause time and altitude discrepancies. I hope that's not the case.

[don1reed]

True Position: N 0°S x W 0°E, C000 S0 D13 m. Boat type 7b.
Date: 1.X.1939, SH3, Single Missions.
Equipment: MaGui F, with 60° sextant centered on vertical reticule of Attack Scope, (both created by makman94), zeroed on horizon. Time piece: As displayed in game with game stopwatch for seconds.
Height of eye: 1.5 m ASL
True Position per SH3: SH3/Documents/data/cfg/SingleMissions/SM1.map
[Waypoint], Pt0 = 0

Time: 01.01.40 «Schedar Br 350, Ho 32°20’.
Time: 01.02.05 «Capella Br 038, Ho 24°20’.
Time: 01.02.30 «Aldebaran Br 067, Ho 43°50’.

Sight Reduction: Stand alone program, “Navigator”
Calculated position: L 0°8.8’S, l 0°3.9’W
Distance away from true position (c2 = a2 + b2 = 9.6 nm SW of 0°).

Surfaced, Course Change (CC) 270° Speed 8.
Lowered scope to 5.5 m (new height of eye) ASL.

Time: 02.12.50 «Schedar Br 070, Ho 27°55’.
Time: 02.13.09 «Capella Br 119, Ho 34°05’.
Time: 02.13.46 «Procyon Br 175, Ho 18°00’.

Calculated position: L 0°8.0’S, l 0°19.4’W.

True Position SH3: [Waypoint] Pt0 = L 0°0.1’N, l 0°8.5’W.

Time: 05.05.02 ƒMoon Br 016, Ho 39°00’.
Time: 05.05.50 «Alpheratz Br 028, Ho 5°30’.
Time: 05.06.19 «Capella Br 083, Ho 43°30’.

Calculated position: L 0°48.4’S, l 1°15.9’W.

True Position SH3: [Waypoint] Pt0 = L 0°0.3’N, l 0°29.7’W.

-…-

Same three bodies using Python and Stellarium:

Time: 05.05.02 ƒMoon Az 287, Ho 37°39.5’.
Time: 05.05.50 «Alpheratz Az 299, Ho 5°32.2’.
Time: 05.06.19 «Capella Az 353, Ho 43°38.8’.

Calculated position: L 0°6.0’S, l 0°23.9’W.

To illustrate these finding, here is a pic: (Scale: 0.1" = 1 nm)
http://i77.photobucket.com/albums/j42/donhreed/SM1.jpg (http://s77.photobucket.com/user/donhreed/media/SM1.jpg.html)

As you can see, the three fixes using the game clock have me heading far to the SW.

I will try it again and adjust the time until I can simulate the boat's true position and get back with results.

[don1reed]

Ran Single Mission again from N 0°S x W 0°E. Course 000 Speed 0 Depth 13 m. Same equipment as in Post #44. As an aid to my ancient eyes this time, I used a Bausch & Lomb 3x magnifying glass to get a better view of the screen.^^see note below.

Date: 1.X.39

Time: 01.01.07 *Schedar Br 350, Ho 32°20', AP 52.1'
Time: 01.01.42 *Alpheratz Br 325, Ho 53°40', AP 58.2'
Time: 01.02.05 *Markab Br 292, Ho 48°40', Ap 56.7'

Calculated position: Lat 0°16.0'S x Long 0°2.5'E.

I don't like those results. We're starting off on the wrong foot from the gitgo. So, I try it again by adjusting the times slightly with the Navigator program Software:

Time: 01.06.55 *Markab Br 350, Ho 32°20' AP 19.4'
Time: 01.02.55 *Alpheratz Br 325, Ho 53°40', AP 16.5'
Time: 01.02.33 *Schedar Br 292, Ho 48°40', AP 3.7'

Calculated position: Lat 0°00.4'N x Long 0°01.4'E.

These results are much better and reasonable.

Surfaced. CC270° S8.
^^Note: Began using 3x magnifying glass.

Time: 02.23.15 *Markab Br 016, Ho 29°45', AP 17.5'
Time: 02.23.50 *Alpheratz Br 037, Ho 39°35', AP 33.6'
Time: 02.24.20 *Schedar Br 068, Ho 27°00', AP 12.5'

Note: The above times are unaltered game clock times.

Calculated position: Lat 0°1.7'N x Long 0°3.8'W.
True Position:[Waypoint] Pt0=-20107.32, 404.38 = Lat 0°00.2'N x Long 0°10.0'W.

Time: 05.06.05 *Regulus Br 168, Ho 23°20', AP 16.2'
Time: 05.06.39 *Alphard Br 190, Ho 33°30', AP 32.7'
Time: 05.07.01 *Mirfak Br 064, Ho 31°55', AP 41.5'

Calculated position: Lat 0°00.0'S x Long 0°35.9'W.
True Position: [Waypoint] Pt0=-60329.71, 419.41 = Lat 0°00.2'N x Long 0°30.1'W.

Note: The above times are unaltered game clock times.

Full disclosure: In order to get the steadiest possible measurements, I paused the game for each sight as the spacing between each tick mark of the 60° sextant is measured in pixels, therefore the need for a magnifying glass. In RL when single-handed sailing, the skipper/navigator uses a lap-counter stopwatch to gather appropriate data while taking sights.

I'll continue on this cruise and post more data as it accumulates.

[don1reed]

Proceeding on C270 S8.
Date: 1.X.39

True game position: [Waypoint] Pt0 = -298336.40, -4000.98 = Lat: 0°2.0'S, Lon: 2°29.2'W.

Time: 21.28.04 *Antares Ho 7°10'
Time: 21.28.39 *Shaula Ho 18°40'
Time: 21.29.07 *Schedar Ho 24°55'.....Lat: 0°9.0'S, Lon: 2°56.7'W.
----------------------------------------------------------------------------------------
True game position: [Waypoint] Pt0 = -325498.80, -4176.55 = Lat: 0°2.1'S, Lon: 2°42.7'W.

Time: 23.25.52 *Nunki Ho 12°55'
Time: 23.26.08 *Altair Ho 28°10'
Time: 23.26.39 *Vega Ho 7°50'.........Lat: 0°3.8'S, Lon: 2°41.4'W.

http://i77.photobucket.com/albums/j42/donhreed/sm2-3.jpg (http://s77.photobucket.com/user/donhreed/media/sm2-3.jpg.html)
-----------------------------------------------------------------------------------------
Date: 2.X.39
True game position: [Waypoint] Pt0 = -396314.54, -4710.25 = Lat: 0°2.3'S, Lon: 3°18.1'W.

Time: 04.16.22 *Capella Ho 43°45'
Time: 04.16.39 *Schedar Ho 15°20'
Time: 04.17.08 *Hamal Ho 44°35'.......Lat: 0°00.6'N, Lon: 2°59.7'W.

http://i77.photobucket.com/albums/j42/donhreed/sm2-4.jpg (http://s77.photobucket.com/user/donhreed/media/sm2-4.jpg.html)
-----------------------------------------------------------------------------------------
Used above LOP with Sun to attempt a Running Fix:
True game position: [Waypoint] Pt0 = -465015.32, -5117.11 = Lat: 0°2.5'S, Lon: 3°52.5'W.
Time: 09.00.16 Sun Ho 43°30'..........RFix: Lat:0°3.9'S, Lon: 3°46.4'W.

^^Note: Normally a Navigator would take a noon sight, but since I'm straddling the Equator and limited with a 60° sextant, the Sun at noon is not visible through the sextant as the Sun would be at my Zenith then.

True game position: [Waypoint] Pt0 = -550292,69, -3142.90 = Lat: 0°1.6'S, Lon: 4°35.1'W.
Time: 14.57.15 Sun Ho 46°55'..........Lat: 0°5.6'N, Lon: 4°24.6'W.
-----------------------------------------------------------------------------------------
True game position: [Waypoint] Pt0 = -630913.53, -2510.91 = Lat: 0°1.3'S, Lon: 5°15.5'W.

Time: 20.30.22 *Peacock Ho 32°45'
Time: 20.30.39 *Nunki Ho 50°40''
Time: 20.30.45 *Antares Ho 20°38'.....Lat: 0°00.9'N, Lon:4°58.8'W.
-----------------------------------------------------------------------------------------
Date/Time: 04.17/3.X.39 Wx: Heavy Clouds, Light Rain, Zero Vis, Beaufort 8, Sea 7, Dir 265°
CC308 S7. Heading NWxW, determining if proceeding away from the Equator if readings will
begin to deviate.

Date/Time: 11.50/3.X.39 Wx: No change.

Date/Time: 18.50/3.X.39 Wx: Same.

Date/Time: 04.09/4.X.39 Wx: Same. Nearest Land: Cape Palmas, Ivory Coast, B 019, 203 NM.

Storm finally blew itself out, we can see the stars again.

True game position: [Waypoint] Pt0 = -1181318.97, 271413.48 = Lat: 2°15.7’N, Lon: 9°50.6’W.

Time: 19.20.42 *Schedar Ho 7°55’
Time: 19.21.02 *Alpheratz Ho 17°30’
Time: 19.22.34 *Enif Ho 54°45’……………Lat: 2°2.5’N, Lon: 12°41.7’W.

As can been seen, calculated position and True position are no longer close. Latitudes are still reasonably close, but the Longitudes are a lost cause.

1st experiment: Reduce the GMT time by increments, settled on 11 minutes, then recalculated.

Time: 19.09.42 *Schedar Ho 7°55’
Time: 19.10.02 *Alpheratz Ho 17°30’
Time: 19.11.34 *Enif Ho 54°45’……………Lat: 2°2.5’N, Lon: 9°56.2’W. (Reasonable.)
------------------------------------------------------------------------------------------------------------------------------------------
Date 5.X.39
True game position: [Waypoint] Pt0 = -1284901.53, 353631.96 = Lat: 2°56.8’N, Lon: 10°42.5’W.

Time: 04.42.10 *Schedar 18°25’
Time: 04.42.30 *Hamal 47°00’
Time: 04.42.41 *Diphda 27°25’…………….Lat: 2°51.6’N, Lon: 13°26.1’W. (Another Lost Cause.)

2nd experiment: Reduce the GMT time by 11 minutes again, then recalculated.

Time: 04.31.10 *Schedar 18°25’
Time: 04.31.30 *Hamal 47°00’
Time: 04.31.41 *Diphda 27°25’…………….Lat: 2°52.1’N, Lon: 10°41.2’W. (Reasonable.)

Here is a pic of my sextant scope screen (by makman94). I've circled three navigational stars in yellow, Nunki (high), Shaula (middle) tail of Scorpio, and Antares (low). Antares is in position to be measured. Each will be brought to the vertical reticule, timed and measured in turn.

http://i77.photobucket.com/albums/j42/donhreed/sm2-5.jpg (http://s77.photobucket.com/user/donhreed/media/sm2-5.jpg.html)
-------------------------------------------------------------------------------------------------------------------------------------------
As I proceed N toward Wilhelmshaven, I expect more discrepancies and will adjust the time when I reach them.

[don1reed]

@vanjast & makman94:

Judging by my results, (not wanting to take up more bandwidth than necessary), players interested in CelNav with SH3 can obtain good results; but at this stage, only as a mathematical exercise. Without going on a time consuming SH3 world wide Geographical Survey, and posting lists of timing errors, the Navigator will not know how to adjust the internal game clock, other than trial by error. Frankly, just guessing, I chose an 11 minute reduction adjustment because my boat was about 11° West of Prime Meridian. Without a lot more testing, I do not know if subtracting one minute for each degree W of prime will be, and/or, is the rule of thumb.

In RL the Navigational Chart is an essential part of the sailor's tool box. Drawing a course between two geographical points, then lining the course with the edge of parallel rules; then, walking the rules across the chart to the Compass Rose to determine degrees to travel...accurately, cannot be done in game. The inherent errors in the game's F5 chart is one of the reasons CelNav is problematic. It will always mean "flight by wire" courses to follow, no free wheeling at the helm.

But, speaking as a Mod User, I highly recommend that you gentlemen publish your versions of 60° scope sextants.

Respectfully,

[don1reed]

Double post...:o

[don1reed]

Here is my last post to this subject. I'll give an explanation of how your 60° sextant could be use. Lets face it...Silent Hunter is a fantasy world we all escape to. In that regard, I'll use the sextant to take sights while on cruise, then pause the game and use Python and Stellarium to obtain data for my chosen stars like this:

Date: 22.XI.39
True posit via my cpu's file SH3/My Documents/data/cfg/Careers/Anton/1/a.map, [Waypoint] Pt0=876424.32, 936653.95 = Lat: 57°48.3'N, Lon: 7°18.2'E.
Python program looks up this file and feeds the raw data to and opens the Stellarium program. This displays the celestial canopy surrounding my boat as if I were actually at that posit. I then choose a round of three bodies:

Time: 04.18.03 *Procyon Hs 35°42.9'
Time: 04.18.37 *Betelgeuse Hs 29°10.6'
Time: 04.18.50 *Aldebaran Hs 27°29.6'

Get ephemeris from appropriate almanac:

*Procyon
245°57.3'SHA
120°14.8'GHA Aries(4h)
..4°31.5'min/sec(18m 3s)
370°43.6'this is > 360 so subtract
360°00.0'
.10°43.6'GHA star
.+7°16.4'Assumed Lon.(+E Lat, -W Lat)(add or subtract minutes to only leave degrees)(this is our assumed position(AP))
.18°00.0'LHA

..5°22.8'Dec

.35°42.9'Hs
....-4.1'Dip
....-1.3'Alt corr.
.35°37.5'Ho
-35°32.4'Hc.................Hc = asin [(sin Lat sin Dec)+(cos Lat cos Dec cos LHA)]
Diff>5.1'nm to (If Ho is more than Hc, then, TO...HOMOTO)

Our LOP is 5.1nm toward the body's ground point(GP). Our calculated LOP is a small segment of the circle of equal altitude from the body's GP. Since the circle is so huge, our small segment appears as a straight LOP line. We can appreciate the circle's great size from an outer space view; but, here on the surface we cannot. Now we must find in what direction that GP lies. First some rules:

N. Lat:
for LHA > 180°...Zn = Z
for LHA < 180°...Zn = 360° - Z

S. Lat:
for LHA > 180°...Zn = 180° - Z
for LHA < 180°...Zn = 180° + Z

360°
157.8° Zn...................Z = acos [(sin Dec - sin Lat sin Hc) / (cos Lat cos Hc)]
202° Z

So, from our assumed posit(AP) on the 58° parallel, @ 7°16.4'E we construct a line on 202° Az. for 5.1nm. At that point we construct the sight's Line of Position (LOP), perpendicular to our 202° Az.(crossing the "T").

Two more similar LOP with the remaining stars will form our three star fix, our calculated position.

BTW: these two formulae for Hc and Z above, save me from having to purchase and carry six volumns of HO Pub 229 and/or three volumns of HO Pub 249. My hand held calculator is just like a jar of "Prego" pasta sauce...It's in there. ;)
^^NOTE: Carry one (1) volume of Norrie's Nautical Tables as backup.
^^^NOTE: Calculator and Norrie's can be purchased from Amazon via Subsim.

Cheers to all who seek HOMOTO,

[vanjast]

Sorry for the non-reply of late... I'm really busy with hardware development.. that I don't have time to 'play'.. it's a bugger.. but I'll keep tabs :D

[don1reed]

Not to worry. Business before pleasure.

Cheers,

[don1reed]

On current patrol heading W through the Kattegat. I'm using the Attack scope to choose the stars I wish use for navigation.

I save the game. This procedure pauses the game for me to open Python stand-alone program and input the GMT date and time. Python then looks up my computer's SH3/data/cfg/Careers/(my skipper's name)/0/a.map file, does the math indicated in [WAYPOINT], Pt0. Python extracts the geo coord and puts them into and opens Stellarium stand-alone program, where I find the three stars I've selected in the game.

A nice thing to note is we now know that the times are incorrect in SH3; but, that doesn't matter to Python/Stellarium. It uses the game's time and proceeds to find the Altitude and Azimuth of the selected bodies for the game time. A nice built-in work-around.

So, here I am:

http://i77.photobucket.com/albums/j42/donhreed/U45_0309390001.jpg (http://s77.photobucket.com/user/donhreed/media/U45_0309390001.jpg.html)


As the pic above illustrates, which is drawn to scale, it becomes obvious that the F5 chart screen is also incorrect compared to a real Mercator Projection worksheet. Common navigation formula do not work on the game's F5 chart, i.e., S = D / T. Since longitudes are compressed in size at their upper ends north of the equator to meet at the north pole. In game my speed is 7 knots. On the Mercator worksheet, 3.7 knots.

In the pic below, I changed course toward WNW. Another error begins to crop up showing the two courses, calculated vs. the drag n click course, beginning to diverge.

BTW: to make your own worksheets, multiply the minutes of longitude by cos of nearest, whole degree of latitude, i.e., 60' cos 58° = 31.9 or 32. The answer can be mm, cm, 10th of an inch, or whatever measurement you care to use. I chose 10th of an inch to fit on a standard 8.5" x 11" sheet of paper.
http://i77.photobucket.com/albums/j42/donhreed/U45_0609390002.jpg (http://s77.photobucket.com/user/donhreed/media/U45_0609390002.jpg.html)

[don1reed]

This is definitely not the "arcade" way to experience SH3. Not every tool is at our immediate fingertips. As in RL we sometimes must look away from the action to perform menial tasks, i.e. opening a can of ammo to reload; passing 8.8 cm HE through the hatch; climbing down to the deck; being the last through the turm hatch for an emergency dive; doing the math to determine lead angle on the aals vs. target vessel; and, Real Navigation. Each layer of programming magic complimenting realism, we owe to Subsim's modders.

At the end of patrol, if we survive, I can add this to my boat's KTB to hand over to my commanding officers on shore.

Cheers,

http://i77.photobucket.com/albums/j42/donhreed/U45_0909390002.jpg (http://s77.photobucket.com/user/donhreed/media/U45_0909390002.jpg.html)

The action starts on the upper right, then begins to gravitate to the SW, and finally to exit stage left.

Tnx again to vanjast & makman94. A special shout-out to Michael Jones for his brilliant work with Python.

[LemonA]

By, T-Delta, I'm presuming you mean the difference in UT and TT, (Universal Time vs. Terrestrial Time)? If so, then UT (GMT) is the time that is always on display in the game. When placing the cursor over the displayed time, the TT (Local time) will then be displayed.<br />
<br />
<br />
i have asked for Delta T because celestial programs which i know ask for this value:

Delta T from 1920 - 1941
delta T (sec) = 21.20 + 0.84493*t - 0.076100 * t^2 + 0.0020936 * t^3
with T = year - 1920

Delta T from 1941 - 1961
delta T (sec) = 29.07 + 0.407*t - (t^2/233) + (t^3 / 2547)
with T = year - 1950

Example
Delta T for (jan) 1939
21.20 + (0.84493*19) - (0.0761 * (19^2))+ (0.0020936 * (19^3)) = 23.935

Delta T
http://pgj.pagesperso-orange.fr/deltaT.htm

[don1reed]

I'm sorry, LemonA, "Delta t" is not referenced within HO-211, HO-229, HO-249, Norie's Nautical Tables or Bowditch (HO-9); however, I do not have any of the WWII Kriegsmarine's navigational publications or ephemeris they used at my disposal. For anyone who is unaware, some of the HO pubs I reference above are British and American publications that were used during the war.

If you have a Kriegsmarine source, I would be grateful and very much interested in their methods for both enlightenment sake and also to use within SH3.

edit: to be fair, the closest thing I could come up with is this drawing from a 3rd ed of HO-211 dtd 1943 page 4. It describes "t" as LHA (local hour angle). Note: I redrew this drawing as I did not want to place the book into my scanner for fear of damage to the spine.



http://i77.photobucket.com/albums/j42/donhreed/scanho2110001.jpg (http://s77.photobucket.com/user/donhreed/media/scanho2110001.jpg.html)

Tnx,

[don1reed]

@ LemonA:

http://pgj.pagesperso-orange.fr/deltaT.htm

I've translated your included link. And I believe that the Delta t you reference is already incorporated into the daily pages of the Nautical Almanac. Its a calculation that mariners don't have to bother with if they rely upon the HO pubs and an up-to-date almanac. The Delta t is a built-in feature.

The Almanac I use for navigation within SH3 (1939-1945) is built-into a commercial navigation program, i.e., NAVIGATOR v.4.5.135 by Omar Reis www.tecepe.com.br/nav.

I hope this helps.

Cheers, or, as we used to say in the Army(in Korea while playing poker): Juan, won one Won. :)


Don

[makman94]

hello to all ,

i will just put here some findings via our converstion with Don1Reed ( which prooves that stars are correctly modelled in game ) that may be usefull to moders at future.

the date is 1/Octomber/1939 and location is longitude=0 deg ,latitude=0 deg

the following pics are prooving that the stars are correctly placed on sh3's sky BUT (here comes the problem and we all haven't enjoy celestial navigation yet) the game's clock is three hours behind the correct time. by setting the time at stellarium exactly +3 hours to sh3's time look at the following pics to see the 'magic' at sh3's sky:

Capella in stellarium:
http://imageshack.us/a/img855/2686/jg3.png
Capella in sh3 (bearing and height of star matches 100%):
http://imageshack.us/a/img266/773/lvnu.png
Ruchbah in stellarium:
http://imageshack.us/a/img585/6418/6ng.png
Ruchbah in sh3 (bearing and height of star matches 100%):
http://imageshack.us/a/img845/2032/rvu7.png

the time is not the only problem though that is effecting stars's positions. the location also is causing problems becuase at other locations (not at longitude=0 deg ,latitude=0 deg) we must add +2 or +4 hours to stellarium in order the skies (real and sh3's) to match.
this has nothing to do with greenwich time zones (we checked it and doesn't work.how many hours we must add to stellarium according to our position on map still is a mystery)

once the clock is 'solved' then a good hack at the files which are altering the stars's layer must be done and match it with the correct time

lets hope !

[don1reed]

:rock:

Most excellent, my Khal.

[Karl Heinrich]

That's quite the breakthrough Makman, great work!

[TheDarkWraith]

For the Cel Nav enthusiast, is there a way to Mod the MaGui F or any Obs scope to have a movable (rotatable with mouse wheel or up/down cursor keys) vertical 0 to 90° angle indicator installed alongside the viewer lens as I've drawn on this snap?

For SH3 no. For SH5 yes, I've already added it via a patch (you use it just like you use the stadimeter). Since you use it just like the stadimeter you first place the zero reference line of the scope on the horizon and then click the stadimeter icon (you have to click the enable sextant first). Then you place the green line (just like stadimeter) on the star of place of interest and read out the angle val returned (it's updated in real time so as you move the mouse up/down the angle val changes). I currently have one problem with it though: the angle val shown is the number of vertical graduation marks of the scope. I can give any degree of precision necessary for this angle value (currently have it limited to 2 decimal places). The great thing about this angle val is it is magnification power independent - meaning it's calibrated to the current zoom level. So no matter what zoom level you use it will return the correct number of vertical graduation marks where you have the second green line at on the scope display.

See here for screenshot: http://www.subsim.com/radioroom/showpost.php?p=2087389&postcount=2480

My question is how do you know what the degree spacing is between the vertical graduation marks? If I can figure out how to calculate the degree spacing between the vertical graduation marks then I can find where in the code it's doing this calculation and grab the number and multiply it by the angle val to get the true angle in degrees.

[don1reed]

Hello, TDW.

Here is a FREE online Almanac: http://www.tecepe.com.br/scripts/AlmanacPagesISAPI.dll

At the bottom you can input any WWII date. It will give you The Greenwich Hour Angle for any navigational star, planet, moon or sun, as well as the Declination.

The same site offers all the visible celestial bodies for any Lat/Long.
It will give each body's REAL altitude (Hc) calculated. You could use this as a reference.

Your work is magnificent btw.

I have not been able to op SH5 since they removed online sign in.

[TheDarkWraith]

How does all this camera AngularAngle and ticker tape for the scopes go together? I know AngularAngle has something to do with FOV but what :06:

[don1reed]

For reference sake, if you know your exact Lat/Long, as in SH3/data/cfg/Careers/....map file

[Waypoint]
PointsNb=12
Pt0=-149885.14,7091927.38,-13.28

These numbers can be divided by 120000 to obtain Lat/Long as used by Python in conjunction with Stellarium for sh3.

I'm completely unfamiliar with the workings of SH5, but I'm positive You are and know where to get that info. The Almanac that I reference above will get you the true degrees of altitude of any celestial body from any location, so it may be possible to measure a body's altitude with your sh5 sextant and compare it with the (Hc) altitude of the almanac to adjust your sextant.

[TheDarkWraith]

For reference sake, if you know your exact Lat/Long, as in SH3/data/cfg/Careers/....map file

[Waypoint]
PointsNb=12
Pt0=-149885.14,7091927.38,-13.28

These numbers can be divided by 120000 to obtain Lat/Long as used by Python in conjunction with Stellarium for sh3.

I'm completely unfamiliar with the workings of SH5, but I'm positive You are and know where to get that info. The Almanac that I reference above will get you the true degrees of altitude of any celestial body from any location, so it may be possible to measure a body's altitude with your sh5 sextant and compare it with the (Hc) altitude of the almanac to adjust your sextant.

I can get my exact position in real time (SH5 makes this real easy with it's scripting abilities) so that's no problem. SH5 code is SH3/4 code enhanced. Makes it really easy to find things :D

Thanks for the info. Some people are testing your information and I hope they will report back their findings. Then I can take that data and write some calibration code to return the true angle.

[don1reed]

BZ and all the best.

:salute:

[TheDarkWraith]

BZ and all the best.

:salute:

Well the feedback from one person so far is success. I don't know what this stuff means but can you verify his post?

http://www.subsim.com/radioroom/showpost.php?p=2087915&postcount=2513

Looks like the angle val I pulled from the game is perfect and nothing more needs to be done to it :D

[don1reed]

Nicely done. A Line of Position within 5 to 6 nm is remarkable. Easily within line of sight from the turm of a Uboat in clear Wx. :up:

[TheDarkWraith]

Nicely done. A Line of Position within 5 to 6 nm is remarkable. Easily within line of sight from the turm of a Uboat in clear Wx. :up:

Excellent. You are obviously way more familiar with this than I am. I can code anything, doesn't mean I necessarily understand it :-?

[don1reed]

It seems we are both involved with navigation in one form or another. Whether stars or 1's and 0's, your efforts will have made the course easier to follow. Well Done.

[makman94]

Well the feedback from one person so far is success. I don't know what this stuff means but can you verify his post?

http://www.subsim.com/radioroom/showpost.php?p=2087915&postcount=2513

Looks like the angle val I pulled from the game is perfect and nothing more needs to be done to it :D

hello TDW,

The angle that you are reading is absolutely ok to use becuase it is the stadimeter's angle which is absolutely correct.
this angle is always ok no matter what angular angle is altered at the cameras.dat and no matter what zoom you choose even if it is <1 .
the <1 zoom idea(from Vanjast) and findings are 100% tested and checked.
the stadimeter line always is reading the correct degrees (your tester is wrong about the <1 zooms. all is ok at whatever zoom you want to work)

something else that i noticed at your tests is that slept your intention that there is difference between the decimal values and the DMS values.keep that in mind ,next time that you compare data from stellarium (which are at DMS format) with your app data (which are at decimal format)

also, there is at sh3 ,exept from the clock problem, one more problem: the sun and the moon are slightly displaced (about 1 or 2 degrees at Latitude and maybe ,can't remember now, at Longitude too) which is not happening with the stars which are absolutely correct. i am suspecting that the same displacement at sun and moon will still be present at sh5 so you(your testers) must check it.

something else that is realy amazing (but i haven't installed the sh5 to check it myself) is that the clock appears to show the correct time (time in game matches with time at stellarium) . this is the big problem in sh3 , the clock (read a few posts above about it).
i noticed that at sh5 the time is called ''Naut'' . what is this ? if ,indead, that is the time that we need to appear in game , can you make a patch to order this time appear in sh3 too ?

[Fahnenbohn]

Hem... excuse me, but... i don't understand very well. What is the conclusion of all these discussions ? Have you reached a solution ? Is it usable in the game ? :hmm2:

[JeromeHeretic]

IMHO it is usable. Problem is that clock in your sub is set to nautical timezone of place where your sub is in moment of game load. You must do time correction by yourself.
Look at history in this thread: http://www.subsim.com/radioroom/showthread.php?t=193974&page=11