Navigational stars in Silent Hunter 5

Originally Posted by derstosstrupp

Aha I see, ok thanks. I was operating on the assumption that the time correction worked to offset even any declination errors such that using “real” almanac would yield correct results in any case where the corrected UT is displayed. In other words, I had assumed that the mod was trying to force real-world results through the time correction.

That said, my fixes are indeed not totally exact (allowing for possible measurement error), so I can understand what you are saying about the declination being fundamentally different than reality, which is unfortunate. But at least for the moment not wildly off, and still workable.

After correcting Sun.txt, everything will work fine together with Sun almanac, which I compiled specifically for SH5.

[derstosstrupp]

Originally Posted by Alpheratz

After correcting Sun.txt, everything will work fine together with Sun almanac, which I compiled specifically for SH5.

Thank you for making an effort with this!

Originally Posted by derstosstrupp

Also, if you need any help with fixing the sun data, I would be happy to assist. Any way to make this more like reality is a step in the right direction. Navigating in this game makes it so much deeper.

Thank you, your help would be greatly appreciated. I tried to send you a link to edit the file, but I'm not sure if my letter reached you.

Column A must be edited. Column A is edited according to columns H (declination in decimal degrees), I (minutes of arc for declination), J (increment in declination in minutes of arc).
What has already been corrected is filled in yellow.

[derstosstrupp]

Originally Posted by Alpheratz

Thank you, your help would be greatly appreciated. I tried to send you a link to edit the file, but I'm not sure if my letter reached you.

Column A must be edited. Column A is edited according to columns H (declination in decimal degrees), I (minutes of arc for declination), J (increment in declination in minutes of arc).
What has already been corrected is filled in yellow.

Ok great thanks! I did receive, will have a look!

Thank you very much, derstosstrupp, for your prompt assistance in correcting sun declination in New Sextant mod. My preliminary testing revealed no errors. Link to the sun.txt file, which should replace the corresponding New Sextant mod file:

https://drive.google.com/file/d/1cw6...ew?usp=sharing
I propose to test this on measurements of the sun. I will continue testing as well.

NOTA BENE! My guess turned out to be wrong.

Originally Posted by Alpheratz

When measuring the Sun, when in the sextant interface field you enter the value "0" to indicate the celestial body being measured, the sextant "knows" that you are measuring the lower limb of the solar disk and the sextant reading is the altitude of the solar disc center, taking into account the influence of dip + refraction. that is, you don't need to add sun semidiameter to the measured value.

When you measure the lower limb of solar disc altitude, then New Sextant readings represent the sun's altitude reduced by the actual (historical) sun semidiameter. You need to add the historical sun semidiameter to the measured sun lower limb altitude. I will rework my Sun Almanac to include a historical sun semidiameter.

[derstosstrupp]

Originally Posted by Alpheratz

Thank you very much, derstosstrupp, for your prompt assistance in correcting sun declination in New Sextant mod. My preliminary testing revealed no errors. Link to the sun.txt file, which should replace the corresponding New Sextant mod file:

https://drive.google.com/file/d/1cw6...ew?usp=sharing
I propose to test this on measurements of the sun. I will continue testing as well.

NOTA BENE! My guess turned out to be wrong.

When you measure the lower limb of solar disc altitude, then New Sextant readings represent the sun's altitude reduced by the actual (historical) sun semidiameter. You need to add the historical sun semidiameter to the measured sun lower limb altitude. I will rework my Sun Almanac to include a historical sun semidiameter.

You are very welcome! I will test tonight as well.

The updated Sun Almanac 1939 - 1945 is ready with the indication of the Sun semidiameter, for full work with the New Sextant mod.

https://drive.google.com/file/d/1x_U...ew?usp=sharing

[derstosstrupp]

Originally Posted by Alpheratz

The updated Sun Almanac 1939 - 1945 is ready with the indication of the Sun semidiameter, for full work with the New Sextant mod.

https://drive.google.com/file/d/1x_U...ew?usp=sharing

Thank you sir!

[vdr1981]

Originally Posted by Alpheratz

The updated Sun Almanac 1939 - 1945 is ready with the indication of the Sun semidiameter, for full work with the New Sextant mod.

https://drive.google.com/file/d/1x_U...ew?usp=sharing

Replaced old "SH5 Sun 1939-1945 every 4 hours.pdf"...

Originally Posted by derstosstrupp

In game I normally get a morning twilight 3-star fix, and then a running fix during the day using a noon latitude sight advanced to another afternoon sun line (normally 3 hours later for a good azimuth change).

If you test the New Sextant mod with this method, keep in mind that there are limitations due to the fact that WORLD = MAP in SH5. This imposes restrictions to advance one line of position to another line of position made after a long time (observations with baseline shift, "Sonnenbeobachtungen mit Versegelung"). In fact in SH5 you only have 2 options.

1. Between the measurements of the first and second altitudes your Heading = 0 or 180, then this formula works to transform the first taken altitude and refer it to the zenith of the second observation:

delta h = Speed ​​[knots] * 0.9265 * time [hours] * cos (Azimuth - Heading)

2. Between the measurement of the first and second altitudes your Heading = 90 or 270, then the corrected first formula works:

delta h = Speed ​​[knots] * 0.9265 * time [hours] * cos (Azimuth - Heading) * cos (latitude)

If Heading is different from 0, 180, 90, 270, then it is impossible to calculate "delta h" using a calculator or tables.

[derstosstrupp]

I have thought about this as well. It might be sufficient when the azimuth is further east or west to apply the correction for “spherical transfer” to the resulting line of position before you advance it. My first Sunline is normally a latitude line, so no issue there, but my second one in the afternoon after three hours is of course about 45° shifted, so that would need such a correction.

I should add that I don’t typically use the German running fix method of plotting both lines of position from the second observation. I understand that method, but I find it much easier to simply just DR the first LOP physically on the map.

Of course I might be all wet on the above, and it may likely be invalid, but at least it’s close enough for government work. The litmus test for me is 10nm. If my intercepts are larger than 10 nm using my DR as AP, then I worry.

Yes, I agree that in practice it is more convenient to use graphic solutions.

A prerequisite for the correct operation of NewSextant is the disabling option "No stabilize view" in gameplay settings. In a separate NewSextant mod, GameplaySettings.cfg was adjusted so that when any difficulty level is selected, "No stabilize view" option is always false (disabled). In test build 2.2.23 at any difficulty level from easy to realistic, NoStabilizeView = true, so you must manually disable "No stabilize view". It is certainly not difficult. I just think it makes sense to automate this mandatory default action.

[vdr1981]

Originally Posted by Alpheratz

A prerequisite for the correct operation of NewSextant is the disabling option "No stabilize view" in gameplay settings. In a separate NewSextant mod, GameplaySettings.cfg was adjusted so that when any difficulty level is selected, "No stabilize view" option is always false (disabled). In test build 2.2.23 at any difficulty level from easy to realistic, NoStabilizeView = true, so you must manually disable "No stabilize view". It is certainly not difficult. I just think it makes sense to automate this mandatory default action.

This will be sorted out in final version of the update...


BTW, tell me guys what do you think about this new sextant mask file with thinner lines...I guess it should provide more precision during the measurements.



https://www.mediafire.com/file/5mid4..._Mask.rar/file

Originally Posted by vdr1981

BTW, tell me guys what do you think about this new sextant mask file with thinner lines...I guess it should provide more precision during the measurements.



https://www.mediafire.com/file/5mid4..._Mask.rar/file

It's a great idea , the thick crosshair lines always got in the way.