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03-26-16, 03:53 AM | #46 | ||||
Count Dracula
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local noon is described in post #1. PS. u can use also Stellarium a great software
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03-26-16, 04:42 AM | #47 |
Stowaway
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RN on SH5
Awesome work people, trying to make this work on my side to join the party
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03-26-16, 04:55 AM | #48 | ||
Grey Wolf
Join Date: Jan 2014
Location: 50.1° N, 14.4° E
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You need to know which hemispehere you are on before this calculation (to decide if you will be adding, or subtracting and how ) How do you now initially you haven't cross equator if you are completely lost? Quote:
How to get LHA from Almanac? I want to find even longitude for myself, that Excel needs to calculate it somehow, but i haven't found how Maybe i can ask even another way: 1) Are we able to get longitude in another time, than when the sun is at highest position? (I expect no) 2) Can i get longitude by knowledge which GMT time is the sun at highest position? I expect so, because it should be something like +15 degrees E for every hour after 12:00AM or +15 degrees W for every hours before 12:00AM minus GHA Thank you for quick response!
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Check my mods (Downloads tab) u-boats documentaries 1) Real navigation - target motion analysis cheatsheet 2) Real navigation - Perfectly controlled approach 3) Real navigation - How to prepare torpedo Attack with basic trigonometry Really needed: Learn RAOBF optical targetting Last edited by palmic; 03-26-16 at 05:19 AM. |
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03-26-16, 05:20 AM | #49 | |
Count Dracula
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u know where u was last time before the celestial fix ... u always need to make a dead recognition fix ....so not complete lost ...... and also a tip most of the german uboat mission was in the north hemisphere ...... Local Hour Angle (LHA). In astro navigation, we need to know the position of a celestial body relative to our own position. LHA is the angle BNU on the Earth’s surface which corresponds to the angle ZPX in the Celestial sphere. In other words, it is the angle between the meridian of the observer and the meridian of the geographical position of the celestial body (GP). Due to the Earth’s rotation, the Sun moves through 15o of longitude in 1 hour and it moves through 15 minutes of arc in 1 minute of time. So the angle ZPX can be measured in terms of time and for this reason, it is know as the Local Hour Angle. LHA is measured westwards from the observer’s meridian and can be expressed in terms of either angular distance or time. For example, at noon (GMT) the Sun’s GP will be on the Greenwich Meridian (0o). If the time at an observer’s position is 2 hours and 3 minutes after noon, then the angular distance between the observer’s meridian of longitude and the Greenwich Meridian must be (2 x15o ) + (3x 15’) = 30o 45’. Because it is after noon at the observer’s position, the longitude of that position must be to the East of the Greenwich Meridian since the Earth rotates from West to East. Therefore the observer’s longitude must be 30o 45’ East and since LHA is measured westwards from the observer’s meridian, the LHA must also be 30o 45’. However, it should be noted that as the Earth continues to rotate eastwards, the GP of the Sun will continue to move westwards so the LHA at the observer’s position will be continually changing. Greenwich Hour Angle (GHA). As discussed above, the angle between two meridians of Longitude can be expressed as an hour angle. The hour angle between the Greenwich Meridian and the meridian of a celestial body is known as the Greenwich Hour Angle. Rules for calculating LHA: Long East, LHA = GHA + LONG (- 360o as necessary) Long West, LHA = GHA – LONG (+ 360o as necessary) Example 1. : If Long. is 90oE. and GHA is 300o Then LHA = GHA + LONG -360o = 300o + 90o = 390o – 360o = 30o Example 2: if Long. is 90oW. and GHA is 45,o we have: LHA = 45o – 90o = -45o + 360o = 315o Example 3: If your longitude is 35o 46’ East and the GHA of Mars is 39o 53’.8. What is the LHA? Remember the rule: Long East, LHA = GHA + LONG (-360o ) GHA = 39o 53’.8 LONG = 35o 46’.0E (+) LHA = 75 o 39’.8 . (Remember 60 minutes in 1 degree) Example 4. Your assumed longitude = 125o 13’.0W. The GHA of the Sun is 243o 44’.7 What is the LHA? Long West, LHA = GHA – LONG (+360o ?) GHA = 243o 44’.7 LONG = 125o 13’.0W (-) LHA = 118o 31’.7 Example 5. Longitude is 120oW. GHA is 70o. What is the LHA? LHA = GHA – LONG (+360o ?) GHA = 70o 00’.0 LONG = 120o 00’.0 W. (-) LHA = -50o 00’.0 360o 00’.0 (+) LHA = 310o 00’.0 Example 6. Longitude is 90oE. GHA is 340o What is the LHA? LHA = GHA + LONG (-360o ?) GHA = 340o LONG = 90oE (+) LHA = 430o 360o (-) LHA = 70o
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Last edited by Sjizzle; 03-26-16 at 05:43 AM. |
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03-26-16, 05:47 AM | #51 | |
Grey Wolf
Join Date: Jan 2014
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I would just complain this approach as main description for get longitude in your post #2, because its not clear how that spreadsheet calculates it and its not IMO realistic to use excel in 1939 |
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03-26-16, 05:53 AM | #52 | |
Count Dracula
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my pleasure also i have posted a link for the celestial fix basics see the post above
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03-26-16, 05:56 AM | #53 |
Grey Wolf
Join Date: Jan 2014
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Yeah, read it, thanks!
I made printable cheatsheet to get into it easily without need to alt-tab out of the game
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Check my mods (Downloads tab) u-boats documentaries 1) Real navigation - target motion analysis cheatsheet 2) Real navigation - Perfectly controlled approach 3) Real navigation - How to prepare torpedo Attack with basic trigonometry Really needed: Learn RAOBF optical targetting Last edited by palmic; 03-26-16 at 06:46 AM. |
03-27-16, 04:46 PM | #54 |
Count Dracula
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@palmic take a look here how to navigate without navigation officer ....i calculated my own position
PS. i don't use TDW's UI
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03-27-16, 07:34 PM | #55 |
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Any chance of someone doing a Celestial Nav step by step tutorial?
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SH3 Guide: S3G by BLITZKR!EG Currently - SH5 TWoS - SH3 GWX + MaGui and more - SH3 LSH 2015 + Ahnenerbe's Gui |
03-28-16, 02:45 AM | #56 | |
Count Dracula
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read the first posts of this thread !!
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03-29-16, 12:59 AM | #57 |
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Sorry Sjizzle, I should've been more specific. The noon sightings I understand... it's the Stars, Planets, Moons stuff that makes me scratch my head. I'll have to keep watching those vids, which are really good, until it sets in.
From a procedures standpoint, do you just operate via the noon-time fix and DR? And does that work pretty well for the most part? I'm wondering if drift, currents, etc. are built into the game, TWoS specifically. Thanks!
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SH3 Guide: S3G by BLITZKR!EG Currently - SH5 TWoS - SH3 GWX + MaGui and more - SH3 LSH 2015 + Ahnenerbe's Gui |
03-29-16, 03:23 AM | #58 | |
Count Dracula
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heya.... yup i make 2 celestial fix a day 1 noon and 1 at the midnight using the stars but for the stars celestial fix i didn't made a tutorial was busy in RL and also completely forgot about it ..... u can really lost yourself on the sea when is bad weather cos there is no sun and u must make a DR fix and sometimes is hard to keep the heading cos u drift out from the course .....
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03-29-16, 09:43 AM | #59 |
Officer
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Gotcha. How often do you miss your fixes? ie. scattered clouds making you miss the sun overhead, or bad weather? Have you had to go long times with no fixes? That actually sounds kinda fun, but could be a little frustrating. lol
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SH3 Guide: S3G by BLITZKR!EG Currently - SH5 TWoS - SH3 GWX + MaGui and more - SH3 LSH 2015 + Ahnenerbe's Gui |
03-29-16, 04:24 PM | #60 |
Grey Wolf
Join Date: Jan 2014
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Is it possible to make fix by polar star here?
It should be easiest way isn't? Thanks for all your work, this is one of best mods ever |
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