How To Calculate Compass Error by Amplitude of the Sun

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How To Calculate Compass Error by Amplitude of the Sun

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Күн бұрын

How To Calculate Compass Error by Amplitude of the Sun! A short video where I explain how to calculate a ships Gyro compass error from a bearing of the Sun using the amplitude method.
Ask any questions in the comments - I’ll do my best to answer them.
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Pro Forma: www.alistairba...
NOTE: This video makes use of selected pages from the British Admiralty Nautical Almanac (Admiralty Publication NP314). The example uses the 2016 version of the publication so if you’re doing the calculation for a different year the numbers won’t be the same.
If you prefer to read than watch a video you can find my article that accompanies this video here / z9kvbfnckeb
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Opening Tune: Good Starts by Jingle Punks
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Пікірлер: 40

@phillpauley6672 6 жыл бұрын

You may have just saved my life. I’m very glad I’m just barely close enough to shore to get a weak signal to watch this video. Hopefully headed back to shore. Thanks again if this works. If not, well... this will probably be me last comment... May God help us!

@MFDOOOOM 2 жыл бұрын

Did you make it back 😂

@daryndalton4479 3 жыл бұрын

Thank you for these clear tutorials.

@AlistairBaillie 3 жыл бұрын

Glad you like them!

@ObtuseFang 3 жыл бұрын

Thank you! Your explanation helped me a lot. Although, it seems that Amplitude should be written down as W8.9N so that we end up with Azimuth 278.9 even without looking at the table in the pro forma.

@juranteanin321 Жыл бұрын

⁷

@Bullshockey 7 жыл бұрын

Very Helpful, Thanks!!

@arode8 6 жыл бұрын

i was wondering where is the amplitude formula then i see that you put Az instead of Amp, i was always using the azimuth method and i glad to see this video.

@AlistairBaillie 6 жыл бұрын

Thanks for pointing that out - I also didn't notice :) You are of course correct, it should be written as "Amp" not "Az" on the proforma sheet.

@SeaThroughMyEyes 5 жыл бұрын

Yes amplitude is not there man

@molasjerwin 2 жыл бұрын

Hello sir, I'm a Maritime Transportation students, I just want to ask on how to Obtain LMT and hence the GMT of rising or setting from the almanac. thank you

@camirothe1688 2 жыл бұрын

Hello Alistair, thanks for this video. Can you please expand on how you can do this using the tables instead of using the scientific calculator?

@AlistairBaillie 2 жыл бұрын

Hi Cami - I explain the use of the Nautical Tables in this video: kzfaq.info/get/bejne/ea2fnbeTzqnNpoU.html

@anantgite9354 4 жыл бұрын

Thanks

@necoorec 5 жыл бұрын

Hi. Thank you so much for the video. One question: If latitude and declination are from different hemispheres how do we proceed?

@jonascagape520 4 жыл бұрын

What is the favourable instance to use when checking compass error using the sun's azimuth?

@opeyemiojutiku1264 4 жыл бұрын

Hi Alistair, Thanks for the video. Quick question.... I noticed you didn't use the time gotten from the sunrise/set table in the almanac. Pls confirm to me that it's completely fine to use GPS GMT gotten just immediately after taking your bearing or did you just skip that step to save time. Thanks.

@AlistairBaillie 4 жыл бұрын

Opeyemi Ojutiku you need to use the actual time that you have obtained the bearing (in the case of this example it was 20:18:10 UTC) - where you obtain this time from is up to you - the easiest would be to take the current UTC time from a GPS unit at the time you take the bearing.

@opeyemiojutiku1264 4 жыл бұрын

@@AlistairBaillie very helpful, thanks a lot... In school we would mostly take the time of rise/set from the almanac and then convert to UT as well as ship's time. UT would now be used to proceed on solving the question. That made me start to over think things like how to know for sure what time the sun was exact 2/3 it's diameter from the horizon and how it might only be possible to get that info from the almanac. Thanks once again for your time.

@AlistairBaillie 4 жыл бұрын

@@opeyemiojutiku1264 In reality given that you're doing it by eye you'll never be able to be so accurate in real life - there are too many potential errors (reading the bearing, recording the time, calculation rounding errors) - also the almanac's sunrise/sunset time is only given to within 1 minute. In short it's sufficient to estimate when it's 2/3 above the horizon.

@narupolpaoain8234 4 жыл бұрын

THNK YOU SIR

@craigtaylor4613 5 жыл бұрын

Hi Alistair, Thanks for the video, just wondering what software you use to make your videos?

@AlistairBaillie 5 жыл бұрын

Final Cut Pro

@craigtaylor4613 5 жыл бұрын

Alistair Baillie copy that! By the way I'm using your videos to brush up on my celestial for my masters yacht

@AlistairBaillie 5 жыл бұрын

Thanks glad you’re finding them useful, good luck with your exams!

@regilboriva1652 3 жыл бұрын

Finding the true bearing for example Azimuth is NW. we know that quadrant NW were going to minus from 360. How do I know if it is going to add to 270? Thanks in Advance

@AlistairBaillie 3 жыл бұрын

This video is for Amplitude. The amplitude formula is related to East or West which is why you add/subtract from either 90 or 270 based on what quadrant your answer is within. Azimuth is related to North or South which is why you add/subtract from either 0/360 or 180 based on what quadrant your answer is within.

@denchlibot2608 3 жыл бұрын

What the meaning of H? Should I put H or different names?

@AlistairBaillie 3 жыл бұрын

H refers to the gyro error being high - this is traditionally a British terminology, in other countries it may be referred to as “west”.

@Jhumiille 5 жыл бұрын

The link is different pls give correct form thanks

@AlistairBaillie 5 жыл бұрын

Apologies - you were the only one to notice this (including myself when I checked) - While the old file was still correct, I have now corrected the file available on my website so that it matches the one used in the video. www.alistairbaillie.co.uk/blog/?attachment_id=1192

@sailingbeast6180 3 жыл бұрын

WHY LL IS TAKEN FOR SUN AND NOT UL?

@AlistairBaillie 3 жыл бұрын

In order to use the Amplitude method, the body needs to be on the Celestial Horizon, for the sun this is when its lower limb is 2/3 its diameter above the visible horizon - this is the easiest to judge by the eye than say the upper limb being 5/3 above the horizon. Refraction (and curvature of earth) also plays a part and is essentially negligible when using the lower limb so can be ignored, if using the upper limb it has to be corrected for - the figures for these corrections are not given in most nautical almanacs so a second book would be needed and it's just generally a lot of unnecessary complications.

@elmerbequiojr.2611 4 жыл бұрын

Are you there? What if I dont have the time to begin with?

@PinsAcrosstheWorld 4 жыл бұрын

ELMER BEQUIO JR. you need the time you took the the observation.

@elmerbequiojr.2611 4 жыл бұрын

In the problem given there is no time, so I was confused. But I able to get the time in the nautical almanac 2020 looking at the sunrise of the latitude. I very much appreciate your reply. I am now in my third year next school year taking up BS Marine Transporation. Please upload more videos like this it is a big help for a student like me.

@Devinnorrahs 2 жыл бұрын

you arent using 2016 almanac your using 2017

@necoorec 5 жыл бұрын

Hi. Thank you so much for the video. One question: If latitude and declination are from different hemispheres how do we proceed?

@AlistairBaillie 5 жыл бұрын

Hi, for the calculation it doesn't matter as we are not interested in the sign, just the numerical value of each. When it comes to naming the Amplitude, we name based upon whether it is sunrise or sunset and based upon whether the Declination is North or South using the little table on the right of the proforma. (Note: I have updated the proforma on my website so it matches the one used in the video today, I didn't notice I had uploaded the wrong file when I published the video! The updated file is here: www.alistairbaillie.co.uk/blog/?attachment_id=1192 )

@necoorec 5 жыл бұрын

@@AlistairBaillie Thank you very much!!