The correct thing is to convert degrees to minutes (multiply by 60) first: (5 * 60) / 7 which = 42.85 minutes of latitude per minute of time. So the correct answer is 42.9 when we round up, NOT 42.6.
There are a few other ways to calculate it. The angular height of the observed Sun is just the sum of corrections [for dip, astronomical refraction, terrestrial refraction (from horizon to eye it is about -.18´ times the eye-height in feet), semidiameter, and parallax; except for parallax they are each negative]; rearrange the height formula to instead find the longitude difference between observer and Sun, and then determine the West longitude of the Sun. Interpolate in an almanac to find when the Sun will have that longitude. Or use a convenient time and exact position, and compute a line of position.
The purpose of the sunrise/set amplitude is compass correction. It's a way to check the accuracy of your magnetic or gyro compass. This is only the first half of the calculations. After this you must work out the azimuth bearing of the set/rise and compare that to your observation, (you usually use the gyro repeater on the bridge wing).
Hi, just looking for some help, please. 7mins into this video it explains longitude of 073.561 divided by 15 degrees = 4.929. When I do this calculation I get 4.904. What am I doing wrong here, thank you
your interpolation is strange , proper way is 05:24 - 05: 17 = 7 min / 5 DEG = 1.4 min change every deg, then for 41= 05:24 - 1.4 min = 05 22.6 = round it to 05: 23 min
You can't divide minutes by degrees... The correct thing is to convert degrees to minutes (multiply by 60) first: (5 * 60) / 7 which = 42.85 minutes of latitude per minute of time. So the correct answer is 42.9 when we round up, NOT 42.6.
Why would you use New York time all the charts and tables is set up in GMT time zone and if you are using New York time just add five hours to the time like like if it is 05:00 in New York in London England (GMT) it is 10:00 so you add five hours to your clock time at the start. I think you are over working it.
Finally I find an explanation, which really explains how it is done. Thanks
Isn't the change per minute supposed to be (300 / 7) or 42.85 minutes of latitude per minute of time, and NOT 42.6?
The correct thing is to convert degrees to minutes (multiply by 60) first: (5 * 60) / 7 which = 42.85 minutes of latitude per minute of time. So the correct answer is 42.9 when we round up, NOT 42.6.
Great explanation! Thanks that was a huge help!
Thank you so much for this wonderful and absolutely amazing content and explanation...FROM INDIA/
Now that's concise. (You must have a captive audience down the pub when folks ask you about navigation or maths!)
THANK YOU VERY MUCH 🙏❤️
Simple and effective
There are a few other ways to calculate it.
The angular height of the observed Sun is just the sum of corrections [for dip, astronomical refraction, terrestrial refraction (from horizon to eye it is about -.18´ times the eye-height in feet), semidiameter, and parallax; except for parallax they are each negative]; rearrange the height formula to instead find the longitude difference between observer and Sun, and then determine the West longitude of the Sun. Interpolate in an almanac to find when the Sun will have that longitude.
Or use a convenient time and exact position, and compute a line of position.
The purpose of the sunrise/set amplitude is compass correction. It's a way to check the accuracy of your magnetic or gyro compass. This is only the first half of the calculations. After this you must work out the azimuth bearing of the set/rise and compare that to your observation, (you usually use the gyro repeater on the bridge wing).
If longitude is east all i have to do is minus the sunrise at latitude, with the time difference of longitude, is that correct?
Hi, just looking for some help, please. 7mins into this video it explains longitude of 073.561 divided by 15 degrees = 4.929. When I do this calculation I get 4.904. What am I doing wrong here, thank you
HI all, just in case you are all wondering :) I worked it out. (I also now get 4.928) Nothing to see here :)
your interpolation is strange , proper way is 05:24 - 05: 17 = 7 min / 5 DEG = 1.4 min change every deg, then for 41= 05:24 - 1.4 min = 05 22.6 = round it to 05: 23 min
You guys are confusing me, 😪
You can't divide minutes by degrees... The correct thing is to convert degrees to minutes (multiply by 60) first: (5 * 60) / 7 which = 42.85 minutes of latitude per minute of time. So the correct answer is 42.9 when we round up, NOT 42.6.
it is the same thing. you just do it with the different way. The interpolation can be made with several ways.
thanks a lot
appreciate it
Can you please add .... moonset and moonrise
How to get the 42.6
When it comes the
5√7?
How do you get the 51.6 minutes?
Why would you use New York time all the charts and tables is set up in GMT time zone and if you are using New York time just add five hours to the time like like if it is 05:00 in New York in London England (GMT) it is 10:00 so you add five hours to your clock time at the start. I think you are over working it.
I will be...so thanks for you ... if will add the translation to Arabic language 🙄🥺
Plane and simple, can you do celestial observation about LOP
Yes.
Next video in series: ua-cam.com/video/vGHd62xyCRY/v-deo.html
Just want to be sure of my latitude
How to get the 42.6
When it comes the
5√7?