Intercept calculation and direction of position line - Sun as a celestial body
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- Опубликовано: 31 янв 2025
- Using an example, this video explains the calculations involved in deciphering the intercept and the orientation of the position line in the topic of celestial navigation.
Contents of this video will benefit mariners preparing for exams (written and oral examinations).
Mariners will also benefit by watching the following videos:
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Intercept (Sun -Example 2): • Intercept Calculation ...
Intercept (Star- example 1): • How to use the Interce...
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Intercept (Planets): • How to use the Interce...
Intercept (Moon): • Calculating the interc...
Staggered observations (Example 1): • Staggered Observations...
Staggered observations (Example 2): • Staggered Observations...
Staggered Observations (Example 3): • Staggered observations...
Variation, deviation, and compass error: • What is the Variation,...
Longitude, GHA and LHA: • Relationship between l...
Ambiguity of chronometer time: • The ambiguity of chron...
Twilight: • Twilight: Nautical nav...
Calculating sunset time: • Calculating sunset tim...
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Using back angle (Meridian Passage): • Using the back angle o...
Long by chron (Sun): • Longitude by chronomet...
Long by chron (Sun -Part 1): • Long by Chron - Part 1...
Long by chron (Sun -Part 2): • Long by Chron - Part 2...
Long by chron (Star): • Longitude by chronomet...
Long by chron (Planets): • How to use Longitude b...
Long by chron (Moon): • Longitude by chronomet...
Ex-meridian (Sun): • How to use the Ex-meri...
Ex-meridian (Stars): • How to use the Ex meri...
Ex-meridian (Planets): • How to use the Ex-meri...
Ex-meridian (Moon): • Ex-meridian method for...
Polaris: • Polaris (Pole Star) - ...
PZX triangle: • PZX triangle Rational ...
Venus as morning or evening star: • Why Venus is known as ...
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Circumpolar bodies (Theory): • Circumpolar Bodies Cel...
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I won't forget to thank you for the thousand time for these bountiful and very helpful videos 💙
Thanks again for making these!
You are most welcome buddy:)
Perfect
How do you create a fix from this?
Thank you sir,very much helpful video
thank you sir very informative
Is it necessary to sketch the graph if the they are only finding the calculation and position of the line?
More than perfect
Many thanks........
Can A & B have a negative sign , or do we neglect the occasionally negative sign of the (Tan LHA) or (Sin LHA) when calculating A & B ?!!
Sir pls for this particular question can you show the actual plot on radar plotting sheet.. Thanks a lot
Thanks sir.
Dear Sir
Is it possible that you can solve an example of intercept method when 090°
Sir if we calculate LHA by this method then why we use long by crone formula in other questions. Please reply sir.....
How to do the calculation when longitude is not given but its mentioned body on east of meridian
What is east of meridian in questions
Please can you send me the link ,solution of simultaneous observation and staggered observations
Hello sir ,I want to clear one think if longitude is East ,so do we suppose to subtract our Zone Time from the given ships time to Get the approx UT time/date. Because here you have added East , Can you please clear that .
You’re right. We subtract East and Add West.
If true altitude is greater than calculated altitude the intercept is towards. Isn’t it? (True greaterrrrr towards )
No, true-tiny-towards is correct:)
Imagine looking up at a lighthouse light which is calculated at 45 degrees for your assumed position. If the angle you measure is only 30 deg, then are you nearer to the lighthouse or farther away? Clearly you are farther away from the lighthouse than your assumed position. So it follows that if the true altitude is greater than than calculated one, you must be closer to the lighthouse.
@@SteeringMariners "Tabulated (i.e. Hc)-Tinier-Towards" is the mnemonic I see most often in publications, which is a good reason not to rely on mnemonics as they are ambiguous!
I see you are using zenith distance (CZD) and if you subtract this from 90 you get Hc=28d 3.5'. Your Ho=27d 43.0' so Hc>Ho, which is "away" as you correctly say in your video.
I know this is a very old comment, but this briefly confused me, and I wanted to clear it up for anyone else currently studying. Actually..TheJDenz is correct. They both are correct. They're just tackling the intercept calculation differently.
If you calculate the intercept using CZD by using the end formula CZD=Cos-1(0.47036) and then subtracting True Alt from 90... then yes --- True-Tiny-Towards.
If you calculate the intercept using Hc (calcuated alt) using the end formula Hc=Sin-1(0.47036) then also yes... = True Alt > Hc = Towards // True Alt < Hc = Away
The intercept is 20.5' away either way....As George said below, this can make using a mnemonic very confusing depending on the method you use.
Thank you but question, how do I find the ITP POSITION? Should I use plane sailing method?
Sir l am not understood the position line one more time explain sir or else give one more clear vedio
Sir is PL or IPL is the same thing ?
Well PL stands for position line, not sure if you mean IPL or ITP? ITP means intercept terminal point.
It was ITP . Thank you so much sir .