04-28-2023, 04:21 PM
This is a very interesting topic and I've enjoyed watching the development of it, especially as PeterB explains the procedure.
For curiosities sake, I have several questions related to determining Ap λ in Eastern longitudes and am hoping you men can answer them.
1- Your DR λ can be way off in a bad case by several degrees because of weather, current, sea sickness, etc. So when you finally get the chance to make an observation you'll see your DR λ and resulting Ap λ (and LHA for the sight reduction to get Hc) are far away from the LOP. So, lets say your Ap λ shows that you're 3 degrees (180 nm) away from the LOP. Would you then adjust your Ap λ (and then LHA) complete the sight reduction process again to obtain an intercept that's much closer to the LOP?
2- Exam questions and the "right answer". Getting the right answer based on a difference of less than 30' is fine but in reality it's unimportant....unless the test requirement is to have an Ap λ that's 30' or less from the DR λ. If that's the case then I agree. In looking at the literature available, no one is observing this requirement or even cares about it. But, for a simpler and shorter intercept the 30' minute or less necessity is a very good idea. When using Ho. 249 we plot from whole degree of latitude and no minutes.
Thanks guys,
Fred
For curiosities sake, I have several questions related to determining Ap λ in Eastern longitudes and am hoping you men can answer them.
1- Your DR λ can be way off in a bad case by several degrees because of weather, current, sea sickness, etc. So when you finally get the chance to make an observation you'll see your DR λ and resulting Ap λ (and LHA for the sight reduction to get Hc) are far away from the LOP. So, lets say your Ap λ shows that you're 3 degrees (180 nm) away from the LOP. Would you then adjust your Ap λ (and then LHA) complete the sight reduction process again to obtain an intercept that's much closer to the LOP?
2- Exam questions and the "right answer". Getting the right answer based on a difference of less than 30' is fine but in reality it's unimportant....unless the test requirement is to have an Ap λ that's 30' or less from the DR λ. If that's the case then I agree. In looking at the literature available, no one is observing this requirement or even cares about it. But, for a simpler and shorter intercept the 30' minute or less necessity is a very good idea. When using Ho. 249 we plot from whole degree of latitude and no minutes.
Thanks guys,
Fred