Moon altitude corrections

[mordase]

Would appreciate some advice how to handle the Upper/Lower Limb and Horizontal Parallax corrections for the Moon when using an artificial horizon with the two images of the moon superimposed on each other. As the centre of the Moon is being measured do you just interpolate the Upper/Lower Limb corrections for the half way point? What about the 30' correction when using the Upper Limb? Do you ignore this, or use half the value as you are measuring the altitude of the centre effectively? Advice would be greatly appreciated. Ed.

 

[Portland Billy]

moon sights

Why are you using the moon ? It is the most correction prone and unreliable of all the heavenly bodies.
In almost fifty years of navigation I've only attempted it in dire circumstances (only about twice), and then treated the results with a dose of caution.
A bit like a position line from a radio direction finder !!

 

[mordase]

The question was regarding how to correct moon altitudes when using an artificial horizon. The Moon altitude correction tables do not make it clear how or if to apply Upper/Lower limb and HP when you are measuring the altitude of the centre of the moon which is what happens when you superimpose the images with an articial horizon. The fact that a moon sight requires more acuracy and involves more corrections is understood. Thank you.

 

[bossifrance]

You should not superimpose, use upper- or lower limb that's far more accurate also with an artificial horizon.