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Re: Lunar trouble, need help
From: Frank Reed
Date: 2008 Jun 15, 18:33 -0400
From: Frank Reed
Date: 2008 Jun 15, 18:33 -0400
Hi Jeremy. I have a little working theory on your lunars. I suspect that you took what I call "Inside Limb" lunar distances rather than "Near Limb" lunars. With Near Limb lunars, you bring the Moon over to the Sun so that they just touch with the two disks side-by-side with no overlap and no gap between them. With an 'Inside Limb' shot you bring the Moon's disk inside the Sun's disk and bring it into contact with the far limb (note that this is not what is meant by a "Far Limb" lunar in which you bring a star at night over to the limb opposite the star). Assuming that this is the case, we can convert your Inside shot to a Near shot by subtracting twice the Sun's semi-diameter which would be 31.5'. Then the average error in the set is 0.8 minutes of arc (which may indeed be due to an error in index correction as Jim suggested) and the standard deviation of that set is around 0.25'. Shooting an "Inside" lunar is not normal practice, but if you've never seen lunars done or diagramed, there's no way that you would know that. I think it's harder to shoot those alignments than a standard Near Limb lunar. Of course, this is just a speculation. If you're quite sure you shot these lunars by bringing the Moon and Sun side-by-side, then the problem must lie elsewhere. -FER PS: If you select "Far Limb" lunar in my online calculator for a Sun sight, you get a result that really doesn't mean anything since Far lunars actually don't make any sense when the other body is the Sun. Maybe I will change that to calculate Inside Limb lunars. --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---