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    Re: Adding beta Capricorni to the web-based lunars calculator?
    From: Frank Reed
    Date: 2013 Jul 26, 09:24 -0700

    Peter, you asked:
    "Any chance beta Capricorni could be added to the list of lunars bodies in Frank Reed's web-based calculator?"

    Not likely. I think Mr. Reed is very busy right now. :)

    And you wrote:
    "I remember running across some mention of the star in the navlist archives as the "tenth lunar star" "

    Yes, that was one of my messages from about eight years ago. It seems clear that beta Cap was dropped because it's just too hard to use. Maskelyne originally included it because there are no bright stars near the ecliptic in that part of the sky. I would speculate that he got feedback in the following few years from users who most likely explained that beta Cap was difficult to find and difficult to bring into proper contact with the Moon's limb since it's so faint. On the other hand, modern users can work up calculations like this for nearly any star. My stand-alone software, which I am dusting off again right now for class use, will clear lunars for any of the 57+1 standard navigational stars.

    Peter, you added:
    "If there's any interest, I can post a plot of my errors across a few dozen lunars so far. Mostly biased positive by around 0.5', even after fixing a collimation problem."

    Of course. Please do. A positive bias like that suggests a simple error in index correction. How do you normally test index error? I don't recall --what type of sextant do you use? It's good you're using a 6x30 scope. With that magnification, there's every reason to expect you'll be able to get your mean error down to about a third of a minute of arc on individual lunars, with no bias.

    -FER


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