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    Today's lunar observation
    From: Frank Reed
    Date: 2012 Jun 23, 15:58 -0700

    Here's a set of lunars from about 45 minutes ago, complete with object altitudes to play with...

    The sextant is an Astra IIIB with 7x35 telescope. Index correction is -0.3'. Air temperature was 79 F and pressure was 29.82 inches Hg. Height of eye about 27 feet. Altitudes are all lower limb. Times are all GMT. The Moon was a somewhat indistinct crescent high in the southwest. The Sun was in the west. All of the altitudes were taken based on an "estimated" horizon since there's a shoreline a few miles off (could have done dip short sights but estimating works, too).

    First an altitude of the Moon:
    22:05:20: Moon_alt = 47d 55'

    Next an altitude of the Sun:
    22:06:40: Sun_alt = 22d 33'

    Now three lunar distances:
    22:08:20: LD = 49d 18.3'
    22:09:45: LD = 49d 19.3'
    22:11:00: LD = 49d 19.7'

    Another altitude of the Sun:
    18:12:28: Sun_alt = 21d 29'

    And finally another altitude of the Moon:
    18:14:02: Moon_alt = 46d 38'

    Note that all of these can be averaged to one "middle" time. That is, average the lunars, separately average the two Sun altitudes, and then average the two Moon altitudes. You're left with one observed lunar, one Sun altitude, and one Moon altitude all effectively simultaneous. You can clear these using the lunars clearing tool on my web site: http://ReedNavigation.com/lunars/.

    These sights were taken from Beavertail State Park here on Conanicut Island, where a group of us shot lunars two weeks ago and, if the weather holds, we should have a few folks there taking sights tomorrow afternoon, too.

    -FER

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