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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Irradiation and manual navigation
From: Brad Morris
Date: 2010 Mar 6, 11:33 -0500
From: Brad Morris
Date: 2010 Mar 6, 11:33 -0500
Interesting paper http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19680023984_1968023984.pdf. The statement that follows the 50 to 40 second irradiation effect for the moon's disk outside the earths atmosphere is very entertaining. "...a 2.5 log unit neutral density filter would reduce this [the irradiation effect] to about zero. The temptation to use a bright high contrast planetary disk as a target in navigation sightings [in space] apparently should be avoided." My takeaway from this is that irradiation may be present if the image isn't well shaded. How would I know if the image isn't well shaded? Should I just continue to add shades until the image is dimly seen? At that point, do we know that the irradiation effect goes to zero? ----------------- I saw a show on the TV about space navigation on the Apollo mission. The show focused primarily on the MIT computer and how it was designed. However, the show also made several mentions of the fact that some of the Apollo astronauts also took observations with a space sextant. I would expect that those measurements are a matter of public record and the comparison of position relative to the ground based telemetry derived position are available. Now that would be an interesting read and certainly provide compelling evidence to this discussion. Best Regards Brad