Message from discussion
Solar eclipse magnitude
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From: "Greg Neill" <gneill...@OVE.THIS.netcom.ca>
Newsgroups: sci.astro
References: <43ef6400_1@x-privat.org>
Subject: Re: Solar eclipse magnitude
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Date: Mon, 13 Feb 2006 13:54:36 -0500
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"Cristiano" <cristiano...@NSquipo.it> wrote in message news:43ef6400_1@x-privat.org...
> I wrote a program to calculate the parameters of an eclipse.
>
> For the 2006 Mar 29 solar eclipse I get the magnitude 1.0260, while here:
> http://sunearth.gsfc.nasa.gov/eclipse/OH/image1/SE2006Mar29-Fig2.GIF
> there is 1.0515.
>
> In that site
> http://sunearth.gsfc.nasa.gov/eclipse/SEcat/SEcatkey.html
> it is said that: "Eclipse magnitude is the fraction of the Sun's diameter
> obscured by the Moon."
> which is clearly wrong because with that definition the maximum magnitude
> would be 1.
>
> In my program I used the formula:
> G= (Sl + Ss - d) / 2 / Ss
> where Sl and Ss are the Moon and Sun semidiameters and d is the distance
> between the center of the Sun and of the Moon.
>
> With my prog I get the NASA's magnitude when I do Sl/Ss which is 1,0521.
>
> Is there any standard definition for the magnitude?
>
> Thanks
> Cristiano
Try here:
http://www.csiro.au/helix/eclipse/solar/eclipse_area.html
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