Re: OT: Luminosity question

From: Björn Gimle (bjorn.gimle@gmail.com)
Date: Thu Nov 28 2013 - 09:18:55 UTC

• Next message: Derek C Breit: "RE: OT: Luminosity question"

```I might find the answer from the W figure with some research.

But the original question is easy, since the Sun's magnitude is given as
-26.7 here, and diminishes by a factor of distance^2.

Using the Brigg (10-) logarithm for a distance of 10 AU (=1) where the Sun
is 100 times fainter = 5 magnitudes,
you have the formula -26.7 + 5 * log AU
With parsec you would subtract the constant 5*log(206265)

/Björn

2013/11/28 Bob King <nightsky55@gmail.com>

> Hi everyone,
> I realize this is off topic, but how do you calculate the sun's apparent
> magnitude at any given distance? Or, to turn the question around, how do
> you find out at what distance the sun appears a particular apparent
> magnitude?
> I know that if anyone could tell me, this would be the place to ask since
> satellite magnitudes depend on size, distance. If this helps, the sun's
> luminosity is 3.9x10 to the 26th W (watts).
> Thank you for your help.
>
> Best regards,
> Bob
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