[amsat-bb] Re: use of PI in amsat development practice

Bent OZ6BL oz6bl at fern.dk
Sun Mar 14 10:01:14 PDT 2010

On 2010-03-14 17:22, Samudra Haque wrote:
> Hi, Pi-Day is today (3/14/2010) also we just sprang forward by 1 hour.
> (http://www.cnn.com/2010/TECH/03/12/pi.day.math/index.html?hpt=C2) and
> apparently it's also Einsteins Birthday!
> (http://en.wikipedia.org/wiki/Albert_Einstein)
> Wow a lot of key dates here.
Unfortunately Pi-day can not be celebrated in Europe as we have no month
14 over here. ;-)
> My question is: in amateur satellite design/planning how many
> significant digits are used to calculate the value of pi? Is there a
> significant difference in results between (4 decimal poinits) and (3
> decimal points).
> In professional space missions, such as NASA, what is the practice
> with regards to use of Pi ? Are there any published standards?
> Using Excel, is there any way to generate a large range of pi ?
I have often used the expression

pi = 4 * arctan(1)

to get Pi with full machine accuracy in a program.

73,  Bent

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