On Sat, 23 Feb 2008 08:41:34 -0800 (PST), IsaacKuo <mechdan@[EMAIL PROTECTED]
>
wrote:
>On Feb 23, 9:03 am, Crown-Horned Snorkack <chornedsnork...@[EMAIL PROTECTED]
>
>wrote:
>> How many stars can be seen by telescope?
>
>> Eye has standard angular resolution of about 1 minute (or larger) and
>> can see magnitude 6.
>
>> There are estimated to be something of 5000 to 6000 stars up to
>> magnitude 6 - over the whole heavenly sphere.
>
>I recently wondered the same thing, because I'm trying to analyze
>the performance of an occultation sensor network. The basic
>idea behind an occultation sensor network is that each sensor
>drone simply stares at all known pinprick light source stars and
>looks for any of them briefly winking out. This corresponds to
>a detection of a target.
Do be careful to consider diffraction effects here - they are every
bit as important for light flowing around a small obstacle, as for
light flowing through a small hole or slit.
The math to do this right, esp. for complex shapes, gets rather hairy,
but I think that if both the source-target and target-sensor ranges
are large compared to d^2/y, d = target diameter and y = wavelength
of light being observed, the poisson spot will fill the umbra and
you won't get an occultation - even if the target completely obscures
the light source in purely geometric terms.
--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
*John.Schillin@[EMAIL PROTECTED]
* for success" *
*661-718-0955 or 661-275-6795 * -58th Rule of Acquisition *
|
