in astronomy tau-sinc is used. What does it mean?

Answer 1

Hi Bill

Sinc(x) is the sine-cardinal function, a sampling function used in signal processing. You may have come across it if you've worked with Fourier transforms or signal processing. The function is most simply defined as

sinc(x) = {x=0|1, x=/=0|sin(x)/x}

In astrophysics the greek letter Tau (T) is used to denote proper time. Proper time is the time intervals measured by an object in its own rest frame, so it's a Lorentz invariant time interval (important in relativity). If the sinc function in question is a function of proper time then it would be written as sinc(Tau) and could conceivably be referred to as stau-sinc.


Hope this helps!
The Chicken

Answer 2

Tau is the Greek letter T, and like all the Greek letters they are assigned to stars within the constellations.

You probably heard wrong. Perhaps it was Tau Ceti, which is one of the dimmer stars of the constellation Cetus the Whale.

The brighter stars of all constellations are designated Alpha and Beta. So, Tau being well down the alphabet, designates one of the dimmer stars of any constellation.

Answer 3

tau-sync ?

maybe with tau in the greek letter form i would summise it's something to do with telescopes.

As the night sky is constantly moving, tau could be related to the movement of rotation or maybe something to do with light contrast / refraction / etc

hope this helps

Answer 4

neither wiki nor google can find it.

you must be mis-spelling it.
E.g. it is either sync (from syncronise) or sink (as in kitchen sink) - although neither of these turns up any search results either.