What about an ADEV/TDEV plot of the pulsar J0437-4715?
On Fri, Jul 29, 2016 at 12:39 AM, Jim Palfreyman <[email protected]> wrote: > Hi All, > > Tom gave me a nudge to look here - I hadn't been following this thread. > > For those that don't know, I study pulsars and so the way we measure what > pulsars do could be relevant to this discussion. > > First, I have never heard of a Q measure when referencing a pulsar. I think > the key here is that it's not resonating as such. Rotating yes, resonating > no. > > Pulsars spin and slow down due to giving off energy (magnetic dipole > radiation). So in the pulsar world we mainly refer to spin frequency (F0) > and frequency derivative (F1). With some of the younger and more "erratic" > pulsars, F2 (and further) can be modelled. > > Here's some data on the Vela pulsar (hot off the presses - measured just > now): > > F0 11.1867488542579 > F1 -1.55859177352837e-11 > F2 1.23776878287221e-21 > > Vela is young and erratic. Millisecond pulsars are outstanding clocks. > Here's the data for J0437-4715 - one of the most stable pulsars we know > about: > > F0 173.6879458121843 > F1 -1.728361E-15 > > I'm sure the "Q" of Vela would be pretty decent - but I can tell you now, > as a time-keeper, she's useless. > > > Jim Palfreyman > > > > On 28 July 2016 at 20:50, Tony Finch <[email protected]> wrote: > >> Neville Michie <[email protected]> wrote: >> >> > The conical pendulum has a simple form of a weight on a string, instead >> > of oscillating in one plane as a conventional pendulum, it swings around >> > in a circular orbit in the horizontal plane. It has a definite resonant >> > frequency. >> >> I don't think it does have a resonant frequency, any more than the Earth >> does: the angular velocity of the pendulum is sqrt(g/h) where h is the >> height of the pendulum; give it more energy, it swings higher, so h is >> smaller, so the frequency is higher. >> >> Tony. >> -- >> f.anthony.n.finch <[email protected]> http://dotat.at/ - I xn--zr8h >> punycode >> South Thames, Dover: Southwesterly 5 or 6. Slight or moderate. Rain or >> showers. Good, occasionally poor. >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
