Nice, Jim!!!
On 2018-04-13 01:54, Tom Van Baak wrote:
Amazing news... 1.2.3.
1) Many of you know that pulsars are weird astronomical sources of
periodic signals. Some are so accurate that they rival atomic clocks
for stability! True, but I don't have a 100 foot antenna at home so
I'll take
Bill Hawkins writes:
> It seems that pulsars are rotating stellar objects that have no reason
> to change their rotation, except to decay.
The whole point of that exercise was to determine which of the theories
that predict what the internal structure of a neutron star looks like is
more likely
kins
>
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Dana
> Whitlow
> Sent: Friday, April 13, 2018 8:39 AM
> To: Tom Van Baak; Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Pulsars, clocks,
of hard science fiction.
Bill Hawkins
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Dana
Whitlow
Sent: Friday, April 13, 2018 8:39 AM
To: Tom Van Baak; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Pulsars, clocks
Tom's discussion about pulsars brought back some memories...
Many pulsars exhibit skipped pulses. And one curiosity that I didn't see
mentioned in Tom's discussion is that some pulsars even exhibit behavior
reminiscent of the "sawtooth jitter" so evident in the PPS outputs of most
GPS receivers.
Amazing news... 1.2.3.
1) Many of you know that pulsars are weird astronomical sources of periodic
signals. Some are so accurate that they rival atomic clocks for stability!
True, but I don't have a 100 foot antenna at home so I'll take their word for
it. Plus, you have to account for a myriad
Hi all,
With all the recent talk of clocks etc in spacecraft I though you guys
might like this...
http://www.csiro.au/en/Portals/Media/Pulsars-make-a-GPS-for-the-cosmos.aspx
regards
Tim
===
.. and some more information from ESA:
jim...@earthlink.net said:
You also get direction, so for a navigation system, you can figure out
where you are.
I'm still missing the big picture.
If I'm working off direction, why are pulsars interesting? Why radio vs
optical? There are lots of bright stars out there. Why not use them
Le 30 sept. 2013 à 09:19, Hal Murray a écrit :
jim...@earthlink.net said:
You also get direction, so for a navigation system, you can figure out
where you are.
I'm still missing the big picture.
If I'm working off direction, why are pulsars interesting? Why radio vs
optical?
Hi Hal
The setup is a spinning disk with holes in it.
Adjust the speed of rotation until it beats with the pulsar.
I think you need a small telescope for the bright pulsars.
Yes, you are quite right. I recently done this with an 8 amateur telescope
and it is possible to reconstruct the
Le 28 sept. 2013 à 14:26, Magnus Danielson a écrit :
On 09/28/2013 02:15 PM, Jim Lux wrote:
Don't forget the Doppler and relativistic effects of the earth moving
around the solar system barycenter. But that's not much different
than you do for GPS (e.g. knowing satellite orbits, etc.)
On 9/29/13 3:42 AM, mc235960 wrote:
Le 28 sept. 2013 à 14:26, Magnus Danielson a écrit :
I think the radio elescope(s) needed are much smaller. There are apparently 2 pulsar
clocks installed here in europe, one in St Catherine's church Gdansk and the other in the
European Parliament,
On 09/29/2013 03:11 PM, Jim Lux wrote:
On 9/29/13 3:42 AM, mc235960 wrote:
Le 28 sept. 2013 à 14:26, Magnus Danielson a écrit :
I think the radio elescope(s) needed are much smaller. There are
apparently 2 pulsar clocks installed here in europe, one in St
Catherine's church Gdansk and
There really is no such thing as a 'bright' pulsar. They are something
like 16 Mag at best. This is not exactly naked eye.
-John
===
b...@evoria.net said:
Just to satisfy my curiosity: what's easiest to detect galactic pulse
emitter (regardless of type), and what's the
...@earthlink.net
To: time-nuts@febo.com
Subject: Re: [time-nuts] Pulsars make a GPS for the cosmos
On 9/29/13 3:42 AM, mc235960 wrote:
Le 28 sept. 2013 à 14:26, Magnus Danielson a écrit :
I think the radio elescope(s) needed are much smaller. There are
apparently 2 pulsar clocks
On 9/29/13 1:52 PM, Tom Knox wrote:
Actually Dr Kent Irwin at NIST has developed very small and extremely sensitive
detectors using SQUIDs.
Not exactly a project that can be duplicated at home though. There are a number
of articles about his work on line.
depends on who's home... Don't you
No I don't have room since I set up my dilution refrigerator for Football
season.
Thomas Knox
Date: Sun, 29 Sep 2013 14:24:12 -0700
From: jim...@earthlink.net
To: time-nuts@febo.com
Subject: Re: [time-nuts] Pulsars make a GPS for the cosmos
On 9/29/13 1:52 PM, Tom Knox wrote
On 09/26/2013 08:25 PM, Tom Knox wrote:
It seems you would need to think of the Pulsar as the clock behind the GPS
sat. You then have an algorithm to add the other need information at the rec
end. To make things easier add to the constellation one master clock signal
with corrections and
On 9/28/13 4:14 AM, Magnus Danielson wrote:
On 09/26/2013 08:25 PM, Tom Knox wrote:
It seems you would need to think of the Pulsar as the clock behind the GPS sat.
You then have an algorithm to add the other need information at the rec end. To
make things easier add to the constellation one
On 09/28/2013 01:42 PM, Jim Lux wrote:
On 9/28/13 4:14 AM, Magnus Danielson wrote:
On 09/26/2013 08:25 PM, Tom Knox wrote:
It seems you would need to think of the Pulsar as the clock behind
the GPS sat. You then have an algorithm to add the other need
information at the rec end. To make
Don't forget the Doppler and relativistic effects of the earth moving
around the solar system barycenter. But that's not much different
than you do for GPS (e.g. knowing satellite orbits, etc.)
Naturally. You also needs to compensate for their decay-rate as you try
to span longer periods.
On 09/28/2013 02:15 PM, Jim Lux wrote:
Don't forget the Doppler and relativistic effects of the earth moving
around the solar system barycenter. But that's not much different
than you do for GPS (e.g. knowing satellite orbits, etc.)
Naturally. You also needs to compensate for their
jim...@earthlink.net said:
Scrolling down, it looks like they're getting a whopping 0.5 dB SNR on
the Crab Nebula pulsar.
How much of the noise comes from local sources vs thermal or galactic?
I'm missing the scale factor for the big picture. How big a volume does this
work over before I
On 9/28/13 7:32 AM, Hal Murray wrote:
jim...@earthlink.net said:
Scrolling down, it looks like they're getting a whopping 0.5 dB SNR on
the Crab Nebula pulsar.
How much of the noise comes from local sources vs thermal or galactic?
These are amateurs, so they're probably not using
A couple of points:
Pulsars are pretty faint and the only solution to that is antenna
aperture. We looked at that while doing SETI a ways back. Receivers are
now quite close to the theoretical limit as far as noise temperatuse.
There is very little room for improvement.
Pulsars are not
Pulsars are not infrinitely stable. They slowly decay, and, worse,
randomly undergto 'star quakes' which upset their timing. This was proven
in the 1960s.
John,
You are correct, but it is a simple opportunity rather than a major problem.
The solution is to monitor multiple pulsar sources.
Knox
Date: Sat, 28 Sep 2013 09:18:10 -0700
From: j...@quikus.com
To: time-nuts@febo.com
Subject: Re: [time-nuts] Pulsars make a GPS for the cosmos
A couple of points:
Pulsars are pretty faint and the only solution to that is antenna
aperture. We looked at that while doing SETI a ways
Yes, but to use them for interstellar navigation, as suggested, when the
propagation delays are 10,000 years or more complicates things.
What is contemplated is comparing the clocks, as they were thousands of
years ago, where they were thousands of years ago, with largely unknown
motions. You
Hi Tom,
On 09/28/2013 07:49 PM, Tom Knox wrote:
I am just thinking out loud on this, But it seems you could use carrier phase
from plain star light since the light spectrum from stars have spikes and
notches which are constant and using the same concept as the Hubble Constant
a spacecraft
Just to satisfy my curiosity: what's easiest to detect galactic pulse emitter
(regardless of type), and what's the minimum setup to reliably look at it,
whether it's just during night time, or whatever. Just seeking perspective, I
haven't just won the lottery.
Bob
Hi
If you are on the surface of the earth, you face the sun from time to time.
That creates some issues that you would not have in a deep space setting. In
deep space you don't have to correct for all sorts of orbital issues as well.
This is one of those - not so easy here - sort of things.
From what I remember, with the 1000' Aricebo dish and pretty good LNA,
there were a literal handful of RF photons per pulse... less than 10
maybe.
-John
===
Just to satisfy my curiosity: what's easiest to detect galactic pulse
emitter (regardless of type), and what's the
The sune is hugely bright in the RF.
I've been able to see it at 2.2 GHz with nothing more than a horn a foot
or so across and a receiver w/ a NF of maybe 8 dB (cavity preselector
mixer IFA... ACL SR-209).
There was a noticable difference between pointing at the sun and in
another direction.
On 9/28/13 3:55 PM, Bob Stewart wrote:
Just to satisfy my curiosity: what's easiest to detect galactic pulse emitter
(regardless of type), and what's the minimum setup to reliably look at it,
whether it's just during night time, or whatever. Just seeking perspective, I
haven't just won the
Thanks to all respondents. Perspective is a hard thing to find in this group.
=)
Bob
From: Jim Lux jim...@earthlink.net
To: time-nuts@febo.com
Sent: Saturday, September 28, 2013 6:33 PM
Subject: Re: [time-nuts] Pulsars make a GPS for the cosmos
On 9
. Forster j...@quikus.com
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Sunday, September 29, 2013 12:13 AM
Subject: Re: [time-nuts] Pulsars make a GPS for the cosmos
The sune is hugely bright in the RF.
I've been able to see it at 2.2 GHz with nothing more than
On Sun, Sep 29, 2013 at 6:55 AM, Bob Stewart b...@evoria.net wrote:
I haven't just won the lottery.
Yet. You left out the yet.
--
Sanjeev Gupta
+65 98551208 http://www.linkedin.com/in/ghane
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To
There's no yet to it. I don't play. =)
From: Sanjeev Gupta gha...@gmail.com
To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency
measurement time-nuts@febo.com
Sent: Saturday, September 28, 2013 10:13 PM
Subject: Re: [time-nuts
b...@evoria.net said:
Just to satisfy my curiosity: what's easiest to detect galactic pulse
emitter (regardless of type), and what's the minimum setup to reliably look
at it, whether it's just during night time, or whatever. Just seeking
perspective, I haven't just won the lottery.
An
: Wednesday, September 25, 2013 7:38 PM
Subject: [time-nuts] Pulsars make a GPS for the cosmos
Hi all,
With all the recent talk of clocks etc in spacecraft I though you guys
might like this...
http://www.csiro.au/en/Portals/Media/Pulsars-make-a-GPS-for-the-cosmos.aspx
regards
Tim
--
VK2XAX
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Pulsars make a GPS for the cosmos
I remember when pulsars were first discovered one speculation was that they
were interstellar navigation beacons established by intelligent life forms.
Regards.
Max. K 4 O DS
If there is Alien life on this planet they are most assuredly Time-Nuts.
Thomas Knox
From: paul.ree...@uk.thalesgroup.com
To: m...@maxsmusicplace.com; time-nuts@febo.com
Date: Thu, 26 Sep 2013 08:59:17 +0100
Subject: Re: [time-nuts] Pulsars make a GPS for the cosmos
Some of them might
On Thu, Sep 26, 2013 at 3:59 PM, REEVES Paul paul.ree...@uk.thalesgroup.com
wrote:
Some of them might be... you could certainly speculate that any
culture that has attained sufficient technology to make interstellar travel
possible (and need navigation beacons) would probably have
From: gha...@gmail.com
Date: Thu, 26 Sep 2013 16:48:14 +0800
To: time-nuts@febo.com
Subject: Re: [time-nuts] Pulsars make a GPS for the cosmos
On Thu, Sep 26, 2013 at 3:59 PM, REEVES Paul paul.ree...@uk.thalesgroup.com
wrote:
Some of them might be... you could certainly speculate
Hi all,
With all the recent talk of clocks etc in spacecraft I though you guys
might like this...
http://www.csiro.au/en/Portals/Media/Pulsars-make-a-GPS-for-the-cosmos.aspx
regards
Tim
--
VK2XAX :: QF56if23 :: BMARC :: WIA
___
time-nuts mailing
The Ham expert on this has to be Tom Clark, W3IO, of AMSAT and the TAC system
offered at one time by TAPR. He did a lot of timing professionaly using these
as I recall.
N0UU
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jim...@earthlink.net said:
If you want something that isn't run by governments,and is a technical
challenge, how about pulsars? I'd guess (not having looked into it at
all) that is would be cheaper to set up a station to receive pulsars than
to run a Cs standard.
What sort of gear does
...) slowing down but should be good for a while yet ;-)
regards,
Paul Reeves G8GJA
-Original Message-
From: Hal Murray [mailto:hmur...@megapathdsl.net]
Sent: 05 October 2010 07:30
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Pulsars (was: 60 KHz
Hal Murray wrote:
What sort of gear does it take to hear a pulsar?
... Is there a convenient one up near the north pole?
A potential target is PSR0329+54, 1.5 Jansky at 400Mhz,
which corresponds to about 1.5E-26 W/m^2/Hz.
I did some rough calculations and concluded that with
a 16dB gain
October 2010 07:30
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Pulsars (was: 60 KHz Receiver)
jim...@earthlink.net said:
If you want something that isn't run by governments,and is a technical
challenge, how about pulsars? I'd guess (not having looked
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