Observing by listening

A question from an ignorant layman...

Whenever I read about radio astronomy, I see the observations presented
as either graphs or multi-coloured maps of the sky. Do radio
astronomers ever observe by donning a pair of headphones?

"RN" wrote in message ...
A question from an ignorant layman...

Whenever I read about radio astronomy, I see the observations presented
as either graphs or multi-coloured maps of the sky. Do radio
astronomers ever observe by donning a pair of headphones?

Only in the movies, as far as I am aware. They might use a small receiver
and headphones to track down sources of interference such as car ignitions.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

RN wrote:
A question from an ignorant layman...

Whenever I read about radio astronomy, I see the observations presented
as either graphs or multi-coloured maps of the sky. Do radio
astronomers ever observe by donning a pair of headphones?

Only if they are listening to their iPod.

The signals don't make much (any) sense until they are all combined in a
computer to build up a map of the sky. A big dish scope sees only a tiny
patch of sky and has to sweep the beam slowly across the sky to scan an
image line by tedious line.

The interferometers for aperture synthesis track the source for many
hours and combine the signals received at pairs of small antennae to
measure fringes. The computer takes the inverse Fourier transform of
these raw data to make the final map with a resolution determined by the
longest baseline. The VLA which has a Y shape rather than a simple E-W
linear array can do a snapshot look see in a few minutes, but to get
high signal to noise you have to integrate for a longer time.

The only time someone might don headphones is when the local taxi
service or more usually car ignition or a distant weather balloon is
breaking through and saturating a front end amplifier. This happens

Although thinking about it there are a few examples where headphones
might be used in anger for time resolved celestial signals...

The pulsar researchers must do it from time to time since some of their
signals are clearly in the audio band. Even then I suspect they stack
and average the periodic signal to clean it up (rather than listening to
it in real time). Examples online at Jodrell:

http://www.jb.man.ac.uk/~pulsar/Educ...ds/sounds.html

Also Jupiter which has its own Radio Jove website (and is easy enough to
DIY with a crude antenna and short wave receiver).

http://www.spacetoday.org/SolSys/Jup...iterRadio.html
(links off that page seem broken)

Regards,
Martin Brown

In message , RN writes
A question from an ignorant layman...

Whenever I read about radio astronomy, I see the observations presented
as either graphs or multi-coloured maps of the sky. Do radio
astronomers ever observe by donning a pair of headphones?

The signals sound like differences in noise; not terribly exciting. I
do amateur radio and can hear solar and galactic noise. It just sounds
like a hiss.

I know a guy who does weak laser communication and has a very
sensitive optical receiver -18" fresnel lens objective. He says he can
hear stars twinkling. Like astronomers , he curses street lights; they
produce a background hum.

Brian
--
Brian Howie

Brian Howie wrote:

In message , RN writes

The signals sound like differences in noise; not terribly exciting. I
do amateur radio and can hear solar and galactic noise. It just sounds
like a hiss.

I know a guy who does weak laser communication and has a very
sensitive optical receiver -18" fresnel lens objective. He says he can
hear stars twinkling. Like astronomers , he curses street lights; they
produce a background hum.

Brian

Hi Brian,

I find that interesting. When you say 'signals', what do you mean? Are
you able to differentiate between solar and galactic noise? ...or does
it all sound the same?