What is the highest radio frequency used for radio astronomy?

[Chris L Peterson]

On 30 Aug 2007 15:03:23 GMT, Margo Schulter <mschulter@web1.calweb.com>
wrote:


They are called submillimeter waves, and represent the transition
between what is widely accepted as "radio" and what is widely accepted
as "optical".

IMO the best way to categorize EM bands is by the nature of the
equipment we use to measure energy in those bands. Submillimeter
radiation is detected using special receivers which combine optical-like
sensors (bolometers) and radio-like sensors (heterodyne receivers and
tuned antennas). I think its best to simply consider the range from
about one millimeter to 1/10 millimeter as "submillimeter", neither
radio nor optical (IR).

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

[Profumo]

Peter Webb wrote:


She didnt say anything at all about this. Why are you "contending"
contenacity contumaciously?

[Paul Schlyter]

In article <1188490924.299814.37650@e9g2000prf.googlegroups.c om>,
laura halliday <marsgal42@hotmail.com> wrote:


Given today's CCD chips which indeed are electronic devices, does that
mean todays optical telescopes, with CCD chips which detect light
electronically, have become radio telescopes?

--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stockholm dot bostream dot se
WWW: http://stjarnhimlen.se/

[Paul Schlyter]

In article <sardd3d4g8vutoetbhl97eo7g1jbhidjd3@4ax.com>,
Chris L Peterson <clp@alumni.caltech.edu> wrote:


Or perhaps we could consider that wavelength band both "optical" and
"radio", since radiation at those wavelengths probably can be detected
both with radio and with optical equipment.

And if one wants to decide on some single wavelength limit between
"radio" and "optical", 0.3 millimeter appears to be a good choice
since it resides near the middle of this "submillimeter" band. This
corresponds to a frequency of one TeraHertz.

--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stockholm dot bostream dot se
WWW: http://stjarnhimlen.se/

[Dan Tilque]

Paul Schlyter wrote:


And in fact, e-m radiation at and around that frequency is often
called Terahertz radiation, or Terahertz waves, or T-rays, etc.
More specifically, from 300 GHz to 3 THz is the Terahertz band.
This terminology seems to be used more in non-astronomical
fields.

http://en.wikipedia.org/wiki/Terahertz

--
Dan Tilque

[Richard Tobin]

In article <fb8v7n$13it$1@merope.saaf.se>,
Paul Schlyter <pausch@saaf.se> wrote:


Seems logical to me. Anything above 316kHz is nearer to 1MHz than to
100kHz.

-- Richard

--
"Consideration shall be given to the need for as many as 32 characters
in some alphabets" - X3.4, 1963.

[Paul Schlyter]

In article <9uWdnfv33_LaQ0rbnZ2dnUVZ_jWdnZ2d@comcast.com>,
Dan Tilque <dtilque@comcast.net> wrote:

That's a little illogical. It's like considering a frequency slightly
above 300 kHz to belong to "the Megahertz band" ....




--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stockholm dot bostream dot se
WWW: http://stjarnhimlen.se/

[Paul Schlyter]

In article <fb903i$174t$1@pc-news.cogsci.ed.ac.uk>,
Richard Tobin <richard@cogsci.ed.ac.uk> wrote:

There's a difference between "the Megahertz band" and "the One Megahertz
band". The former can be interpreted as the band from 1 MHz to 1 GHz
for instance, instead of your interpretation from 0.316 to 3.16 MHz....



--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stockholm dot bostream dot se
WWW: http://stjarnhimlen.se/

[Chris L Peterson]

On Fri, 31 Aug 2007 12:13:05 GMT, pausch@saaf.se (Paul Schlyter) wrote:


No, it's _more_ logical. It's having arbitrary names for various regions
of the EM spectrum that isn't entirely logical.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

[BradGuth]

On Aug 30, 12:33 am, Radium <gluceg...@gmail.com> wrote:
For obtaining eye candy that's entirely outside of our physical reach,
and for the most part having been getting further away as we speak,
the 3.438 THz might be fine and dandy for accomplishing that spendy
look-see which can't possibly benefit humanity or that of our badly
failing environment.

Much above 0.1 THz is where such photons if transmitted from Earth
simply do not reflect unless the target offers a nifty array of
parabolic dishes, or of some other artificial reflective surface.
Outside of our magnetosphere, such as within our moon's L1, is where X
band of 8 ~ 12.5 GHz or possibly as great as Ka Band of 26.5 ~ 40 GHz
might become interesting and/or essential if future space travel is to
avoid those nasty bits and pieces of debris that'll otherwise clean
your clock upon encountering such, with C Band of 4 ~ 8 GHz being a
little better off for those slightly larger targets and perhaps best
of all S Band of 2 ~ 4 GHz offering a compromise that'll still yield
more than sufficient image resolution of a given planet or moon, along
with offering a darn good reflective signal to noise ratio.

However, if the potential target is the least bit intelligent worthy,
as many should be, as such why not use a blue~violet laser cannon, UV-
a, or possibly good old X-rays or even gamma ?

Though gravity can be directly measured, of what we can't manage thus
far is the two-way frequency applications of utilizing said
gravitons. Perhaps there again, the mutual gravity nullification zone
of our moon's L1 could allow for the limited use of gravitons, and
this alternative might become better yet once we've relocated that
moon to Earth's L1.
- Brad Guth