How long until....

They produce something for astronomy with a liquid lens?
This technology seems about to take off for cameras.
Maybe eyepieces with tunable characteristics that would
allow them to be a better match to whatever scope they
are being used with?

On 12 Nov 2004 22:53:19 GMT, (Rod Mollise) wrote:


They produce something for astronomy with a liquid lens?

Hi Rich:

I don't know.

What do _I_ wonder about? Why a man with your incredible wealth of experience
doesn't choose to make a real contribution to this group, which you could, and
which would be both valued and appreciated. ;-(

Sorry, are you labouring under the impression that this group is your
yahoo group? But please, why don't YOU describe what constitutes
acceptable subjects for this one? I'll probably ignore it, but I'd
like to hear.
-Rich

"RichA" wrote in message
...
On 12 Nov 2004 22:53:19 GMT, (Rod Mollise) wrote:


They produce something for astronomy with a liquid lens?

Hi Rich:

I don't know.

What do _I_ wonder about? Why a man with your incredible wealth of
experience
doesn't choose to make a real contribution to this group, which you
could, and
which would be both valued and appreciated. ;-(

Sorry, are you labouring under the impression that this group is your
yahoo group? But please, why don't YOU describe what constitutes
acceptable subjects for this one? I'll probably ignore it, but I'd
like to hear.

Rich,

You are pretty much spewing, seemingly posting any little thing that pops
into your head. When it first started, I wondered "what the heck happened
to Rich?"

Clear skies, Alan

On Sat, 13 Nov 2004 02:46:56 GMT, "Alan French"
wrote:

"RichA" wrote in message
.. .
On 12 Nov 2004 22:53:19 GMT, (Rod Mollise) wrote:


They produce something for astronomy with a liquid lens?

Hi Rich:

I don't know.

What do _I_ wonder about? Why a man with your incredible wealth of
experience
doesn't choose to make a real contribution to this group, which you
could, and
which would be both valued and appreciated. ;-(

Sorry, are you labouring under the impression that this group is your
yahoo group? But please, why don't YOU describe what constitutes
acceptable subjects for this one? I'll probably ignore it, but I'd
like to hear.

Rich,

You are pretty much spewing, seemingly posting any little thing that pops
into your head. When it first started, I wondered "what the heck happened
to Rich?"

Clear skies, Alan

Unreal. The post concerned liquid lenses and for some reason, it has
absolutely NO merit in this forum, even though liquid lenses have been
shown to be better than diffraction limited and could very well have
applications for the hobby. My suggestion? If people want very
narrowly-defined subjects, catering only to their interests or what
they perceive as being "on topic" or informative, then they should
form their own moderated group and tightly control the subject matter.
There are plenty of venues that allow this.
-Rich

"RichA" wrote in message
...

Unreal. The post concerned liquid lenses and for some reason, it has
absolutely NO merit in this forum, even though liquid lenses have been
shown to be better than diffraction limited and could very well have
applications for the hobby. My suggestion? If people want very
narrowly-defined subjects, catering only to their interests or what
they perceive as being "on topic" or informative, then they should
form their own moderated group and tightly control the subject matter.
There are plenty of venues that allow this.

Rich,

No one said anything about moderating the forum. The liquid lens discussion
is only one of many you have posted lately, and was actually one of the more
reasonable topics. But you've had a lot along the lines of "What if
refractors were painted yellow instead of white?"

Clear skies, Alan

On Fri, 12 Nov 2004 22:01:27 -0500, RichA wrote:

Unreal. The post concerned liquid lenses and for some reason, it has
absolutely NO merit in this forum, even though liquid lenses have been
shown to be better than diffraction limited and could very well have
applications for the hobby...

Do you have a reference here? I fail to see how any lens can be "better than
diffraction limited" since diffraction is what ultimately defines the
theoretical performance of any optics.

_________________________________________________

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

Unreal. The post concerned liquid lenses and for some reason, it has
absolutely NO merit in this forum, even though liquid lenses have been
shown to be better than diffraction limited and could very well have
applications for the hobby.

I'll play. Sounds interesting:
http://www.space.com/scienceastronom...or_000924.html

"By a happy accident of physics, a spinning liquid forces its surface into the
perfect shape for a telescope mirror. Capitalizing on this, scientists at the
University of British Columbia (UBC) have built a 236-inch (6-meter) Liquid
Mirror Telescope, or LMT, set to capture its "first light" later this summer...
It collects starlight with a plate of mercury 6 meters across spinning at about
5 rotations per minute.
The UBC's telescope costs about $1 million. A conventional telescope with a
regular solid glass mirror of the same size would require an outlay of about
$100 million. A large part of the savings comes from not making, polishing,
testing and mounting a standard mirror....
The concept of LMTs can be mapped back to the 18th century. Experiments that
utilized the concept were conducted in the 1800s and the early 1900s, but the
results were disappointing.
The concept was sound, but the technology available was too crude to make it
work...
Vibrations from the ground around the telescope made image-smearing waves in
the mercury. To achieve sharp images, the focal plane must not move. This
requires the rotation of the vessel holding the mercury to vary less than one
part in 100,000 during the exposure..."

Rich Anderson wrote:
Unreal. The post concerned liquid lenses and for some reason, it has
absolutely NO merit in this forum, even though liquid lenses have been
shown to be better than diffraction limited and could very well have
applications for the hobby.

What on earth does "better than diffraction limited" mean? By definition,
diffraction limits everything. The fact that diffraction imposes a less
stringent limit on larger apertures than it does on smaller apertures
doesn't change that.

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

...even though liquid lenses have been
shown to be better than diffraction limited

Wouldn't 'not-diffraction-limited' be the only thing better?
Still sounds like they put out some killer images:
http://www.physicstoday.org/vol-57/iss-7/p82a.html

SSX

On 13 Nov 2004 03:58:16 GMT, (SaberScorpX) wrote:

"By a happy accident of physics, a spinning liquid forces its surface into the
perfect shape for a telescope mirror. Capitalizing on this, scientists at the
University of British Columbia (UBC) have built a 236-inch (6-meter) Liquid
Mirror Telescope, or LMT, set to capture its "first light" later this summer...
It collects starlight with a plate of mercury 6 meters across spinning at about
5 rotations per minute...

This system has been running for years. As a practical matter, it is limited to
imaging the zenith.

_________________________________________________

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