> Winfield Hill wrote:
>> John Larkin wrote...
>>>
>>> On Thu, 11 Apr 2019, George Herold wrote:
>>>
>>>> My son shared this video by Vertasium on the black hole pic,
>>>> https://www.youtube.com/watch?v=zUyH3XhpLTo
>>>>
>>>> https://www.youtube.com/watch?v=S_GVbuddri8
>>>
>>> It's always hard to tell real pictures from animations
>>> and "artists conceptions." There should be a convention
>>> to identify unreal images.
>>
>> These images have been called pictures, i.e., photographs,
>> and I think that's a fair name. They're created from a
>> 200GHz, "telescope" with a diameter of the whole earth.
>> Made from data from multiple simultaneous radio telescope
>> images, in perfect phase synchronization. The more you
>> read about it, the more you'll agree this is a real image.
>
> Is it feasible to get more optical resolution with an array of Hubbles?
Only if you can combine them coherently - which is very difficult.
Michelson & Pease did the very first true optical interferometry back in
the 1920's on Mount Wilson - measuring stellar diameters of red giants.
It required Michelson's genius level experimental flair to make it work.
Keck can be configured to operate as an optical interferometer and
several prototypes like COAST and ALMA and MRO can do it in near IR.
https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA04493http://www.mro.nmt.edu/about-mro/interferometer-mroi/
> Would the light have to be brought into phase to make that work? It's
> surprising they could do that even at 1.5mm.
Essentially yes at least to within a sufficiently short time delay to be
able to detect interference fringes at the bandwidth being used. The
really tedious part is finding those fringes when the raw data is
brought together from the disparate antennas to the offline correlators.
There are a couple of get out of jail free cards whereby with 3 or more
antennas you can get uncorrupted phase information about the sky even in
the presence of bad atmospheric interference called closure phase. Four
or more antenna gives you closure amplitudes as well. These are good
observables that depend only on what the sky looks like and the geometry
of the interferometers making the measurements.
One reason that VLBI can be damaging to instruments is that dropping
from N to N-1 antennae loses a lot of information so the big scopes try
to stay on track even when storms are approaching. Sometimes they get
caught out and are unable to stow the thing safely so take storm damage.
--
Regards,
Martin Brown
Reply by ●April 22, 20192019-04-22
Nauga <popop@gemail.com> wrote in news:q9kkjk$1g42$1@gioia.aioe.org:
>> I wanna keep it forever, not lose it forever. I may get it
>> sliced in half to make two pool stick inlays out of.
>
> I think it would gum up the saw.
Like your mother gummed up the world with you?
It is a rock, dipshit.
I know where and how to get it sliced. Rocks do not exhibit saw
blade gumming issues.
The glue only comes in after to attach it to the inlay position.
How to you chumps get so damned convoluted?
Reply by Nauga●April 22, 20192019-04-22
On 04/21/2019 11:01 AM, DecadentLinuxUserNumeroUno@decadence.org wrote:
>>> Maybe I should post a pic of it.
>>>
>>> Sounds like it'd be perfect to skip into a pond.:-)
>>>
>>>
> I wanna keep it forever, not lose it forever. I may get it sliced in
> half to make two pool stick inlays out of.
> On Sun, 21 Apr 2019 18:01:14 +0000 (UTC),
> DecadentLinuxUserNumeroUno@decadence.org wrote:
>
>> Winfield Hill <hill@rowland.harvard.edu> wrote in
>> news:q9i8dk02r5h@drn.newsguy.com:
>>
>>> DecadentLinuxUserNumeroUno@decadence.org wrote...
>>>>
>>>> I have a rock in my pocket which I found among some aggregate
>>>> while walking one day. It looks like it took a very long time to
>>>> get as smooth as it has, and it is so thin, it is rare for one
>>>> to last that long being that thin. I keep it as a 'luck charm'.
>>>> I figure it was part of a glacial flow that may have lasted
>>>> thousands of years many thousands of years ago. Must be really
>>>> hard media too. Maybe I should post a pic of it.
>>>
>>> Sounds like it'd be perfect to skip into a pond. :-)
>>>
>>>
>>
>> I wanna keep it forever, not lose it forever. I may get it sliced
>> in half to make two pool stick inlays out of.
>>
>> Gorilla Glue to the rescue!
>
> I hate that stuff. If a tiny bit gets on your fingers, you may as well
> cut them off. Ditto a tiny spec on a sink or on a workbench.
>
> A glue gun and some epoxy is all a Real Man needs.
>
> Well, maybe some wood glue too.
>
>
I repaired a frost damaged concrete planter a couple of weeks ago. GG
was exactly the right medicine for damp friable concrete.
Agreed about the finger issue though. I expect barrier cream might
help--certainly a bit of olive oil keeps your fingers separate till the
glue sets up. ;)
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.nethttp://hobbs-eo.com
Reply by Phil Hobbs●April 22, 20192019-04-22
On 4/21/19 11:29 AM, Tom Del Rosso wrote:
> Winfield Hill wrote:
>> John Larkin wrote...
>>>
>>> On Thu, 11 Apr 2019, George Herold wrote:
>>>
>>>> My son shared this video by Vertasium on the black hole pic,
>>>> https://www.youtube.com/watch?v=zUyH3XhpLTo
>>>>
>>>> https://www.youtube.com/watch?v=S_GVbuddri8
>>>
>>> It's always hard to tell real pictures from animations
>>> and "artists conceptions." There should be a convention
>>> to identify unreal images.
>>
>> These images have been called pictures, i.e., photographs,
>> and I think that's a fair name. They're created from a
>> 200GHz, "telescope" with a diameter of the whole earth.
>> Made from data from multiple simultaneous radio telescope
>> images, in perfect phase synchronization. The more you
>> read about it, the more you'll agree this is a real image.
>
> Is it feasible to get more optical resolution with an array of Hubbles?
>
> Would the light have to be brought into phase to make that work? It's
> surprising they could do that even at 1.5mm.
There are large-scale ground-based interferometric optical telescopes
today. They have to use a lot of adaptive optics to control for the
soupy atmosphere, and special care is needed to get the delays correct.
See e.g.
<https://www.eso.org/public/usa/teles-instr/technology/interferometry/>.
It gets harder at shorter wavelengths, of course.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.nethttp://hobbs-eo.com
Reply by Phil Hobbs●April 22, 20192019-04-22
On 4/21/19 11:22 AM, Tom Del Rosso wrote:
> John Larkin wrote:
>> On Sat, 13 Apr 2019 12:42:25 -0000 (UTC), Cursitor Doom
>> <curd@notformail.com> wrote:
>>
>>> On Fri, 12 Apr 2019 22:09:43 -0700, John Larkin wrote:
>>>
>>>> Einstein was right even when he thought he was wrong.
>>>
>>> Be interesting to know what E. would have made of the more recent
>>> discovery regarding the increasing rate of expansion. I'm guessing
>>> that would have clusterfucked even *his* brain.
>>
>> He derived the concepts of black holes and stimulated emission, then
>> wrongly assumed that bh's would not actually exist and that lasers
>> were thermodynamically forbidden [1]. He probably got the cosmological
>> constant idea wrong+right.
>>
>> [1] as did most eminent scientists.
>
> So was it thought that getting the photons in phase would require a kind
> of demon?
AIUI it was more of an in-the-box thinking problem. For a thermal
system *in equilibrium*, in the limit T->infinity all the level
populations are equal, so there's no finite temperature that will get
you a population inversion.
However of course it's easy to make non-equilibrium systems.
Until the 1950s it was thought that you couldn't make fringes using
light from different sources, either. That was one of those "settled
science, 99% of physicists agree" things that turned out to rest on an
incorrect interpretation of quantum mechanics. (Not on the math--that
ridiculous Copenhagen thing again.)
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.nethttp://hobbs-eo.com
Reply by ●April 21, 20192019-04-21
upsidedown@downunder.com wrote in
news:ko1qbepn4rn0e3j8giiv3cd5bms7os3v07@4ax.com:
>
> It is done at least between two nearby telescopes at least in
> near-IR. One problem is the different atmospheric disturbances
> between the telescopes.
>
One reason hundreds of images are used to compile into one.
In space, the clarity would be a huge boost.
Pretty soon, we should be seeing some JWST images.
However The JWST is far bigger than Hubble is.
Earth is not good for IR observation spaceward.
Better directly from space.
Plenty of birds up there already.
<https://en.wikipedia.org/wiki/James_Webb_Space_Telescope>
Reply by ●April 21, 20192019-04-21
upsidedown@downunder.com wrote in
news:ko1qbepn4rn0e3j8giiv3cd5bms7os3v07@4ax.com:
> It should be easy if multiple 2,5 m space mirrors are connected to
> the same rigid structure which follow the target.
>
No. Does not have to be tied together. Only needs to point at and
view target from those separated points.
Have you seen those cameras that take a single picture but can be set
to multiple focal points after the shot is 'created'?
Think of them as rods and cones of a retina. Exept each of these
carries more than a single element. Not a lot though. At a high
separation each telescope will represent less pixels each, but more on
the final.
It is like watching a nearly blind guy look at his watch. He has to
wiggle around the image and his eye to get rods and cone illuminated
with the image he wants, because he has to peer around his cataracts.
Reply by ●April 21, 20192019-04-21
On Sun, 21 Apr 2019 11:29:06 -0400, "Tom Del Rosso"
<fizzbintuesday@that-google-mail-domain.com> wrote:
>Winfield Hill wrote:
>> John Larkin wrote...
>>>
>>> On Thu, 11 Apr 2019, George Herold wrote:
>>>
>>>> My son shared this video by Vertasium on the black hole pic,
>>>> https://www.youtube.com/watch?v=zUyH3XhpLTo
>>>>
>>>> https://www.youtube.com/watch?v=S_GVbuddri8
>>>
>>> It's always hard to tell real pictures from animations
>>> and "artists conceptions." There should be a convention
>>> to identify unreal images.
>>
>> These images have been called pictures, i.e., photographs,
>> and I think that's a fair name. They're created from a
>> 200GHz, "telescope" with a diameter of the whole earth.
>> Made from data from multiple simultaneous radio telescope
>> images, in perfect phase synchronization. The more you
>> read about it, the more you'll agree this is a real image.
>
>Is it feasible to get more optical resolution with an array of Hubbles?
It should be easy if multiple 2,5 m space mirrors are connected to the
same rigid structure which follow the target.
>Would the light have to be brought into phase to make that work? It's
>surprising they could do that even at 1.5mm.
It is done at least between two nearby telescopes at least in near-IR.
One problem is the different atmospheric disturbances between the
telescopes.
Reply by ●April 21, 20192019-04-21
John Larkin <jjlarkin@highlandtechnology.com> wrote in
news:oikpbeljp2bhm5g2h1ns6gqth3u88dsgq9@4ax.com:
> On Sun, 21 Apr 2019 18:01:14 +0000 (UTC),
> DecadentLinuxUserNumeroUno@decadence.org wrote:
>
>>Winfield Hill <hill@rowland.harvard.edu> wrote in
>>news:q9i8dk02r5h@drn.newsguy.com:
>>
>>> DecadentLinuxUserNumeroUno@decadence.org wrote...
>>>>
>>>> I have a rock in my pocket which I found among some aggregate
>>>> while walking one day. It looks like it took a very long time
>>>> to get as smooth as it has, and it is so thin, it is rare for
>>>> one to last that long being that thin. I keep it as a 'luck
>>>> charm'. I figure it was part of a glacial flow that may have
>>>> lasted thousands of years many thousands of years ago. Must be
>>>> really hard media too. Maybe I should post a pic of it.
>>>
>>> Sounds like it'd be perfect to skip into a pond. :-)
>>>
>>>
>>
>> I wanna keep it forever, not lose it forever. I may get it
>> sliced
>>in half to make two pool stick inlays out of.
>>
>> Gorilla Glue to the rescue!
>
> I hate that stuff. If a tiny bit gets on your fingers, you may as
> well cut them off. Ditto a tiny spec on a sink or on a workbench.
>
> A glue gun and some epoxy is all a Real Man needs.
>
> Well, maybe some wood glue too.
>
>
Shoe Goo is a goof one too! Excellent, in fact, for clear jobs.