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Notes on video lecture:
The Nature of Images
Choose from these words to fill the blanks below:
day, photographs, teeming, cosmic, daguerreotypes, light, second, intervals, obtaining, register, radiation, energy, eerie, three, astronomical, light, inundated, moon, second, red, models, photons, darker, blue, output, visual, tungsten, useful, problematical, Daguerre, photographic
images
we are                    with images in our daily lives
enticing us to buy products
to remind us of an event
to please our artistic tastes
photographs
it's hard to imagine a time when people didn't have                       
1840
people were astonished to find that they could capture a              image of a moment in time in the minutest detail far surpassing any method that had ever come before
the first                              were called "the mirror with a memory"
photographs in astronomy
photographic images of one kind or another constitute almost the sole means of analyzing                          objects
it therefore behooves us to understand exactly what is involved in                    these images, how we perceive them, and what they can tell us
earliest photographs of astronomical objects
1851: the         
some of the early photos of the 19th century were distinctly           
street scene taken by Louis                  in 1838 of the Boulevard du Temple
a street always                with people and horse-drawn carriages
yet no one is to be seen except for a tiny figure at the lower left who is getting his shoes shined and was thus motionless for long enough to have his image appear on the                          plate
every other moving object could not                  on it
thus began a quest still with us today for speed, speed, and more speed so that we can capture progressively shorter and shorter time                    in our cameras, our telescopes and even out iPhones to be more and more sensitive to           
when they do become more sensitive, we can acquire an image in less time and we say we have increased the temporal resolution of observation.
today we can capture in 1/10000th of a              what took Daguerre hours to register on his camera
we cannot only record the        a photograph is taken
but we can time-tag each individual packet of light as they are received into our instruments
we call these packets of light               
these photons are the providers of almost all of our astronomical data
each photon provides
1. time of arrival
this allows us to see if the object we are looking at is changing its intensity or light              as a function of time
we can search for time variability of              sources
2. spatial position that each photon came from
how clear the image is
in color photographs we have energy information
blue light is more energetic than        light
x-rays are more energetic than          light
but black and white representations of objects can be more              than colored ones
e.g. you can see which parts are              than others
any representation of an x-ray source is going to be a bit                           
3. energy spectrum
the energy of each photon
how many photons of each energy gets emitted per             
a vital fingerprint for understanding the chemical composition of astronomical objects
give insights into the energy producing mechanisms governing their                   
just as florescent lamps work differently than                  light bulbs
so do cosmic sources have different ways to produce their             
therefore the energy spectrum can tell us what the object is made of and how it produces its           
and that's it, all we can glean from tiny pinpoints of light coming from distant light scattered about the universe are these            bits of data encoded into each photon
from these data we can construct              to understand the diverse inhabitants of the cosmos

Vocabulary:

daguerreotype, n. the first publicly announced photographic process and the first to come into widespread use during the early 1840s  ""The mind with a memory" are what the first daguerreotypes were called."

People:

John Adams Whipple (1822-1891)
Early American photographer who pioneered astronomical and night photography known for his extraordinary early photographs of the moon
  • first in the United States to manufacture the chemicals used for daguerreotypes
  • first to produce images of stars other than the sun (Vega and Mizar-Alcor stellar system)

Spelling Corrections:

inticingenticing

Ideas and Concepts:

Via this afternoon's Analyzing the Universe class: "Since photographic images of one kind or another constitute almost the sole means of analyzing astronomical objects, it behooves us to understand exactly what is involved in obtaining these images, how we perceive them, and what they can tell us."
On the last two centuries of increasing temporal resolution of observation, via this afternoon's Analyzing the Universe class:

"Some of the early photographs of the 19th century were distinctly eerie. For example, this street scene taken by Louis Daguerre in 1838 of the Boulevard du Temple in Paris shows a street that was always teeming with people and horse-drawn carriages, yet in the image no one is to be seen. However, if you look closely in the lower left-hand corner, you'll see a tiny figure who is getting his shoes shined, and was thus motionless for long enough to have his image appear on the photographic plate. Every other moving object could not register on it.

Thus began a quest still with us today for speed, speed, and more speed so that we can capture progressively shorter and shorter time intervals in our cameras, our telescopes, and even out smart phones. As these devices become more and more sensitive to light so that we can acquire an image in less time, we say we have increased the "temporal resolution of observation". Today we have reduced the temporal resolution of observation down to a point that we can record in 10000th of a second what took Deguerre hours to register on his camera."
On our limited source of data to study the cosmos, via this morning's Analyzing the Universe class:

"From the millions of tiny pinpoints of light scattered about the universe, we are only able to glean three bits of data encoded into each photon that reaches us:

1. TIME OF ARRIVAL:the changing intensity of light output as a function of time

2. SPATIAL POSITION:where exactly the photons come from

3. ENERGY CONTENT:how many photons of each type of energy gets emitted per second, a vital fingerprint for understanding the chemical composition of astronomical objects, since just as florescent lamps work differently than tungsten light bulbs, cosmic sources have different ways to produce their energy and the energy spectrum can tell us what the object is made of and how it produces its light

And that's it, these three bits of data are all we have to construct models that explain the diverse inhabitants of the distant cosmos."
On the difference between the words "cosmos" and "universe", via this morning's Analyzing the Universe class: "There's very little actually. Cosmos means "the universe seen as a well-ordered whole" and universe means "all existing matter and space considered as a whole, or the cosmos." The words can often be used synonymously, or you can use cosmos explicitly when you are referring to the well-ordered aspect of the universe. In addition, "cosmological" is used as the technical adjective, e.g. "cosmological redshift", since the adjective "universal" is often used in non-technical contexts and so a term such as "universal redshift" would be confusing."
The Nature of Images
Image Formation
Capturing Images of X-Ray Sources from Space