PHYS 005 Lecture Notes - Lecture 5: Film Speed, Focal Length, Orion Nebula
4 Jul 2018
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4/11 Session 5
Reading- Ch.6 Sect. 1,2,4,5
Artistic v. scientific pictures
Camera limitations
Atmospheric turbulence- high speed of winds makes video wobbly
Light pollution- prevent us from seeing 90% of the stars
●telescope around earth’s orbit to prevent those 2 limitations
Exposure time- amount of time light is absorbed into a camera
●Fractions of a sec.- 1/10, 1/100, 1/1000 etc
History of photography
Oldest existing photograph- several days of exposure
●Nicephore niepce- window at leGras 1826
Things from the camera obscura are flipped upside down
Light burned through different layers
●Existed well before 1936
○James Maxwell in 1855
○3 sep images through red/green/blue filters
■Put them together -> colored image from 1850
Astrophotography
● 1840 -20 min of exposure time
●1851 solar eclipse- 80 min
●1880- telescope taking pic
●1880- orion nebula
○3 yrs later- gas & stars become visible- 60 min exposure time
○1874- Venus- exact distance btw earth, sun, & planets
■Distance one of the most complicated things to get from astrophotography
More pixels= higher resolution- more details in the pics
●ccd= charged coupled devices
●CcD in cameras adopted by astronomy in the 1970s become part of our phones
●Collect different color lights sep
We convert the electronic detection into colors we can process
●***pics are not true colors from outer space- false colors
so that we can get what kind of light
are emitted fr star
Aperture- opening that allows u to capture what you want to see
●Eye-iris -> when there is a lot of light- low aperture
○dark-> dilated pupils to increase aperture & let more light in
Document Summary
Atmospheric turbulence- high speed of winds makes video wobbly. Light pollution- prevent us from seeing 90% of the stars. Telescope around earth"s orbit to prevent those 2 limitations. Exposure time- amount of time light is absorbed into a camera. Fractions of a sec. - 1/10, 1/100, 1/1000 etc. Things from the camera obscura are flipped upside down. Put them together -> colored image from 1850. 3 yrs later- gas & stars become visible- 60 min exposure time. 1874- venus- exact distance btw earth, sun, & planets. Distance one of the most complicated things to get from astrophotography. More pixels= higher resolution- more details in the pics. Ccd in cameras adopted by astronomy in the 1970s become part of our phones. We convert the electronic detection into colors we can process. ***pics are not true colors from outer space- false colors so that we can get what kind of light are emitted fr star.
