Refracting telescope
Galileo and the telescope: size limitations of a refrcting telescope
Reflecting telescope
Newton build this b/c he did not like chromtaic observation b/c the divergence of the lines
Cassegrainian
Galiero telescopes
Lowell Observatory 24'' Clark Reflector
Name after a company name clark. The man name Lowell and was independently wealthy. Built late 1800's and group of astronomers, to find the best spot in the southwest and put in Mexico. Was subject to significant sandstorm and was not good b/c of the [art
Lowell Observatory
made of steel, balance matter for a telescope, has two refractors, has a door to clean the lens, dome made out of cedar mode, take 24 wheel and hubcaps tires and put a small motor
Italian Astronomers
saw a channel on mars and got interpretative as canals.
Three types of reflectors
Casegrain, newtonian, coude telescope
Casegrain
The light hits the objective, then reflects off the the secondary mirror convex and goes the other way.
Newtonian
does not have a hole, light enters and hits the primary mirror and hits the focus secondary mirror
coude telescope
hits the primary mirror and hit the focus and hits secondary mirror
lowell Mesa 72" Perkins reflector
72" objectives,
Ranging the moon McDonald Observatory
Any light that that hit reflect it back to know the distance from the moon. The moon is moving away from the Earth
200 Inch hale telescope
Many years the largest b/c of the objective diameters. Made a second one b/c it did not have balance
Keck telescope
interferometer and is the world largest binoculars and 10 meters in diameter. They can independently work or as a interferometer. Keck died and lend his fund which was 80 million dollars.
Mirrors of Keck telescope pg 7
has 36 mirrors and call adaptive optics
Gemini North Mauna Kea
hole
Multiple mirror whipple observatory
gather all 6 mirrors and has a objective diameter of 24 feet. Stuart optics did not like it and put a 6meter mirror. They took of the six to the navy.
140 foot Green bank close
Radio telescope, National Radio observatory in west virginia
Byrd 100-m Green Bank 8/00
fhjd
Arise space and earth radio
orbiting telescope
Hubble st
1970s and had problems. The image was fuzzy. They test each telescope and did not have the money to do it as a whole. The big hubble pass the razor test and eventually found out that the razor tester did it incorrectly by a size of human hair. They took a
More orbiting Telescopes
Spitzer (IR)
Chandra (x ray)
Cobe (Microwave Background)
GRO (gamma)
Spitzer telescope
Sheild keeps cool
Chandra (x ray telescope)
pg 14
Cobe
Measure and looking microwave for the big bang . It has to be shielded from the sun. It has to be a refrigerator of heluim and detect radiation.
Gamma ray observatory
They are penetrative and two gamma ray detector
SOFIA
Stratospheric Observatory For Infrared Astronomy
Piper did the discovery of the ring around Uranus. Infared detecting telescope
Light Pollution: A problem
problem of major observatory
La circa Recent times
the lights affect the astronomers which goes up to clouds
Functions of Astronomical Telescopes
Light gathering Power most important
Resolving Power less important
Magnifyinh Power No importance
Light gathering power
Measure of how many photons are collected by the telescope. The most important function. LGP=25d^2
diameter=diameter of objective in inches
Resolving Power
A measure of the smallest detail which can be seen with a telescope of a certain objective diameter. The number shows the number of the smallest telescopes. Measure in seconds of arc. RP=4.6/d. Theoretical number b/c the atmosphere affect it. Magnificatio
Medium
stays in the transfer wave
Regular reflection
requires smooth surface
How the magnitude system works
the magnitude difference of exponents
Magnitudes of Stars
...
Apparent magnitude
...
Absolute magnitude
The magnitude of star if it was moved a distance.