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Class introduction
ASTRONOMY 535
OBSERVATIONAL TECHNIQUES
CLASS NOTES
Fall 2021
Instructor: Jon Holtzman
Class introduction
Light, magnitudes, and the signal equation
Light
Magnitudes and photometric systems
Colors
Magnitude-flux conversion
Observed fluxes, the signal equation, and photometry
Photometry
Uncertainties and error analysis
Distributions and characteristics thereof
The binomial distribution
The Poisson distribution
The normal, or Gaussian, distribution
Importance of error distribution analysis
Confidence levels
Noise equation: how do we predict expected uncertainties?
Signal-to-noise
Background noise
Instrumental noise
Error propagation
Distribution of resultant uncertainties
Determining sample parameters: averaging measurements
Weighted mean of a series of exposures
Can you split exposures?
Random errors vs systematic errors
Observing principles and tools
Time systems
Solar time
Sidereal time
Calendars
Coordinate systems
Celestial coordinate systems
Local coordinate systems
Finding positions of celestial objects
Orientations of objects in the sky
Observability
Tools
Using telescopes
Plannning observing
Digital imaging and display
Image display
Spatial resolution
Dynamic range: brightness and contrast
nonlinear scalings
color maps and pseudocolor
true color images
other display functions
Standalone display tools
Digital imaging file formats
Gain and readout noise
Digitization
Determining gain and readout noise
Basic data reduction
Effects of the earth's atmosphere
Night sky emission
Transmission of atmosphere
Sources of extinction
Airmass and zenith distance dependence
Atmospheric refraction
Seeing: theory and practice
Other sources of seeing
What does seeing cause the image to look like?
Astronomical optics and telescopes
Single surface optics and definitions
Multi-surface systems
a lens (has two surfaces)
plane-parallel plate
Two-mirror telescopes:
Definitions for multi-surface system: stops and pupils
Telescope technology
Large mirror types
Mirror coatings
Telescope mounts
Aberrations
Surface requirements for unaberrated images
Aberrations: general description and low-order aberrations
Aberration compensation and different telescope types
Sources of aberrations
Ray tracing
Physical (diffraction) optics
Adaptive Optics
AO Examples
INSTRUMENTATION
Location of optics
Refractive optics and chromatic aberration
Field Flatteners
Focal plane reimagers
Pupil reimagers
Filters
Fabry-Perot Interferometer
Spectrographs
Astronomical spectrographs
Dispersing elements
Operational items: using a spectrograph
Non-dispersive spectroscopy
Detectors
Basic Principles and Properties
Digitization
Dynamic range
Determining gain and readout noise
CCDs
CMOS detectors
IR detectors
UV and other detectors
Data Reduction: details and subtleties
Data reduction steps
Bias level subtraction
Bias structure subtraction
Linearity correction
Dark current subtraction
Preflash subtraction, or deferred charge correction
Shutter shading correction
Flat fielding
Spectroscopic data reduction
Calibration product considerations
Modern data reduction pipelines
