home observation science solar system stars our galaxy cosmology astrobiology exoplanets astrophotography
icon Introduction
icon Astronomy Tools
1. Electromagnetic Spectrum
2. Atmosphere Limitations
3. Space Observations
1. Telescopes
2. Radio
3. Space Tools
4. Photography
5. Spectroscopy
6. Computers
7. Advanced Methods
8. Radio Astronomy
icon Basic Mathematics
Scientific Notation
Log Scales
icon Physics
- Basic Units of Measure
- Mass & Density
- Temperature
- Velocity & Acceleration
- Force, Pressure & Energy
- Atoms
- Quantum Physics
- Nature of Light
- Brightness
- Cepheid Rulers
- Distance
- Doppler Shift
- Frequency & Wavelength
- Hubble's Law
- Inverse Square Law
- Kinetic Energy
- Luminosity
- Magnitudes
- Convert Mass to Energy
- Kepler & Newton - Orbits
- Parallax
- Planck's Law
- Relativistic Redshift
- Relativity
- Schwarzschild Radius 
- Synodic & Sidereal Periods
- Sidereal Time
- Small Angle Formula
- Stellar Properties 
- Stephan-Boltzmann Law
- Telescope Related
- Temperature
- Tidal Forces
- Wien's Law
icon Computer Models
icon Additional Resources
1. Advanced Topics
2. Guest Contributions
Astronomy Tools - Photography

An in depth look at astrophotography has been left to the dedicated section Astrophotography. This section briefly introduces why we use photography in Astronomy.

There are many important tools in Astronomy, but nothing is more valuable than a camera - in the case of the late 20th and beyond the CCD is invaluable. It all comes down to what our eyes can perceive. Our eyes are great for day to day activity, but to scrutinize faint object looking through a telescope, our eyes are the last choice. Our sensory retina is just not designed for such tasks.

Gaseous appearance of nebula and galaxies are evident when viewing with the eye, but chances are the image will be mono-chromatic - one color. The larger the telescope, the discerning a particular object may be, but the vivid color is just not there. All of the pretty Hubble images or images in magazines of celestial objects are captured via long period exposures.

There are basically two methods of photography today: film and CCD. Film based photography reigned supreme in regards to field of view. The CCD chips in the early days covered may a few degrees of sky at one time while plate film covered as much as 14 degrees at one time. As CCD's grew larger, cheaper, and better, CCD's have proven to be the workhorse for astrophotography. The reasons are simple:

  • CCD's (Charged Coupled Devices) are linear in response - meaning that twice the exposure means twice the signal; film is not
  • There are no chemicals required
  • CCD image is ready almost immediately, film must be developed (and sometimes the image may not be what was intended)
  • CCD's store numerical data so numerous data analysis can be performed without damage to the original; film could be scanned, but that uses pricey drum scanners

CCD's are not without their share of problems - computer error, heat, noise - but most of these errors can be removed by data reduction methods. The Astrophotography Advanced Topics has a project paper I wrote that uses these data reduction techniques.

Back to Top

Search | Site Map | Appendix
©2004 - 2024 Astronomy Online. All rights reserved. Contact Us. Legal. Creative Commons License
The works within is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.