CCD Imaging

Image Reduction – Overview

Image processing goes through pre-processing (calibrating images using darks, biases, and flat-fields) and post-processing (When images are digitally reduced: WCS Coordinates, removal of Cosmic Rays, Transformed, etc)

CCD Imaging


Airmass is the path length for light from an astronomical object to pass through the Earth’s Atmosphere, and a greater airmass means dimmer targets


Stellar Motions

Stellar motions divide star movement into three categories: radial motion, proper motion, and a combination of the two (space motion).


Celestial Coordinates

Similar to latitude and longitude, Right Ascension and Declination define the celestial coordinate system used to locate and place celestial objects.


Instrumental Magnitude

Instrumental magnitude is derived from the raw counts of a CCD image, and can be combined with other measurements to achieve both apparent and absolute magnitude.


Luminosity, Temperature and Radius

By utilizing the Stefan-Boltzmann Law and the basic properties of a sphere's surface area, a star's luminosity, temperature, and radius can be mathematically related and thus used to calculate each other.


Why Study Variable Stars

From measuring the distances to galaxies to discovering new planets, studying variable stars allows us to refine our current understanding of astrophysics and get to the heart of how our universe works.



The Landolt catalog has become the de facto standard for transforming to the UBVR CIC system, and place photometric observations on a common platform.