Blog

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

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

Stars

Stellar Motions

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

Stars

Celestial Coordinates

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

Stars

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.

Stars

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.

Overview

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.

Photometry

Landolt

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

Photometry

Standard Photometric Stars

Photometric-standard stars are stars that have had their light output in various passbands of photometric system measured very carefully. They provide a means to not only calibrate your photometric system, but give a common “yardstick” from which all measurements can be compared.