CCD Imaging

Bad Image Examples

This lesson provides multiple examples of poor-quality images and explains both the reasoning behind the results and some of the specific cases in which they may still be of use.

CCD Imaging


Seeing is an important concept that describes how clear an image's subject is when viewed through the Earth's atmosphere.

Astro Catalogs

AAVSO Areas of Interest

The American Association of Variable Star Observers (AAVSO) serves as a dedicated research and outreach organization that allows both professionals and amateurs contribute to the vast and dynamic field of variable star research in countless unique ways.



The AAVSO Photometric All-Sky Survey (APASS) is a key all-sky survey that helps various research programs measure, adjust, and standardize their photometric systems.


Point Spread Function (PSF)

Point Spread Function (PSF) uses known optical behaviors of both stellar light and the imaging system to decrease the complexity of images and create visual separation between objects for more accurate study.


Aperture Photometry

Aperture Photometry, key to all studies in photometry, is one of the two most common methods of measuring the flux output of a star and is the most accurate when used with non-crowded images.