CCD Equipment Basics

Understanding Image Scale and Field of View

When it comes to telescopes for visual observation, bigger is better: a larger aperture will gather more light and the observer will see more at the eyepiece.  For CCD imaging, on the other hand, aperture is less important.  What really matters is focal ratio.  The focal ratio determines how much light is picked up by the… More »

Imaging Accessories

Below are the most common accessories used by beginning CCD imagers to make life under the stars a little easier. Dew Shields and Heaters Moisture forming on the front lens of a Schmidt-Cassegrain telescope can easily ruin a CCD imaging session (or even visual observation, for that matter).  A dew shield fits onto the front… More »

Video Cameras

There are two types of video cameras for astrophotography. The first is planetary cameras, used for imaging solar system objects at high frame rates. The other are deep-sky video cameras, which integrate longer exposures to give a “real time” view of deep sky objects. Planetary Video Cameras Above: Typical planetary imaging camera, the Celestron Skyris… More »

Imaging Mounts

A sturdy mount is obviously important for visual observing–the lack of a quality mount is a primary complaint about cheap telescopes–but for astrophotography, the mount is every bit as important as the telescope itself.  The mount’s ability to hold the telescope steady during a long exposure (and in breezy conditions), as well as the tracking… More »

Imaging with other Telescope Designs

Other Telescope Designs While the Schmidt-Cassegrain, Newtonian, and refractor are the most common optical designs used for CCD imaging and observing in general, other types are becoming increasingly popular. Classical Cassegrain Above:  Optical layout of a Classical Cassegrain telescope The Classical Cassegrain is actually a fairly uncommon type of telescope, but we discuss it since… More »

Imaging with a SCT

Probably the most popular telescope design is the Schmidt-Cassegrain telescope (SCT).  The SCT is a versatile design, good for both imaging and visual observation.  It is compact for portability and ease of use, and is relatively inexpensive compared to other systems. SCTs offer the most versatility. They are good for visual observing, deep-sky photography and planetary… More »

Imaging with a Newtonian

The modern theory of optics is due in great part to Isaac Newton.  Much has been written about the fantastic achievements of Newton, but it was a misconception of his that led to his greatest astronomical invention.  While studying refracting telescope lenses, Newton came to the conclusion that it would be impossible to design a… More »

Imaging with a Refractor

The refractor is the oldest telescope design.  It is by far the most familiar design (it’s what Galileo used in the 17th Century, and it’s what Marvin the Martian used in the cartoons).  Refractors have been used to produce some of the most stunning wide-field amateur astrophotos ever taken. Above:  The optical layout of a… More »

Choosing the Right Camera

There are many options to consider when choosing a CCD camera, but usually there are a couple majors factors which can make the decision easier. Admittedly cost is one of the most important factors, but there can be a variety of cameras available within your price range. Matching a CCD camera to a particular telescope… More »