Telescope Camera | Universe Today

Written by Tammy Plotner

What is a telescope camera? That's a good question! There are telescopes that are cameras and there are cameras that are made for telescopes. At the same time there are telescopes and there are cameras that can be used together! Let's take a look at some of these variants and see if we can unclutter some of the confusion behind the telescope camera…

Telescopes That Are Cameras

An optical telescope is a telescope that you can also use your eyes to see a distant light source through – but some telescope types are not optical, they're digital light gatherers. Such is the case of ULTRACAM, a cluster of large and sensitive digital cameras located in the Canary Islands. Unlike conventional long-exposure photography, ULTRACAM takes 1,000 frames per second to help reveal fast moving events in our universe. Another example of a telescope that is a camera is the Hubble Space Telescope, which is also able to observe in the visible part of the spectrum.

Most telescopes that are designed to be cameras are not aimed at the visible end of the spectrum, however. That is the case of telescope cameras like the Spitzer Space Telescope that images in the infrared. At the opposite, we have the EIT aboard the SOHO orbiting spacecraft, which images in the extreme ultraviolet end of the spectrum. Still other telescope cameras, like GLAST, image our universe in exotic things like gamma rays!

Telescopes Meant For Cameras

Here on Earth, we also image the universe in a variety of ways through a variety of telescopes as well. However, the designs of the telescopes we use are far more limited. While any telescope design can be used for astrophotography, serious scientific studies are usually conducted with telescopes made in the Ritchey-Chretien, Astrograph and Dall-Kirham design.

However, let's think more about the amateur level and what types of telescope work more favorably for astrophotography. Again, serious astrophotographers favor the RC, but excellent results are also achieved with the Schmidt-Cassegrain (also first developed for photography), the Maksuktov-Cassegrain, the refractor and the reflector telescope. Literally volumes can be written about why each telescope design excels at being used with a camera and each one poses its own unique abilities and problems.

Cameras For Telescopes

Right now, the most popular form of telescope camera is called the CCD – or charge coupled device. Unlike traditional cameras, the CCD camera uses a small, rectangular piece of silicon called a Charge-Coupled Device to gather and imprint incoming light instead of film. The silicon chip is a solid-state electronic component comprised of light-sensitive cells called photosites. Each photosite is its own pixel – just one tiny cell in the whole body of a photograph that could contain hundreds of thousands of pixels! When incoming light strikes the photosite, the photoelectric effect occurs and creates electrons for as long as exposure occurs. The electrons are then kept "stored" in their individual cells until a computer unloads the array, counts the electrons and reassembles them into the "big picture". Although there's just a bit more to it than that, CCD imaging is one of the fastest growing fields of astrophotography. Unlike traditional film cameras which only captures about 2% of gathered light, CCD cameras can respond up to 70%. – making them amazingly efficient for astronomy applications.

Another popular telescope camera is the Digital SLR – or digital single-lens reflex camera. It is a is a digital camera that uses an automatic mirror system and pentaprism or pentamirror to direct light from the lens through the viewfinder eyepiece. Like the CCD camera, it is coupled to an optical telescope and a timed exposure shot is taken and the image is then manipulated with software until the desired effect is achieved.

Another form of telescope camera is called the video eyepiece cam, or eyepiece cam. This is a simple apparatus that makes use of modern technology in a very inexpensive way. Just insert it into your optical telescope's eyepiece socket and turn it on. It connects to a television monitor and provides a digital image exactly as if there were a tiny camcorder inside. It isn't good for very faint objects, but it is a wonderfully inexpensive way to enjoy simple astrophotography.

Another form of telescope camera is the webcam and a device called the stellacam. The ordinary webcam of a computer can often be purchased in low lux models and modified to take series of images through the telescope eyepiece and the stellacam is a model specific application which also stacks and digitalizes these images to produce great results.

Other telescope cameras also include ordinary film and digital cameras as well taken with timed exposures. There is very little limit to what can be achieved!

Filed under: Astronomy