Friday, October 18, 2013

Astrophotography Using A Pc

Even amateur astrophotographers on a budget can capture beautiful images such as this one.


Astrophotography has produced some of the most breathtaking images of our nearby universe and has inspired countless astronomy buffs to embark upon this fascinating field. You may think you need to break the bank in order to see other planets, stars, and galaxies; in reality, any amateur astronomer with a modest budget can do it. All you need is a personal computer, some software and any image-capture device ---even a webcam--- to capture images that lay bare the wonders of the cosmos.


Digital Cameras


The digital revolution in imaging technology ---specifically the advent of the charged coupled device (CCD), a key component in every digital camera--- has empowered amateur astronomers on a budget. Digital SLR (single-lens reflex) cameras are perfect for astrophotography and have gone down in price over the last years from the thousands to the hundreds of dollars. Two features distinguish SLR cameras from less expensive point-and-shoot models: lens and variable shutter speeds. The ability to change focal length on a lens grants the device a lot of flexibility in capturing images at different distances. According to Neale Monks, author of "Astronomy with a Home Computer," shutter control represents a key feature: the slower the shutter speed, the more light is able to enter the CCD when taking a picture. This usually results in better, clearer images of sky objects (think of a CCD as the digital equivalent of a roll of film in a traditional camera). Also, the slower the shutter speed, the more susceptible the picture is to image blur due to camera movement, so bring a tripod along. Dedicated astronomical cameras with much larger CCD chips also exist for the high-end market.


Telescopes


You don't necessarily need telescopes when taking beautiful pictures of the heavens, although they certainly come recommended, especially if you want to take high-quality images. Several types of telescopes exist, with a Schmidt-Cassegrain telescope (SCT) being among the most popular. A particularly noteworthy subtype of SCT is a "go-to" telescope, which you can connect directly to a computer and control through the computer itself, manipulating its direction and focus, among other parameters. You can also hook up a digital camera to a telescope's eyepiece using a technique called afocal photography, with which you can produce truly astounding images.








Webcams


A webcam offers one of the simplest and least expensive ways to practice astrophotography. You can combine a webcam with a telescope and its image will show instantly on a computer monitor, allowing for group viewing. It also produces surprisingly good images, particularly of the inner solar system, according to David Ratledge, an author and editor of several astrophotography books. Despite their surprising quality, webcams primarily record digital video instead of still pictures, and the images don't come out as clear as with an SLR camera, for instance. But that's where computer software comes in.


Software


Planetarium (or sky charting) programs are by far the most popular type of astronomical application, according to Monks. As the name suggests, these programs offer a map-like projection of the night sky and some of them come with features that allow you to control go-to telescopes. When it comes to applications for optimizing astrophotography images, there exist multi-purpose (and expensive) image editing solutions such as Photoshop that let you piece together several different photographs of the Moon's surface, for example, into a wide panorama. Several other applications specialize in astrophotography and utilize a variety of image manipulation techniques. Chief among these techniques is stacking, and it works especially well for webcam video. A stacking application takes all of the frames in a video, "stacks" them one over the next, and combines all the visual information from every stacked image, essentially merging them into an ultra-crisp picture.


Online Resources








Between the sheer amount of telescopes, digital cameras, webcam devices, computer configurations and software applications, the combinations for achieving quality astrophotography are endless and run the gamut from really cheap to second-mortgage costly. Luckily, you can find a lot of information regarding this field on respected online sites for enthusiasts. You can also find plenty of free and/or shareware versions of astronomy and astrophotography applications online.

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