Stars from a fixed tripod

Now for the stars. On a starry, moonless night, put the camera on a sturdy tripod, aim at a familiar constellation, set the aperture wide open, focus on infinity, and take a 10- to 30-second exposure at ISO 400 or 800. You'll get something like Figure 4.5 or Figure 4.6.

For this project, a 50-mm f /1.8 lens is ideal. Second choice is any f /2.8 or faster lens with a focal length between 20 and 50 mm. Your zoom lens may fill the bill. If you are using a "kit" zoom lens that is f /3.5 or f /4, you'll need to

Figure 4.3. The Moon, photographed by holding a Canon Digital Rebel (with 28-mm f /2.8 lens wide open) up to the eyepiece of an 8-inch (20-cm) telescope at x 50. Camera was allowed to autofocus and autoexpose at ISO 200. Picture slightly unsharp-masked in Photoshop.

make a slightly longer exposure (30 seconds rather than 10) and the stars will appear as short streaks, rather than points, because the earth is rotating.

If your camera has long-exposure noise reduction, turn it on. Otherwise, there will be a few bright specks in the image that are not stars, from hot pixels. If long-exposure noise reduction is available, you can go as high as ISO 1600 or 3200 and make a 5-second exposure for crisp star images.

Focusing can be problematic. Autofocus doesn't work on the stars, and it can be hard to see a star in the viewfinder well enough to focus on it. Focusing on a

Figure 4.4. Lunar seas and craters. Nikon D70s with 50-mm f /1.8 lens wide open, handheld at the eyepiece of a 5-inch (12.5-cm) telescope at x 39, autofocused and autoexposed. Image was unsharp-masked with Photoshop.

very distant streetlight is a good starting point. Then you can refine the focus by taking repeated 5-second exposures and viewing them magnified on the LCD screen as you make slight changes.

The picture will benefit considerably from sharpening and contrast adjustment in Photoshop or a similar program. You'll be amazed at what you can photograph; ninth- or tenth-magnitude stars, dozens of star clusters, and numerous nebulae and galaxies are within reach.

This is of course the DSLR equivalent of the method described at length in Chapter 2 of Astrophotographyfor the Amateur (1999). It will record bright comets, meteors, and the aurora borealis. In fact, for photographing the aurora, a camera with a wide-angle lens on a fixed tripod is the ideal instrument.

Figure 4.5. Orion rising over the trees. Canon Digital Rebel (300D) at ISO 400, Canon 18-55-mm zoom lens at 24 mm, f /3.5, 30 seconds. Star images are short streaks because of the earth's motion.

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Comet

Figure 4.6. Blitzkrieg astrophotography. With only a couple of minutes to capture Comet SWAN (C/2006 M4) in the Keystone of Hercules, the author set up his Digital Rebel on a fixed tripod and exposed 5 seconds at ISO 800 through a 50-mm lens at f /1.8. JPEG image, brightness and contrast adjusted in Photoshop. Stars down to magnitude 9 are visible.

Figure 4.7. Comet Machholz and the Pleiades, 2005 January 6. Canon Digital Rebel (300D) with old Pentax 135-mm f /2.5 lens using lens mount adapter, piggybacked on an equatorially mounted telescope; no guiding corrections. Single 3-minute exposure at ISO 400, processed with Photoshop.

Understanding Adobe Photoshop Features You Will Use

Understanding Adobe Photoshop Features You Will Use

Adobe Photoshop can be a complex tool only because you can do so much with it, however for in this video series, we're going to keep it as simple as possible. In fact, in this video you'll see an overview of the few tools and Adobe Photoshop features we will use. When you see this video, you'll see how you can do so much with so few features, but you'll learn how to use them in depth in the future videos.

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