Northern Arizona astronomy: Shooting the moon - an astronomical project

Sky chart/Barry Malpas

Sky chart/Barry Malpas

WILLIAMS, Ariz. - Prior to the 21st century, which is not all that long ago, astrophotography was a complicated, time consuming, and often costly prospect requiring large telescopes that tracked the sky, and cameras with film that involved chemical development. However, with today's digital photographic technology, it is possible to obtain good lunar photographs using a small telescope or binoculars, and your own digital camera, or even a cell phone.

Equipment requirements:

• Small telescope or binoculars mounted on a steady tripod.

• Inexpensive (~$100) small, hand-held digital camera with 6-20 megapixel resolution, viewing screen, and auto exposure setting. (A good example is the Nikon Coolpix camera series.) Or, a cell phone with 6, or greater megapixel image capability.

• Unfortunately, cameras with large expensive lenses that do not match the relative size of the eyepiece will not do well using this technique.

Orientation and focusing:

1. Set up the telescope or binoculars mounted on the tripod directed on the moon.

2. Focus the lunar image as best you can with your eye.

3. Hold your camera, placing the camera lens up to the eyepiece so that the axis of the optical line-of-site of both the camera and eyepiece are directly aligned (see the illustration below).

4. With your camera set to auto, the image of the moon should appear on the digital screen of the camera. (Should the image appear a bit fuzzy, you can use the focusing capability of your telescope to adjust the image of the moon onto the viewing screen so it is as clear as possible.)

5. With a steady hand, carefully depress the shutter button to take the picture. (If you move while taking the image, it will come out a little blurry. So, take as many shots as you need to give you a good selection of images to choose from.)

6. Best results are obtained during lunar crescent to gibbous phases when the sun casts shadows of the craters across the lunar surface along the lunar terminator.

Notes and Suggestions:

Camera Lens Size: A small lens size of about ½ inch or so in diameter is best. Larger lens will cause the image to either vignette or pick up stray light from other sources.

Exposure: Your camera should have a small rectangular area on the viewing screen ( [ ] ) that adjusts the exposure. If you move the rectangle over a part of the lunar terminator, the side where craters cast the longest shadows, this will provide the greatest contrast for the camera to focus.

Flash: If your camera has an auto flash that cannot be turned off, cover the flash with your finger to avoid any stray bright light from affecting the image.

Zoom: If your camera has a zoom feature, you can use it to bring the image in a little closer. However, do not try to zoom in too close. It will be much more difficult to obtain a clear image. Greatest results are when the moon just fills the camera's view screen.

Checking image clarity: Most digital cameras allow you to use the zoom feature to check the clarity of the images just taken. By zooming your image in you will be able to see the many lunar details on your photograph.

The Williams Monthly Star Party - Friday, July 24

Members of the Coconino Astronomical Society, in conjunction with the city of Williams, will host a Star Gazing Party from 7:30 to 9:30 p.m. on July 24, at Glassburn Park, in the natural area west of Rod's Steakhouse parking lot. Several large telescopes will be on hand to view the moon, planets and other celestial objects. You may wish to bring a folding chair, or blanket, and your own binoculars.

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