Moondark for November: 1 + 1 = 3
“Golden Age of astrophotography”? “Never more accessible or with more promise?” Even “easy?” Perhaps not “easy” yet, but most assuredly not just hype either. Off-the-shelf digital cameras surely take a lot of the pain out of astrophotography. Mass production keeps the price low--did you know that these cameras can be used for ordinary photographs as well? But another key advantage is that the images can be altered and added to produce images otherwise impossible. And often most remarkable.
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Here are two from my photo album, representing the extremes in field of view, from wide angle constellation shots to capturing fine planetary detail. In no way do these push the limits of the techniques--others in our club and elsewhere are producing far superior results. But I can tell you that these were fun to take and process. The secret was in the math, combining individual frames to extract a wealth of detail. Software widely available makes this easy.

Scarcely 17 arc seconds across when this image was captured, Mars (at right) still reveals impressive detail. I attached a Vesta Pro Scan 690 webcam to my 10" LX-200 with a 3x Barlow in between (f/30). Two-star alignment of the alt-az mount kept Mars with in the frame and allowed plenty of time to make focus as sharp as possible. My laptop captured 600 images, exposed 1/33 s each at five per second. The freeware program K3CCD Tools has a Planetary Wizard function that practically automated aligning and compositing the best 100 frames. Unsharp masking and a stretch produced the image above (reduced 50% to fit in this space). The South Polar Cap and Mare Cimmerium dominate the lower half of the gibbous disk.

At the extreme opposite, spanning over 60º in field of view, the below composite covers the the southern sky from the Pointers, Alpha and Beta Centauri (lower left), to Canopus (top right). Four, 16 s frames were taken with 3-megapixel Olympus 3020 on pocket tripod, and later manually combined with MaxIm DL to remove the Earth's rotation. Here is one of my favorite parts of the sky: the Southern Cross, the Coal Sack dark nebula, and Eta Carinae  and numerous other dark and bright nebulae. I was delighted to see that it recorded the Large Magellanic Cloud halfway down the right side of the frame. Reduced to 25% of the original size of 2048 x 1536, camera noise persists as the vertical striping near the bottom, although a FFT filter should take care of that. 

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The bright winter sky will soon be overhead. Saturn's getting high, and Jupiter isn't far behind. Digital camera or webcam--have I convinced you to put one on your Christmas list?

Thanks especially to Tom Pomponio for his demo of K3CCD Tools and to Eric Todd for posting his far superior Mars images to the club’s Yahoo! group. Mouse-over the above images to display a labeled image. Moondark is written by Doug Miller, published on the web, and printed in the Delmarva Star Gazers' Star Gazer News. This document was last revised on 26 October 2003. Text and images copyright © 2003 by Douglas C. Miller, All Rights Reserved. This material may not be reproduced in any form without prior permission.