Andromeda in the Woods

Here’s the result of processing a wide-field view of Andromeda, taken on March 19:

pproc_bpm 120s 800iso 4C curves, greycstore IMG_5657 Framed

This was a 2-minute piggy-back camera exposure with a 50 mm lens. In other words, with the camera sitting atop the CPC-800 telescope and tracking the sky. An equatorial wedge was used to eliminate field rotation during the 2-minute exposure.

Canon 40D Parameter Notes
Shot through Canon EF 50mm F/1.8 II Lens Stopped to F2.8
ISO 800
Exposure 120s
Exposures Only 1

The telescope was set up on my back deck on a cold, march night. Too cold for me! once things were setup I used iAstroHub as a wireless remote link to control the Canon 40D camera. I waited for the images to roll in from the comfort of my home while I watched TV. The iAstroHub link allowed a last shot at this without me freezing my butt off!

Andromeda is setting and won’t return for several months. This was a last opportunity to photograph it on a clear, dark night before it set behind the trees and for the upcoming spring and summer. A day or two later showed significant interference from moonlight and clouds.

Tracking was particularly good that night and the wide-field lens eased tracking constraints considerably. The lens was stopped down to F2.8, but there’s still coma aberrations near the edge of the field, some of which I’ve cropped off. I’ve been experimenting with an external aperture mask to reduce that, but no great successes yet.

There was an interesting article in Sky and Telescope magazine about aperture masks:

“Aperture Masks for Camera Lenses
Here’s a novel way to make your camera lens perform like a high-quality refractor.
By Richard S. Wright, Jr.”

I have a few more wide-angle shots of the double-double cluster, and heart and soul nebulae, and I hope to process those soon.

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