Horsehead Nebula and Noise Reduction

The Horsehead Nebula in Orion is shown here to illustrate the noise reduction and SNR increase obtained from image additions.

The image on the LEFT is a single 20 min exposure with an ST-7 in red light using a 6-inch f/7.5 A-P EDF in basically average seeing.

The image on the RIGHT is a co-added image created from 4-20 minute exposures which were shifted and rotated for registration using IDL S/W written by the author.

For non imaging visitors, the image above is of a nebula in Orion. What you are seeing is a glowing cloud of hydrogen gas ( the brighter areas of the image ) which has a dark obscuring gas cloud in front of it. This dark cloud of gas just happens to have a shape that our minds recognize as a silhouette of a horse's head ( or more like a stylized Knight chess piece ! ). This faint nebula is located near the left most (eastern) star of the 'belt' of Orion ( the Hunter ) in our winter sky (or Summer sky for Souther observers!).

All images and text at this site are protected, copyright 1997 Brad D Wallis and may be used only for personal purposes. These images and text may not be copied or reproduced for any other purposes without the express written consent of the author.

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