Markarian's Chain in Virgo - Posted March 16, 2006
An interesting grouping of galaxies that when viewed all together form a sort of string or chain. They are gravitationally bound to each other and as a whole they even exert measurable gravitational pull on the Milky Way and the local group of galaxies that we are a part of. I annotated a version that can be seen by clicking here, there are over 20 bright galaxies in this shot and many more smaller, dimmer ones that I did not annotate.
Not counting Moon shots, this image is my first mosaic. It is a composite of 6 individual frames, I could have done it with only 4 by rotating my camera 90 degrees. I took 60 minutes of luminance exposure for each of the 6 frames over 2 nights. For the color, I took 15 minutes of red and green, and 20 minutes of blue for each frame over the course of 3 more nights. That's not much data per frame, processing the color channels was a struggle. Also, the seeing conditions varied from night to night making it difficult to combine the frames seemlessly into the mosaic. Overall it was a LOT of work, both in the field collecting data and at the computer putting it together. It was a learning experience, there are certainly many flaws in the image, but it was an interesting project and I'm not unhappy with the result.