Who doesn't like to play with pinwheels? The Pinwheel Galaxy ranks among the most popular astrophotography targets, with expansive spiral arms that spring from tightly-coiled ends arrayed along the edge of the galaxy's golden-yellow core, and then branch out with seemingly endless bifurcations, knots of blue star clouds, and brilliant-pink HII regions. In springtime I finally took a turn to "turn the Pinwheel", so to speak, with my CDK600, which had been on my bucket list since first light two years ago.

The position angle that I ended up adopting, with the Pinwheel's longest arm mainly dangling down, is not used nearly as often as pointing it up, or to a side, and wasn't what I had planned at the outset. But I ended up having to crop the full frame close to the end of that longest arm, with a very bright star otherwise intruding into the frame in that direction, while the space that was available on the opposite side seemed to create a better overall balance with this orientation. 

The image is from just under 6 hours of integration in luminance, and 8 hours in RGB colour, acquired over the course of eight nights at the end of April and the beginning of May. I've posted it at the full resolution of my CDK24/FLI KL4040 camera combination, which is about 0.47"/pixel, though I'm not sure it really stands up to that level of scrutiny! The field of view is about 30'x28'.

While working on the image, I thought it would be fun to find out which objects are the most popular Astrobin targets. I'm not aware of an existing compilation, so I did a quick and *very* rough survey, trying to make educated guesses as to which targets might have top ranking. My best candidates for the top two are the Orion Nebula at #1, with about 19,000 hits in a search for "M42", followed by a large gap to the Andromeda Galaxy, which I think is #2, with more than 12,000 results in a search for "M31". If I missed anything more popular than either of those two, I'd love to hear about it! There seems to another noticeable gap after that, with for example the North American nebula (NGC7000) at about 8800 hits, and M51 around 8300, while M101 is further down at about 6300, bunched together with a number of objects of comparable popularity, but still well ahead of many other prime targets, such as the Ring Nebula, to pick one last example, with "M57" generating about 3000 hits.