A portrait of three comets each passing the Pleiades and in a similar location relative to the star cluster, but taken over a span of 14 years. And I shot the first (Machholz) and latest (Wirtanen) comets with the same lens, a 200mm telephoto, from my backyard in Alberta, while the middle image of Lovejoy I shot with a 135mm telephoto for a wider view than the others, and it was shot from New Mexico. On the left is Comet Machholz (C/2004 Q2) discovered in 2004 by amateur astronomer Don Machholz, at centre is Comet Lovejoy (C/2014 Q2) disovered in 2014 by amateur astronomer Terry Lovejoy from Australia, while on the right is Comet 46P/Wirtanen, discovered in 1948 by professional astronomer Carl Wirtanen. All the comets became bright enough to be visible to the unaided eye, though only just. But all were fine photogenic targets, with Lovejoy sporting the long blue ion tail. I shot Comet Machholz with a Canon Rebel 300D cropped-frame camera, Comet Lovejoy with a full-frame Canon 5D Mark II, and Comet Wirtanen with a Canon 6D MkII full-frame camera. So with the different sensor sizes and the use of two different lenses the images scale is not the same over the three images.
A portrait of two comets each passing the Pleiades and in a similar location relative to the star cluster, but taken nearly 14 years apart. And I shot both with the same lens, a 200mm telephoto, from my backyard in Alberta. On the left is Comet Machholz (C/2004 Q2) discovered in 2004 by amateur astronomer Don Machholz, and at centre Comet 46P/Wirtanen, discovered in 1948 by professional astronomer Carl Wirtanen. Both comets became bright enough to be visible to the unaided eye. I shot Comet Machholz with a Canon Rebel 300D cropped-frame camera, and Comet Wirtanen with a Canon 6D MkII full-frame camera, so the image scale is different between the two images. So … on the far right is a version with the two images layered and auto-aligned with Photoshop, so the stars and field scale and orientation of the Machholz image match and register with the Wirtanen image. Pretty remarkable that Photoshop was able to do that on images so different in scale and orientation. Having lots of stars helped. This version shows the location of two comets with respect to the Pleiades best.
The small asterism in Vulpecula called the Coathanger, aka Brocchi’s Cluster, aka Cr399, in the northern summer sky. The field is about equal to a binocular view, as it was shot with a 135mm telephoto on the Canon 60Da. This is a stack of 4 x 80 second exposures at f/2.2 and ISO 1600, unguided on the Sky-Watcher Star Adventurer tracking mount. Two additional exposures with the Kenko Softon filter blended in to provide the fuzzy star glows. Taken from home, August 18, 2014.
