Bill Richards
Well-Known Member
We have another comet - Leonard. This one's not as bright as NEOWISE, but I managed to capture it as it passed in front of M3 (a large Globular Cluster consisting of about 500,000 stars, 32,600 light years from Earth). The last time Comet Leonard passed by us was 70,000 years ago. It will be brightest 1-2 hours before dawn in the eastern sky on Dec 12th, then get increasingly closer to the sun as Christmas approaches. And this time around, its orbit will cause it to be flung out of our solar system forever so it will never be seen again.
Comets are notoriously difficult to photograph for a number of reasons:
1) They are moving relative to the star field. Star-tracking mounts track the stars as they move across the sky, but comets are inside our solar system and moving very fast. The video in this album shows how much it moved in a 90 minute span. This motion makes it very difficult to capture enough light for a good image without blurring the comet head.
2) Comets only begin to glow when they get close to the sun. That presents 3 problems - they are only visible near the horizon where the atmosphere is thickest (and most light polluted), they can only be photographed for a couple of hours before sunrise or after sunset, and the sun's inevitable skyglow greatly reduces the quality of the images.
The final image shown here is the result of 2 hours of imaging the morning of 12/3/2021 and 2 more hours the morning of 12/5/2021, followed by over 16 hours of post-processing.
Comets are notoriously difficult to photograph for a number of reasons:
1) They are moving relative to the star field. Star-tracking mounts track the stars as they move across the sky, but comets are inside our solar system and moving very fast. The video in this album shows how much it moved in a 90 minute span. This motion makes it very difficult to capture enough light for a good image without blurring the comet head.
2) Comets only begin to glow when they get close to the sun. That presents 3 problems - they are only visible near the horizon where the atmosphere is thickest (and most light polluted), they can only be photographed for a couple of hours before sunrise or after sunset, and the sun's inevitable skyglow greatly reduces the quality of the images.
The final image shown here is the result of 2 hours of imaging the morning of 12/3/2021 and 2 more hours the morning of 12/5/2021, followed by over 16 hours of post-processing.
