Reverse Figure "4" Motions
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by RackAttack
I've marked a handful of images with moving bright spots as what I thought were asteroids in some type of retrograde motion loop. But then I saw a "Flat Field Defect" in a image show the same motion. So much for my "asteroid retrograde theory." View a few of my "Favorites" and you'll see.
Question becomes: What is the significance of the "reverse figure '4' motion" in any image by, what must be, artifacts?
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by nlmarsh in response to RackAttack's comment.
I see similar things, & have called them 'quad artefacts'. How to contact the head Serang, & get a notion as to the causes, & whether we are wasting time, or not??
nlmarsh
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by dudrea
Hi For me it's an artefact.. There's quite a lot like that. Youd shouldn't bother you with that... Reverse 4 motion is explained in tutos. Don't remind exactly where. Suppose something about repositioning the set between each picture
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by CTidwell3
http://talk.asteroidzoo.org/#/boards/BAZ0000003/discussions/DAZ0000180
Basically, the telescope moves between taking each frame to a) be more efficient and b) cause artifacts to move in a non-linear pattern making them easy to identify from the linear movement of asteroids.
Definitely not wasting time here. It's one of the first things I look for in each image -- obvious artifacts. If I can mark them in all 4 frames, I know the pattern that all other artifacts in that set will move in, so when I see any other movement I can look for where I would expect an artifact to be if it were one. This often makes it easier to quickly identify additional artifacts.
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by RackAttack
Thank you all!
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