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Guiding Error Canceler


Guiding a star is very important to make a beautiful picture. Especially globular clusters's images are very sever for guiding error, so people try to concetrate correcttion of the periodic motion of telescscope.
Fortunately we have a tool of image process, deconvolution, and we do modify and improve the images. Why don't we use it for guiding error? Most filters, sharpner filter, improve stars and objects in 4 ways, which are upper, lower, right, and left. The guiding error in only one way, which mean one direction, and I noticed that one direction sharpener filter could improve or remove the guideing error.

Typical PSF of sharpner is
0 -1 0 -1 5 -1 0 -1 0
However, we don't need 4 ways and modify it to this PSF
0 0 0 -1 3 -1 0 0 0
This PSF is a sharpner for the horizen direction. Let's try it for a globular cluster, M13.


�@ Left : before , Right : after

It is improved!!
Pay attention to this; worse images, low SNR, are not suitable for this PSF because noise is also and enhanced. Use this PSF for higer SNR images.
Sometimes the guiding error is longer or shoter. Make PSF wider for longer case, and do PSF smaller for shorter case. The amplitude of values of PSF is how the images are enhaced, so enter dicimal numbers if your softwware can use and want to do that slightly. If your software mormalizes the PSF' volume, don't care about dicimal numbers because the mormalization transfers each integers to dicimal numbers. Remember make the summation of numbers ONE for non-normalization tools.

If you have only lower SNR images, use soften filter after guiding error cancelation. The noise should be removed by soften filter.


2001,2,20

Astronomy

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