graphic design, open source, science

IRIS astrophothography tips

IRIS astrophothography tips

 

Reducing noise with staking is invers proprtional of square root of number of images, for 4 images, you reduce noise by 1/2, for 9 image is 1/3 etc

 

Some useful command lines:

SAVE name       // save pic/fit file in working directory

LOAD name       // load pic/fit file from working directory

DARK        //after secting star free area

WHITE2       //after selecting a g2v type star

SAVEJPG  name 1-5         //Name is the name of the file, 1 is best quality

RL iter coef        // iter usually 10-15, use 0 for no noise and 1 or 2 for relaxation noise reduction

BG       //

BGNOISE     //

GAUSS2  .7       //reduce noise

RL2  60 0      //deconvolution of image using a modifyed Rycharson-Lucy algoritm , 60 iterations and o for original Lucy algoritm , if you use 1 the strenghts of the algorithm will decreased in noisy areas

Notes: A .The above commad works best if the image is power of 2, use WINDOW3 command with a selected center area, B.You have to select a non saturated star for PSF - spoint spread function, C. It is important to have the background lrevel close to 0, use for that OFFSET or NOFFSET command

COREGISTER MR MB     //registter MB on to MR save te result as MR_reg or something , note that the images can be from different optical instruments

SCALECOLOR  R  G  B   3     //equalize the levels in each of three images (gain and offset), you have to have selected a G type star

SPLIT_RGB R G B      // save on disc 3 16bit images coresponding color chanels

RGB2HSI R G B H S I    // create from the color channels another 16bit images coresponding to Hue, Saturation and Intensity

TRICHRO R G B    // create a 48bit  color image from the r g b 16 bit , or use more compact  TR R G B

 

 

 

 

 

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