PSFImage - Script by Hartmut Bornemann to automate the creation of a PSF profile

[Mike1485]

Hi Stuart

You are right that the Moffat reference is to the mathematical function used to model the star shape. The number following the "Moffat" designation refers to one of the parameters (beta) of the Moffat function. If you know the beta parameter that best matches the stars in your image then you can select the appropriate function. If not, as you have, select the "Moffat" choice and the script will try to find the best beta, along with the other Moffat parameters, to match your stars.

The more "blocky" the generated psf the smaller the number of pixels over which your stars are spread. Deconvolution works best on images where the stars are well or over sampled, ie they cover several pixels - these are the images on which deconvolution will have greatest beneficial effect.

This document details the DynamicPSF process available in PixInsight. It has some very helpful information on PSFs.

CS, Mike

 

[StuartT]

Hi Stuart

You are right that the Moffat reference is to the mathematical function used to model the star shape. The number following the "Moffat" designation refers to one of the parameters (beta) of the Moffat function. If you know the beta parameter that best matches the stars in your image then you can select the appropriate function. If not, as you have, select the "Moffat" choice and the script will try to find the best beta, along with the other Moffat parameters, to match your stars.

The more "blocky" the generated psf the smaller the number of pixels over which your stars are spread. Deconvolution works best on images where the stars are well or over sampled, ie they cover several pixels - these are the images on which deconvolution will have greatest beneficial effect.

This document details the DynamicPSF process available in PixInsight. It has some very helpful information on PSFs.

CS, Mike

Thanks for explaining Mike. Very helpful indeed.

But I am surprised to be getting blocky PSF with this image. The image scale is 0.956"/px - surely that's not undersampled is it?

 

[ghostofrecon]

is there documentation on the different PSF functions?

 

[Mike1485]

is there documentation on the different PSF functions?

Yes, look in the document linked in my previous post in this thread.
CS, Mike

 

[nhey]

User error, but annoying nonetheless: PSFImage works very well, and thanks for creating it. I don't know if others run into this, but I keep making the same error and paying the price. Running it on a relatively small preview works quickly. Running it on a full frame can take a long time. I am not infrequently careless that I have selected the preview before asking the script to run and off it goes on the full frame. Every time I try to either cancel or abort the process, PI comes to a grinding halt, with no escape other than to force it to quit. Not a big deal, but all changes from the last save on are lost.

Is this a known problem? unique to my use? is there a solution other than to be more vigilant?

 

[StuartT]

User error, but annoying nonetheless: PSFImage works very well, and thanks for creating it. I don't know if others run into this, but I keep making the same error and paying the price. Running it on a relatively small preview works quickly. Running it on a full frame can take a long time. I am not infrequently careless that I have selected the preview before asking the script to run and off it goes on the full frame. Every time I try to either cancel or abort the process, PI comes to a grinding halt, with no escape other than to force it to quit. Not a big deal, but all changes from the last save on are lost.

Is this a known problem? unique to my use? is there a solution other than to be more vigilant?

I hadn't thought of running it on a preview. That would sure speed things up as it's very slow on a full image.
Only problem is, where to place the preview (as stars in the centre are coma free, those to the edges not always)