The images below show a method of creating an excellent starless image with Affinity that does not have noticeable artifacts left over in the place of large stars.
Starnet does a great job of identifying nearly every star in an image. However, the manner in which it which fills in the pixels of large stars leaves much to be desired.
The Inpaint function of Affinity does a masterful job of filling in a selected area with the patterns and symmetries that surround it. The method shown below uses the star mask generated by Starnet and the Inpaint function of Affinity to create a starless image.
The saved selection of stars to be Inpainted is based on the star mask. The key to achieving a seamless transition between the Inpainted stars and the surrounding nebulosity is growing the size of the selection until there are no artifacts left over from small stars. The selections of large stars need to be grown much more than is necessary for small stars, so a separate large star selection is created and then combined with the small star selection.
A starless image can be created entirely without using any cursor based tools. However, because the selection is based on a star mask, some areas of bright nebulosity may be included in the selection. If the results are too offensive, the original star mask may need to be adjusted or you can simply remove the unwanted selections with the Selection Brush Tool.
The starless TIFF created in Affinity is used with a mask in PixInsight to overwrite the stars of the original XISF image. The result is a 32 bit XISF starless image with only the pixels of the stars being substituted with the Inpainted stars of the Affinity TIFF.
The integration time of the Ha image used here is 25 hours (300s x 300). The equipment used was an Esprit 100, ASI 183MM, and 3nm Astrodon. The pixel scale is .9 arc sec.
Original
Full resolution Original Ha (saved as a 32 bit TIFF): https://cdn.astrobin.com/images/74298/2021/06692944-378a-4328-9a93-c5f468c5ad12.tif
Link to the original Ha XISF: https://www.dropbox....w/Ha.xisf?dl=0
Starless
Full resolution original Ha with the stars overwritten with the Affinity starless TIFF (saved as a 32 bit TIFF): https://cdn.astrobin.com/images/74298/2021/09dcf29f-42d9-401d-9200-a445efc67248.tif
Link to the Original Ha XISF with the stars overwritten with the Affinity starless TIFF: https://www.dropbox....ss Ha.xisf?dl=0
1. Preparing the mask
1. Saving the mask as a selection
3. Creating a small star selection
4. Creating a large star selection
4. Combining selections
5. Inpainting the selection
6. Trial and Error
7. Overwriting the stars in the original XISF with the Affinity starless TIFF
Starnet does a great job of identifying nearly every star in an image. However, the manner in which it which fills in the pixels of large stars leaves much to be desired.
The Inpaint function of Affinity does a masterful job of filling in a selected area with the patterns and symmetries that surround it. The method shown below uses the star mask generated by Starnet and the Inpaint function of Affinity to create a starless image.
The saved selection of stars to be Inpainted is based on the star mask. The key to achieving a seamless transition between the Inpainted stars and the surrounding nebulosity is growing the size of the selection until there are no artifacts left over from small stars. The selections of large stars need to be grown much more than is necessary for small stars, so a separate large star selection is created and then combined with the small star selection.
A starless image can be created entirely without using any cursor based tools. However, because the selection is based on a star mask, some areas of bright nebulosity may be included in the selection. If the results are too offensive, the original star mask may need to be adjusted or you can simply remove the unwanted selections with the Selection Brush Tool.
The starless TIFF created in Affinity is used with a mask in PixInsight to overwrite the stars of the original XISF image. The result is a 32 bit XISF starless image with only the pixels of the stars being substituted with the Inpainted stars of the Affinity TIFF.
The integration time of the Ha image used here is 25 hours (300s x 300). The equipment used was an Esprit 100, ASI 183MM, and 3nm Astrodon. The pixel scale is .9 arc sec.
Original
Full resolution Original Ha (saved as a 32 bit TIFF): https://cdn.astrobin.com/images/74298/2021/06692944-378a-4328-9a93-c5f468c5ad12.tif
Link to the original Ha XISF: https://www.dropbox....w/Ha.xisf?dl=0
Starless
Full resolution original Ha with the stars overwritten with the Affinity starless TIFF (saved as a 32 bit TIFF): https://cdn.astrobin.com/images/74298/2021/09dcf29f-42d9-401d-9200-a445efc67248.tif
Link to the Original Ha XISF with the stars overwritten with the Affinity starless TIFF: https://www.dropbox....ss Ha.xisf?dl=0
1. Preparing the mask
1. Saving the mask as a selection
3. Creating a small star selection
4. Creating a large star selection
4. Combining selections
5. Inpainting the selection
6. Trial and Error
7. Overwriting the stars in the original XISF with the Affinity starless TIFF
