From the April 2011 issue

A different type of filter

June 2011: This technique is so elegant that you may hear yourself ask, "Who was that masked High Pass filter?"
By | Published: April 25, 2011 | Last updated on May 18, 2023
These before and after images show the results of using the author’s technique of masked High Pass filtering on astroimages. Tony Hallas

Some years ago, imagers discovered a new way to enhance the detail in an astrophoto that proved superior to the unsharp mask in Photoshop. Follow me through these steps to uncover the power of what I call masked high-pass filtering.