The following classifications of the various types of deep-sky sketches are solely my opinion only:   

                 Detailed visual telescope sketching:  Observing an object through a telescope via an eyepiece. Drawing the object on paper or a sketch card “as verbatim” as possible using a pencil, or pencils of various hardness.   

     I’m a visual back yard observer after more than forty years.  All of my sketches are made using a pencil and a 5 x 8 blank note card with a 3-inch circle.   

     Impression sketching:  A sketch made at the eyepiece, using a pencil, charcoal, or chalk and representing what the observer mentally perceives, without a great degree of scale or detail. 

      It’s my opinion that John Mallas of “The Messier Album” used this technique, for the majority of his sketches.    

     “The sketches were made on vellum-type drafting paper with a soft pencil, using finger smudging and erasing until the desired effects were achieved.”  John Mallas 

     Computer-enhanced sketching:  A sketch generated sketch using a computer, from “most of the time” a rough pencil sketch.    

     The following are a few of my sketches, using only a pencil, an eraser and a blank 5 x 8 notecard with the colors inverted with a computer or scanner.