I read from many astronomy magazines that before the camera costs went down and astrophotography was all the rage... they did sketching. At the eyepiece.
It is an endeavour requiring every bit of attention right up to the final details... while battling eye strain, back pain and the mozzies if you're in the summer, or the cold in the winter.
It goes roughly like this :
Prepare a piece of A4 paper with a circle on it. (Easier to draw your target.)
Use pencil to mark the stars you see in the star cluster.
- for higher quality, they use different pencils for different stars of varying brightness!
Scan the drawing, invert the colours in PS and you're done!
Now's here's some of my fist attempt in astro-sketching... don't bleed your eyes...
This may be my only time at astro-sketching... as I have already gotten the T-ring and found out that I can picture star clusters more beautifully... but who knows?