Hello Ed and Al!
Thanks a lot for your kind words!
I am glad, if people like the sketches!
As for the re-processing: first thing I do is scanning the sketches, then I do an automatic correction of contrast, brightness etc.
The next step is inverting the sketch and adjusting the brightness to exactly that degree, where not much information on the objects is lost, but where scanning artifacts are no longer visible, this can be a bit tricky. Then I start polishing up the sketches, this means erasing mistakes, pencil streaks, all that stuff that simply happens, while sketching on the telescope. The next step is re-processing the stars, this means that I assign a certain brush size in Adobe Photoshop to the relative brightness of a star, then I erase the hand-drawn star until there is just one pixel left marking the exact position, the brush is then centered just above that pixel with exactly the right size and one click on the mouse produces a nice and round star, which still looks natural, not computer generated.
In the next stage colour and glow can be added to the stars, this is done in a combination of tools, mainly various brush functions and the gaussian blur, it can be tricky and there is no general order in which to apply the various functions, even though I've come up with a certain routine.
If the object is a star, double star or open cluster, the process is now almost finished. If the main object is a galaxy or nebula, this object must also be reworked, though not as "radical" as the stars, it is mainly left, how it was drawn, some blur can be added, a bit of tidying up can be done, errors removed etc.
The final step is lighting the brightness of the background (+11 in the brightness adjustment tool in Photoshop), to enhance the detail and make it all look more natural.
Last but not least the drawing can be presented in the internet (and torn to bits by far superior sketchers
).
My aim is to use the benefits of digital processing without losing the natural look of a hand-drawn picture, I am not sure, how successful I am.
To illustrate the steps described above, I attached another drawing of the phantastic Plejads, one of the mighty winter objects here. It's completely fresh out of the press, finished in these minutes. The drawing was processed in exactly the described way above. Without the help of digital reprocessing, I could never have added the bluish glow, we all know, from observing this wonderful cluster. Still, I think it looks quite natural.
Merope Nebula was not visible, unfortunately.
OK, I hope, I wasn't going into detail too much, perhaps it becomes apparent, how much work goes into those sketches, even though they are no match for the might photographs presented here. As for the Plejads, I took me about 20 minutes to draw them on the telescope and about 45 minutes to re-process them, this adds up to more than an hour of work!
If there is any interest, I could write a tutorial to pass on my limited knowledge, but if you want to see real astronomical art, look for Jeremy Perez on the net, the guy is fantastic, many ideas, I use for re-processing, have in one way or the other originated from his mind, I just took them and worked around on my own, but I owe him a lot!
Sebastian