I have been experimenting a bit with digital sketching. A long while back, I had purchased a Wacom pen tablet for the PC, and actually tried using that at the eyepiece to sketch. It was unwieldy to say the least, and I have not used it since. Most recently, with the addition of a generic Android tablet, and a smaller but versatile iPod, I've been doing digital sketches more and more. On both products, I use Sketch Book Mobile, and find the program fits my needs very well. They have a free version, but the pay-for version offers more tools, so I recommend that.
I can easily see a few posts dedicated exclusively to sketching at the eyepiece using this product, and some techniques that I employ, but of now, I'll just share some of my most recent examples with you to show you that they are quite capable devices for sketching.
First up, NGC 752, a nice open cluster in Andromeda I did earlier this year. Now for this particular example, I created a "template", basically a circle on a black background, on my PC and emailed it to myself so that I can save it on my Android tablet. I then simply opened this up using the sketch program (Sketch Book Mobile or SBM for short), and started with plotting of stars. Digital sketching permits you to easily and accurately capture subtle star colors, as noted by one of the prominent stars in this OC, which had a slight orange hue to it.
Note that for some odd reason that I still don't know why, there seems to be some artifacts around the stars. Its odd, because I do not seem them on the tablet itself, or even on the PC for that matter, but when uploaded to Blogger or other sites, it becomes apparent.
Next is M79, a globular cluster in the constellation Lepus. Now one of the great benefits to digital sketching is the ability to pinch-to-zoom. This, and the fact that SBM has a nice selection of tools that can make sketching certain objects a bit easier for amateur astronomers. For instance, globular clusters can be a challenging object to sketch. You need to relay the idea of molting, and some brighter clusters, depending on the size of the scope your observing them with a the time of course, can even be resolvable to the core. With digital sketching, I pinch-to-zoom, make my pen tool the smallest possible size, and start tapping my screen to easily add lots of stars in the core, with just a hint of stars on the outer fringes of the globular cluster itself. If you make a mistake, just hit the undo button, and the program undo's the last change for as often as you hit the undo button.
NGC2360 is a nice open cluster in Canis Major. This cluster is also the very first object that Caroline Herschel independently discovered and cataloged, so way to go Caroline! This sketch was done on black paper, with a white chalk pen. I like chalk, it is softer then led, so I feel I have more control over how I convey the brightness of stars, and it's particularly nice for deep-sky objects as well, but it has the tendency to smudge. White gel pens are nice as well, but in the cold weather, the gel can be hard to tease out from the ballpoint, and I generally find myself tapping the pen a few times on the paper before I can get the flow back.