There are two basic methods of recording astronomical images seen through the eyepiece of a telescope. Photography (these days, usually digital imaging with a CCD camera) is one, the other is sketching.
Astronomical sketching and drawing has a long and esteemed history. Many astronomers believe it is still unrivalled for recording and illustrating transient phenomena (such as TLPs) or for taking advantage of the fleeting moments of extreme clarity that result from the turbulent atmosphere through which Earth-based astronomers carry out all their observing.
Unfortunately, astronomical sketching and drawing is seldom taught as such, and is regarded by many amateur astronomers as the province of a talented few. This is not the case - the necessary techniques can be taught, just as portraiture and still-life drawing can be (and is) taught.
I've been doing astrophotography for many years, but I've admired the drawings made by some of my colleagues. This book is written as illustrated tutorials that are organized by target. So the authors show how they sketch the Moon, the Sun, the planets, comets, star clusters, nebulae, and galaxies. The instructions seem clear, and there are recommendations concerning media and equipment. There is an appendix of drawing forms. The tutorials are all for monochrome sketching, except for sketching the Sun in hydrogen-alpha.
Very detailed book on sketching in astronomy. Repetitive in describing the methods used, however to me this seems a good way to instill the mindset of what to do. The tools needed are minimal and are also repeated in all the chapters.
This is a fantastic overview of astronomical sketching, covering a variety of different objects (the moon, comets, the sun, three of the planets, star clusters, nebulae, and galaxies) and techniques (graphite pencil, charcoal, pen, white chalk on black paper, and colored chalk on black paper). There are step-by-step directions for each sketch and the book is loaded with advice and tips for those who aren't already experienced in the use of these materials (or need a quick reminder).
There are multiple projects for each object type, although I'm a little disappointed that all four projects for the moon focus on craters. Luckily, this team produced another book all about sketching the different features of the moon, and one covering the sun's features, too.
This is a must-have resource if astronomical sketching is something you're interested in. If you just want some tips to make the sketches in your observing log a little more accurate you could probably get away with borrowing a copy from the local library, but if you really want to hone your skills you're going to want your own copy for frequent reference.