Just wanted to bring this up, with perhaps some tips and observations on a not so used aspect of our craft. Sketching!
First of all, just to make one thing clear: YOU DON'T NEED TO BE AN ARTIST TO SKETCH YOUR FOV! It does not matter if you can't draw a stright line. Lines are not required. However..observation is!
Why sketch it? Why not just take a pic of it? One of the main reasons for sketching is to improve your powers of observation. It's one thing to look into the eyepiece. Its quite another to actually put down what you see on paper. When forced to do that, you will see more. Stars you thought were not there all of sudden leap out at you. and you can record it. You will also see patterns of stars , such as cicles, triangles, squares in which you can quickly draw in.
The first thing to do is to get a notebook. I have one without lines, and fairly compact so it's easy to carry into the feild ( or backyard) Some notebooks come with one page blank, and another with lines, so you can mix notes with sketches. You can also use those "journal" types notebooks, as long as you can find one without lines ( although if the lines do not bother you..then use it) You can also personalize the notebook by pasting your fav galaxy or DSO on the cover and back ( I have the Orion nebula on mine
The notebook becomes an extension of you. Something to look back on through the years, as well as what you have learned in the craft.
Use a pensel, not a pen. The mechanical pensels are good for this and can also be clipped onto the notebook rings when not in use.
Next is to get a red light that can be independent, so you don't need to hold it while sketching. My solution was to hang a red filtered small lantern from the tripod of my scope, and placing a board across the eyepiece holder to act as a desk. ( two in one, and makes for less setup time as well) Some Red lights made for astronomical use allow you to hang it around your neck which is also a solution.
You also need a round template in which to draw the FOV. I use a lens cap from my 50MM refractor, but things found around the house that allow you to draw a circle ( jar lids) will do fine. You can also purchase round templates at a stationary store. A nicely drawn round circle instead of trying to hand draw a circle greatly improves the look of your drawings! Again..no lines or artistic talent is needed!
OK..you got M31 in your eye-piece. Time to do a sketch. Open your notebook, put in the date and observing conditions and what object you are sketching as well as eyepeiece and magnification. Use your circle template to draw in the FOV . Now look into the eyepiece. Start by putting in the stars around the edges. Look for patterns that can help you record the stars quickly. You are only putting dots on paper, with perhaps larger dots for brighter stars. Again..no artistic talent needed..it's only dots on paper!
Then put in the actual deep sky object. If it's a galaxy or a globular cluster, darken the brightest part and go outwards. Then using your finger, smudge it so the pencil lines are not there, but you see a nice "fuzz" to it, and looking more like the object in your scope then pencil lines. I have found smudging really works for a lot of deep sky objects. In some open clusters, you can see where there are more stars you can't see behind the brighters ones. Smudge it to indicate this, with the brighter stars left there for comparison! Smudging also works great on nebulas as well.
Also as mentioned, the more you view what is in the eyepiece, the more details you will see and even more stars leap out at you. Another techique is to use "averted vision" which is looking off to the side of the FOV. More will present itself. Record it as you see it!
For open star clusters, you are looking for patterns to easily put down the dots into the notebooks FOV. You will be very surprized on all the different patterns you will see and seem to form "sub-constellations" on thier own. On some of my sketches, I have even drawn in the patterns, like half circles, triangles, squares, and rectangles.For example, did you know that the double cluster in perseus is surrounded by a square of six bright stars holding the double cluster in?
Now the moon and planets are a different subject altogether.
For the moon, it would be impossible to draw in the whole FOV as there is so much detail. So concentrate on a single crater. Use high magnification to zero in on the crater you want to observe. Then sketch in roughly the area by using circles ( for craters) and rough areas of the sea's. Then go for shading, which may take some artistic talent, but you are only drawing what you see. Again, the more you observe it, the more detail you will see.
After making your sketch, add notes:a personal description of the object, just as if you were a Herschel or Messier seeing the object for the first time.
The main purpose of sketching is to increase your observing skills, not make artistic renderings of the sky ( although it may go in that direction!) It also becomes a personal record, one that you can treasure for years as you become more learned and skilled in the craft of deep sky exploration.