I have over 45 years of experience at the eyepeice and wanted to share these techniques with you, though I don't sketch or keep a notebook. Remember that observing and just looking are vastly different from one another.
Transparency
What transparency is the dimmest star seen by the naked eye and how clear the sky appears. To an experienced observer, transparency is everything. A wonderfully transparent night makes all the difference from a so-so night. Learn to look for signs of excellent transparency during the daytime such as blue sky, jet trails (the trails should be short, not stretching across the sky, indicating a dry upper atmosphere), and clear sunsets and sunrises.
Seeing Conditions
The steadiness of the sky is also very important. This is known as seeing or twinkling. Is the star under high power steady or is it moving about? How I determine the seeing conditions is to look at the stars with the naked eye. Start from the horizon and work up the zenith. If the star are twinkling more the 30 degrees above the horizon then don't bother go read a book instead.
Dark Adaptation
For deep-sky objects, dark adaptation is essential. Benefits continue to accrue for hours: the difference between 20 minutes of dark adaptation and two hours is 1/2 a magnitude.
Averted Vision
Averted vision works best if you know where to aim your eyes in the field of view. Move your averted vision zone around the field of view as you desire. Look for a bit here, look for a bit there (your scan pattern). Do not fixate on the center of the field. If you stare too long at a single point, objects will literally begin to disappear from your view. Tap the telescope tube in addition to moving your eye: this helps to 'pop' objects into conscious visibility.
Focusing
Unless you have astigmatism, try looking without glasses. Refocusing the eyepiece will take care of near and far sighted eyes. Position the eyepiece as far outward as possible then focus inward until the stars just come to focus. This is the most relaxed, infinity focused position for your eye. Moving the focuser inward results in a slightly more magnified view, but at the expense of focusing your eye close-in, which is tiring.
Center Your Eye
Your eye needs to be centered over the eyepiece and looking down its axis. You also need to position your eye at the correct distance from the eyepiece. You can look up the eye relief spec for the eyepiece to get a guide. In the field move your eye away and towards the eyepiece.
Use Filters
Get a nebula filter. These filters really help to make subtle detail more noticeable. A filter is more important than aperture because a nebula filter increases contrast more so than aperture. Try different filters, try different filters with different eyepieces. Colored filters work very well on the planets. They will enhance and bring out certain surface details. Use a neutral density filter on the Moon, it cuts down of the brightness and increases contrast.
Vary Magnifications
I am constantly surprised by the view at very different magnifications. However, going past what seeing allows that night is always painful. What is the seeing limit? Only way to know for sure is to run through your sequence of eyepieces.
Rest and Comfort
Take breaks, drink some water, remember to blink. Comfort at the eyepiece is worth a half magnitude. Get an observing chair, rotate the focuser to a better viewing angle, set up a small table next to you for your eyepiece case, tool chest and tablet or phone. Make it easy on yourself.
Observe and Observe More
Observer experience is worth 2 magnitudes. There is no substitute for hours at the eyepiece. How often do you observe a week? What can you do to increase your observing hours? Make the telescope more portable, join others observing. Hours of practice are necessary to become an expert.
Take Your Time
Time at the eyepiece is worth a magnitude (objects gradually become recognizable or detectable over a period of time and then they fade after a prolonged period of continuous observing). A few minutes brings awareness to detail that's thrilling and satisfying but do not stop there. More awareness and detail comes after observing for an hour or more on an object. The most difficult objects are only there part of the time. The seeing will stabilize and your concentration will be at your peak with your eyes paying attention to the proper place in the field.
Keep A Notebook, Sketch To Observe
Sketching helps in becoming a better observer. By sketching you learn to look for finer details which will translate to the visual and vice versa. Be warned the there are techniques to sketching which in itself takes time to learn.
Observe For Yourself
The vast majority of observers are truthful to themselves, knowing or not caring that they will fail to convince doubters. It's all subjective Each observer tends to notice or emphasize certain features. If I see something, great; if I don't, that's great too. Knowing that it is beyond my observational powers is worthwhile too. The variation in appearance on different nights with different transparency and seeing through different eyepieces can be striking. M1, the Crab Nebula, can look quite different from scope to scope and night to night.
The Psychology Of Seeing
Psychological factors are as important as physical factors such as sky darkness, object brightness, aperture and magnification. What we consciously see is heavily influenced by our expectation of what is to be seen and of our training. These expectations and training can be said to form a bias. We want to ensure that training and knowledge of an object's particulars helps us see more but does not fool us.
Clear and Dark Skies, Dave Holland
