9
ASTRONOMICAL OBSERVATION TIPS
A reliably quick way to judge seeing conditions is to look at bright stars
about 40° above the horizon. If the stars appear to twinkle, there is
significant atmospheric distortion and viewing at high magnification will
not be ideal. If these stars are steadily bright, chances of successful
viewing at high magnification are much better.
Judging the transparency of the air is also important in determining
viewing conditions. The best air is free of moisture, dust, and smoke,
which tend to scatter light, reducing a viewed object’s brightness.
How many stars can you see with your naked eye? If you are unable
to see stars of magnitude 3.5 or dimmer, transparency in your area is
poor. A good indicator star for this test is Megrez (mag. 3.4) - the star
in the Big Dipper connecting the handle to the dipper. If Megrez is not
visible, elements in the air will negatively affect your view.
DARK-ADAPTING YOUR EYES
When you go out into the dark, your eyes need time to adjust. You
will initially be able to see only a fraction of the stars and objects your
eyes are capable of. Remain in the dark (don’t look at any lights or cell
phones) for at least 30 minutes, and your eyes should be around 80%
of their full dark-adapted sensitivity. Every time bright light comes into
your eye, the dark-adapting process will start over.
When eyes are fully dark-adapted, you will probably still need to see
what you’re doing. Use a red-light flashlight to maneuver around the
area. A regular flashlight covered in red cellophane will work, but red
LED lights are best.
