Watching the sky: tips for beginners

Sky conditions

Sky conditions are generally defined by two atmospheric characteristics, the visibility or stability of the air and transparency, the scattering of light due to the amount of water vapor and particulate matter in the air. When you look at the Moon and the planets, and it looks like water is running over them, you probably have bad "vision" because you are looking through turbulent air. Under good "seeing" conditions, stars appear steady, without blinking, when you look at them with unaided eyes (without a telescope). The ideal "transparency" is when the sky is inky black and the air is unpolluted.

Selection of an observation site

Travel to the best location that is reasonably accessible. It should be away from city lights and upwind from any sources of air pollution. Always choose as high an elevation as possible; This will take you above some of the lights and pollution and ensure you are not in ground fog. Sometimes low fog banks help block light pollution if you drive over them. Try to have a dark, unobstructed view of the horizon, especially the southern horizon if you are in the northern hemisphere and vice versa. However, remember that the darkest sky is usually at the "Zenith", directly above your head. It is the shortest path through the atmosphere. Do not attempt to observe any object when the light path passes near any protuberance in the ground. Even extremely light winds can cause great turbulence in the air when they flow over the top of a building or wall. If you try to observe on any structure, or even on a sidewalk, the movements you make can cause the telescope to vibrate. Pavement and concrete can also radiate stored heat, which will affect observation.

Viewing through a window is not recommended because window glass will greatly distort images. And an open window can be even worse, because warmer indoor air will escape through the window, causing turbulence that will also affect images. Astronomy is an outdoor activity.

Choose the best time to observe

The best conditions will have still air and obviously a clear view of the sky. It is not necessary that the sky be free of clouds. Often, broken cloud conditions provide excellent visibility. Do not view immediately after sunset. After the sun sets, the Earth is still cooling, causing turbulence in the air. As the night progresses, not only will visibility improve, but air pollution and ground lights will often decrease. Some of the best observing times are usually early in the morning. Objects are best observed when they cross the meridian, which is an imaginary line that crosses the zenith, from north to south. This is the point at which objects reach their highest point in the sky. Observing at this time reduces bad atmospheric effects. When looking near the horizon, you see through a lot of atmosphere, complete with turbulence, dust particles, and increased light pollution.

Cooling the telescope

Telescopes require at least 10 to 30 minutes to cool to outside air temperature. This may take longer if there is a large difference between the temperature of the telescope and the outside air. This minimizes heat wave distortion within the telescope tube (tube currents). Allow longer cooling time for larger optics. If you are using an equatorial mount, use this time for polar alignment.

Adapting your eyes

Do not expose your eyes to anything except red light for 30 minutes before observing. This allows your pupils to expand to their maximum diameter and build up levels of optical pigments, which are quickly lost if exposed to bright light. It is important to observe with both eyes open. This prevents eyepiece fatigue. If this is too distracting, cover your non-use eye with your hand or an eye patch. Use indirect vision on weak objects: The center of your eye is the least sensitive to low levels of light. When seeing a faint object, do not look directly at it. Instead, look slightly to the side and the object will appear brighter.