Lighting Rules
2008 OSP Lighting Rules
The Oregon Star Party supports the International Dark Sky Association in it's work to protect the night skies from light pollution.
In order for everyone to get the maximum enjoyment from the dark skies here, we have put together a few rules about lighting after dark and the reasons behind them. Please read through this information and share it with everyone in your party.
Please plan in advance to cover your flashlights and all the white lights in your trailer or RV before you leave home.
Rules
The number one rule is “don’t use light unless you absolutely need it”. The light that we want to see is from the sky, not from ourselves. You’d be surprised how easy it is to see the road well enough to walk on it without a flashlight on.
Where light is necessary, use only faint red light. A bright flashlight with a single layer of red tape is too much light. Use a small flashlight or put enough red tape over the beam to reduce it’s output so that it is just enough light to work by when you are fully dark adapted.
Either disable your car’s dome and trunk lights or cover them with red tape. Even if you don’t think you’re going to need to get into your car or trunk at night, you never know.
Don’t leave lights on when you’re not using them. If you are away from your RV, don’t leave the porch light or any interior lights on – even if they're red.
Use only dim red light inside tents and RVs at night. Even though you have curtains closed or windows covered in black plastic, some light still leaks out and takes away someone’s enjoyment of the night.
Anyone using a computer anywhere on site must fully shield the monitor so the monitor does not affect the dark adaptation of visual observers or interfere with the astro-imagers and photographers.
Green Lasers are not allowed except by the OSP for the Sky Identification and Limiting Magnitude programs and then only until 9:30 pm.
Reasons
Our goal is to be able to see the faint lights in the sky as well as possible. Your eyes are sensitive to an incredible range of brightness, but it takes time for them to adjust to very low lights. A substance called visual purple is slowly created in our eyes when lighting conditions are very dim, increasing the eye’s sensitivity to very faint light. This increase in sensitivity is called “dark adaptation” and typically takes 20 to 30 minutes. It is only after becoming fully dark adapted that we can see and appreciate the fainter objects in the sky. Unfortunately, even brief exposure to brighter lights (such as the light from a flashlight or a car’s dome light) destroys the visual purple and the dark adaptation process must start over. That is why even a little bit of white light is so harmful. You may only be exposed to that light for a couple of seconds, but it can set your observing time back by 20 minutes.
It is interesting that red is not nearly as harmful to visual purple as white light. Exposure to red light still harms a dark adapted eye, but not to the extent of white light. That is why we only allow red light. Another important factor in getting the most from the night sky is contrast. Contrast is the difference in light levels between the object you are viewing and its surroundings. Now, usually we think of an object’s surroundings as the area of sky around it. However, it also involves anything that your eye can see from outside the eyepiece. Any stray light near a telescope (red or otherwise) cuts down on the contrast and makes objects more difficult to see. For this reason, it is important to keep your red flashlights aimed down at the ground or at your star charts and not at the person set up next to you.
WATCH THOSE LIGHTS - RED TAPE IS AVAILABLE AT THE REGISTRATION TENT and THE INFORMATION TENT!