Star Party Tips: Red Astronomy Flashlights

Posted by E. Gazelle on February 1, 2009

What is the single most important thing you need to know when attending an Astronomy Star Party? The answer is to avoid using or shining any form of white light after dark at any such gatherings.

The reason has a lot to do with the way our eyes function. In order to see the faintest deep sky objects, the surrounding areas should be pitch dark to allow our pupils to be fully dilated.

After about 30 to 45 minutes in the dark, your pupils will gradually dilate allowing more light to enter your eyes so that you may see better in the dark. Besides enabling you to move effortlessly about in the dark, you will be able to see faint deep sky objects. This will help you get the most from your stargazing activities.

Our retinas are highly sensitive to bright white light and the slightest amount will trigger the muscles around the pupils to relax in order to shut out the glare. Smaller pupils means less light entering your retinas thus interrupting the continuity of your observation.

Once exposed to bright light, you will have to wait another 45 minutes or more to get accustomed to the darkness again. The brighter the white light, the longer it will take for your eyes to re-adjust to the dark.

Bring A Red Flashlight

Do you know why a red flashlight is ideal for night time sky watching and star parties? Well, red light, on the other hand, has little effect on your retinas. The red light from such a flashlight is not overwhelmingly bright and glaring, unlike white LED light. In short, red light has lesser impact on your night vision compared to white light. Therefore, a red flashlight is ideal for extended night-time sky watching. Use them for best viewing comfort and stargazing results. It is good practice to keep one red astronomy flashlight in your stargazing tool box.

Although naked-eye observation is a good way to start, eventually, you may want to progress to a pair of binoculars or a telescope, since they can help you see fainter deep-sky objects such as galaxies and star clusters. While your eyes are getting accustomed to the darkness, it is a good time to let your telescopes and other stargazing equipment adjust to the outside temperature.

Here are more useful tips for astronomy star parties:-

• If you think you have to open and close your car door or trunk after dark, remember to turn off the interior and trunk lights or have them covered with red translucent tapes.
• Make sure all car headlights are off (or properly covered) when arriving or departing any astronomy star party observation site after dark.
• If you HAVE to take photos, do switch off the flash!
• Refrain from flashing any kind of flashlight, red or otherwise, at eye level. Keep the beam low and shine towards the ground.

Always bear in mind that the next person might have set her equipment up for long-exposure astrophotography. The smallest amount of light, even from a lighter or a match, will ruin the entire night’s effort.