WELCOME TO NoVAGO U: ALL ABOUT THE OPTICS
This geocache will illustrate a few principles about how we perceive light in different ways based upon the fequencies of the rays of light and the diffractive properties of the reflective surfaces illuminated by the light source. Note that one or more special tools are required to complete the field puzzles in this multi-stage geocache, but what you need is provided or likely already travelling with you.
The posted coordinates take you to Bren Mar Park. Bren Mar Park borders Edsall Road on a ridge. The park was acquired by Fairfax County piecemeal, and is about 35 acres. The trail system in the park is extensive, and connects to the neighboring streets as well as to Edsall Road. The trails are laid out in places along lush, out-of-control greenery that smothers what likely used to be cleared fields and now looks like "seas of green" that borders a stream valley. There are also a lot of briars in the woods, along with the expected collection of poisonous plants, spiderwebs and bugs if you are doing this during the warmer seasons. Given the extensive overgrowth in these areas and in the perimeters of the woods along the trail, I recommend staying on the trails for all stages of the geocahe until your destination is less than 50 feet from a trail, open field, path, or old road bed.
One point of interest -- There are a couple of small grassy areas adjacent to the parking area where there used to be a house and small detached building. Those buildings were removed within the last few years but nothing else has been done to improve those spaces for park visitors. At the time this geocache is published, you can still see those structures if you use google street view.
In order to find the geocache, proceed to the posted parking coordinates. From the posted parking coordinates (not the posted location for the geocache -- use the parking coordinates for this part) you will be approximately 150 feet away from the first physical cache stage. Although you could walk around in a circle 150 feet away from the parking coordinates and eventually find the first stage, you should be able to narrow your search quite a bit by rearranging these fourteen digits into a set of coordinates that are 150 feet from the parking coordinates: In deference to the park's history, it may also help to prioritize search areas closer to where the house on the property used to be.
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All stages in this geocache, including the parking, use the same degrees and minutes. The changes in the coordinates for the different stages of the geocache are for the decimal minutes in the latitude and the longitude (N 38 48.XXX W 77 08.XXX). The other thing that will help you narrow the search is to consider that the coordinates for the first physical stage will be very similar to the posted parking coordinates because they are only 150 feet away.
The first physical stage is about the size of a water bottle and gives you a field puzzle and the tool you need to find the coordinates for the next physical stage. The optics there rely on different properties of colored filters. Given that many people, particularly men, have some degree of color blindness with blues and greens, I have tried to mitigate that by providing redundant information using slightly different color bands. There are extra tools provided here so you are may take one of them as a souvenier. Please make sure to leave at least one of them with the puzzle, and please send me a message when the supply is low so I can replenish that stage. After you have the coordinates for the next stage, I recommend finding the trail that will take you there rather than following your GPS to bushwhack to it.
The next stage is well hidden and about the size of a thick bumper sticker, so look carefully. It is probably where you think it is, but easily overlooked. The field puzzle for this stage works best if you have sunlight to aid in your examination. And by that I mean TAKE THE OBJECT TO WHERE YOU HAVE A CLEAR VIEW OF THE SUN TO SHINE ONTO IT and look at the reflection. YOU MAY WANT TO LOOK AT THE PHOTO GALLERY FOR INSTRUCTIONS. When things are properly aligned the information you need will pop out clearly. If you are staring at it on a cloudy day you may get enough information using the flashlight on your phone to make some educated guesses where you need to go next, but your results may vary. I have tried to use other kinds of flashlights to test this puzzle and they generally do not work as well as the single LED on a phone flashlight. The sun is your best light source to investigate this reflected light.
That stage will give you the coordinates for the final stage, a nice walk on the trails to a shoe-box sized container protected by prickly terrain and stocked with some cool swag.
Please handle all field puzzles carefully and replace as found (assuming they were not found out in the open).
This geocache was placed with permission from Fairfax County Parks Authority. No night caching.
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