This cache is the fourth in a series that I have added to my “rock collection.” So far Big Bertha, Big Ben and Big Mac are my other big rock caches. I discovered this particular candidate after picking up another cache of mine to do repairs on it. After picking up my other container I was headed east along a gravel road. My purpose for not going back home right away was that I wanted to see a magnitude – 8 iridium flare as long as I was out and about. As I headed east toward the centerline along which I could best see the flare I passed by this rock. Being on this particular road I thought to myself, “So that’s why it's called that! I’ve long wondered how it got its name.” You'll understand what I'm talking about when you get to the cache site. [No need to elaborate on what I've just said about the road's name in your posts please.]
To begin the process of locating this big baby, go to Black Hawk County Online and explore the mapping software until you find the Robinson Bird Sanctuary in the Greenbelt along the Black Hawk Creek. Once you find it and get the magnification about like what you see in this picture, click on the little ruler icon on the upper right of the map area. Now click on the spot where Prescotts Creek enters the bird sanctuary on the east side. See the red line I made here). Now carefully place the curser over to the point where Prescotts Creek is shown to enter the Black Hawk Creek. Read off the distance as listed at that point and record it. You will need to use your measurement in equations 1a and 1b to obtain a coordinate for determining where to begin looking for the location of the cache in an aerial photo. NOTE: it will not matter if you are a few feet off in your measurement along the creek.
Following is equation 1a: [Your measurement in feet] ________ ÷ 10,000 + 42.3246 N° = the latitude coordinate that you that you need to begin with at a Teraserver website. Use the same measure in equation 1b to get a corrected longitude. Equation 1b = [Your measurement in feet] ________ ÷ 10,000 + 92.0728 W° = the longitude coordinate that you need to begin with at the Teraserver website.
[[UPDATE! 10/20/13 The URL for Terraserver has changed. Here is the new one: http://www.terraserver.com/home.asp The coordinate must now be in the degrees, minutes, second format. I hope the imagery works. It's now in color. The terraserver logos are very much in the way as well. I suppose using Google Earth would be better.]] Now go to Teraserver Viewer. Once there type in the decimal coordinate you determined. With that done click on “Go.” Now zoom out two clicks so that the scale = 16 meters per pixel.
The cache is located in the yellow circle shown here. Once you think you have the spot using 16 m resolution click on what you believe to be the “cache corner.” Now zoom in to a 2 m resolution and click on the place where the cache itself is. Look at the coordinate listed just above the picture that comes up. Notice that it has been converted to the standard GPS format for you. Use the coordinate checker listed below to see if your coordinate is within 25 feet of the actual location.
I will tell you that the thousands place in both the minutes of latitude and longitude are 5 and 1 respectively.
You can check to see if your coordinates (converted to degrees/decimal minutes) are accurate to within 25 feet at Geochecker.com.
That’s it! Go find the cache!