Updated Stage 2 in 2015 after the original Stage 2 was painted over.
This is a 3 stage multi cache with an astronomy theme. You will need access to a computer after the first and second stages and before the final. The cache can be found by car, boat or bicycle (no bikes on the trail at the final) with a bit of walking. Very suited for a winter find. This requires web based astronomy software as listed below to help solve the puzzle. Note that the stars were used for positioning and navigating long distances for thousands of years before GPS was developed.
The first stage gets you to a plaque with a date. Record this date.
The coordinates for the second stageare shown below and bring you to the front door of a building. Record the 3 digit address as a time (hour:min PM)..
This is the hard part! Astronomers use the Celestial Coordinate System to specify a direction into space from a observing site on earth. The Celestial space stays fixed while the earth spins on its axis and orbits the sun. GPS coordinates correspond (in a way) to the Celestial Coordinate System used in astronomy. The GPS coordinates use two numbers (latitude and longitude) to specify a point on earth. Review the description of Declination and Right Ascension RASC Calgary Centre - A Complete Guide to Right Ascension and Declination and how they correspond to the latitude and longitude used by GPSr’s. The following questions will help you.
- What is the definition of zenith?
- What is the celestial equator?
- Does Declination correspond to the North or West coordinate on your GPSr?
- Right Ascension (RA) relates to the other GPS coordinate as well as which other measurement (4th dimension)?
Determine the name of the star directly overhead on that day and at that time found in the first and second stages. Also determine the last 3 digits of the HIP50abc number for that star.
The Declination for the zenith is read directly from the GPSr (Question 3). The RA must be calculated based on the local time and date and position.
Since 1894, astronomical time is based on Coordinated Universal time (UTC) historically based on Greenwich time without Daylight Savings. Peterborough, ON is in the Eastern time zone (Standard Time zones were established by Sir Sanford Fleming who had a local connection). Eastern time is 5 time zones (hours) west of Greenwich. The sunrise in Greenwich occurs before sunrise in Peterboro. If the date discovered above falls into the Daylight savings period, that will reduce the UTC by 1 hour. Calculate the UTC for the discovered time and date.
The UTC can then be converted to Local Sidereal Time (LST). LST basically undoes the fine work of Sir Sanford Fleming to produce a local (not standard) time based on the sunrise on the vernal equinox (about March 20). For our purposes, the LST is the same as RA used in star mapping. Note: these times are now based on the same type of atomic clocks used in the GPS system rather than sunrise times.
Use the coordinates for stage 1 (you may ignore seconds) and the date and time, you must calculate LST. I present a simple calculation that will get you within several light years of the correct star. Each 15 degrees of longitude represents 1 hour. Because the earth revolves around the sun, noon for each solar day is about 4 minutes later. The 12 hours is because the sun is observed at noon but the day begins at midnight. Calculate and record the LST. This is the same as RA used by astronomers.
There are a number of virtual telescopes which can be pointed to the Declination and RA calculated above. See Your Sky and select options as shown.
You will see a view of the stars in the sky. The center of the screen is directly overhead.
- Determine the Name of the star overhead on that day and at that time. Also search for the last 3 digits of the star catalog HIP50abc number.
Final
The final is located in the Canal Nature Area within 50m of the trail. Parking is available at N44 20.703 W7817.255. The coordinates for the final are: (N44 20.545 + abc) (W78 17.079 + abc) The swag in the cache has a space and astronomy theme.
If you found this cache interesting, please feel free to explore Astronomy software further. You may also wish to join a local astronomy club. I got a lot of help from one of the members setting this cache up.
http://www.peterboroughastronomy.com/
Cool astronomy software such as Microsoft Research World Wide Telescope ™ or Google Earth Sky™ or Meade Autostar Suite™ is available. This astronomy software does all the calculations done above.
Notes:
- Family Friendly
- Winter Friendly
- Even when the stars are not visible to the human eye, they are still up there.
You can check your answers for this puzzle on Geochecker.com.