This stellar puzzle cache, in honor of a milestone achievement by one of geocaching's brightest stars, is part of the Fizzy Fest 10K series.
Astronomers classify stars by analyzing their spectra. A star's spectral type is designated using the sequence of letters O, B, A, F, G, K, and M. These letter classes correlate with surface temperature, with O the hottest and M the coolest. Each letter class can be further divided into numeric sub-classes ranging from 0 to 9, with 0 the hottest and 9 the coolest. Sirius, the brightest star in our night sky, is a bluish-white star of type A1. Our Sun is a type G2 star.
K-type stars are orangish stars that are slightly cooler than our Sun. The three brightest K-type stars in the sky are Arcturus in the constellation Boötes, Aldebaran in the constellation Taurus, and Pollux in the constellation Gemini. All are easily visible from suburban skies and are noticeably orange.
The cache is NOT at the posted coordinates, but the following ten K-stars (10K, get it?) will allow you to determine the correct coordinates. The ten stars can be located at the given azimuths and altitudes when observed at the given locations and at the given dates and times. All ten stars are bright enough to be visible with the unaided eye in any moderately dark location.
| K-Star |
Observation Parameters |
Spectral Type |
| Observing Location |
Local Date & Time |
Azimuth |
Altitude |
 |
N 37° 41.017' W 121° 26.061' |
09/03/03
21:06 PDT
|
187° 09' |
+22° 09' |
K2.5 IIIa |
|
N 37° 17.411' W 121° 57.121' |
05/05/05
23:09 PDT
|
101° 14' |
+29° 27' |
K2 III |
|
N 39° 17.702' W 119° 41.222' |
06/16/07
21:26 PDT
|
253° 54' |
+17° 00' |
K2.5 III |
|
N 37° 39.484' W 121° 48.316' |
05/15/10
22:26 PDT
|
36° 24' |
+57° 49' |
K2 III |
|
N 38° 38.082' W 121° 26.844' |
09/24/11
23:25 PDT
|
287° 58' |
+40° 32' |
K2- IIIab |
|
N 35° 06.434' W 106° 37.128' |
03/07/13
23:13 MST
|
314° 31' |
+43° 24' |
K0 IIIb |
|
N 42° 09.448' W 096° 18.019' |
07/17/14
22:01 CDT
|
40° 21' |
+35° 46' |
K1.5 Ib |
|
N 37° 41.800' W 121° 01.600' |
12/31/16
21:07 PST
|
4° 09' |
+22° 13' |
K4- III |
|
N 39° 04.894' W 120° 54.975' |
07/19/18
22:09 PDT
|
77° 36' |
+44° 21' |
K0 III |
|
N 37° 40.362' W 121° 52.619' |
02/12/19
23:03 PST
|
318° 05' |
+33° 39' |
K3- Ib-IIa |
Puzzle notes:
- All dates and times are local for their locations and take Daylight Saving into account if in effect.
- Azimuth angles are measured from true north and increase eastward.
- Altitude angles take the effects of atmospheric refraction into account.
- All stellar positions were calculated using the web version of Stellarium and confirmed with the Windows version of Cartes du Ciel.
- Stellar classification is somewhat subjective. Depending upon the source used, spectral types for any given star my differ by up to two numeric sub-classes. The spectral types listed above are per the SIMBAD database.
- To aid with identification, the spectral types above also include each star's luminosity class, which is designated with a Roman numeral and correlates to the size of the star. The stars above include class I supergiants through class III giants. Our Sun is a class V main-sequence star.
You can validate your puzzle solution with certitude.