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Indication feature of the locations of Sirius and Arcturus
The two powder blue circles overlapping the waxing and waning moon
patterns display the loci of Sirius and Arcturus. Sirius, with an apparent
magnitude of −1.5, is the brightest in the stars in the whole celestial sphere
excluding the Sun (Bayer designation: α CMa, declination −16° 42 ' 58 "
and right ascension 6h 45m 09s at the equinox J2000.0). Arcturus, with
an apparent magnitude of −0.0, the fourth brightest stars there (Bayer
designation: α Boo, declination +19° 10 ' 57 " and right ascension 14h 15m 40s
at the equinox J2000.0).
Each locus has 72 dots with dates whose center indicates the first, eleventh
and twenty-first days of each month (based on the noon of the universal time
in the average year). Using the loci and the azimuth/altitude lines on the
transparent dial, you can determine rise and set of Sirius and Arcturus at the
current time including the current day (using the upper edge of the sunrise/
sunset line for determination) and can obtain their direction and altitude in
their appearance.
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