From: Stephen Martin (ilium@juno.com)
Date: Sat 28 Jun 1997 - 21:18:19 EEST
Malcolm Cohen
Malcolm asked about visible equinoxes. The only thing I can think of
which would be obvious is that the planet Lightfore would rise and set in
exactly the same star/constellation on such nights. On other nights,
because of the shorter or longer night length, he would rise and set in
somewhat different places.
BTW, the following are the current accepted dates for the equinoxes and
Spring Equinox -- Freezeday/Disorder Week/Sea Season -- 1st day of year
This makes the winter season longer than the summer season, which makes
solstices:
Summer Solstice -- Fireday/Harmony Week/Fire Season -- Yelm HHD
Autumnal Equinox -- Clayday/Fertility Week/Earth Season -- Earth HHD
Winter Solstice -- Fireday/Illusion Week/Dark Season
sense given the tilt of the Dome.
I have been working with Greg over the last few months on some of the
details of celestial mechanics, and have made a few determinations which
he seems happy with. For various reasons, I have determined that the Sky
Dome tilts 9 degrees to the north in summer, then tilts 10.6 degrees to
the south in winter. That is not much of a difference, true. However, if
day length is set to vary in the same ratio (not a requirement,
certainly, but esthetically pleasing), this gives us quite a bit of
variation.
On the Spring and Autumn Equinoxes, day and night are each exactly twelve
(Theyalan) hours in length. At midsummer, day is 14.4 hours long and the
shortest night of the year lasting 9.6 hours. At midwinter, day and night
length varies a bit more, with day being only 9.2 hours long, and the
longest night of the year lasting 14.8 hours.
If these day and night lengths are correct, then we can also determine
some information about Theya and Rausa's visibility. Greg does no longer
accepts the information given for them in Elder Secrets, and gave me
different parameters to work with. Now, Theya is always visible for
exactly 4.8 (Theyalan) hours each night. In other words, she rises 4.8
hours before Dawn in all seasons. Rausa, on the other hand, is always
visible for exactly half the night. In summer, she sets 4.8 hours after
Dusk, but in Winter she sets 7.4 hours after Dusk.
There are a couple of important results of this information. First, Rausa
is always seen to be setting, and Theya is always seen to be rising. When
Rausa is rising and Theya is setting, the Sun is in the sky, and both are
invisible.
Second, Theya and Rausa are only visible together in the sky once a year,
for a brief moment at midnight on midsummer's day.
Finally, Theya ALWAYS rises the exact same height in the sky, every
night, while Rausa is higher in the sky in Winter than in Summer, since
she has longer to fall.
I have begun work on a celestial chronology for Gloranthan history (i.e.,
from the Dawn to 1625 or so), figuring out which stars appeared,
disappeared, changed, etc. I would appreciate it if anyone with obscure
events which I might have missed could send them to me. Also, if anyone
has ideas on how various cultures view the stars and other stellar
objects I would like to hear them. The Book of Drastic Resolutions has an
article on The Night Sky in Prax (and includes some general
clarifications and corrections to previously published star information),
and I have some ideas about the Doraddi, but I would like information on
other cultures as well.
Stephen Martin
ilium@juno.com
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The Book of Drastic Resolutions
drastic@juno.com
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