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(meteorobs) Planispheres



Over time we have recommended planispheres to novices in our field.  I
recently purchased a planisphere that is different than any other
planisphere I have ever seen and is worth describing though I do not
think it is at all new.  It is called the "Precision Planet and Star
Locator" from the SKY & TELESCOPE publishing company.  It was designed
and manufactured by David Kennadal in Sweden.  I am not sure that I
would recommend it to a rank beginner but it is really handy for any
regular observer.  A normal planispher consists of two essential disks
with a star map and date indexed on one and a mask and local time index
on the other.  This Planispher has five essential disks.  I won't
describe each disk but outline the functions this instrument (really an
analog computer) can perform.  You can compensate for your distance East
or West of your time zones meridian.  There are functional dotted lines
enabling you to estimate both the declination and true azimuth of any
object.  You can approximate your local sidereal time.  You can map onto
the star map with a cursor any object for which you have the right
ascension and declination such as the meteor radiant.  With the aid of
tables supplied you can locate the Sun and planets as well as determine
twilight times.  With this many disks I am sure a clever person can
invent even more functions.  I must confess that I like gadgets and this
one has kept me busy for hours as well as giving me very useful
data.                 Robert G.

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