WitDubMulVar  STAR  ATLAS  GUIDE   2
Tom  Whitney    256-6234      E-Mail

OBSERVING
In Dark Sky w/ good Eyesight, Optics, & Seeing - Visibility & Separation w/ :
      Eye - Mag 6 & 500"                      50 mm Binos - Mag 9 & 4"
      90 mm Scope - Mag 10 & 3"         4" Scope - Mag 11 & 2"
      8" Scope - Mag 12 & 1.5"
PURKINJE EFFECT - Eye less sensitive to color in low lite & more sensitive to
    Blue & Green.  Makes Dim Star near Brite Star appear more Green or Blue
DAZZEL EFFECT - Eye sees more White w/ increased star briteness or Aperture
CONTRAST COLOR EFFECT - Eye sees Color/Tint more intensely if Star seen near
    Star of Contrasting Color/Tint
ANALOGUS HUGHES EFFECT - Eye sees Color/Tint less distinctly if Star seen
    near Star of similar Color/Tint
DEFINITIONS
Averted Vision - Concentrating on object not in Vision Center.  Periphery more
    Sensitive in Dark. Cones more concentrated in Vision Center, Rods in Periphery
Components - Stars in Double or Multiple Star System
Dark Adaptation - Process by which Human Eye more sensitive to Lite.  Most
     Adaptation occurs 15-20 mins., then for 30-45 mins. Eye produces chemical
     to further increase Lite Sensitivity
Direct Vision - Concentrating on object in Center of Vision
Double Star - 2 Stars that appear close
     Naked Eye Double - 2 Stars that appear close to the Naked Eye
     (1) Optical Double - 2 Stars that appear close in a Telescope
     (2) Optical Double - 2 Stars that appear close in a Telescope, but are not
           Gravitationally Bound
Binary - 2 Stars that are Gravitationally Bound, in Mutual Orbit
      Non Visual Binary - 2 Stars Gravitationally Bound, but not Optically Visible
Multiple Star - 2+ Stars that appear close
      Naked Eye Multiple - 2+ Stars that appear close to Naked Eye
      (1) Optical Multiple - 2+ Stars that appear close in Scope
      (2) Optical Multiple - 2+ Stars that appear close in Scope, but not (all)
             Gravitationally Bound
Multiple Star System - 2+ Stars Gravitationally Bound, in Mutual Orbits
Position Angle - Direction of Secondary/Component from Primary, measured
      Clockwise from North as 0
Primary - usually the britest Star of Double or Multiple Star
Secondary - usually dimmer of Double Star
Seeing - how Steady Telescope Image is,  effected by : Tube Currents -
      Turbulence & Temp. Differences in Telescope
      Ground Seeing - Turbulence & Temp. Differences in Observing Area
      Atmospheric Seeing - Turbulence & Temp. Differences in Atmosphere
Transparency - Clearness of Sky