Download EXOPLANET OBSERVING FOR AMATEURS

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Chapter 2
Observatory Tour
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Since I will be using real data to illustrate systematic errors I will describe my
observing systems. Note the use of the word "systems" in the plural form. Even with
one telescope it will matter whether you are configured Cassegrain or prime focus,
and whether a dew shield is used, or whether a focal reducer lens is used, and where
it's inserted. Every change of configuration will change the relative importance of the
various systematic error sources. During the past year I have had three different
telescopes, so I am aware of issues related to telescope design differences - such as
the problems produced by meridian flips (i.e., Celestrons). All of these telescopes
have had 14-inch apertures with catadioptic optics: Celestron CGE-1400, Meade
RCX400 and Meade LX200GPS. Most of my illustrations will be with the last one.
These are typical telescopes now in use by advanced amateurs for exoplanet transit
observations.
I use a sliding roof observatory located in Southern Arizona, at an altitude of 4660
feet. Atmospheric extinction values for B, V, R and I bands are typically 0.25, 0.16,
0.13 and 0.08 magnitude per air mass.
Figure 2.01 “Hereford Arizona Observatory” with a canvas-covered sliding roof.
The Minor Planet Center has assigned it a site code of G95.
All control functions are performed by a computer in my house, using 100-foot
cables in buried conduit (the control room is shown as Fig.s 2.03 and 2.04). For all
Cassegrain configurations I use an SBIG AO-7 tip/tilt image stabilizer. It can usually
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