Paramount User Guide
137
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P a g e
A black-filled square indicates that the joystick is centered and the mount is not slewing via the
joystick inputs.
A green-filled square indicates that the joystick is issuing slew commands to the highlighted axis.
Note that the joystick handle can be moved diagonally so as to issue slew commands both axes at once
(N, E, S, W or NE, NW or SE, SW). In this case, two adjacent squares will be green.
Periodic Error Correction Tab
The
Periodic Error Correction
tab is used to generate and manage periodic error curves for the Bisque TCS
control system. The
Bisque TCS PEC Table
tab is used to retrieve, save, delete and view the periodic error
correction curve. The
Compute PEC Curve
tab is used to determine the optimal periodic error curve based
on mount tracking data.
The Paramount has precision worms and gears that slew the mount’s axes and track the earth’s relative
motion compared to the stars. As the worm rotates, imperfections in the drive system (on the order of
one
twenty-millionths
of one inch
) introduce a predictable “back and forth” drift at the eyepiece.
This drift is called
periodic error
and is present in all worm and gear drive systems. The mount’s periodic
error can be virtually eliminated using
periodic error correction
. Here is an overview of the periodic error
correction process. Step by step details follow.
How to Train and Apply Periodic Error Correction
1.
Create a
tracking log
that records the magnitude of the mount’s periodic error over three or more
revolutions of the worm. See “Collecting and Using Periodic Error Tracking Data” on page 142 for
details how to create a tracking log.
2.
Open the tracking log in the
Compute PEC Curve
tab.
3.
Fit an optimal periodic error curve to the tracking log data.
4.
Save and permanently store the optimized periodic error curve to the mount’s firmware.
5.
Turn on the
Apply PEC Corrections
checkbox to apply periodic error corrections.
The importance of applying periodic error correction to tracking depends on several factors:
The magnitude of the mount’s periodic error. All mounts have slightly different periodic error
due to machining variations. The greater the periodic error, the more noticeable the back and
forth “drift” in right ascension and more elongated stars in photos.
The scale of the imaging system. Tracking demands for an imaging system with an image scale of
four arcseconds per pixel or larger are less demanding than on a system with an image scale of
one arcsecond per pixel or less.
The local seeing and weather conditions. A turbulent jet stream caused by nearby mountain
ranges (here in Golden, Colorado, for example) can produce average seeing errors from three to
five arcseconds per pixel and rarely better. A laminar, more stable atmosphere in regions like
Florida or Southern New Mexico in the USA often produce periods of sub arcsecond seeing.
Содержание ME II
Страница 56: ...Paramount User Guide 56 P a g e Paramount ME II Front View Figure 20 The front view of the Paramount ME II...
Страница 57: ...Paramount User Guide 57 P a g e Paramount MX Front View Figure 21 The front view of the Paramount MX...
Страница 58: ...Paramount User Guide 58 P a g e Paramount MX Front View Figure 22 The front view of the Paramount MX...
Страница 85: ...Paramount User Guide 85 P a g e Paramount ME II Rear View Figure 44 The rear view of the Paramount ME II...
Страница 86: ...Paramount User Guide 86 P a g e Paramount MX Rear View Figure 45 The rear view of the Paramount MX...
Страница 87: ...Paramount User Guide 87 P a g e Paramount MX Rear View Figure 46 The rear view of the Paramount MX...
Страница 103: ...Paramount User Guide 103 P a g e Paramount ME II Side View Figure 59 The side view of the Paramount ME II...
Страница 104: ...Paramount User Guide 104 P a g e Paramount MX Side View Figure 60 The side view of the Paramount MX...
Страница 105: ...Paramount User Guide 105 P a g e Paramount MX Side View Figure 61 The side view of the Paramount MX...
