3
B. Display scroll rate
The rate of scrolling messages is displayed: SCROLL 5. Set
the flashing digit using the UP and DOWN buttons. 0 is very
slow, 9 is very fast. Press ENTER to go to the next step.
c. Encoder settings
The proper encoder settings (ratios) for your specific tele-
scope mount must now be entered into Sky Wizard. The
encoder ratios are based on the resolution of the encoder
used, and the way that it is installed on the mount. If you have
purchased one of Orion’s Sky Wizard Installation Kits, the
encoder ratios are as follows:
ORION PART# TELESCOPE TYPE “R” ENCODER RATIO “D” ENCODER RATIO
#27103
Meade 8" and 10"
-02925
-02160
Schmidt-Cassegrain
#27102
Celestron Classic 8
-04000
-04000
and Powerstar 8
#10301
Celestron C8+
-04000
+02160
and Celestar 8
#10306
Celestron CM1100,
-04000
-04000
CM1400
#2395
Orion and Celestron
+03000
+03000
Great Polaris (GP)
#27121
Orion 6" and 8"
-04000
+04000
Deep Space Explorer
#27122
Orion 10" and 12.5"
-04000
+04000
Deep Space Explorer
#27131
Small Dobsonian
-04000
+04000
#27132
Medium Dobsonian
-04000
+04000
#27133
Large Dobsonian
-04000
+04000
#27134
Giant Dobsonian
-04000
+04000
Sky Wizard will first prompt you to enter the “R” encoder ratio.
Use the UP and DOWN keys to select the proper character,
and then press
ENTER to move to the next character. When
the last digit in the “R” encoder ratio is input, pressing
ENTER
will prompt you to enter the “D” encoder ratio. Use the UP and
DOWN and ENTER keys to input the “D” encoder ratio. When
the last digit is entered, the word
INSTALL will appear again.
The installation is now complete. If you have made a mistake
entering characters in the
INSTALL mode, you must begin
the installation again, proceeding all the way through until the
word
INSTALL appears again.
Determining Encoder ratios for custom
installations
(Skip this section if you have purchased one of the Sky
Wizard Installation Kits)
If you are custom installing a pair of encoders on your tele-
scope’s mount, then you will need to calculate the proper
encoder ratios to be entered into Sky Wizard. The encoder
ratios are essentially the number of “steps” detected by the
encoder when the telescope is fully rotated about one of its
axes. Custom installation is generally not recommended,
since it will usually require the user to machine parts.
There are two basic ways to attach an encoder to a telescope
mount: directly or by use of gears. Direct attachment is when
an encoder is directly coupled to the motion of one of the
mount’s axes. Geared attachment means that gears are used
to couple the motion of the mount with the encoder.
For direct encoder attachment, the encoder ratio is simply the
number printed on the encoder. Typically this number will be
2160 (standard resolution) or 4000 (high resolution). So, for
example, if you are using a 4000-step encoder directly cou-
pled to the RA axis of your mount, you would enter + or - 04000
in the
INSTALL mode when prompted by the “R”. To deter-
mine whether the “+” or “-” sign should be used (encoder
polarity), consult the section entitled “Encoder Direction Test”.
For geared encoder couplings, the encoder ratio is the encod-
er resolution (the number printed on the encoder) multiplied
by the ratio of the gears being used. The gear ratio is the
number of teeth on the gear attached to the mount divided by
the number of teeth on the gear attached to the encoder’s
shaft. For example, let’s say that you are using a 400-step
encoder that has a gear with 60 teeth attached to its shaft. On
the mount, you are using a 120-tooth gear to couple the
motion of the telescope in RA with the gear on the encoder
shaft; this yields a gear ratio of 120/60, or 2. The final encoder
ratio would then be 4000 x 2 = 8000. Thus when prompted by
the “R” in the
INSTALL mode, you would enter + or - 08000.
Again, to determine the encoder polarity (the “+” or “-” sign)
that should be used, consult the section entitled “Encoder
Direction Test.”
Encoder Direction test
The purpose of the encoder test is to make sure the encoders
are set to the correct polarity, correct ratios, and that nothing
is slipping. You must do this test before trying the Sky Wizard
at night. It is the last step in the installation procedure before
going out into the field. Please do this test before calling Orion
support for assistance.
Equatorial Telescopes: Point the telescope up and slightly
toward the South so the Dec. is at 0° on the original (mechan-
ical) setting circles. Rotate the original RA (mechanical)
setting circles so that RA = 00. Turn the Wizard off, then back
on to clear the Wizard and press ENTER after it reads
DEC=0.
Press MODE and scroll to
ENC TEST mode. Press ENTER
and it should read
000+000.
Move the declination axis to 90° north. The display should
now show
000+090 if the Dec. axis “sign” is correct. If the
display reads
000-090 re-enter the INSTALL mode and
change the + or - sign for the Dec axis (D). If the second
numerical value is not 090, then either the encoder ratio is
incorrect, or the encoder is not properly coupled to the decli-
nation axis of the telescope mount. Check to see if you have
entered the correct encoder ratios in the INSTALL mode. Also
check to make sure the connection of the encoder to the dec-
lination axis of the mount is proper and secure. If the display
reads
090+000 (change in first numerical value, no change in
second numerical value), then the leads from the Sky Wizard
cable are reversed; swap the leads by first disconnecting
them from the encoders and then re-attaching them to the
opposite encoder. If the display reads
000+000, then the
encoder is not properly “speaking” to the Sky Wizard; usually
this is because the cable lead attached to the encoder is
