ASTRO-PHYSICS GTO - Advanced Features; Sync Function

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ADVANCED FEATURES
The following paragraphs detail some very important and powerful features of your Keypad and servo drive system. Be
sure you read this section carefully and understand the material presented. Sync and Re-Calibrate are vital parts of the
GoTo system. The Meridian Delay feature is a tremendous asset when imaging, as well as being an integral part of the
GTO Quick Star Drift method of polar alignment. They are only of value, however, when used correctly. With both Sync
and Re-Calibrate, the best calibration objects to use are single bright stars. Single bright stars are easy to distinguish, and
you don’t have to guess at where the center is. Solar system objects are useful for daytime observing and setup, but be
careful! If you use the sun as your sync object, you must be sure to use a solar lter on both your nder scope and your
objective to protect your eyes! Other solar system objects, although useful for daylight and twilight calibrations are never
as good as a single bright star. Because the moon and planets move in relation to the rest of the sky, their positions must
be calculated. They are also not point sources, so again you must estimate the center, (not too hard with Mars, but more
of a challenge with a crescent moon).
Sync Function
Please note: The Sync command should only be used AFTER you are properly polar aligned!
Sync is used typically at the start of an observing session or after the mount has been moved by hand. Sync calibrates
the mount on a known object in the database, one to which you have positioned your telescope manually. Sync also
establishes the orientation of the mount with respect to the telescope, counterweight shaft and pier. Sync assumes that
you have placed your telescope on the proper side of the meridian, i.e. a telescope placed on the west side of the mount
pointing to a star in the east. This assures that the telescope will be positioned on the proper side of the mount for all
subsequent objects. PLEASE READ THE COMPARISON BETWEEN “SYNC” AND “RE-CALIBRATE” BELOW TO AVOID
POTENTIAL PROBLEMS! These are typical uses of Sync.
Startup – Your mount is polar aligned and Auto-start is set to “no”
1. The Site Menu will display when you power up the mount. If you had not parked, the mount will start tracking in R.A.
immediately. However, if you had parked in positions 1, 2, 3, 4 or 0 at the end of the last session, the mount will NOT
start tracking until you choose your location from the site menu.
2. Choose your location. This will send location, date, time and daylight savings information to the mount. The Sync,
Align, and Resume menu will now appear.
3. Point your telescope to a known bright star or solar system object. Make sure the object is on the opposite side of the
meridian from the telescope – see below. Center it in the eyepiece. (If the object drifts, you will know that you are not
truly polar-aligned).
4. Select: “1=Star Sync” and scroll through the common star names using <PREV and NEXT> until you nd the one that
is centered in your eyepiece. The solar system objects are at the end of the list. Remember, you can use the <PREV
button to scroll from the back of the list.
5. Select your target object by pressing the corresponding number (1, 2 or 3) and then press GoTo. This will sync on the
object. The mount will not actually slew anywhere. The Main Menu will appear. Begin observing. Note: to help prevent
mistakes (maybe you pressed “1” for Algedi when you meant to press “2” for Algenib ??) the Keypad will not allow you
to sync on an object that is below your horizon.
Startup – Your mount is polar-aligned, Auto-start is set to “yes”, however the telescope has been moved
1. The Main Menu will display when you power up and the mount will start tracking (whether you parked at the end of the
last session or not).
2. Manually point your telescope to a known star or solar system object. Make sure the object is on the opposite side of
the meridian from the telescope – see below. Center in the eyepiece (if the object drifts, you will know that you are not
truly polar-aligned).
3. Go to “1=Objects” → “5=Stars”. The Star Selection Menu will appear. (The solar system objects are at the end of the
list.) Use <PREV and NEXT> to scroll through the list.
4. Select your target object by pressing the corresponding number (1, 2 or 3). The Star Selection screen for that star will
appear. Note: the “>” sign has been left off of the screen to help prevent accidental syncing. DO NOT press GoTo.
Also note: to help prevent mistakes (maybe you pressed “1” for Algedi when you meant to press “2” for Algenib ??) the
Keypad will not allow you to sync on an object that is below your horizon.
5. Press NEXT> and the Sync conrmation screen will appear.