Aligning The Ra Setting Circle - Celestron Ultima 11 Instruction Manual

Make the appropriate adjustments to the polar axis to eliminate any drift. Once you have eliminated all the
drift, move to the star near the eastern horizon. The star should be 20 degrees above the horizon and within
five degrees of the celestial equator.
If the star drifts south, the polar axis is too low.
If the star drifts north, the polar axis is too high.
Again, make the appropriate adjustments to the polar axis to eliminate any drift. Unfortunately, the latter
adjustments interact with the prior adjustments ever so slightly. So, repeat the process again to improve the
accuracy checking both axes for minimal drift. Once the drift has been eliminated, the telescope is very
accurately aligned. You can now do prime focus deep-sky astrophotography for long periods.
NOTE: If the eastern horizon is blocked, you may choose a star near the western horizon, but you must
reverse the polar high/low error directions. Also, if using this method in the southern hemisphere, the
direction of drift is reversed for both R.A. and DEC.

Aligning the RA Setting Circle

In order to align the R.A. setting circle, you must first polar align the telescope mount. Second, you need to
know the names of a few of the brightest stars in the sky. If you don't, they can be learned by using the
Celestron Sky Maps (#93722) or consulting a current astronomy magazine. To align the R.A. setting circle:
1. Locate a bright star near the celestial equator. The farther you are from the celestial pole, the
better your reading of the R.A. setting circle. The star you choose to align the setting circle should
be a bright one whose coordinates are known and easy to look up. (For a list of bright stars to
align the R.A. setting circle, see the list at the back of this manual.)
2. Center the star in the finder.
3. Center the star in the field of view of the telescope.
4. Start the clock drive so that the mount tracks the star.
5. Look up the coordinates of the star. You can consult a star catalog or use the list at the end of this
manual.
6. Rotate the R.A. circle until the proper coordinates line up with the R.A. indicator. The R.A.
setting circle should rotate freely. The R.A. setting circle has a marker every six minutes with each
hour labeled.
The R.A. setting circle is now aligned and ready to use. The R.A. setting circle is clutched to the R.A. gear
rotation. As long as the drive is operating, the circle does not need to be reset once indexed to the correct
coordinate (i.e., once aligned). If the drive is ever turned off, then the R.A. setting circle must be reset once
reactivated.
Once you have finished this process you are ready to use the setting circles to locate objects in the night sky.
See the section on "Using the Setting Circles," for specific information.
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Ultima 9 / and Ultima 11 Manual
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