Appendix E - Operational Tips
107
When you place your diagonal in a position (i.e. upright, or to the left 20º, or to the right 45º, etc..) for
observing, it introduces some amount of cone angle in the altitude direction. This does not matter unless
you rotate the diagonal. When you rotate the diagonal, some component of the altitude cone angle is
transferred to azimuth. So when you align the telescope to your alignment stars, don’t change the position
of the diagonal. If you do change the position while you are observing an object, move the diagonal back to
its original position before slewing to the next object. (You only need to worry about this if you are
concerned about maximum pointing accuracy. Don’t worry about this if you are just observing.)
There is azimuth cone angle introduced by a star diagonal too. But, there is not a way to counter it without
using a collimated star diagonal. The cone angle is usually pretty small on the diagonals and the effect of
the angle is cut in half if you align to objects between 30º and 60º in altitude. The effect is maximized at
the zenith and the horizon.
The bottom line of diagonal use if pointing accuracy is an issue.
1. Align stars with the diagonal in one orientation around the optical axis.
2. Use the same orientation of the diagonal to align and to find objects.
3. For the absolute best pointing accuracy, use a laser collimated diagonal in one position only or don’t
use a diagonal at all.
Viewing objects below the horizon
The Ultima 2000 does not stop you from slewing the telescope to an object that is below the horizon. On
large professional telescopes it can be dangerous for the telescope to slew below the horizon, but there is no
danger to the Ultima 2000. Since you can slew below the horizon, you can get a feel for the locations of
celestial objects in the sky; even if they are not yet in the sky. The Ultima 2000 can still point to them. If
you see the telescope slew just below the horizon to the East, you know the object is going to rise shortly.
If you want to illustrate to your friends or yourself how the Earth is rotating, it might be instructive to slew
to the Sun at 2:00 AM in the morning. The Ultima 2000 will point to you where the Sun is. You can have a
feel of how the stars rise and set and rise again!
Using Cord Wrap
In the event that the telescope continues to slew in only one direction in azimuth while the Cord Wrap
feature is on, you may need to cycle the power OFF, then turn the power ON again. This should return the
telescope to slewing in the direction that will keep it from wrapping the powercord around itself. If you are
not using an external power source, it is useful to turn the Cord Wrap Control to OFF.
Slewing Autostop
The Ultima 2000 has an auto stop feature should you need to stop the telescope from slewing. The first way
to stop your telescope from slewing is to press any of the diamond buttons on the hand control. The second
way is to push the tube slightly in the opposite direction to which it is slewing. This will also abort the
slew. One consideration to the second method is that if the telescope is not balanced in altitude, it is
possible that when the telescope slews to an object, the telescope may move slightly in the opposite
direction which will abort the slew. To fix this, either carefully balance the telescope or press the GO TO
command again. Another consideration is that from time to time, when the telescope is commanded to slew
to an object, it may pass by the object in the final phase of centering . Instead of stopping at the object the
motors stay on and the telescope continues pass the object. The telescope has not lost its alignment but has
been confused by the abort command and does not successfully abort. When this occurs, press any of the
diamond buttons to finally abort the slew, then slew to the object again.
To Next Page
Loading...
