| CONTENTS
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| Default Form |
Expanded Form |
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| Offset from Target |
| The offset function allows the observer to offset the telescope
without affecting the Current Target Position (see note). The offset
function is usually used to make comparatively small moves. Offsets are automatically set
to zero when the telescope is moved to a new target via the "Move to Target" button in the
Main Window.
To offset the telescope, enter the size of the move, in arcseconds, into the box surrounded by
the N, S, E, and W buttons, and push the appropriate one
to initiate the move. Offsets entered in this way are relative offsets, i.e., they
are additive, measured with respect to the position to which the telescope is currently pointed
(i.e, the current target position plus any offset displayed in the Total Offset boxes).
One may also enter offsets into the Total Offset boxes, initiating the move by pushing
the Set buttons. Offsets entered, in this way are absolute offsets, i.e., they are
measured with respect to the current target position, irrespective of any offsets already entered.
The cummulative offset from the current target position is displayed in the Total Offset
boxes. The Back to Target button returns the telescope to the current target position.
On initiating an offset, the "On Target" panel in the Main Window will turn yellow and change
to "Moving to Target." When the offset is completed, the panel turns green and displays the
"Offset from Target" message.
The Store button expands the widget to the form illustrated at right, above. The
Store Current Position button saves the the present cummulative offsetsi as displayed
in the Total Offset boxes (this does not move the telescope). If the telescope is again
offset, the stored position may be recovered by pushing the Return to Stored Position
button (this does move the telescope). The Set Target to Current Pos button changes the
current target position to the present position, i.e., the cummulative offsets are added
to the current target position and the result becomes the current target position (this does
not move the telescope).
Note: In the world of POCO, Current Target Position has a very specific meaning.
The Current Target Position may or may not be the same as the position to which the telescope
is currently pointed, and it is important to make the distinction. Current Target
Position is always used herein to refer to the coordinates which were entered into the
Main Window's target panel and to which the telescope
was most recently set, using the "Move to Target" button. Offsets and guider corrections will move the
telescope, but the Current Target Position always remains the same until new coordinates are
entered and a new "Move to Target" command is issued, or until the Set Target to Current Pos
button is pushed.
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