The 48" autoguider program runs from the PC. Boot the PC (ctrl-alt-del) and make sure the camera, both tv screens and video pointer are turned on. Adjust gain of camera until you can see stars, but the stars don't "bloom". The guider will work with stars that are very faint, so don't worry about that.
The guide rate on the DFM Mac should be set to .50, this will happen automatically whenever the Realtime System is started. It can also be reset thru the TCS program.
To start guiding, slew to the star you want to observe. If the program is not running on the PC, type in "guide" or "irguide", depending on the instrument mounted on telescope. This will start a procedure that first sets all pickoff mirrors to zero, and then puts the pickoff mirror on axis, and sets up on-axis focus. Wait until you see the menu.
Choose "A" from the menu to Acquire a guide star. This will start by putting the mirror at the top right of the "horseshoe". The mirror will stop at this position, and you are asked if a candidate is in the guider tv screen. You can answer "G" if you see a star, or you can enter a segment number between 0 and 41. The program keeps track of all off-axis focus values in relation to the on-axis focus, and will adjust focus to the correct value for each segment.
Click here for view of the Topbox Horseshoe.
In general, the segments start at the top right of a "horseshoe", and are numbered sequentially clockwise. If you type anything but "G" or a segment number, the mirror advances to the next segment in order. If you go through all 42 stops and don't find a star, you must move the telescope slightly, and repeat this procedure.
Once a star is in the field, use the pc arrow keys to position the cross hairs on top monitor on a guide star, then type a G to guide.. You can use the keypad keys 7,9,1&3 to move diagonally as well, as long as NUMLOCK is off.
While guiding, messages will be shown with the x and y axis centroid error in pixels. You will see another message starting "Moving" each time it moves the telescope. Errors should be >= 3.0, and motions should be less than 3, but average 1. If it makes too many motions, or "wobbles", ie. continues to move west, east, west east, etc, adjustments should be made to the variables. Guiding has begun. Wait a few seconds, until corrections become small and infrequent, then begin exposure. If the guider loses the star, the message "object gone" will be shown. Realign the crosshairs in bottom monitor if needed, for later reference..
If you wish to suspend guiding, or leave the program, hit any key on the PC. This will bring you to the top level menu shown here:
The procedure is the same as described above.
This will show you the current focus value, and ask for a desired value.
This brings up the parameters menu, shown below:
D to toggle profile drawing (default F)
N to set number of frames summed (default 2)
O to change in-axis focus setting (permanent)
T to set minimum threshold (default 0.90)
C to change center X-Y coordinates
Q to resume guiding
This routine will display the x and y profiles, showing the center. It also slows the guider down, and is not usually desirable. Typing D at this time will enable/disable drawing.
Reset the interval allowed prior to telescope movement. Starts at .9 pixels, where each pixel ~= .48". If this is set too low, "wobble" will occur. If two low, large corrections are required frequently. Frames summed can effect this action also.
This will allow you to change the X and Y coordinates which represent the center of you chip. These are the numbers that determine the on-axis position of the chip, and all off-axis positions will change to reflect changes in these values. Be sure of changes before you make them. A change here will be remembered on subsequent invocations of the program.