Integrated Telescope Automation System
The ITAS-18 package was developed for use on the 46-cm telescope of the Stephen F. Austin State University Observatory. It is intended to provide complete and integrated control of the telescope and its primary function of CCD photometry through a menu driven operating system. The software was developed in C with an assembly language interface to control the interrupt driven functions and the pulse counting. The system as of this writing consists of two computers, a telescope control computer and a camera control computer. Each runs similar software, but there are differences. See the page called slot cards to see how each computer is configured.
- Turn on the wall switches marked computer and telescope on the master switch panel on the northwest wall. Open the wooden cabinet. A power strip is mounted inside of the cabinet against the lower right hand wall. The strip powers all of the equipment in the cabinet. The computer monitors are powered down normally so that the computers and monitors do not receive power at the same time. If necessary, attach the 9-pin DIN cable from the connector marked HP on the telescope control computer to the hand paddle.
- The camera head is normally stored below the floor to take advantage of the A/C. Mount the camera plate by holding the nameplate of the camera on the right hand side. A 9/16" wrench is kept in the cabinet to tighten the bolts. Connect the chiller lines from the chiller (under the telescope wedge) to the camera head. Attach the camera control cable from the camera head to the controller. Turn on the chiller, the camera controller, and the control monitor. Never power the camera controller with the camera attached without first attaching and powering the chiller.
- Take the end cap off of the telescope and store in the slot on the north side of the dome. Also remove the end cap on the eight-inch guide scope and its finder. The guidescope has a storage eyepiece inserted. Remove this eyepiece and put into the 26 mm Plössl stored in the cabinet in its own container.
- The software makes assumptions about the location of the telescope at power up. Called HOME position the telescope is 15° above the due South point. HOME is marked on the DEC setting circle. The fork should be level, representing an Hour Angle of zero.
- For normal CCD photometry you will want to set up for flat fields first. The white spot screen is stored below the floor. Be very careful with the white spot as the paint is easily scratched. The white spot screen mounts onto two brackets protruding out of the dome slit. Be sure to mount the screen with the spot pointed inward. Two adjustable arms are hooked through holes on the lower edge of the screen and stand in caps on the outside of the dome slit. These arms are also stored below the floor.
The low bank of lights must have filters mounted in front of the lamps. Each of the four lamp stations has one lamp with a threaded top end and one lamp without threads. The filters screw into the former. The filters are stored in a plastic carrying case below the floor. The lamps themselves are powered through 12-V transformers, one for each bank of lights. As of this writing the exact arrangement of this power is changing, but for now is done by plugging and unplugging the line leading to the transformer into a power strip next to the telescope pier.
- Run the program called ITAS-18 by typing itas-18 and Enter. You will first of all be asked whether you have run planner for the current date. The procedure is different here than with the 41-inch system. Here the nightly data are stored under different files by using the calendar date as the file name. There data are always stored to the same files. Since different nightly coordinates will be computed for the stars, different catalogs will be used from night to night, and basic calendar information depends on the night, it is important that you know that planner has been run. A "yes" response allows you to proceed, while a "no" will terminate the ITAS-18 program. After a "yes" response the program asks for the initials of the user. Start and stop times for the observing run will be stored on an observing log along with the user ID at the end of the run. ITAS-18 now reads the nitefile and starfile files that planner has created and then displays
|1. Read the Most Accurate Clock|
|2. Set the clock manually|
Selecting option 1 (either by placing the highlight bar on this option and pressing Enter or by pressing 1) directs ITAS-18 to reset the computer clock using the Heath Most Accurate Clock. This option is not currently available for the 46 cm telescope. Accurate timing is obtained by entering WINDOWS and running 4th Dimension, which sets the computer clock to an accurate time base. Selecting option 2 brings up the additional screen
|Enter hour :||**|
|Enter minute :||**|
|Enter second :||**|
|Press ESC to abort|
|Press ENTER to set,||
After filling in the entries and pressing Enter after each entry, a small overlay window informs you to press Enter to set the time. If 4th Dimension has been used to accurately set the computer clock, this window may be bypassed by typing ESC immediately.
- Now you have arrived at the main menu of three_c. The tracking motor should now be operating on the telescope. The visual cue that it is tracking is the YM-25!
= displayed in the upper left hand corner of the screen with the
Y blinking and changing color. The character is the ASCII character code 13 (CR) and the is the ASCII character code 10 (LF). The filter wheel will be turning to the Clear position, which also senses the internal LED/Photodiode. A pop down window will appear such as
|Stars Now Up
This is a selection set box. The cursor will be on the first entry (Lambda Sgr in this case). Use the HOME and END keys to select the star you wish and press ENTER. The list contains all objects from your catalog that are presently in the sky at altitudes greater than 20° sorted in order of set time. Only the first ten stars meeting these conditions are displayed, but the window scrolls if there are more than ten stars to list. After you have made your selection, several windows will change as explained below. The telescope will be moving from the HOME position (refer to the definition of HOME above) to the selected star and the filter wheel will be turning to the clear filter.