TRES TCS User's Guide

Created 07/03/08 by TG
Updated 10/01/19 by EF

This document describes the TRES TCS program, which controls the 1.5m telescope from the flwo60 Linux PC. The system provides controls via a Graphical User Interface (GUI).


This document covers the program TRES TCS, the Telescope Control System in use with the FLWO 1.5m telescope for the TRES intrument. The basic purpose of TCS is to control the new TCSGalil from flwo60, a Linux AMD FX-8350 Eight Core PC, and move the telescope. It also manages catalogs, and inserts information from the telescope and catalogs into the FITS file headers. Most of the GUI actions have associated command line versions that may be typed into the TELSHELL command line, for example "tele enable". See Telshell.


The only way users should start TCS is by starting the Realtime system. TCS is an integral part of the Realtime system; it is started automatically whenever you type gotres to start the Realtime System. If you attempt to start Tres TCS independently, bad things may happen! Also, you should only exit this program by typing exit in the telshell window.


The TCS window will display a series of buttons and a list of information. The information updates every few seconds, and accepts no input. To select any button place the cursor on the button and depress the left mouse button. The first row of buttons, starting at top left laid out vertically, have the following functions:

The second row of buttons, horizontal lay out: The last row of buttons, horizontal lay out:


Some of these buttons when selected will cause a window with further choices to appear. This section will explore these windows, and their usage. In most cases these windows were designed to pop-up, be used, and disappear. For these windows, other windows will not work until the current pop-up has been dismissed.


When you click on NEW COORDS this window appears for selection of the next telescope position desired, either manually or via catalog management commands. The single white line can be used to display the last coordinates entered from this menu by using the up-arrow key.

If you wish to manually type in coordinates, simply put the cursor anywhere inside the white line, and type coordinates, for example :

  12:12:12 32:00:01 1950.0 or   12 12 12 32 00 01 1950.0

Spaces or colons are used to separate the fields RA, DEC, and EPOCH. A control-K entered on this line will delete from the cursor to the end of the line, and the delete key will delete the character prior to the cursor. The epoch field is optional, but Ra and Dec MUST BOTH be entered!

This window also allows the management of catalogs. When typing into the white line, three catalog commands are recognized:


Please note that a catalog MUST be loaded before you can retrieve objects. After manually entering coordinates click on the "OK" button to transmit coordinates to PC-TCS. That will happen automatically if you select from a catalog. In a few seconds, the "Slew Enabled" message will appear on the PC. and you can click on the "Slew Enabled" button, and the telescope will slew to those coordinates. See the catalog section below for specification of catalog layout, location, names, etc...

Under this area is a window which displays the loaded catalog, and you may select an object from this window by right clicking on that line.


 If you select Load Catalogs, this window pops up, and  will allow selection of catalog directory, and your choice  of catalogs to load from that directory.
Object catalogs have the following format, illustrated from the file furesz.mct:

!P.I.: Furesz
!Program: 140 Pulsators
AUPeg        21:24:00.2 +18:16:43. 2000.0  0.00 -1.3
V411Lac      22:28:58.3 +50:57:47. 2000.0 -0.02 -0.3

The first two lines specify The P.I. and Program for the catalog. If these lines are in the file, the information from these two lines will be placed in the headers of all objects selected from this catalog. Subsequent lines have four fields. The first field describes object name, the second file is the entry for R.A, the third field is DEC, and the next field is epoch. The final two optional fields are for proper motion in RA and Dec. The Dec value is in arcseconds per century. The RA value is the change in RA in seconds of time over a century. To convert the change in RA to arcseconds per century on the sky, multiply by 15*cos(Dec). After the listed fields, do not pad with spaces. Object names must have fewer than 20 characters (fewer is better) and may not contain embedded blanks, as the program uses blanks as delimiters and IRAF will hate it. Use of dashes or minuses and plus marks in object names may confuse IRAF, and should be avoided.

All users should be able to write in the catalog directory. Please be careful and avoid clobbering existing catalogs! Catalogs should be stored in /Realtime/lib/catalogs/tres. If you change a catalog, please make sure that it is group writable when you are done, i.e. "chmod g+w mymunged.mct".


As of 5/2010, all catalogs are checked for consistancy prior to being loaded into TCS. There are several catagories of errors trapped. If the catalog fails any of the tests, it WILL NOT LOAD, and an error window will pop up for short period of time. A description of the error and the line number of the first error found will be printed to the error output window.

The catalogs are tested using the standalone probgram testcats. If a catalog fails to load, use testcats to test and then correct the catalog. For example: testcats /Realtime/lib/catalogs/brightstars.mct One of the more common errors includes using a file created on a Windows machine, which will contain dos style new-line carriage-return combos at the end of lines. In this case it will complain about a special character 13. A program to easily fix this error is convert_dos, which runs like this; convert_dos /Realtime/lib/catalogs/brightstars.mct Encrypted catalogs are not checked in this fashion yet.

When you click on the Rates Menu button, this window appears :

Tele Tasks

When you click on the Tele Tasks button, this window appears :
Clicking on Set TelePos will produce this window:
It will contain the last coordinates that you used for a slew. After centering your target manually, hit OK, and it will set your coordinates to where you slewed.

Clicking Cosdec, Track, and Dome widgets will toggle that value. Track and Dome need to be on for Dome to follow telescope. Cosdec should stay on.

Stow Dome will turn off Dome, and send the dome to its stow position.

Init Dome will reset the dome encoder after a partial revolution.

Selecting Dome to Az will produce this window:   

  where you can enter a dome azimuth.   The dome will move to that azimuth when you click OK.

Selecting Stow Tele will turn off telescope tracking and stow it. Note that this command DOES NOT stop dome tracking. At the end of the night, you should stow both telescope and dome , use the (Stow All).


When you click on the SFocus button, this window appears
The focusing mechanism uses a stepper motor controlled on tres-bench via the TCS window to change spectrograph focus. The size of the movement can be changed with the Focus Set button. The current spectrograph focus position is displayed underneath "SFocus."