How it came to life

At this point my first thought was to start programming a simple interface to the camera control box running under LinuX. I started programming with TCL/TK and C but when I wanted to run the first checks with simple image display work (there was luckily no other function implemented yet) I had to update the 486 computer with a proper version of LinuX. At this point i decided to reinstall LinuX from scratch as the old version was too old to be updated in a sensible way. While setting up the installation options a saw a thing which caught my interest: together with DOSEMU a function called XDOS was mentioned.

After finishing the installation of LinuX I then started to configure the DOS emulator. I knew that CCDOPS was running with it but the old versions I had tried so far did not include X11 support. At this point I was lucky - thanks to SBIG the CCDOPS software uses standard SVGA calls which are supported by DOSEMU using the XDOS command. This is what came out of this test phase:
 

The remote setup

CCDOPS is running under XDOS, the X11 interface of the DOS emulator which is available with LinuX. When the environment variable DISPLAY is set properly any X11 output can be send via a network connection to a host computer. This means that the 486 is running CCDOPS, controlling the camera via RS232 and sending the display stuff back to the pentium. Image 1 shows the basic setup.

When this setup is used there is one restrictions: in graphics mode the fonts used by CCDOPS do not work with the X11 interface - but as I know what the software expects me to do in 99% of the cases and all basic setup can be done from the text mode this means no problem. When this was running I tried to do some more things with the emulators on the LinuX distribution: I tried WINE, the windows emulator. When doing some tests I found that wine has improved very much as well. A lot of standard windows programs (like Word6, Excel, even the filemanager) can be started and used. The filemanager even works on the linux partition as long as short filenames are used! But that was not the point. Lucky enough I found even GUIDE5 working with the emulator. Click here to see the X11 screen with GUIDE5 and CCDOPS running (CCDOPS runs on a remote computer!). Although the menu colors of GUIDE look something strange and wine displays some warnings it really works satisfying.
 

A typical observing session

• Start both computers with Linux
• Start DOSEMU locally on the 486 in the dome. Then point the telescope to the area your object of desire is. Use the local mode of DOSEMU which display ALL graphics to do the focusing.
• Take a dark and flatfield image with the proper settings (temperature and exposure time). Save both to disk (this is important as when CCDOPS is restarted remotely these images within the camera would be lost!) and shut down CCDOPS and DOSEMU without shutting down the camera cooling.
• Go to the other computer and start guide, do the remote login and start the DOSEMU with the X11 display send to the Pentium.
• Take a snapshot and determine the exact position of the telescope with GUIDE. When you know the direction where to move the scope to let the camera move it for one second in declination and in righ ascension in that direction. Measure the distance it was moved from the previous point. Then measure the rest of the distance and let the scope move for the appropriate time to reach the correct position. This sounds weired but works with more precision than I expected.
• Make the camera settings (exposure time and mode) and upload the previously taken dark image to the camera.
• Take your exposures as you are used to.
• Don't forget to shut down CCDOPS and XDOS when you go to the dome to point to another position and start the procedure for another image! Only one can run at a time - either XDOS or the standard version of DOSEMU.

A look ahead

Well, maybe you just read about XCCD. XCCD is an X11 software so you just do not need the DOS emulation any more. The basic setup is the same though...