Sternwarte Universitšt Bonn

BUSCA Manual

Version 0.9a

Oliver Cordes (email: )

Bonn/Calar Alto , May 2001

Calar Alto Observatory

Table of contents

Startup (for observers)
  1. execute the command start_busca in the instrument window or in a xterm;the BUSCA GUI appears on the screen
  2. the initialization is finished when Program initialized! appears in the status line. (In case error dialog boxes pop up, click OK .)
  3. if the status window CCD status is idle, choose CCD->Voltages on from the menu, the CCD should switch to continuous scan
  4. check the temperatures and the LN2 status of all channels in the status window (should be green or OK)
  5. enter the observer data (only necessary, if you start the software for the first time)
  6. the system is now ready to observe
  7. if you want to activate the sound output of the software you have to switch on the speakers above the monitors and to start the program audiocontrol in a xterm and press the button headphones

Data aquisition
  1. enter the exposure time and number of exposures you want
  2. enter the object name or press the button last name on the right side  (the button is orange, if a last name is available)
  3. choose the type of the exposure
  4. choose the channels you want to read out or press the button all on the right side to select all channels
  5. choose a CCD frame definition
  6. press the button Start Exposure and the exposition begins, during an exposition you can press the buttons BREAK or Pause. BREAK means that you abort the current and following exposure(s). If you press Pause, you have the choose,to break or continue (e.g. when the dome vignets the pupil and you had moved the slit) the exposition
  7. the exposition is finished, when you see Taking exposure(s) finished! in the statusline. If you have pressed BREAK (see above) you will see Taking exposures(s) aborted! You will also hear a double beep and a funny sound if you  have activated the sound output. (see  startup procedure )
  8. in any case you can now start a new exposition!

Closing (for observers)
Quit the program , use File->Quit from the menu or press Crtl-Shift-Q

CCD frame definition

CCD frame definition means in this case that you have to choose which part of the CCD you wanr to read out and which readout mode (binning) you want to use. BUSCA has four 4kx4k CCD devices. The pixel scale are 0.17" per pixel (15mu). To use the 4kx4k frame or a part of these frame means that you readout the CCD without any binning or with binning 1. For normal use at Calar Alto (seeing conditions up to 1") you can use the CCD in binning 2 mode. Then you have a pixel size of 0.34". You also reduce the readout time for the 2kx2k to 2:20s. The readout time for 4kx4k is about 8min.

There two different ways to choose a CCD frame definition:

  1. use a predefined definition
    you have to choose one entry in the menubox in the middle of the exposure area labeld CCD-Frame.
  2. make a user specific definition

Observer data

Click to enlarge

To enter the observer data choose Config->Set observer data from the menu. In the dialogbox  you can enter these parameters:

Error message

startup error messages:

Startup (only for technicians)
  1. execute the command start_busca  in the instrument window or in a xterm
  2. after the main window appeared on the screen, there are sometimes some error dialog boxes, click OK in this cases
  3. the initialization is finished, when Program initialized! appears in the status line
  4. check the status window at the right bottom of the main window for the entries CCU and UC,  these must be OK, if not check the serial and parallel communication from the computer to the two controller, choose CCD->Activate CCD Controller or UC->Activate UC Controller from the menu
  5. reload the CCD database from the menu: CCD->Reload database
  6. switch on the CCD voltages from the menu:  CCD->Voltages on
  7. flush the CCD's with the large button labeled Flush CCD
  8. check the temperatures and the LN2 status of all channels in the status window (should be green or OK)
  9. setup the observer data
  10. the system is now READY!

Sounds (only for technicians)



binning binning means that you can combine neighbour pixels together; you get the sum of the fluxes from all pixels; you can also save readout time, but you looses the resolution of the image (binning 2 means, you combine a square of 4 pixels to one pixel)
CCU CCD Control Unit, all the hardware for controlling the CCDs
LN2 chemical sign for Liquid Nitrogen, here used for cooling the CCDs
FOV the Field of View, the area in the sky which is covered by the CCD 
UC Universal Control, this unit is controlling the filter wheels, the shutter , the temperature of the CCDs and the evaporation rate of the LN2 in the dewars
continuous scan default mode of the CCDs between 2 exposures, deletes charges of the CCDs