Curtis Computer Acquisition Camera CCDS, SBIG ST-9 User Manual

CCDS Acquisition Camera

User’s Manual

J. Marshall

05 August 2005

Background:

The CCDS acquisition (slitviewer) camera was replaced in August 2005. This modern
CCD camera is much more sensitive than the old system! It should also be easier to use.

The new acquisition camera is a SBIG ST-9 CCD camera. The system specifications are
listed on the next page. This camera is controlled with SBIG’s control software,
CCDOps. This software runs on a pc running Windows XP.

The old camera on the CCDS has been replaced, along with some of its infrastructure, by
the much smaller ST-9 camera. The old video monitor has been replaced with a new pc
monitor, keyboard, and mouse. The control pc lives in the computer room (on the small
red rack) and is clearly marked.

This upgrade should be in all respects an improvement to the functionality of CCDS, and
should not represent much of a change of usage for the observer. In particular, all of the
existing optics were retained in this upgrade, the only hardware that was replaced was in
fact the camera itself.

Please note that one important change with this upgrade is that the field-of-view of the
acquisition camera is no longer centered on the CCDS camera. In particular, to center an
object on the CCDS detector, the object must be placed near the South (right-hand) side
of the acquisition camera field-of-view.

Previously it was a struggle to acquire targets as bright as 17th magnitude; it is now easy
to obtain targets down to 20th magnitude in 5 seconds!

CCDS Acquisition Camera User’s Manual

System Specifications

(Measured)

Camera model SBIG ST-9
CCD chip KAF0261E
Format 512x512

20x20 _m pixels
Cooling Single-stage TEC
Readout Time ~ 1 second

Gain 1.8 e-/DN
Dark Current ~1 DN/s/pixel @ 0 C
Read Noise 6.6 DN
Bias 130 DN
Saturation 65 K DN

At the 2.4m:
Pixel Scale 0.23 arcsec/pixel
Field of View 1.97 arcmin

At the 1.3m:
Pixel Scale 0.41 arcsec/pixel
Field of View 3.54 arcmin

CCDS Acquisition Camera User’s Manual

Quick Start Guide

1. If the system is not running when you start observing, open the CCDOps program on
the control computer (it should open up automatically when you log on as “Visitor”).
The CCDOps toolbar should be displayed on the desktop.

2. Establish link with the camera by clicking the “EstLink” button on the toolbar.

3. Turn on CCD cooling by clicking “Setup” on the toolbar and turning temperature
regulation to “Active”. The setpoint should be about 20 degrees C below the ambient
dome temperature—do not set it too low as this will cause the CCD to overheat!
Click OK to close the setup box.

4. Click “Focus” on the toolbar and enter an integration time. Click OK to begin taking
exposures. The camera reads out in ~1 second, so exposures shorter than 1 second
give roughly a 1 Hz update rate.

5. Make sure the cooling capacity gauge (lower right corner of desktop) reads less than
~60%. If not, raise the system temperature setpoint.

6. To change the exposure time, stop the focus sequence by clicking “Focus” again.
Click “Focus” to start a new sequence and enter a new exposure time.

7. To save an image, click “Save” on the toolbar. This will save the window currently
open on the desktop. This is useful for aligning the same object on different nights.

CCDS Acquisition Camera User’s Manual

Using the Acquisition Camera

1. Startup

Log on to the ccdsacqcam machine by clicking on the “Visitor” account on the Welcome
Screen. There is no password associated with this account. CCDOps should open
automatically when you log on to this account. If not, open the program by double­clicking on the CCDOps desktop icon.

IMPORTANT: DO NOT unplug the USB cable from the camera while CCDOps is
running! If you do this you will need to reboot the control computer and may need to
reinstall the drivers. If you need to unplug the USB cable for some reason, first close
CCDOps, then proceed.

Once the CCDOps startup screen goes away, you should see the CCDOps toolbar (see
Figure 1). Click on “EstLink” in the CCDOps toolbar—this will establish a link with the
camera. It should take about 5 seconds; if it takes longer than this or displays an error
message, you will need to reboot the computer. See Appendix A.

Figure 1. CCDOps Toolbar

2. Turn on Temperature Regulation

Click the “Setup” button on the toolbar or go to Camera -> Setup in the pull-down menu.
This dialog box will appear (Figure 2):

CCDS Acquisition Camera User’s Manual

Figure 2. Setup dialog box

Make sure Temperature Regulation is set to “Active” and that the Setpoint is about 20
degrees below ambient.

IMPORTANT: The system temperature setpoint should be set to about 20 degrees C
below the ambient temperature in the dome. If the cooling capacity gauge (lower right of
CCDOps screen, see Figure 3) reads more than 60%, the temperature setpoint is too low.
This will cause the CCD to overheat and may cause damage to the camera.

Figure 3. CCDOps status bar (from lower left corner of CCDOps desktop). This example
shows (from left to right): an established link, normal unbinned (high resolution)
imaging, and the temperature setpoint set to 0.19 degrees C. The cooling capacity gauge
reads 58% capacity, and there is a red filter in the beam.

For normal operation, all other settings should also be as shown in Figure 2.

Click OK for these settings to become active.

It generally takes a few minutes for the system to equilibrate at a new set point. If you
change the temperature setpoint and after 5 minutes the cooling capacity gauge still reads
> 60%, the setpoint is still too low.