October30 | Sigma QUick Infrared Camera manual

October>30, 1997

object h[time [name]]iSetup for object

object prepares qcdcom to take an exposure of a general target. You can specify integration time as the ﬁrst argument and an object name as the second. The object command sets the automatic actions: # of resets: 1, shutter on, readout on.

Example: object 300 N3031 (set integration time to 300 sec and object name to N3031) Example: object 0.18 (set integration time to 0.18 sec )

auto hiset automatic action

auto goes through the choices for the automatic actions, and allows you to set each. You should not normally need to use auto directly, since you can use the object, dark, etc. commands for most normal exposures. It is provided for those who need to do fancy things. The automatic actions are:

#reset: n Number of times to reset the chip before starting the exposure. Should usually be set to 1.

Shutter on/off Controls whether the shutter should be opened for the exposure. Usually set to ON, otherwise no ﬂux from sky gets to detector.

Readout on/off Controls whether the chip should be read out at the end of the exposure. Usually ON.

Write on/off Controls whether a FITS ﬁle should be written after the chip is read out. Usually ON to save data. This can also be set using the command set save.

idle on/off If on, at the end of a readout the chip is placed in a continuous reset, or idle, mode.

double correlated read on/off Controls whether the device is read out before and after the shutter opening, or only after. If reading before and after, the difference between the two are taken, and this difference is written to the FITS ﬁle. Double correlated read ON is the normal operating mode.

Number of samples n controls how many frames to co-add in the double correlated read. For each exposure, the chip will be reset and read n times before opening the shutter, and read n times after the shutter closes. Usually set to 1.

chop on/off Controls whether a beamswitched pair of integrations is performed for each go command. If at the UH 88-inch, the beamswitch is done automatically. Use with caution. The on and off source frames are differenced and the result is stored in a ﬁle with the name constructed from the data ﬁle name plus “chop” added

instead of the ﬁle number. This ﬁle is overwritten every time a new chop is done.

dummy read on/off In order to get the array into a stable mode, a “dummy read" is done immediately before the read that is saved as data. This occurs both before and after the integration. This should be turned on for normal operation. The "dummy read" may not be necessary for broad-band imaging. Not using a dummy read causes the ﬁrst three lines of each quadrant to be slightly unstable with respect to the rest of the array on the level of 5-10 ADU’s. For narrow-band imaging, this may be a signiﬁcant effect. The conservative approach is to use the dummy read. This will add 5 seconds overhead to each image.