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Data Acquisition with the Lynxx

The Lynxx software is under the D:CCDSLYNXX directory and the software package can be executed by entering CCD.

Once in the Lynxx Menu the first thing that must be done is the TEC must be turned on, the command to activate it is under initialize. The chip needs approximately fifteen minutes to cool sufficiently. The filepath for images to be stored will always be set to the default. This should be reset to F: each time the software is restarted. See Table 3 for the capacity of Lynxx images that can be held on various drives.

There are two methods to obtain an image using the Lynxx. Using the expose command will take a 12 bit image that has a readout time of .5 second. The second method is the full-frame focus command which utilizes the camera's ability to readout 8 bit images. This has the benefit of having a shorter readout time, which is about one third of a second. Sub-frame images can be readout in .3 seconds and are 96 pixels high by 82 pixels wide as compared to 192x165 for the full frames.

When observing time dependent phenomena, it is useful to use the green monitor" to video tape the observations. It is possible to tape images on the monitor, using the video port on a VCR. Simultaneously a connection with the radio broadcast of WWV" (the time counter) using the audio port can be made. This setup will give an extremely accurate time-image correlation for observations.

All corrections made to an image are permanent, therefore it is not advised to use stretch or log scale until the image is saved or copied. False color is useful to enhance contrast in nebulous structure and between faint objects in an image while not affecting the actual image. The image can be saved using the image save command under save/load. The image filepath should be check to ensure the correct filepath. The format for saving images form the Lynxx is *******.ccd.

The Lynxx has six frame buffers so that multiple frames can be stored in RAM simultaneously, three of these buffers usually hold calibration data. Certain calibration frames, such as thermal frames, bias frames and flat field frames, should be taken because they play a key role in data reduction. Bias and thermal frames can be acquired by using the commands under the initialize menu. The thermal frames are always placed in the fourth frame and the bias frames are always placed in the fifth frame. The flat field frames are stored in the sixth frame. It is best to take five twilight flats in each filter using the expose command. An alternative means of finding flats can be used at Stony Brook: sky flats. Sky flats are medianed images of a relatively starless field. The get flat field command is not recommended because the normalization process the Lynxx uses creates extra noise.



next up previous contents
Next: The ST-4 Up: Data Acquisition Previous: Target Finding



Scott J. Wolk
Mon Nov 25 15:41:03 EST 1996