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We encourage other users to write down/document other issues as they come up, and the solutions they find.
PROBLEM: When acquiring images, code fails with an error like:
Traceback (most recent call last):
File "/home/sashab/Documents/sashas_python_scripts/pixis/ConvertPIXISRawToFits.py", line 143, in <module>
convertRawToFits(source_file, target_file, source_dir = source_dir, target_dir = target_dir, target_suffix = target_suffix, header_elems_to_add = additional_header_elems);
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File "/home/sashab/Documents/sashas_python_scripts/pixis/ConvertPIXISRawToFits.py", line 49, in convertRawToFits
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flat_img_arrays = [struct.unpack(img_fmt, data_set) for data_set in separated_data]
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File "/home/sashab/Documents/sashas_python_scripts/pixis/ConvertPIXISRawToFits.py", line 49, in <listcomp>
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flat_img_arrays = [struct.unpack(img_fmt, data_set) for data_set in separated_data]
struct.error: unpack requires a buffer of 2097152 bytes
OTHER SIGNS OF ERROR:
Identified instrument is a Demo:
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(Like): Temperature is -40 degrees C
SOURCE OF PROBLEM:
The computer cannot connect to the camera, and is therefore generating data off of the 'Demo' PIXIS instrument. This artificial image does not conform to the format expected by the code that converts the .raw image to a .fits image, and the code fails with the above error.
POSSIBLE SOLUTION(S):
- Make sure that camera AC-DC converter (black, labeled PIXIS Camera) is turned on (switch is flipped to | rather than 0).
- Power strip has a green light to indicate it is turned on, though it is covered by black aluminum tape. You can peel back the tape to check, if you like.
- Make sure USB connecting computer to camera is plugged in at both ends (perhaps give the ends an extra push to make sure they are connected).
- Make sure camera power cord is connected to the camera.
PROBLEM: Acquired images show very little or no light, particularly noticeable with calibration light sources:
Here is an example of such an image (right panel of Figure below), taken with the HG-2 calibration light source. Notice how the lines in the right panel are very ragged; not the clean image of the fiber tip, as seen through the slit, that we hope for (left panel):
OTHER SIGNS OF ERROR:
Images taken of the sky show little or no light, although all connections are good and the lens is on sky.
If you disconnect the cage system joining the slit and fiber to the grating, it is possible to pear through the slit and look for light from the fiber tip behind. When the fiber is illuminated by a bright enough source (HG-2 light, for example, one can see the light from the fiber tip shining through. UNDER GOOD CONDITIONS, the data should look like this (note the bright yellow-white light shining through the slit):
If the system is not working, the light shining through the slit will be either non-existent, very faint, and/or ragged.
SOURCE OF PROBLEM:
The multimode optical fiber and the 5 um slit have slipped out of alignment.
POSSIBLE SOLUTION(S):
Only one