huibintemaspampipeline
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huibintemaspampipeline [2017/06/27 10:55] – [Limited bandwidth observations] huibintema | huibintemaspampipeline [2019/02/18 11:37] – [Old hardware-correlator observations] huibintema | ||
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Then we derive calibration and flagging information from the primary calibrator(s), | Then we derive calibration and flagging information from the primary calibrator(s), | ||
<code python> | <code python> | ||
+ | uvfits_file_name = " | ||
pre_calibrate_targets( uvfits_file_name, | pre_calibrate_targets( uvfits_file_name, | ||
</ | </ | ||
Line 40: | Line 41: | ||
./ | ./ | ||
- | There' | + | The pipeline run can be summarized by typing: |
+ | <code python> | ||
+ | summarize_spam_log( " | ||
+ | </ | ||
+ | |||
+ | |||
+ | There' | ||
----- | ----- | ||
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channel_range = [ 150, 425 ] # example channel range to keep | channel_range = [ 150, 425 ] # example channel range to keep | ||
pre_calibrate_targets( uvfits_file_name, | pre_calibrate_targets( uvfits_file_name, | ||
+ | </ | ||
+ | |||
+ | ----- | ||
+ | |||
+ | ==== Old hardware-correlator observations ==== | ||
+ | |||
+ | If you downloaded data from cycle 17 or earlier, it is likely correlated using the GMRT Hardware Backend (GHB; a.k.a. the hardware correlator). For frequencies of 325 MHz and higher, the 32 MHz bandwidth is typically split over an upper-side band (USB) and lower-side band (LSB), both captured in separate LTA files (typical extensions are .lta and .ltb). In SPAM, both sideband LTA files need to be pre-processed separately: | ||
+ | <code python> | ||
+ | convert_lta_to_uvfits( lta_file_name ) | ||
+ | convert_lta_to_uvfits( ltb_file_name ) | ||
+ | </ | ||
+ | The next step is run using the // | ||
+ | <code python> | ||
+ | pre_calibrate_targets( uvfits_file_name_lta, | ||
+ | pre_calibrate_targets( uvfits_file_name_ltb, | ||
+ | </ | ||
+ | The resulting UVFITS files for USB and LSB per target can be combined: | ||
+ | <code python> | ||
+ | uvfits_file_name_usb = " | ||
+ | uvfits_file_name_lsb = " | ||
+ | uvfits_file_name = " | ||
+ | combine_usb_lsb( uvfits_file_name_usb, | ||
+ | </ | ||
+ | The output UVFITS file can be processed further in the main pipeline. | ||
+ | |||
+ | Regarding the main pipeline, there are two options that may be relevant to get to better results. The first option related to the situation explained above, where two sidebands (USB and LSB) are joined together to cover 32 MHz of bandwidth. In that case, it may help to turn on an image-based flagging option that treats the joined USB and LSB separately. Reason for this is that the USB and LSB have separate signal chains, and thus there can be system problems that relate only to one of the two sidebands. | ||
+ | <code python> | ||
+ | process_target( target_uvfits_file_name, | ||
+ | </ | ||
+ | |||
+ | The second option is to turn on baseline-based calibration, | ||
+ | <code python> | ||
+ | process_target( target_uvfits_file_name, | ||
</ | </ | ||
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----- | ----- | ||
+ | |||
+ | Feedback: [[huib.intema@curtin.edu.au|Click here]] | ||
huibintemaspampipeline.txt · Last modified: 2020/10/05 17:46 by huibintema