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cso:instruments:tippers [2013-07-05 07:03]
sradford [Troubleshooting]
cso:instruments:tippers [2014-09-30 00:05] (current)
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 +====== Tipping Radiometers ======
 +Two instruments use the skydip technique to measure the atmospheric transparency at the CSO.
 +Both instruments were originally developed at the NRAO.
 +One is a narrowband heterodyne radiometer tuned to 225 GHz.
 +This has been operating almost continuously since it was installed in 1989. 
 +Versions of this instrument have been operated at other astronomical sites including the
 +South Pole and the Chajnantor Plateau in Chile. ​  
 +The other is a broadband instrument with a filter matching the 350 μm atmospheric window.
 +This was installed at the CSO in late 1998. 
 +Identical copies of this instrument remain in operation at the South Pole (2835 m)
 +and in Chile at APEX on the Chajnantor Plateau (5100 m) and at the CCAT site on Cerro Chajnantor (5612 m).
 +This article summarizes the measurements.\\
 +Observing Conditions for Submillimeter Astronomy,
 +Radford, S. J. E., 2011, in Astronomical Site Testing Data in Chile, ed. Curé, M., Otárola, A., Marín, J., & Sarazin, M., RevMexAA (SC) 41, 87 [ [[http://​adsabs.harvard.edu/​abs/​2011RMxAC..41...87R|ADS]],​ [[http://​arxiv.org/​abs/​1107.5633|arXiv/​1107.5633]] ] 
 +==== Troubleshooting ====
 +If the 225 GHz optical depth has stopped updating on the antenna monitor screen:
 +  * If the [[http://​www.cso.caltech.edu/​tau.dat|data]] (second column) update every 10 min, but persistently show 0.000, the instrument window may be covered by snow or ice. Wait until it melts.
 +  * If the parking lot [[http://​|camera]] is also offline, there may be a network problem. Power cycle the ethernet hub in the welding shed.  ​
 +  * If the data still do not update, cycle the instrument power and restart the logger:\\ ''​kilauea>​ **tipperreset.csh**''​
 +If the 225 GHz optical depth updates on the antenna monitor screen but not on the web page, remove any orphan lock files: \\ ''​lapakahi>​ **ls /​srv/​www/​htdocs/​tau_plot/​LOCK.* **''​ \\ ''​lapakahi>​ **sudo rm /​srv/​www/​htdocs/​tau_plot/​LOCK.* **''​
 +Please notify the staff if any of these remedies are necessary.
cso/instruments/tippers.txt · Last modified: 2014-09-30 00:05 by sradford
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