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cso:instruments:tippers [2013-07-05 07:03] sradford [Troubleshooting] |
cso:instruments:tippers [2014-09-30 00:05] (current) sradford |
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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]] ] | ||
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+ | |||
+ | ==== 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://128.171.86.101|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. | ||
+ |