NRAO Home  >  Green Bank  |  Wiki Topic:    GB > PTCS > InformationForProjectTeam > PTCSProjectPlan > AncillaryPTCSInstrumentation

Changes | Index | Search | Statistics | Go

Ancillary PTCS Instrumentation

• This work requires time from Todd, JD, Jason, John Ford and Joe Brandt

• Related links: Dynamic scheduling project notes, ALMA Ancillary Weather Instrumentation
• Misc instrument work (in order of priority):
  • Pyrgeometer status page
  • 3mm Tipper
    • Some pictures of the hardware are located here: /netapp/web/gb/homes/mstennes/tipper_photos/
    • Some history is provided by Brian here, however it is out-of-date, e.g. the Tipper-Tipper directories in the /home/gbtlogs area are completely empty.
    • Jim Braatz provided me a summary of the situation when he last worked on it. There were two major problems: 1) frequent "bad" data (often due to weather = too cloudy, or temperature inversion); 2) The statistics on the website ignored unfittable data -- Jim was in the process of changing this when he stopped working on it.
    • Hardware status: As of October 2005 there was a problem with the encoder. The last entry was Nov 2005 on this webpage, the last data found in /home/archive/gbtlogs is from 2005_11_14.
    • Software for fitting data automatically is probably turned off (was a cron job in aips++ manager account?).
    • Jim Condon notes that its present location may be too far from GBT to accurately reflect conditions there. Is there a convenient place to move it?
    • As of November 2007, the tipper has been removed and placed in storage.
  • Multi-color tipper: as advocated by Ron, this would tell us more about liquid water droplets, see this paper by Maetzler (1992) and this one by Marzano 2002
    • For water vapor, a recent paper from Las Campanas shows that PWV can be measured with high-resolution optical spectroscopy
    • IRMA is a 20 micron instrument for measuring water vapor
  • New instrumentation for wind measurements (e.g. ultrasonic, ultrasonic ($2500), or hot wire?).
    • We should wait for Kim's analysis to proceed further before going off with this task.
  • 11.727 GHz Phase Interferometer (100m baseline) PhaseInterferometer
    • Was hit by lightning in 2004 and possibly sustained damage. Need to check with Galen.
    • Archival data from 2000-2004 has been obtained from Simon Radford and placed in /netapp/users/groups/ptcs/data/Instrument/phaseMonitor/phimon-gb
    • The rms pathlength is 221,387,707 microns (25%,50%,75%-iles); compared to Mauna Kea = 32,60,140 microns
  • Optical pointing camera (low priority)
  • Mid-infrared camera to view the dish from the subreflector
    • to get temperature distribution of surface
    • something similar to the one from Inframetrics (now FLIR) that Kim rented for two weeks
• Need to follow up on the effects seen by Todd, e.g. the inclinometer "wiggles" during beamswitches
• Follow up on "hysteresis" -- analyze the 8 drift scan maps and see if a longer dedicated run would be useful (Todd)
• More generally, need to track down and fix all causes of tracking error. Perhaps as a first step, we should try to implement a quantitative number (derived from QD,inclinometers,accelerometers) that expresses the overall level of vibration in real-time to the observer or operator screen. (Todd)

-- JohnFord - 19 Jan 2007